6-氯烟酸甲酯 、
methyl 2-amino-5-butylthiophene-3-carboxylate 以there is obtained 3.2 g of 2-butyl-4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidine-7-carboxylic acid, methyl ester的产率得到2-butyl-4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidine-7-carboxylic acid, methyl ester