反应详情

To the solution of 16 g of crude 4-(6carbomethoxyhexyl)-thiazole-5-carboxylic acid methylester (VIII, R1 = H) in 50 ml of ethanol 100 ml of 2 N sodium hydroxide solution was added, the reaction mixture was refluxed for 30 minutes, then acidified with 5 N sulphuric acid under ice-cooling. On extracting the aqueous reaction mixture with 3 × 150 of ml ethyl acetate, the extract was dried over sodium sulphate and evaporated in vacuo. Recrystallization of the obtained crude product from diethylether afforded 9.4 g of 4-(6-carboxyhexyl)-thiazole-5carboxylic acid (IX, R1 = H). M.p.: 151°-153° C.

1. temperaturethe reaction mixture was refluxed for 30 minutes
2. temperaturecooling
3. extractionOn extracting the aqueous reaction mixture with 3 × 150 of ml ethyl acetate
4. dry with materialthe extract was dried over sodium sulphate
5. customevaporated in vacuo
6. customRecrystallization of the
7. customobtained crude product from diethylether