NO142060B - PLANT GROWTH REGULATOR. - Google Patents

Description

The invention relates to plant growth regulators which contain one or more compounds with the general formula

where-n means the number 1 or 2 and X the number 0 or 1r idct when n is the number 1, R is hydrogen, sodium, potassium, artmonium, ammonium substituted by one or more lower alkyl, lower alkenyl or hydroxy-lower alkyl groups; straight-chain or branched alkyl, alkenyl or alkynyl groups of up to 20 carbon atoms, or halo-lower alkyl;

when n is the number 2, R is calcium, magnesium or lower alkylene;

Rjy * r>r R3°? R4 means hydrogen or straight-chain or branched lower alkyl, their enantiomers and racemic mixtures. These agents are particularly useful as plant growth regulators before and after germination and as herbicides. The compounds covered by the aforementioned formula I all have the L-configuration as they are derived from the naturally occurring ketohexose, L-sorbose. L-sorbose is the only known naturally occurring form of sorbose. However, the corresponding enantiomer of L-sorbose, namely D-sorbose, can be produced synthetically. It should be mentioned in particular that the compounds corresponding to L-sorbose can be prepared in an analogous way with D-configuration as well as racemic mixtures of these compounds, by using D-sorbose as starting material instead of L-sorbose, or by using a mixture of D- and L-sorbose when the corresponding racemic mixture is desired. The preparative methods are exactly the same, regardless of whether a compound of the L-form, the D-form or the corresponding racemic mixture is used as starting materials. In the same way, all the structural formulas, as stated in the preceding or the following description, are not to be understood as structural formulas that should describe a specific or an absolute configuration, but these structural formulas should include all possible configurations, i.e. they include enantiomers in particular and the racemic mixtures. The examples and the rest of the description relate, when nothing else is expressly stated, to the racemic compounds. The compounds covered by formula I have plant growth-regulating activity and herbicidal activity after and/or before germination. However, the growth-regulating effect after germination prevails, as most compounds have this effect, and as this activity is suitable for controlling the growth of weeds that appear in the lawn. The term "plant growth regulator", which is used here, denotes e.g. a compound which either slows down or stimulates the growth of main or secondary branches, resp. plant shoots. Such a compound is capable of influencing (retarding or stimulating) flower development, initiation of flowering, shoot or branch formation, parthenocarpy, fruit and/or leaf drop and fruit and/or leaf ripening. Furthermore, there are effects and influences of substance transport inside the plant, e.g. stimulation of latex flow and/or, the metabolism or e.g. an increase in the sugar content of the plant, etc. The compounds also have a herbicidal effect. When it comes to lawns, e.g. these regulatory agents delay lawn growth, and can further cause further root shoot formation. In the case of shrub plants, these cause . regulatory activities a delay of growth in height while simultaneously stimulating growth to the side. The term "lower alkylene" denotes a divalent substituent consisting of straight-chain or branched aliphatic hydrocarbons with 1-7 carbon atoms, and can be attached to different carbon atoms. The term "lower alkyl" includes both straight-chain and branched, saturated aliphatic groups, which have 1-7 carbon atoms, such as e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, etc.. Examples of alkenyl and alkynyl groups are allyl, propenyl, butenyl, pentenyl, 1,1-dimethylpropenyl, propargyl, butynyl, pentynyl, hexadiinyl, heptadiinyl and even- tual isomers of these compounds. A particularly preferred alkynyl group is the propargyl group. ;The term "lower alkyl" in combinations such as Halogen-lower alkyl refers to straight-chain or branched hydrocarbons, which have up to 7 carbon atoms, such as e.g. methyl, ethyl, propyl, isopropyl, butyl, tert.-butyl, pentyl, etc. The term "halogen-lower alkyl" includes straight-chain or branched alkyl groups with up to 7 carbon atoms, where 1 or more hydrogen atoms have been replaced by halogens, such as .ex. 2,2,2-trichloroethyl, 2,2-dichloroethyl, 2-chloroethyl, 4-chloro-butyl, 2,2,2-trifluoroethyl, 2-fluoroethyl, 2-bromo-1,1,2,2-tetra- fluoroethyl, 2,2,3,3,4,4,4-heptafluorobutyl, 3,4,4-trifluoro-3-butenyl, etc..; Examples of representatives which can be attributed to formula I, and which have an effect as a plant growth regulator and/or which have a herbicidal effect are: 2,3-0-isopropylidene-4,6-0-(3-pentylidene)-2-keto-L-gulonic acid: 2,3-0-isopropylidene-4,6- O-(2-butylidene)-2-keto-L-gulonic acid; ;2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid monohydrate; ;2,3:4,6-di-O-(2-butylidene)-2-keto-L-gulonic acid. Furthermore, there are salts, such as alkali, alkaline earth, ammonium and substituted ammonium salts, as well as esters, such as e.g. lower alkyl, lower alkenyl and lower alkynyl esters of the aforementioned gulonic acids are also active as plant growth regulators and/or herbicides. Representative compounds of formula I for use in the agents of the present invention are: 2,3:4,6-di-O-isopropylidene-2-keto-E:4gulonic acid monohydrate; Allyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; Potassium 2,3:4,6-di-O-isopropylidene-2-keto-L~gulonate; Ammonium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; Calcium-2,3:4,6-di-O-i sopropyli de n-2-ke t o-L-gulone? t; Dimethylammonium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; N-ethanolammonium-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate5 Methyl-2,3;4,6-di-0-isopropylidene-2-keto-L-gulonate5 Ethyl- 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate 5 3-Chloropropyl-2,3:4,6-di-O-isopropylidene-2-keto-L -gulonate 5 n-hexyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate 5 n-heptyl-2,3:4,6-di-O-isopropylidene-2-keto -L-gulonate5 n-octyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate5 n-nonyl-2,3:4,6-di-0-isopropylidene-2-keto -L-gulonate 5 n-undesyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate 5 2,2,2-trichloroethyl-2,3:4,6-di-O -isopropylidene-2-keto-L-gulonate: n-dodecyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate 5 n-propyl-2,3:4,6-di -O-isopropylidene-2-keto-L-gulonate 5 1-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-decyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate5 2-bromomethyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate 5 2-butyl-2,3:4.6-di-0-isopropylidene-2-keto-L-gulonate 5 i-amyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate 5 bis-2,3:4,6-di-O-isopropylidene-2-ketogulonate ethylene glycol ester; t-Butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate 5 2-pentynyl-2:; 3:4,6-di-O-isopropylidene-2-keto-L-gulonate 5 1-hexin-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 3-methyl-1-butyn-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; ;5-hexenyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate 5 3-pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L -gulonate; Dichloromethyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2-dichloroethyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate 5 2- chloroethyl-2,3:4,6-di-0-isopropylidene-2-keto- L-gulonate; 4- chlorobutyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate 5 2,2,2-trifluoroethyl-2,3:4,6-di-0-isopropylidene-2- keto-L-gulonate 5 ;2-fluoroethyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate 5 2-bromo-1,1,2,2-tetrafluoroethyl-2,3 :4,6-di-0-isopropylidene-2-keto-L-gulonate 5 ;2,2,3,3,4,4,4-heptafluorobutyl-2,3:4,6-di-0-isopropylidene- 2-keto-L-gulonate5 2,2,3,3,4,4,5,5-octafluoropentyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate. Particularly preferred agents contain: Sodium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-propynyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-Pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate. The active compounds are particularly useful in agents for regulating plant growth, and especially the growth of grass and weeds, as well as other unwanted plants, which plants happen to mix in with the deliberately planted plants. The compounds do indeed exhibit a plant growth-regulating effect before germination, but they are, however, particularly useful when they are used as plant growth-regulating agents after germination and as an inducing agent for fruit release. The effect after germination of the active compounds in the agents is confirmed within the scope of the present invention by controlling the growth of unwanted plants. thus it was e.g. until now, it has not been possible to carry out a post-irrigation control of Digitaria sanguinalis with a post-emergence herbicide. However, this is successful with the active compounds in the agents according to the present invention, as the compounds greatly delay the growth and maturation of this grass, thereby preventing the pre-germination and spread of this grass. When checking lawns, and especially wild grass lawns and industrial lawns (e.g. golf courses), it has been shown that you should strive for a maximum delay, which is shown by a reduction in the height of the grass compared to an untreated control sample , of approx. 40 - 60%, whereby a delay of grass growth of 50% is preferable. A delay of less than 40% must already be described as ineffective as the necessary aesthetic effect does not appear visually, and because the necessary maintenance of the lawn is not reduced. On the other hand, a delay in growth of more than 60% is also not desired as the lawn will make a barren impression and quickly become overgrown with weeds and other unwanted plants. The active compounds show herbicidal activity especially against cornflower weeds, such as e.g. Matricaria Species and other weeds, such as Papaver rhoeas, Stellaria media and Capsella bursa pastoris. ;The agents are particularly active in and against the following plants: ;a) Grass species, such as Agropyron repens, Bromus inermis, ;Bromus erectus, Deschampsia flexuosa, Alopecurus pratensis, ;Arrhenatherum elatius, Dactylis glomerata, Festuca pratensis, Trisetum flavescens, Holcus lanatus, Lolium perennial, Poa annua, Poa neumoralis, Festuca ovina, Festuca rubra, Festuca nigrescens, ;Cynosurus cristatus, Agrostic schraderiana, Agrostis stolonifera, Phleum pratense, Phleum nodosum, Cynodon dactylon, Stenotaphrum ;. secundatum, Paspalum notatum, Ermochloa olphiuroides and other grass species for lawns or weed species, sugarcane and cereals, such as rice, wheat, rye, barley, oats, etc.5; b) trees and shrubs, such as e.g. fruit trees, such as apple, pear, peach, cherry and citrus, as well as cocoa, tea, coffee, banana, rubber, olive and notte trees; c) ornamental plants, such as privet, white beech, white cedar, juniper bushes, roses, azalea, chrysanthemum, poinsettia, alpine violets, pyracanta, forsythia, magnolia, petunia and bromeliaceae; d) agricultural plants, such as cotton, soybeans, soil crops, tobacco, flax, sugar beet and. pineapple; e) vegetable varieties, such as solanaceae, (e.g. tomatoes), legumes, pumpkins, melons, etc.5 f) berries, such as strawberries, raspberries, blueberries, blackberries and currants. Furthermore, these compounds are useful as they reduce the cutting of the vines. In order to achieve an even distribution of the active compounds in the growth-regulating agents according to the invention, the compound or compounds are mixed with conventional auxiliaries, modifiers, diluents or conditioners common for herbicides, whereby these are further formulated into solutions, emulsions, emulsifiable concentrates, dispersions, stbv, granules or wettable powder. Liquid formulations of the active substance or active substances for direct spraying can e.g. are produced as aqueous solutions or possibly as solutions in solvent mixtures containing e.g. acetone, methanol, dimethylformamide in the ratio 90:8:2 (volume/volume). In the case of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid, which is also known as DAG, buffered (pH 5-8) formulations are prepared e.g. by adding potassium hydrogen sulphate or organic amines, such as triethanolamine, diethanolamine, etc., to aqueous solutions containing 1% "Tween 20" or other non-phytotoxic wetting agents. The buffering of the reading is necessary as it is known that DAG is unstable in aqueous solutions with a pH value below 5. Emulsifiable concentrates, which contain 25 - 50% or more of the active ingredient, depending on its solubility, can be prepared in suitable solvents, e.g. N-methylpyrrolidine, dimethylformamide, etc. Surfactants, such as e.g. wetting agents, dispersing agents, emulsifying agents, etc., are added in sufficient quantity to obtain a formulation with the intended characteristics. ;Various purposes of use of the active compounds can be improved for the various areas of application when adding compounds that improve dispersion, adhesion, resistance to rain and penetration, such as fatty acids, waxes, resins, wetting agents, emulsifiers, mineral or vegetable oils, binders, etc. On in the same way, one can expand the biological spectrum of these compounds or the agents strongly by adding substances that have bactericidal, herbicidal and fungicidal properties, or by adding fertilizers, chelating agents and other plant growth regulating agents. Examples of herbicides and growth regulators that can be added to the compounds in the agents according to the invention are: 2,2-dichloropropionic acid, N-(4-aminobenzenesulfonyl)methylcarbamate, 2-chloro-4-ethylamino-6-isopropylamino-1,3,5 -triazine, 4-chloro-2-oxobenzothiazolin-3-yl-acetic acid, ;5-bromo-6-methyl-3-(1-methyl-n-propyl)uracil, ;3,5-dibromo-4-hydroxybenzonitrile, ;D,N-ethyl-2-(phenylcarbamoyloxy)propionamide, ;N-(4-bromo-3-chlorophenyl)-N'-methoxy-N'-methyl-urea, methyl-2-chloro-9-hydroxyfluorene-9 -carboxylate, N'-4-(4-chlorophenoxy)-phenyl-N,N-dimethylurea, isopropyl-N-(3-chlorophenyl)-carbamate, ;2,3,5,6-tetrachloroterephthalic acid dimethyl ester (DCPA), ;2,4-dichlorophenoxy-acetic acid, 4-isopropylamino-6-methylamino-2-methylthio-1,3,5-triazine, n-butyl-9-hydroxyfluorene-9-carboxylate, ethylene, ;naphthoxy-acetic acid, ;3 ,6-dichloro-2-methoxybenzoic acid, (+)-2-(2,4-<d>ichlorophenoxy)-propionic acid, 9,10-dihydrc—8a,10a-diazoniaphenanthrene-2A, N1 - (3,4-dichlorophenyl -N,N-dimethylurea, Gibberellic acid, ;Indolylacetic acid, ;ind olylsuccinic acid, ;4-hydroxy-3,5-diiodobenzonitrile, N'-(3,4-dichlorophenyl)-N-methoxy-N-methylurea, 4-chloro-2-methylphenoxy-acetic acid, 4-(4-chloro -2-methylphenoxy)-butyric acid, (+)-2-(4-chloro-2-methylphenoxy)-propionic acid, N-(benzothiazol-2-yl)-N,N'-dimethylurea, ;N1-(3-chloro -4-methoxyphenyl)-NN-dimethylurea, 1,2,3,6-tetrahydro-3,6-dioxopyridazine, ;N'-(4-chlorophenyl)-N-methoxy-N-methylurea, N'-(4- chlorophenyl)-N,N-dimethylurea, Naphthylacetic acid, ;N-l-naphthylphthalamic acid, ;2,4-dichlorophenyl-4-nitrophenyl-ether, 1,1'-dimethyl-4,4'-bipyridylium-2A, 3- (m- tolylcarbamoyloxy)phenylcarbamate, 4-amino-3,5,6-trichloropicolinic acid, 4,6-bis-isopropylamino-2-methylthio-1,3,5-triazine, N-(3,4-dichlorophenyl)-propionamide, isopropyl- N-phenylcarbamate, 5-amino-4-chloro-2-phenylpyridazin-3 (2H)-one, N-dimethylamino-succinic acid, ;2-chloroethyl-phosphoric acid, ;tributyl-2,4-dichlorobenzyl-phosphonium chloride, 2.4 .5- trichlorophenoxypropionic acid, 2.3.6- trichlorobenzoic acid, ;2-chloro-4,6-bis-ethylamino-1,3,5-triazine, sodium chloroacetate, ;2,4,5-trich lorphenoxyacetic acid, ;5-chloro-6-methyl-3-t-butyluracil, ;4-ethylamino-2-methylthio-6-t-butylamino-1,3,5-triazine-(terbutryn), 2,3,5- triiodobenzoic acid, ;1,1,4-trimethyl-6-isopropyl-5-propionyl-indane. ;Examples of fungicides, which can be added to the compounds ;in the agents according to the invention, are the following: 2,4-dichloro-6-(o-chloroaniline)-S-triazine, ;2,4,5,6-tetrachloroisophthalic acid nitrile, ;p- dimethylaminophenyldiazo-sodium sulfonate, ;1,4-dichloro-2,5-dimethoxybenzene, ;manganese-ethylene-bis-dithiocarbamate, ;zinc-ethylene-bis-dithiocarbamate, ;Coordination product of zinc and manganese-ethylene-bis-dithiocarbamate, methyl- 1 (butylcarbamoyl)-2-benzimidazole carbamate, 2-(4-thiazole)-benzimidazole, ;cis-N-[(trichloromethyl)-thio]-4-cyclohexene-1,2-dicarboximide. ;The indicated application amounts are based on the results shown here and do not include such wide margins that all possible cases are covered, as numerous factors will affect the application amount. For example, the amount will not only vary for the different plant species but also within a specific species, e.g. depending on factors such as the size and age of the plant, the particular compound used, the season, the soil and climatic conditions at the time of application, such as air temperature, light intensity, rain and wind. When the compounds or agents are further used by blotting the field, higher concentrations are necessary, as the plants are indirectly treated with this method of treatment in contrast to a direct treatment or application of the agent or compound to leaves and stems, e.g. ;by spraying the plant. The amount of active substance in plant growth regulators therefore varies depending on the plant to be controlled, the required amount of application, the method of application, the active substance used and how far the control of plant growth is desired. In general, the agents in the ready-to-spray form contain less than 50% active substance. In principle, the amount of active substance used is chosen in such a way that effective control of plant growth is achieved. As it e.g. as explained above, when controlling the lawn, such an amount of active substance is used that a delay of the normal growth rate of 40 - 60% is obtained. Similarly, the choice of the minimum amount of use is determined by the smallest amount of active substance capable of causing a growth delay that corresponds to the lower desired limit. The choice of the maximum amount of application is similarly determined by the amount of active substance that causes a growth delay that corresponds to the desired upper limit, i.e. in the case of grass, which is used as an ornamental lawn, the amount that prevents the ornamental lawn from getting a barren appearance, but as on the on the other hand, it prevents too rapid grass growth, and so that unwanted chlorosis (i.e. that the lawn turns yellow) does not occur. In the case of tomato plants, the criteria for an effective growth delay are different as a dwarf-like plant, which means no loss of fruit quality or fruit quantity, is particularly desired. The parameters for an effective growth-regulating activity for such plants are a delayed longitudinal growth, and an enhanced or not delayed lateral growth as a minimum effect and delayed longitudinal and lateral growth as a maximum effect. The amount of active substance, which complies with these criteria or causes these criteria, e.g. in the case of tomato plants determined taking into account the aforementioned views. To achieve the greatest possible effect for growth regulation after germination, quantities of 0.5 kg to 20 kg or more are used per hectares. These amounts are based on the weight of the active compound. In a similar way, the greatest growth-regulating activity after germination will usually be amounts between 1 - 15 kg or more of active substance per hectares. A preferred dosage amount for spray solutions is between 10 and 100,000 ppm. depending on the plant species to be treated and the compound used. A particularly preferred dosage amount is usually between 100 and 20,000 ppm. A further advantage of the use of the active substance in the agents according to the invention is the absence of any lasting effect on the plants or a regulatory effect that remains in the soil. These compounds break down slowly and you thus get a reduction in activity. This effect has advantages due to: a) that one achieves a short-term effect that can be prolonged by subsequent further treatment; b) that the normal growth conditions of the plant return to the extent that the activity decreases; and c) no harmful residues remain either on the plant or in the soil. ;The duration of the delay effect varies depending on the compound used and other factors, such as the treated plant species, climatic conditions, etc. ;Although the compounds according to the invention have a plant growth-regulating and herbicidal activity, they are practically non-toxic to animals. E.g. no rats died when these were fed either DAG or the sodium salt of DAG in an amount of 4 g/kg body weight. The cleavage products, which are initially 2-keto-L-gulonic acid and finally carbohydrates are likewise non-toxic. It is obvious that not all compounds covered by formula I are active against all plants. However, within the scope of the present invention, each of the active compounds exhibits activity towards a particular plant or particular plants, and this activity is a function of the compound. As will be described in more detail below, it is a particular advantage of the present invention that the growth-regulating agents, when used for the treatment of various plants before and after germination, exhibit growth-regulating activity and herbicidal activity. This means that the spectrum of the relevant plants is very broad. The growth-regulating activity of the active compounds in the agents is further confirmed by the subsequent micro-experiments for the determination of activity after germination. A. Experiment with 2, 3:4, 6-di-O-isopropylidene-2-keto-L-gulonic acid as well as salts and esters of this compound. The growth-delayed effect of preferred compounds in connection with grass is shown in the following in greenhouse experiments, and especially the effect after germination for Digitaria sanguinalis and Poa pratensis. The compound to be examined is dissolved in a solvent mixture consisting of 90 parts by volume of acetone, 8 parts by volume of methanol and 2 parts by volume of dimethylformamide. The grass (Digitaria sanguinalis) is 10 days old and slightly less than 2.5 cm tall. Poa pratensis was also cut to a height of approx. 2.5 cm for the connections in question was used. The compounds were sprayed onto the grass in an amount of 0.5 to 8 kg/hectare. The effect, i.e. the growth delay, is determined by measuring the grass cover and grass weight of the cut grass after 11 to 26 days. In the experiments, 3 standard compounds were included as comparison experiments. Maleic hydrazide (6-hydroxy-3-(2H)-pyrridazinone) was used in aqueous solution, i.e. as a water-soluble concentrate (300 g/l). In addition, n-butyl-9-hydroxyfluorene-(9)-carboxylate, hereinafter designated IT-3233, and methyl 2-chloro-9-hydroxyfluorene-(9)-carboxylate, hereinafter designated IT-3456, were used. in the solvent mixture described above. ;Further reference compounds that can be used are CCC (2-chloroethyltrimethylammonium chloride), Alar (N-dimethylaminosuccinic acid), 2,4-D (2,4-dichlorophenoxyacetic acid), MCPA 82-methyl-4-chlorophenoxyacetic acid), CMPP (2-methyl-4-chlorophenoxy-propionic acid), ioxynil (3,5-diiodo-4-hydroxy-benzonitrile) and ethrel (2-chloroethyl-phosphoric acid). The test results are summarized in the following tables I and II. Of the investigated compounds, 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid (DAG) has been shown to be the most active with respect to growth retardation of Digitaria sanguinalis, and ;methyl-, n- the butyl and allyl esters have shown similar action. DAG is more effective against Digitaria sanguinalis and Poa patensis than maleic acid and the two other reference compounds at the same amount of dosage; As solutions in common solvents are not particularly suitable for practical use, DAG and corresponding derivatives were tested in emulsifiable formulations. (25% active substance, 41% xylene, 2% Atlox 3404, 2% Atlox 3403). Several esters were investigated in the aforementioned solvent mixture. In addition, aqueous solutions of DAG containing 1% Tween 20 (polyoxysorbitan monostearate) and then either unbuffered or buffered at pH 5-7 were prepared. Aqueous solutions of salts of DAG, which also contain Tween 20, were included in the investigation. Investigations with regard to growth delay were carried out on a plant spectrum consisting of e.g. Digitaria sanguinalis, soybeans and tomatoes, and with which the plants were treated when they were approx. 2 weeks old. During the treatment, Digitaria sanguinalis was approx. 2 cm height, the soybean plants approx. 5 - 6 cm high with the first leaves, and the tomatoes were 3 - 4 cm high and with 3 - 4 true leaves. Sprays were either used with aqueous solutions, solvent mixtures or emulsifiable concentrates of the active substance. ;The results of this investigation with DAG, its salts and esters in different formulations are given in table III, ;where the delay effect is indicated by numbers. The severity scale is defined as follows: ;0 - no visible growth delay; 1, 2, 3 - slight delay, the plants show little or no reduction in the growth of the visible ;plant parts; ;4, 5, 6 - moderate growth delay, the plants show reduced growth of visible plant parts; ;7, 8, 9 - severe delay, the plants show little or no growth at all; ;10 - no growth. ;The activity of DAG in aqueous solutions is enhanced by buffering to a pH value in the range from 5 - 8, and this effect can be attributed to the increasing stability of DAG in this pH range. This enhancing effect was greater for soybean and tomato plants than for Digitaria sanguinalis. The inorganic salts and esters of DAG were almost as active as DAG itself. Trial data show that DAG, the salts and esters are more active than maleic hydrazide and the reference compound IT 3456, and then as a growth inhibitor after germination for Digitaria sanguinalis, and only slightly less active than a soybean growth inhibitor after germination. The following table IV contains trial data with regard to 12 different useful plants and weeds, whereby the plants were , spr-changed when they were approx. 2 weeks old. Four representative esters of DAG (2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid) were compared with the standard sample, i.e., maleic hydrazide. The same assessment scale as in Table III was used. ;When it comes to tomato plants, length growth is greatly delayed. Instead of this, you can observe a stimulation of the development of side shoots, so that in total you get a branched, bushy plant. It is remarkable that neither the quantity nor the quality of the fruits changes. In tables III to IV, when dosing the salts, esters and other analogous compounds as well as DAG, no account was taken of the acid equivalent. Although the main area of application of the growth regulator according to the invention is a growth regulator which is used after germination, they let. active compounds of formula I in the agents can also be used as growth regulators for germination. E.g. the herbicidal activity for germination of DAG compounds is shown using the n-propyl ester of DAG. The dosage is sprayed in a dosage amount of 8 kg/hectare. Very severe growth delay, (ie little or no growth) for Sorghum halepense, Amaranthus sp. and Digitaria sanguinalis; appear after 20 and 27 days. ;Further investigations of DAG and its salts were carried out with different grass varieties, cereal varieties, ornamental plants, perennial plants and vegetables. Investigations of growth retardation were carried out with different grass species, whereby emulsifiable concentrates of DAG in nitropyrrolidone were used. All species, with the exception of Lolium, were sprung 4 days after mowing. Lolium was cut and sprung on the same day. The effect on the plants, i.e. the growth delay, was determined by measuring the grass cover after 19 or 21 days after seed change. ;i ;Maleic hydrazide (MH) and chlorflurenol (CF); were included as reference compounds. The results are indicated in the following table V. ;B. Growth delay after 21 days, grass height in cm; Table VT shows the effect of DAG and its sodium salt on barley and wheat. Height was measured 41 days after spraying. The effect of DAG (in an emulsifiable concentrate) in nitro-pyrrolidone on two varieties of hedge is shown in Table VII. In the case of carpinus betulus, visual observation two months after the determination according to table VTI showed a strong growth retarding effect, which is indicated in table VII. The amount of active substance in the solvent is indicated in Table VII in %. ;The effect of DAG on apples and vines compared to two reference compounds, CCC and "Alar", is shown in Table VIII. Table IX shows the effect of DAG on geranium compared to CCC as a reference compound. ;The growth delay in Chrysanthemum morpholium for DAG and "Alar" as a reference compound is shown in Table X. ;Table XI shows the effect of DAG and "Ethrel" as a reference compound on tomatoes with respect to plant height and number of flowers. ;DAG, the ammonium salt of DAG and the n-butyl ester of DAG were investigated as growth retarders on Brazilian pepper (Schinus terebinthifolius Raddi) and sumac (Rhus spp.). The plant leaves were sprayed so long that a continuous spray coating was obtained. As a reference compound, "Maintain CF 125" was used (a mixture of methyl-2-chloro-9-hydroxyfluorene-9-carboxylate, methyl-9-hydroxyfluorene-9-carboxylate and methyl-2,7-dichloro-9-hyd roxyfluorene-9-carboxylate). 43 days after the spray change, the reduction was the absence of the longitudinal growth, leaf waste and the deformation of the leaves below. In Table XII, the results are given in numbers. The grading scale is as follows: ;0 - no effect; 1 - delayed length growth; 2 - length growth stopped; 3 - length growth stopped and deformed leaves; 4 - complete leaf drop, new leaves are small and deformed. ;B-1956 is a water-dispersible, resin-based surfactant manufactured by Rohm & Haas. "Maintain CF-125" is a mixture of methyl 2-chloro-9-hydroxyfluorene-9-carboxylate, methyl 9-hydroxyfluorene-9-carboxylate and methyl 2,7-dichloro-9-hydroxyfluorene-9-carboxylate. The oil adjuvant, which is used in the aforementioned formulation, is standard petroleum which is usually used in herbicide formulations, and especially when the herbicide is to be used for the treatment of tree-like plants. This oil supports both the penetration and adhesion of the active substance. "Sun Oil 11E", which is an emulsifiable and non-phytotoxic spray oil, was used in the formulations according to Table XII. The herbicidal effect of DAG alone as well as in combination with also 2,4-D in the spray solution against a number of the species is confirmed with the help of the following table XIII. The data in Table xm refer to a spray solution of ;DAG, an emulsifiable concentrate in nitropyrrolidone. The figures must be understood as control1 percentage, calculated for untreated plants. The herbicidal effect of DAG, either alone or in combination with 2,4-D, was investigated using Daucus carota (wild carrots) by spraying an emulsifiable concentrate in nitropyrrolidone. Table XIV shows percent epinasty 4 and 18 days after spraying. (Epinastia is an unwanted growth, whereby parts of the plant bulge out and often grow downwards). The results in Table XIV show that DAG increases the effect of 2,4-D. Preferred growth-regulating, herbicidal compounds in the agents according to the invention are thus 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid (DAG), the corresponding sodium, potassium, ammonium, calcium and the dimethylammonium salt, as well as the lower alkyl and lower alkynyl esters of this compound, and especially the propargyl ester. It was further found that a growth regulator containing one of the compounds of the general formulas <1>, xll and III' when sprayed on fruit-bearing trees significantly reduces the force that must be used to separate the fruit from the stem. This is shown by comparison with untreated trees. It could further be established that fruit, which had been harvested and which had been treated with the growth regulators according to the invention, were relatively free from damage and decay. The agents according to the invention can be applied to the fruit-bearing trees in liquid or solid formulations. The application can take place over roots, trunks, branches, leaves or fruits. E.g. fruit removal agents according to the present invention can be sprayed or applied to the trees, or the agents can be placed on the ground under the trees, so that the agents can be absorbed by the rats. A preferred method of application, which is also the most effective, consists in applying the agents in the form of an aqueous spray solution. If desired, a formulation based on a suitable organic solvent such as e.g. an oil-like spray solution. In order to achieve the strongest effect when using the normal fruit separation agents according to the present invention, the agent is preferably used one to two weeks (depending on the temperature) before the fruit is harvested. In areas where you have to calculate with rain, and then in time intervals between the application of the agent and the installation, a normal adhesion agent is suitably added to the formulation. Examples of such adhesion agents include e.g. glue, casein, salts of alginic acid, cellulose gum and corresponding derivatives, polyvinylpyrrolidone, invert syrup, corn syrup, etc. ;Fruit separating agents according to the invention contain as active ingredients compounds with the formulas i, nioglll<1>. If desired, conventional, inert materials, such as are used in agriculture in particular when the agents in question serve to treat trees or when they are used in conjunction with active substances in known fruit separation agents, can be added. Such excipients include e.g. also surface-active compounds, carriers, adhesion agents, stabilizers, etc. The concentration of active substance with the general formulas I, m and III' in the new fruit separation agents according to the present invention varies, but in order to achieve an optimal effect it is necessary that a sufficient amount application. Thus, an aqueous spray solution contains from approx. 0.05% by weight to approx. 1.5% by weight of active ingredient. The concentration naturally varies depending on the type of fruit and the stem growth of the tree or shrub. The dosage amount is what really eases the coughing. In the case of spray replacements, the aqueous solution, which contains the fruit separating agent, is sprayed in such a way that the tree is coated with a full coverage spray replacement coating. This requires the use of approx. 3ooo to approx. 9,000 liters of a diluted solution (approx. 0.1 - 1% by weight of active substance) per hectare, and then depending on the number and size of the trees to be treated. For the preparation of a preferred sprbyte formulation containing the fruit separating agent according to the present invention, the active ingredient or a salt thereof is dispersed or dissolved in a carrier, such as water. The liquid sprbyte solution can be added 0.1 to approx. 0.5% by weight surfactant calculated on the weight of the carrier material. Typical surface-active substances are "Triton^-B-1956", i.e. a water-dispersible and resin-based surface-active agent, which is manufactured by Rohm & Haas. Furthermore, "X-77 (Chevron-Ortho)", a non-ionic surface-active agent containing as basic substances alkylaryl-polyoxyethylene glycols, free fatty acids and isopropanol, can be prepared. The fruit-separating means according to the present invention effect the separation of the fruits from a large number of fruit trees. Typical fruits of this species are e.g. oranges, grapefruit, olives, apples, cherries, etc. They also work on other useful plants such as e.g. cotton and soya beans (here you get leaf waste). As already mentioned, the fruit-removal agent is applied to the trees in the form of aqueous solutions. In this respect, the invention also includes equivalent amounts of water-soluble salts of compounds within the scope of formulas I, III and III' in a similar manner. Such salts include e.g. the sodium salt. the potassium salt, the ammonium salt, etc.. ;The new fruit separating compounds in the agents according to the invention containing 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid (known as DAG) are adjusted to a pH value of 5 - 8, for e.g. addition of potassium hydrogen sulfate to aqueous solution. This buffering is necessary due to the known instability of DAG in aqueous solutions with a pH value below 5. In cases where the compounds used are water-insoluble, emulsifiable concentrates or wettable powder formulations of the active substance are prepared, which can be dispersed in water and thus form a spray solution. ;DAG can be prepared as an emulsion concentrate by using N-methyl-2-pyrrolidone or nitropyrrolidone as a solvent. Wettable powder is produced by using an inert diluent, e.g. kaolin. A typical spray formulation that is formulated with a wettable powder contains e.g. active ingredient, approx. 1-5% inert diluent, smaller amounts of dispersant, wetting agent and antifoam agent and the corresponding and necessary amount of water. ;As oranges can be considered typical fruits that become easier to cough up when treated with chemical fruit exfoliating agents, the effect of the new fruit exfoliating agents is illustrated using orange trees. The sodium salt of 2,3:4,5-di-0-isopropylidene-2-keto-L-gulonic acid is being investigated as a fruit-releasing agent on citrus fruits, e.g. oranges. Aqueous solutions containing 0.05% by weight, 0.1, 0.25, 0.5 and 1.0% by weight of this sodium salt and 0.5% "Triton B-1956" are prepared. These plantings are planted on Valencia oranges, pitted swamp grapefruit and red grapefruit trees. One week after the spray change, the only observable effect is a slight leaf drop in the trees treated with a higher dose. Two weeks after the spray change, most orange and grapefruit fruits have fallen off in the trees that were treated with a dose amount of at least 1%. Trees treated with a dose of 0.5% had got rid of approx. half of the fruits, and the remaining fruits hung very loose. In addition to the fruit separation effect, the fruits also showed a clear strengthening of the colour, e.g. a significantly deeper and darker color than the untreated fruits. ;The sugar content and the total solids content in the treated fruits compared to the untreated fruits also had oct. ;Similar results were obtained by spraying e.g. the ammonium salt or the diethylammonium salt or the n-butyl ester of 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid and the sodium salt of 2,3-0-isopropylidene-4,6-0-ethylidene-2- keto-L-gulonic acid. Used as a fruit stripping agent or as a herbicide after or before germination, i.e. as soon as the compounds are used as plant growth regulators, the compounds of the formulas I, III and III' can be prepared and formulated as described above and below. ;2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid monohydrate is a known commercial preparation and is an intermediate product in the production of L-ascorbic acid. It is produced by oxidation of diacetone-L-sorbofuranose in an alkaline or neutral medium. Diacetone-L-sorbofuranose is produced by reacting L-sorbose with acetone in the presence of a strong acid. The nine compounds used in the agents according to the present invention can be prepared by: a) reacting an acid with the general formula in the presence of a base, where R-^/ R2' R 3 °9 R 4 has the formula In the given ;meaning, ;with a compound of the general formula ;;where X means chlorine, bromine or a p-toluenesulfonic acid ester and where ;r,, means straight-chain or branched alkyl,alkanyl,alkanyl of up to 20 carbon atoms or halogen-lower alkyl, ;or ;b) in the case where a compound of formula I is intended, where n means the number 2, one reacts in the presence of a base an ;acid of formula V with a compound of the general formula ;;where X^ and ~ X.^ means chlorine, bromine or iodine and Rg lower alkylene, ; or ; c) in the case where a compound of formula I is intended, and where n means the number 2, reacts an acid halide produced by ; an acid with formula V with a diol of the general formula ;;where Rg has the meaning given in formula VII", ;or ;d) in the case where r a salt of formula I is intended, and where n means the number 1 and R is ammonium or ammonium substituted with one or more lower alkyl, lower alkenyl or hydroxy-lower alkyl, bringing an acid of the general formula V into contact with a compound of the general formula ;;where R7, Rg and Rg mean hydrogen, lower alkyl, ;lower alkenyl or hydroxy-lower alkyl, ;or when n means 2, with calcium hydroxide or magnesium hydroxide. The salts of DAG are prepared in the usual way. For this purpose, DAG is added under vigorous stirring to an aqueous solution of a base at room temperature. In this work process, the solution is kept at a pH value above 7. After the reaction is finished, excess water is removed in a high vacuum. Anhydrous acetone (about 10 parts by volume) is then added to the resulting syrup and stirred overnight. The white crystalline precipitate which forms is filtered, washed with acetone and dried. In the case of non-volatile bases, equivalent amounts of acids are added. If volatile bases are used, such as ammonium hydroxide or dimethylamine, then an excess of base is used and the unused excess is then evaporated away in a vacuum. Then DAG under the usual esterification conditions, such as e.g. by esterification according to Fischer, is not stable, then the new esters of DAG are produced by reaction with e.g. the corresponding lower alkyl, lower alkenyl or lower alkynyl halides under basic conditions at room temperature, and by using inert organic solvents, such as dimethylformamide (DMF). The esters are insoluble in water but soluble in methanol, acetone, ethanol, chloroform, pentane, benzene, ether, etc. The reaction between an acid of the formulas V with an alcohol of the formula IX can preferably be carried out in pyridine as solvent and in the presence of equivalent amounts of p-toluenesulfonic acid chloride. The mixture is heated to a temperature interval of approx. 5° to approx. 50°C, preferably at room temperature (cf. also J. Am. Chem., Soc 77, 6214 (1955)). Furthermore, an acid of formula V can be reacted with an alcohol of formula IX by reacting these reactants in the presence of an equimolar amount of dicyclohexylcarbodiimide in an inert organic solvent. Preferred solvents are methylene chloride, dimethylformamide, ether, tetrahydrofuran or ethyl acetate (cf. also Tetrahedron 21, 3531 (1965)). Solutions consisting of a solvent and a compound according to the invention are certainly suitable for greenhouse experiments, but are not, however, suitable for field experiments. Wettable powder is also not generally applicable as the DAG derivatives must be dissolved in order for them to be able to display the necessary activity. The acid is therefore preferably produced as a soluble powder in combination with buffering agents, as buffering to a pH value of 5 - 9 is essential for the acid. The acid can also be formulated as an emulsion concentrate by using, as will be shown later, N-methyl-2-pyrrolidone or nitro-pyrrolidone: "Atlox 2081B" is a mixture of polyoxyethylene sorbitan esters of fatty acids and acidic resins as well as alkylaryl sulphonates. The salts are water-soluble and require no special formulation. The DAG ester is formulated as an emulsifiable concentrate on a xylene basis, which is then mixed with water. Emulsions containing 25 to 50% by weight can be prepared from these concentrates. Typical emulsifiable concentrates for the DAG ester are indicated below. "Atlox 3403" is a mixture of polyoxyethylene ethers, polyoxyethylene glycerol and alkylaryl sulfonate. ;"Atlox 3404" is a mixture of polyoxyethylene alkyl aryl ether and an alkyl aryl sulfonate. "Emulphor EL 620" is a polyethylated vegetable oil. ;"Drewmulse GMC-8 is the monoglyceride of a lower molecular weight, saturated coconut fatty acid. ;A concentrated solution consisting of sodium 2,3:4,6-di-L-isopropylidene-2-keto-L-gulonate (95% by weight) and Sodium dioctyl sulfosuccinate (5% by weight) is prepared and sprayed. A wettable powder is obtained which is completely soluble in water. In a further embodiment, finely powdered sodium 2,3:4,6-di-O-isopropylidene-2-keto is mixed -L-gulonate with pumice granules To this dry mixture is added water corresponding to 10% by weight of the mixture Part of the sodium salt of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid is now dissolved and serves as a means of binding the remaining solvent sodium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate to the pumice granules. ;In a further embodiment, is added to an aqueous solution of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid with stirring an equimolar amount of diethanolamine A clear solution is obtained, the pH of which is adjusted to 8 by adding d shout diethanolamine. In a further embodiment, ammonia (25% equimolecular amount) is added while stirring to an aqueous solution of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid. A clear solution is obtained if the pH is set to 8 by adding ammonia drop by drop (25%). The compounds of formula I, where R 1 and R 2 or R 2 , R 2 , R 3 , and R 3 have a meaning other than methyl, likewise show growth-regulating action before and after germination. E.g. prevents 2,3:4,6-di-0-butylidene-2-keto-L-gulonic acid in a dosage amount of 8 kg/hectare as a growth regulator for germination the growth of Amaranthus sp. completely after 20 days, and as a growth regulator after germination, the aforementioned acid causes a strong reduction in the growth of red beans. 2,3:4,6-di-0-(3-pentylidene)-2-keto-L-gulonic acid is produced in a dosage amount of 8 kg/hectare as a growth regulator after germination strong growth delay for Amaranthus sp., Brassita caber, Ipomoea sp. and red beans. ;Compounds where the 4,6-0-isopropylidene group has been replaced by another group are produced using the so-called "ketal exchange reaction". For this purpose, DAG is dissolved in the desired ketone, aldehyde, ketal and acetal and an acid catalyst is added. These compounds can also be prepared by using a similar ketal exchange reaction, whereby 2,3:4,6-di-O-isopropylidene-oc-L-sorbofuranose is used as starting material; and by oxidizing the obtained product. Examples of ketones and aldehydes which can be used in the preparative method are those with the general formula R10~ C*- R1;L, where R1Q e.g. means methyl or ethyl, and means e.g. methyl or ethyl. Typical compounds of this type are diethyl ketone and methyl ethyl ketone. Ketones where both residues R^Q and R^ are of equal size are not particularly favorable as these residues are sterically inhibited during the reaction. By using an unsymmetrical aldehyde or ketone, after the reaction cycle the bulky residue will be in "Exo" -position (R^ in formula I), and is responsible for a new center of asymmetry.

Any strong acid can be used as a catalyst. A preferred catalyst is perchloric acid. Further examples of such acids are sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, methanesulfonic acid and trifluoromethanesulfonic acid.

A preferred temperature range for this reaction is between approx. -20° and approx. 50°, whereby the range between 20° and 30° (room temperature) is particularly preferred. The cleavage point for DAG is also the upper limit to which the reaction mixture

can be heated. For this reason, the reaction mixture is not heated above 100°C.

Compounds in which both isopropylidene groups are replaced by other groups are prepared starting from sorbose by following those of Reichstein and Grtissner, Heiv. Chim. Acta, 17, 311 (1934) specified conditions. In this method, a suitable ketone or a suitable aldehyde is reacted with L-sorbose in the presence of a strong acid as a catalyst, e.g. sulfuric acid, at or below room temperature. The intermediate product thus obtained is then oxidized in an alkaline or neutral reaction environment.

In the production of di-O-alkylidene sorbofuranose, perchloric acid, hydrochloric acid, p-toluenesulfonic acid etc. are preferably used as acid catalysts, whereby sulfuric acid is particularly preferred.

As the reaction proceeds exothermically, work is carried out at room temperature or below room temperature, whereby a particularly preferred temperature range is between approx. 0° and approx. -20°.

In the subsequent production of the acid from the sorbofuranose intermediate, the oxidation is carried out in a neutral or alkaline environment and oxidizing agents such as sodium permanganate, potassium dichromate, potassium permanganate/potassium hydroxide and sodium hypochlorite/Ni<++> are used. The two latter oxidizing agents are preferred. The oxidation can also be carried out catalytically by using palladium or platinum and oxygen.

A suitable temperature range is between room temperature and 100°, whereby the range between approx. 50° and approx.-60° are preferred.

E.g. 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid was prepared and during the preparation the regulations in the aforementioned publication in Heiv were followed. Chim. Acta.

Subsequent examples shall illustrate the preparation of the compounds of formula I which are used in the agents according to the invention.

EXAMPLE 1

Etvl-2,3:4,6-di-Q-isopropylidene-2-keto-L-gulonate.

To a solution of 100 g of anhydrous potassium carbonate in 946 ml of dimethylformamide, 292.2 g of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid monohydrate (DAG monohydrate) and then 205.g of ethyl iodide. Stirring is continued for 24 hours at room temperature. The mixture is then filtered to remove inorganic salts and the dimethylformamide is removed by distillation in vacuum (approx. 60°C and approx. 10 mmHg). 200 ml of acetone are added to dissolve the remaining ether. Undissolved inorganic salts are filtered off. The filter cake is washed out with 100 ml of acetone. The filtrate is added to the solution containing the ester and the crude product is isolated by vacuum distillation of the solvent up to a quantity of approx. 500 ml and subsequent cooling of this solution to 5°. The crude product is recrystallized in methanol or methanol/acetone and 284 g of ethyl 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate are obtained, pour temperature: 99 - 100.5°C.

According to this generally applicable regulation,

starting from 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid and 1,2-dibromoethane in a molar ratio of 2:1 of the bis-ester: bis-2,3: The 4,6-di-O-isopropylidene-2-keto-L-gulonate ethylene glycol ester prepd.

EXAMPLE 2

Methyl- 2, 3:4, 6- di- 0- isopropylidene- 2- keto- L- qulonate

To a suspension of 100 g of anhydrous potassium carbonate in 946 ml of dimethylformamide, 292.2 g of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid monohydrate (DAG monohydrate) is added with stirring and then the solution 205 g of methyl iodide. The mixture is stirred for 4 hours at room temperature and then filtered to remove the inorganic salts. The dimethylformamide is distilled from in vacuo.

200 ml of acetone is added to the residue to bring the ester into solution. Undissolved, inorganic salts are filtered off again. The filter cake is washed with 100 ml of acetone. The filtrate is combined with the ester solution and then concentrated in vacuo to a yellow syrup

is formed, which after a period of time crystallizes in the form of large prisms. The vacuum distillation at 127 - 129° and at 0.35 - 0.37 mmHg gives 268 g of a colorless liquid which solidifies on standing. Methyl 2,3:4,6~di-O-isopropylidene-2-keto-L-gulonate melts at 46.5 - 47.5°.

EXAMPLE 3

n-butyl-2, 3:4. 6-di-0-isopropylidene-2-keto-L-gulonate While stirring, a suspension of 100 g of anhydrous potassium carbonate in 946 ml of dimethylformamide is added to 2,3:4,6-di-0-isopropylidene-2-keto-L- gulonic acid monohydrate (292.2 g) and then 197 g of n-butyl iodide. The mixture is stirred for 48 hours at room temperature, then filtered and subsequent removal of the inorganic salts. The dimethylformamide is removed by vacuum distillation. 200 ml of acetone is added to the residue and any inorganic salts still present are filtered off. The filter cake is washed with 100 ml of acetone. The filtrate is combined with the ester solution and concentrated in vacuo. Recrystallization of the residue in methanol-acetone gives 172 g of colorless crystals of n-butyl 1-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, with a melting point of 53.9 - 56.8 °C.

EXAMPLE 4

n-propyl-2, 3:4. 6-di-0-isopropylidene-2-keto-L-qulonate n-propyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate is prepared analogously to the work regulations in examples 1-3, whereby 200 g of 1-bromopropane are used as halide. Yield 150.6 g, melting point 80 - 81°C.

EXAMPLE 5

n-pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate n-pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate is prepared analogously to the work regulations in examples 1-3, whereby 300 g of 1-bromopentane is used as halide.

Yield 503 g; boiling point 195°C/0.5 mmHg.

EXAMPLE 6

n- dodecyl- 2, 3:4, 6- di- O- isopropylidene- 2- keto- L- qulonate n-dodecyl-2,3:4,6-di-O- isopropylidene-2-keto-L-gulonate manufacture

read analogously to the work regulations in examples 1-3, yield 75 g, after two recrystallizations in ethanol; m.p. 10.5°C.

EXAMPLE 7

Allyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate Allyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate is produced analogously to the work regulations in examples 1-3, whereby 133 g of allyl bromide is used. Yield 282 g; m.p. 95 - 95.5°C.

EXAMPLE 8

Isopropyl-2,3:4,6-di-Q-isopropylidene-2-keto-L-gulonate Isopropyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate is produced analogously to the work regulations in examples 1-3, whereby 250 g of 2-bromopropane is used. Yield 116.8 g, m.p. 107.5 - 109°C.

In a similar manner, further straight-chain and branched, aliphatic hydrocarbyl and halogen-lower alkyl esters can be prepared.

EXAMPLE 9

Sodium- 2, 3- 0- isopropylidene- 4, 6- 0- ethylidene- 2- keto- L- qulonate

48 g 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid (DAG)

dissolve in 250 g of paraldehyde. Five drops of 70% perchloric acid are added and then the reaction is allowed to continue for 12 days at room temperature under constant control using thin-layer chromatography or gas-liquid chromatography until it is finished. The solution is then added with vigorous stirring to

16.8 g of sodium bicarbonate, which was suspended in 100 ml of water. Excess paraldehyde and excess water distill off in vacuo. The residue is crystallized in alcohol/water and 50.4 g of sodium 2,3-0-isopropylidene-4,6-0-ethylidene-2-keto-L-gulonate is obtained. Physico-chemical data (nuclear resonance spectrum, mass spectrum, infrared spectrum) show the following structure:

In the same way as described above, other 2,3-0-isopropylidene-4,6-0-(R1-R2)-2-keto-L-gulonic acid (structure I), where the ^ and R2 substituents mean straight chain or branched lower alkyl is prepared.

EXAMPLE 10

2. 3- 0- isopropylidene- 4. 6- 0-( 3- pentvlidene)- 2- keto- L-gulonic acid

29.2 g of DAG are dissolved in 500 ml of diethyl ketone. 5 drops of 70% perchloric acid are added and the reaction is terminated after 72 hours at room temperature. 30.3 g of crude product is obtained.

Purification by recrystallization in chloroform/hexane gives white small leaves, melting point 12 9.8 - 130.2°C.

EXAMPLE 11

2. 3- 0- isopropylidene- 4, 6- 0- ( 2- butylidene)- 2- keto- L-gulonic acid

Dissolve 29.2 g of DAG in 500 ml of methyl ethyl ketone and add 5 drops of 70% perchloric acid. The reaction ends after 72 hours at room temperature. 57.6 g of crude product is obtained. Recrystallization in chloroform/hexane gives the free acid.

Analysis calculated for C13H2007: C, 5o?97; H, 7.24; H 2 O, 5.88 Found: C, 51.09; H, 7.46; H 2 O, 6.20

EXAMPLE 12

2, 3:4, 6- di- O- ( 3- pentylidene)- 2- keto- L-gulonic acid To 4 95 ml diethyl ketone is added dropwise while cooling

to 0° 81 g sulfuric acid and then 120 g L-sorbose. The reaction is terminated after two days of stirring at -10 to -20°.

The mixture is then neutralized with 600 ml of 10% sodium

lye and the excess diethyl ketone are distilled off in a vacuum. 2,3:4,6-di-O (3-pentylidene)-oc-L-sorbofuranose is isolated by extraction with toluene.

31.6 g of 2,3:4,6-di-O-(3-pentylidene)-oc-L-sorbofuranose recrystallized in pentane are heated for 4 hours to 50-60° together with 23.8 g of potassium hydroxide and 15, 8 g of potassium permanganate in 250 ml of water. A further 15.8 g of potassium permanganate are then added and the reaction mixture is stirred without heating overnight. The mixture is filtered, concentrated to 150 ml, cooled to -5° and then acidified to a pH of 3.0 with concentrated hydrochloric acid. The precipitate is filtered off and washed with water. 26.8 g of 2,3:4,6-di-O-(3-pentylidene)-2-keto-L-gulonic acid with a melting point of 144 - 145°C are thus obtained. On

in the same way, other gulic acid derivatives can be prepared, where R^, R2, R3 and R4 mean straight-chain or branched

lower alkyl groups.

EXAMPLE 13

2, 3:4, 6- di- O-( 2-butylidene)- 2- keto- L- qulone re- hydrate 2,3:4,6-di- O-(2-butylidene)-2-keto-L -gulonic acid hydrate is produced according to the working regulations stated in example 15, whereby methyl ethyl ketone is used. The product melts after recrystallization in hexane/chloroform at 96.5 - 103°C.

EXAMPLE 14

2- chloroethyl- 2. 3:4, 6- di- O- isopropylidene- 2- keto- L- qulonate 6 g 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid (anhydrous ) is dissolved in 14 ml of pyridine and 3.2 ml of methylene chloride and added dropwise with stirring and ice-cooling with 3.2 ml of thionyl chloride. After 3 hours at room temperature, the reaction solution with 5.9 ml of 2-chloroethanol is added and then stirred for a further 3 hours. The reaction solution is then taken up in methylene chloride and washed

successively with ice-cold 2-n hydrochloric acid, 2-n caustic soda and water, the organic phase is dried over sodium sulphate and evaporated. The residue is purified on a silica gel bath and then distilled. 5 g of an oily product is obtained, bp.: 88°c/0.01 mmHg.

Analogous to the previous examples, especially examples 1-3

and 14, the following compounds are produced:

allyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 94.5 - 95°C; potassium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 300°C; ammonium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 177.5 - 178.5°C; calcium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 26° - 267°C; Dimethylammonium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point 155 - 165°C; N-ethanolammonium 2,3:4,5-di-O-isopropylidene-2-keto-L-gulonate, pour point: 208 - 209°C; methyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 46.5 - 47.5°C; ethyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 99 - 105°C; n-Butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 54 - 57°C; 3-Chloropropyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, boiling point: 130°C/0.005 mmHg; n-Hexyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, n<25>:i;4544. n-hepty1-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, bp.: 102 - 103°C/0.01 mmHg: n-octyl-2,3:4, 6-di-O-isopropylidene-2-keto-L-gulonate, n^ 25: 1.4538; n-nonyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, n^5: 1.4548; n-undecyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, <25>: 1.4555; 2,2,2-trichloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 65 - 66°C; n-dodecyl-2;3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 10.5°C; n-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 80 - 81°C; i-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate,. flow temperature: 107.5 - 109°C;

n-decyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, bp: 193°c/0.5 mmHg5

2-bromomethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, b.p.: approx. 157°C/0.1 torr;

2-Butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 95.5 - 96.5°C;

1- amyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, b.p.: approx. 135°c/0.1 mmHg;

bis-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate-ethylene glycol ester, pour point: 150 - 151°C;

t-butyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-pentynyl-2,3:4,6:di-O-isopropylidene-2-keto-L-gulonate; 1-hexin-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 3-methyl-1-butyn-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

5-Hecaenyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 3-pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; dichloromethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2-dichloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-chloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 4-chlorobutyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2,2-trifluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-Fluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-bromo-1,1,2,2-tetrafluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2,2,3,3,4,4,4-heptafluorobutyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2,2,3,3,4,4,5,5-octafluoropentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

sodium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, flow temperature: >300°C;

2-propynyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 91.5 - 92.5°C;

n-pentyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, bp.: approx. 195°C/0.1mmHg; 2-(Trimethylammonium)ethyl-2,3:4,6-di-O-isopropylidene-α^L-xylo-2-hexulfuranosonate bromide in

Claims (4)

1. Plant growth regulator, characterized in that it contains one or more compounds with the general formula where n means the number 1 or 2 and X the number 0 or 1, in that when n is the number 1, R is hydrogen, sodium, potassium, annium, ammonium substituted with one or more lower alkyl, lower alkenyl or hydroxy-lower alkyl groups; straight-chain or branched alkyl, alkenyl or alkynyl groups with up to 20 carbon atoms, or halogen-lower-alkyl) when n is the number 2, R is calcium, magnesium, or lower alkylene; Rp R 2 , R 3 and R 3 mean hydrogen or straight-chain or branched lower alkyl as enantiomers and racemic mixtures. 2. Agent according to claim 1, characterized in that it contains methyl-, ethyl-, n-<p>ropyl-, i-propyl-, n-butyl-, n-pentyl-, n-dodecyl-, allyl- or propynyl -ester of 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid. 3. Agent according to claim 1, characterized in that it contains sodium, potassium, ammonium, calcium, the dimethylamine or ethanolamine salt of 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid. 4. Agent according to claim 1, characterized in that it contains sodium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate.