The invention relates to an improvement in relation to a process for preparing a cephem compound of formula (I)
wherein R' is hydrogen or metal salt, R2 is hydrogen, halogen, acetoxymethyl or -CH2-S-R3 in which R3 is 5- or 6-membered heterocyclic ring having 1-4 heteroatoms optionally substituted by lower alkyl, by reacting 2-(2-aminothiazol-4-yl)-2-syn-methoxy iminoacetic acid in the presence of catalytic amount of 4-dimethyl aminopyridine and a condensing agent with 1-hydroxybenzotriazole in certain organic solvent to obtain a solvate of formula (VIII) which is very reactive and stable,
and then by acylating a compound of formula (III),
wherein R1 and R2 are defined above, with the solvate obtained to obtain the compound of formula (I) in very good yield.
本发明涉及一种与制备式 (I) 的头花化合物的工艺有关的改进
其中 R'为氢或
金属盐,R2 为氢、卤素、乙酰氧甲基或-
CH2-S-R3,其中 R3 为具有 1-4 个杂原子的 5 或 6 元杂环,可任选被低级烷基取代、在催化量的 4-二甲基
氨基吡啶和
缩合剂存在下,使 2-(
2-氨基噻唑-4-基)-2-
鞘氨醇-甲氧基亚
氨基
乙酸与
1-羟基苯并三唑在一定的有机溶剂中反应,得到非常活泼和稳定的式 (VIII) 溶剂、
然后将式(III)化合物酰化、
其中 R1 和 R2 的定义如上。