IE46218B1 - Aldehydes - Google Patents
AldehydesInfo
- Publication number
- IE46218B1 IE46218B1 IE613/81A IE61381A IE46218B1 IE 46218 B1 IE46218 B1 IE 46218B1 IE 613/81 A IE613/81 A IE 613/81A IE 61381 A IE61381 A IE 61381A IE 46218 B1 IE46218 B1 IE 46218B1
- Authority
- IE
- Ireland
- Prior art keywords
- aldehydes
- methyl
- formula
- dichloro
- stands
- Prior art date
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
PATENT APPLICATION BY (71) F. HOFFMANN-LA ROCHE & CO., AKTIENGESELLSCHAFT A SWISS COMPANY OF 124-184 GRENZACHERSTRASSE, BASLE, SWITZERLAND.
Price 90p
The present invention is concerned vzith aldehydes.
The aldehydes provided by the present invention have the following, general formula
wherein R^ and R2 each represent a chlorine or bromine atom and m stands for zero or 1.
The aldehydes of formula I hereinbefore are useful intermediates for the manufacture of the polyene compounds which are described and claimed in the specification of
Patent Specification No. 46216. ·
Aldehydes of formula I in which m stands for zero (Ia) can be prepared, for example, by formylating an appropriately substituted benzene (e.g. by allowing a formylating agent to act on said substituted benzene). This can be carried out, for example, by formylating the substituted benzene in the presence of a lewis acid. As formylating agents there can be used, in particular, an orthoformic acid ester, formyl chloride ana dimethylformamide. Especially suitable Lewis acids are the halides of zinc, aluminium, titanium, tin and iron such as zinc chloride, aluminium trichloride, titanium tetrachloride, tin tetrachloride -and,iron trichloride, as
40218 well as the halides of inorganic and organic acids such as, for example, phosphorus oxychloride and methanesulphonyl chloride.
When the formylating agent is present in excess, the formylation may be carried out without the addition of a further solvent. However, it is generally recommended to carry out the formylation in an inert solvent (e.g. nitrobenzene or a chlorinated hydrocarbon such as methylene chloride). The formylation can be carried out at a temperature between 0°C and the boiling point of the formylation mixture.
In the foregoing manner, the benzaldehyde (Ia) is obtained directly from the substituted benzene.
Aldehydes of formula I in which m stands for 1 (lb) can be prepared, for example, by converting an aldehyde of formula I in which m stands for zero in a manner known per se by condensation with acetone at a low temperature (at a temperature in the range of from about 0°C to 30°C) in the presence of alkali metal hydroxide (e.g. dilute aqueous sodium hydroxide) into a (substituted phenyl)-but-3-en-2-one and reacting this ketone with ethoxycarbonylmethylene-triphenylphosphorane under the conditions of a Wittig reaction. The resulting (substituted phenyl)-3-methyl-penta-2,4-dien-l-oic acid ethyl ester is subsequently reduced in the cold with the aid of a mixed metal hydride, especially lithium aluminium hydride, in an organic solvent (e.g. ether or tetrahydrofuran) to give a (substituted phenyl)-3-methyl-penta-2,4-dien-l-ol. This alcohol is then oxidised to give the desired (substituted phenyl)-3-methyl-penta-2,4-dien-l-al of formula Ib by treatment with an oxidising agent (e.g.
manganese dioxide in an organic solvent such as acetone or methylene chloride) at a temperature between 0°C and the boiling point of the oxidation mixture.
i 46218
The following Example describes the preparation of an aldehyde provided by this invention:
Example
2,6-Dichloro-4-methoxy-5-methyl-benzaldehyde (melting 5 point 11O°-111°C) can be prepared from 3,5-dichloro-2-methyl-phenol (melting point 51°-52°C) via 3,5-dichloro-2-methyl-anisole (boiling point 76°C/0.3 Torr; n34 = 1.5538) and
2,6-dichloro-4-methoxy-5-meth.yl-benzyl chloride (melting point 85°-86°C).
Claims (2)
1) Aldehydes of the general formula wherein Rj_ and R 2 each represent a chlorine or bromine atom and m stands for zero or 1. 5
2) 2,6-Dichloro-4-methoxy-5-methyl-benzaldehyde.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT944476A AT351515B (en) | 1976-12-20 | 1976-12-20 | METHOD FOR PRODUCING NEW POLYEN COMPOUNDS |
| CH1238877A CH630329A5 (en) | 1976-12-20 | 1977-10-11 | Process for the preparation of novel polyene compounds. |
| IE2538/77A IE46216B1 (en) | 1976-12-20 | 1977-12-14 | Polyene compounds |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IE810613L IE810613L (en) | 1978-06-20 |
| IE46218B1 true IE46218B1 (en) | 1983-04-06 |
Family
ID=27151124
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE612/81A IE46217B1 (en) | 1976-12-20 | 1977-12-14 | Phosphonium salts |
| IE613/81A IE46218B1 (en) | 1976-12-20 | 1977-12-14 | Aldehydes |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE612/81A IE46217B1 (en) | 1976-12-20 | 1977-12-14 | Phosphonium salts |
Country Status (1)
| Country | Link |
|---|---|
| IE (2) | IE46217B1 (en) |
-
1977
- 1977-12-14 IE IE612/81A patent/IE46217B1/en unknown
- 1977-12-14 IE IE613/81A patent/IE46218B1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| IE46217B1 (en) | 1983-04-06 |
| IE810612L (en) | 1978-06-20 |
| IE810613L (en) | 1978-06-20 |
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