Preparation method for (2Z,4E)11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid isopropyl ester

Abstract

The invention discloses a preparation method for (2Z,4E)11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid isopropyl ester. The method is characterized in that: (2Z,4E)11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid is used as a raw material; N, N-dimethylformamide diisopropyl acetal is used as an esterification reagent which reacts with (2Z,4E)11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid at a temperature in a range of 80 to 100 DEG C for 2 to 5 hours; the reaction is stopped when the content of acid in the raw material is less than 1%; the product of the reaction is subjected to aftertreatment so as to obtain the desired target product. The beneficial effects of the invention are as follows: compared to the prior art, yield of the target product is substantially enhanced; energyconservation in the whole process of preparation is realized; the aftertreatment is easy and operable.

Description

technical field [0001] The invention relates to a preparation method of (2Z, 4E) 11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid isopropyl ester. Background technique [0002] (2Z,4E)11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid isopropyl ester, commonly known as (S)-methoprene, is an effective Insect Growth Inhibitor. It is a new type of specific insecticide that targets the unique growth and development system of insects. After the hormone enters the body of mosquitoes, it will cause the mosquitoes to be underdeveloped, lose their ability to attack and reproduce, and achieve the purpose of reducing mosquitoes from the source. In the prior art, tetraalkyl titanate is often used as an esterification agent, and 11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid is used as a reaction raw material, and the reaction temperature is Synthesize 11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid isopropyl ester within the range of 110-200°C. In the prior art, the esterific...

AI Technical Summary

Problems solved by technology

In the prior art, tetraalkyl titanate is often used as an esterification agent, and 11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid is used as a reaction raw material, and the reaction temperature is Synthesize 11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid isopropyl ester within the range of 110-200°C. In the prior art, the esterification agent is selected It is tetraalkyl titanate, and there are remaining organic titanium during the esterification reaction with the raw material 11-methoxy-3,7,11-trimethyl-2,4-dodecadienoic acid acid salt, need additional solvent to dilute, wash with sulfuric acid, then wash with glycolic acid and potassium carbonate solution, remove the titanate and then concentrate to remove the added solvent to obtain the final product, resulting in very cumbersome post-processing

The prior art obtains a product weight yield of 100%, but the cis-isomer content is as high as 2.5-4%.

At the same time, with tetraalkyl titanate as the esterification agent, although the transition metal titanium ions have a series of washing and removal operations in the post-treatment process, there will always be a small amount of residue in the product, which will cause the finished product to be formed during storage. Type conversion from trans to cis shortens the shelf life of the product

Since the cis product is an ineffective component as an insect inhibitor, the high-temperature reaction and the residual catalysis of trace transition metal ions cause the conversion of the trans to the cis configuration, reducing the purity of the active ingredients of the product, thereby reducing the product quality. The effective active content of