[CH3:1][O:2][C:3]1[S:4][C:5]([C:9]([OH:11])=O)=[C:6]([CH3:8])[N:7]=1.CN(C)C(=O)C.C(Cl)([Cl:20])=O>O1CCCC1>[CH3:1][O:2][C:3]1[S:4][C:5]([C:9]([Cl:20])=[O:11])=[C:6]([CH3:8])[N:7]=1In a similar apparatus to Example 1, 10.4 g (0.06 mole) of 2-methoxy-4-methylthiazole-5carboxylic acid were suspended in 150 ml of tetrahydrofuran, followed by the addition of 0.02 g of N,N-dimethyl-acetamide. Under heating and reflux, phosgene was blown at a rate of 1.1 l/hr for 4.5 hours (0.23 mole). After completion of the blowing, stirring was continued for additional 2 hours. After completion of the reaction, the reaction mixture was filtered and the filtrate was concentrated to obtain 10.8 g of 2-methoxy-4-methylthiazole-5-carboxylic acid chloride. Its purity and yield were 96.2% and 93.9%, respectively.
Wird geladen…