Z-Isomers of compounds of general formula (IV): [wherein R1 is 2-(2-N-protected aminothiazol-4-yl)-2-alkoxyiminoacetyl or the like, R1 is hydrogen or the like; R3 is hydrogen, a carboxyl-protecting group or the like; and R1 is alkyl or the like] can be prepared at high selectivities and in high yields by reacting a compound of general formula (I): [wherein R1, R2 and R3 are each as defined above; and R4 is aryl or the like] with a 4-substituted or -unsubstituted thiazole-5-carbaldehyde in a mixed solvent comprising a chlorinated hydrocarbon and a lower alkanol at a temperature of as low as +5 °C or below.
通式(IV)化合物的 Z-异构体:[其中 R1 为 2-(2-N-保护
氨噻唑-4-基)-2-烷氧基亚
氨基乙酰基或类似物;R1 为氢或类似物;R3 为氢、羧基保护基团或类似物;R1 为烷基或类似物]可通过使通式 (I) 的化合物与 4-取代或芳基或类似物反应,以高选择性和高产率制备:[其中 R1、R2 和 R3 均如上定义;R4 为芳基或类似物]与 4-取代或未取代的
噻唑-5-
甲醛在
氯代烃和低级烷醇组成的混合溶剂中,在低至 +5 °C 或以下的温度下反应。