Reaction of a 2-aminoisoxazole (A, where X is H or OR1) with a thiocyanate and an acyl halide (or their reaction product) and rearrangement of the product gives a 1,2,4-thiadiazole compound (B or C):
The compound B (X=H) can be oxidised and esterified to obtain C (X=OR1). The 3-substituent of compound C (-CH2.CO2R1) may be converted into
The thiadiazole compounds may be used to prepare acylating agents for preparation of therapeutically useful 7-acylaminocephalosporins.
将 2-
氨基
异噁唑(A,其中 X 为 H 或 OR1)与
硫氰酸盐和酰基卤化物(或其反应产物)反应,并对产物进行重排,可得到
1,2,4-噻二唑化合物(B 或 C):
化合物 B(X=H)经氧化和酯化可得到 C(X=OR1)。化合物 C 的 3-取代基(-
CH2.CO2R1)可转化为- .CO2R2。
噻二唑化合物可用于制备酰化剂,以制备对治疗有用的 7-酰
氨基
头孢菌素。