SU789511A1 - Method of preparing ethyl ester of 2-(6'-carboxyhexyl)-cyclopenten-2-one-1 - Google Patents

Description

Union of Soviet

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DESCRIPTION

Inventions

TO AUTHOR'S CERTIFICATE

<>.> 789511

USSR State Committee for Inventions and Discoveries (61) Additional to ed. certificate-wu (22) 3approved on 07/31/78 (21) 2651521 / 23-04 with the addition of application No. (23) Priority

Published 2 3,12.80. Bulletin No. 47

Date of publication of the description 30.12.80 (51) M. Cl. ³

S 07 S 69/74

C 07 S.67 / 317 (53) UDC 547.29 '26.

.07 (088.8) (72) The inventors

D.P. Feldman and M.V.Shimanskaya (71) Applicant

Order of the Red Banner of Labor, Synthesis of the Academy of Sciences of the Latvian SSR Ins / Institute of Organic (54) METHOD FOR PRODUCING ETHYL ETHER

2- (6 ’-CARBOXYHEXYL) -cyclopentene-2-OH-1

This invention relates to a method for producing 2- (b ’-carboxyhexyl) -cyclopenten-2-one-1 ethyl ester used as an intermediate in the synthesis of physiologically active compounds of 11-deoxyprostanoids.

A known method for the production of 2- (6'-carboxyhexyl) cyclopenten-2-one-1 alkyl ester by working out with 2- (oct-7 * -enyl) -cyclopenten-2 • she-1 m-chloroperbenzoic acid, the resulting epoxide is cleaved iodic acid to aldehyde. The aldehyde is further oxidized with Jones reagent and esterified with diazomethane I-.

The process is multi-stage and requires work with peroxide. The yield of the target product does not exceed 42%.

There is also known a method for producing 2- (6'-carboxyhexyl) -cyclopenten-2-one-1 alkyl ester based on the use of methyl 11-ethoxycarbonyl-undec-10-enoate as the starting compound, which is cyclized in the presence of polyphosphoric acid and then etherified with alkanol in a medium of hydrochloric acid m

The process for producing 2- (b ’-carboxyhexyl) -cyclopenten-2-one-1 alkyl ester in this method is; It is long and laborious, including extraction, esterification (16 h), distillation in vacuo, and chromatographic separation of the reaction mixture. The product yield is 35%.

The closest technical solution to this problem is a method for producing 2- (6 ^1- carboxyhexyl) -cyclopenten-2-one-1 alkyl (ethyl) ether by dehydrogenation of 2- (6 ^1- carboxyhexyl) cyclopentanone- alkyl (ethyl) ester 1 followed by esterification of the obtained product in a mixture of dry alkanol (ethanol) and benzene in the presence of η-toluenesulfonic acid as a catalyst. Dehydrogenation of the alkyl ester of 2- (6 ^G- carboxyhexyl) cyclopentanone-1 is carried out in two stages. First, the starting material was reserved with bromine in dry ethylene glycol (7 h), then the low-purity hydrogen was removed by boiling with NaOH in dry ethanol (3 h). Product yield 4 0%.

The disadvantages of this method are the low yield of the target product, as well as the use of bromine and dried solvents.

The purpose of the invention is to increase the yield of the target product and simplify the process technology.

The goal is achieved by the described method for the production of ethyl 2- (6 ^f- carboxyhexyl) cyclopenten-2-one-1 by dehydrogenation of ethyl 2- (· 6 * -carboxyhexyl) -cyclopentanone-1, a distinctive feature of which is the dehydrogenation with divalent copper chloride at a temperature of 80-85 ° C in acetonitrile. The process is preferably carried out with a stoichiometric ratio of 2- (6 * -carboxyhexyl) cyclopentanone-1 ethyl ester and divalent copper chloride equal to 1: 2.

It is also advisable to carry out the process in the presence of oxygen as an oxidizing agent. Moreover, the molar ratio of 2- (b ^, -carboxyhexyl) cyclopentanone-1 ethyl ester to divalent copper chloride can be reduced. ' to 1: 0.6.

The yield of the target product in all cases, based on the initial reaction, is 75-84%. In addition, the proposed method does not use reagents that cause corrosion of the equipment, achieved high productivity of the process and does not require special preparation of solvents.

Example 1 To 0,066 g of 96.3% but of ethyl 2- (6 ¹ '-karboksigeksil) -tsiklopentanona-1 in 9.42 g of acetonitrile is added 0.109 g of cupric chloride (Eg SuC 2H gO). Heated for one hour at a temperature of 85 ° C, then acetonitrile is distilled off in vacuum, and the precipitated copper monochloride is separated by centrifugation. The reaction mixture is further analyzed by gas chromatography (GLC). The yield of the target product is 0.0535 g or 84% of theory, the rest is the starting material (0.3%) and unidentified products (15.70%). The results of elemental analysis of the target product (after purification using preparative thin-layer chromatography on silufol) are as follows.

Calculated,%: C 70.56; H'9.30; About 20.14.

SCCPPOp (238.33)

Found,%: C 70.22; H, 9.41; About 20.37.

EXAMPLE IM ep 2 To 0.533 g of 96.3% solution of ethyl 2- ⁽¹ b '-karboksigeksil) -tsiklopentanona-1 in 18.13 g of acetonitrile dobavlyayut.0,228 g SuS 2Na0 .. After heating on a water in a bath at a temperature of 85 ° C, 0.158 g of 2- (6- ^β- carboxyhexyl) -cyclopenten-2-one-1 ethyl ester is formed over two hours. Oxygen was then passed into this reaction mixture at a rate of 1.25 L / h. After 4 hours, the reaction was stopped, acetonitrile was distilled off in vacuo, acetone, benzene or ether were added to the residue, and the precipitated copper monochloride was separated by centrifugation. The resulting reaction mixture as a result contains (according to (GLC) 0.385 g of ethyl 2- (6 carboxyhexyl) -cyclopenten-2-one-1, 0.03 g of unreacted ethyl 2- (6 ⁽ -carboxyhexyl) -cyclopentanone- 1, the rest is unidentified impurities.The yield of the target product is 75%.

Claims (4)

Claim 1. The method of obtaining ethyl ester 2- (b '-carboxyhexyl) -cyclopentene-2-0 on-1 by dehydrogenation of ethyl ester of 2- (b * -carboxyhexyl) -cyclopentanone-1, characterized in that, in order to increase the yield of the target product and simplification of the process, dehydrogenation is carried out with divalent copper chloride at a temperature of 80-85 ° C in an acetonitrile medium. 2. The method of pop. 1, characterized in that the process is carried out at a stoichiometric ratio of 2- (6 * -carboxyhexyl) -cyclopentanone-1 ethyl ester and divalent copper chloride equal to 1: 2. 3. The method of pop. 1, characterized in that the process is conducted in the presence of oxygen as an oxidizing agent. 4. The method of pop. 3, characterized in that the process is carried out at a molar ratio of ethyl ether, 2- (6 ¹ -carboxyhexyl) -cyclopentanone-1 and divalent copper chloride, equal to 1: 0.6.