反应详情

To a cold (5° C.) mixture of 137.5 g (1.05 mole) of ethyl acetoacetate, 175 ml. of benzene, 325 ml. of water, and 45.8 ml. of 33% sodium hydroxide was added simultaneously 221.05 g (1.430 mole) of m-toluoyl chloride and 190 ml. of 33% sodium hydroxide as described in Example 4. The aqueous solution of sodium salt of ethyl m-toluoylacetoacetate was stirred with 56.3 g of ammonium chloride overnight and worked up as described in Example 4 to give 38.0 g (17%) of crude ethyl m-toluoylacetate after a Kugelrohr distillation (95°-98° C.) at 0.05 mm Hg). A mixture of 20.6 g (0.1 mole) of crude ethyl m-toluoylacetate, 13.6 g (0.105 mole) of sulfuryl chloride, and 30 ml. of chloroform was held at reflux for 6 hours and worked up as described in Example 4 to give 25.0 g of ethyl 2-chloro-m-toluoylacetate, which was used directly as described below. A mixture of 22.5 g (0.1 mole) of ethyl 2-chloro-m-toluoylacetate, 7.6 g (0.11 mole) of thiourea and 100 ml. of ethanol was held at reflux for 2 hours and worked up as described in Example 4 to give 23.0 g of solid, which was recrystallized from ethanol to give 11.6 g (44%) of ethyl 2-amino-4-(m-tolyl)-5-thiazolecarboxylate, m.p. 185°-187° C.

1. distillationafter a Kugelrohr distillation (95°-98° C.) at 0.05 mm Hg)
2. temperatureat reflux for 6 hours