RU2238262C1 - Method for preparing 2,3-fullereno[60]cyclopentanols - Google Patents

Abstract

FIELD: chemistry of metalloorganic compounds, chemical technology.

SUBSTANCE: invention elates to a method for preparing 2,3-fullereno[60]cyclopentanols of the formula (1):

wherein n = 1-3; R means hydrogen atom (H), CH₃, CH₃CH=CH-CH=CH. 2,3-Fullereno[60]cyclopentanols of the formula (1) can be used in fine organic synthesis, in manufacturing physiologically active substances and medicinal preparations. Method involves interaction of fullerene-C₆₀ with triethylaluminium (AlEt₃) in the mole ratio C₆₀ : AlEt₃ = 1:(25-35) in the presence of zirconocene dichloride (Cp₂ZrCl₂) as a catalyst taken in the amount 15-25 mole% with respect to C₆₀ in argon atmosphere, at room temperature (20-21^oC), under atmosphere pressure, in toluene medium for 8 h followed by addition of copper chloride (CuCl) as a catalyst in the amount 15-25 mole% with respect to C₆₀ and carboxylic acid ethyl ester (RCO₂Et) in equimole ratio with respect to AlEt₃ to the reaction mass at temperature -15^oC. Then the reaction mass is stirred at room temperature for 6-10 h followed by hydrolysis of the reaction mass.

EFFECT: improved preparing method.

1 tbl, 9 ex

Description

The present invention relates to the field of organic chemistry, specifically, to a method for producing 2,3-fullereno [60] cyclopentanols of the general formula (1):

where n = 1-3; R = H, CH ₃ , CH ₃ CH = CH-CH = CH

2,3-fullereno [60] cyclopentanols of the formula (1) can be used in fine organic synthesis, in the production of physiologically active substances and drugs.

A known method (Nenitzescu CD, Necsoin I. The Synthesis of Cyclic Alcohols and Olefins be the Interaction of Dimagnesium Halides and Esters. J. Amer. Chem. Soc., 1950, 72, 3483-3486) for producing cycloalkanols, for example, 1-methylcyclohexane -1-ol (2) by the interaction of 1,5-dimagnesium pentane with an equimolar amount of ethyl acetate according to the scheme:

The known method does not allow to obtain 2,3-fullereno [60] cyclopentanols of the formula (1).

The known method (Dzhemilev U.M., Ibragimov A.G., Vostrikova O.S., Vasilieva E.V., Tolstikov G.A. Regioselective hydroalumination of unsaturated hydrocarbons catalyzed by zirconium complexes with alkylalanes. Izv. AN Ser. Chem., 1987, No. 5, 1089-1095) for the preparation of cyclopentanols, for example 1,3-dimethyl-1- (hydroxymethyl) cyclopentane (3), by reacting 2,5-dimethyl-1,5-hexadiene with diisobutylaluminium chloride (i-Bu ₂ AlCl) in the presence of a catalyst Cp ₂ ZrCl ₂ at a temperature of 40 ° C for 2 hours, followed by oxidation of the reaction mass with atmospheric oxygen according to the scheme:

In a known manner, 2,3-fullereno [60] cyclopentanols of the formula (1) cannot be obtained.

A new method is proposed for producing 2,3-fullereno [60] cyclopentanols of the formula (1).

The essence of the method consists in the interaction of fullerene C ₆₀ with triethylaluminium (AlEt ₃ ), taken in a molar ratio of C ₆₀ : AlEt ₃ = 1: (25-35), preferably 1:30, in the presence of a catalyst of zirconacene dichloride (Cp ₂ ZrCl ₂ ) in an amount 15-25 mol.% In relation to C ₆₀ , preferably 20 mol.%, In an argon atmosphere at room temperature (20-21 ° C) and atmospheric pressure in a toluene solution for 8 hours, followed by addition to the reaction mass at a temperature -15 ° C of a catalyst of copper chloride (CuCl) in an amount of 15-25 mol.% In relation to the original fullerene [60 ], preferably 20 mol.%, and ethyl carboxylic acid ester of the general formula RCO ₂ Et, where R = H, CH ₃ , CH ₃ CH = CH-CH = CH-, in an amount equimolar to AlEt ₃ , followed by stirring reaction mass at room temperature (20-21 ° C) for 6-10 hours, preferably 8 hours. The total yield of 2,3-fullereno [60] cyclopentanols of formula (1) is 60-84% after hydrolysis of the reaction mass.

The reaction proceeds according to the scheme:

2,3-Fullereno [60] cyclopentanols of the formula (1) are formed only with the participation of AlEt ₃ , C ₆₀ and the zirconium catalyst Cp ₂ ZrCl ₂ . In the presence of other aluminum compounds (e.g. Bu $\genfrac{}{}{0ex}{}{\text{i}}{\text{2}}$ AlCl, Bu $\genfrac{}{}{0ex}{}{\text{i}}{\text{3}}$ Al Bu $\genfrac{}{}{0ex}{}{\text{i}}{\text{2}}$ AlH, EtAlCl ₂ , Et ₂ AlCl) or other catalysts (e.g. Zr (acac) ₄ , ZrCl ₄ , Cp ₂ TiCl ₂ , Pd (acac) ₂ , Ni (acac) ₂ , NiCl ₂ , Fe (acac) ₂ ) target products (1) are not formed.

Carrying out this reaction in the presence of a catalyst Cp ₂ ZrCl ₂ or CuCl more than 25 mol.% With respect to fullerene [60] does not lead to a significant increase in the yield of target products (1). The use of the catalyst Cp ₂ ZrCl ₂ or CuCl less than 15 mol.% Reduces the yield of the target products (1), which is probably associated with a decrease in catalytically active centers in the reaction mass. The reactions were carried out at room temperature (20-21 ° C). At a higher temperature (for example, 40 ° C), there is no significant increase in the yield of the target products (1), and at a lower temperature (for example, 0 ° C), the reaction rate decreases.

A change in the ratio of the starting reagents in the direction of increasing their content with respect to the starting fullerene [60] does not lead to a significant increase in the yield of the target products (1).

The reactions were carried out in toluene solution. In other solvents (e.g., ether), the reaction does not proceed.

Significant differences of the proposed method.

In the proposed method, fullerene [60] and ethyl esters of carboxylic acids are used as starting compounds, and A1Et ₃ as an organoaluminum reagent. In the known method, 1,5-hexadiene (for example, 2,5-dimethyl-1,5-hexadiene) and an organoaluminum Bu reagent are used as starting reagents $\genfrac{}{}{0ex}{}{\text{i}}{\text{2}}$ AlCl.

The proposed method, unlike the known one, allows to obtain 2,3-fullereno [60] cyclopentanols of the formula (1) based on C ₆₀ , AlEt ₃ and ethyl esters of carboxylic acids under mild conditions (20-21 ° C). The method is illustrated by the following examples.

EXAMPLE 1. In a 100 ml glass reactor mounted on a magnetic stirrer in an argon atmosphere, 45 ml of dried toluene 0.04 mmol C ₆₀ , 0.008 mmol of catalyst Cp ₂ ZrCl ₂ , 1.2 mmol AlEt _{3 are} placed, stirred for 8 hours at a temperature of 20-21 ° C, then at a temperature of -15 ° C add 0.008 mmol of CuCl catalyst and 1.2 mmol of ethyl formate, mix for 8 hours at a temperature of 20-21 ° C and hydrolyze with ethereal HCl solution. 2,3-fullereno [60] cyclopentanol is isolated from the organic layer in 75% yield.

Spectral characteristics of 2,3-fullereno [60] cyclopentanol (1):

IR (ν, cm ^-1): 3400, 2905, 2850, 1700, 1450, 1380, 1150, 1100, 710. ¹ H NMR (α, ppm): 3.41 (1 H at C ^1), 1.86 (2H at C ⁴ ), 2.94 (2H at C ⁵ ).

¹³ C NMR spectrum (α, ppm): 69.54 (C ¹ ), 59.28 (C ² ), 42.96 (C ³ ), 45.89 (C ⁴ ), 37.69 (C ⁵ ). The signals of the carbon atoms of the fullerene fragment are in the region of 133.42-154.16. Other examples confirming the method are given in the table.

The reactions were carried out at room temperature (20-21 ° C) in a solution of toluene in an argon atmosphere without access of light. In all experiments, the number of cyclopentanol substituents in the fullerene molecule [60] varies from 1 to 3.

Claims (1)

The method of obtaining 2,3-fullereno [60] cyclopentanols of the formula (1)

(1) where n = 1-3; R = H, CH ₃ , CH ₃ CH = CH-CH = CH, characterized in that the fullerene C ₆₀ is reacted with triethylaluminium (AlEt ₃ ) in a molar ratio of C ₆₀ : AlEt ₃ = 1: (25h35) in the presence of a catalyst of zirconacenedichloride (Cp ₂ ZrCl ₂ ), taken in an amount of 15-25 mol.% relative to C ₆₀ , in an argon atmosphere at room temperature (20-21 ° C) and atmospheric pressure in toluene for 8 hours, followed by the addition of a catalyst of copper chloride (CuCl) to the reaction mass at a temperature of -15 ° C in an amount of 15- 25 mol.% With respect to C ₆₀ and ethyl ester of carboxylic acid (RCO ₂ Et) in equimolar relative to to AlEt ₃ amount, after which the reaction mass is stirred at room temperature for 6-10 hours, followed by hydrolysis of the reaction mass.