反应详情

Dissolve 3.0 g of 7-benzyloxycarbonyl-1,4-dithia-7-azaspiro[4.4]nonane-8(S)-carboxylic acid, methyl ester in 20 ml of 20% hydrobromic acid in glacial acetic acid and stir the mixture at room temperature for two hours. Add the mixture dropwise to diethyl ether at 0°-5° C. to give 1,4-dithia-7-azaspiro [4.4]nonane-8(S)-carboxylic acid, methyl ester hydrobromide, a brown solid m.p. 156°-158°.