反应详情

16.8 g of 9-carbomethoxy-2-chloro-3ketonononoic acid methylester (VI) and 4.5 of thioformamide (VII, R1 = H) were refluxed in 90 ml of methanol for 1 hour, then methanol was evaporated in vacuo, and the distillation residue was dissolved in 150 ml of 2 N hydrochloric acid. The obtained solution was neutralized with a 5 % solution of sodium carbonate, saturated with ammonium sulphate and extracted with 3 × 150 ml of diethyl ether. The ethereal extract was dried over sodium sulphate, then ether was evaporated. Thus 16 g of crude 4-(6-carbomethoxyhexyl)-thiazole-5-carboxylic acid methylester (VIII, R1 = H) were obtained which could be used without any further purification for the preparation of 4-(6-carboxyhexyl)-thiazole-5-carboxylic acid (IX, R1 = H) according to point (e).

1. custommethanol was evaporated in vacuo
2. dissolutionthe distillation residue was dissolved in 150 ml of 2 N hydrochloric acid
3. extractionextracted with 3 × 150 ml of diethyl ether
4. extractionThe ethereal extract
5. dry with materialwas dried over sodium sulphate
6. customether was evaporated