噻吩磺隆的合成

Synthesis of Thifensulfuron-methyl

以2,3-二氯丙腈和2-巯基乙酸甲酯为原料,在甲醇钠作用下环合制得3-氨基噻吩-2-羧酸甲酯,再经"一锅法"重氮化、氯磺化和氨化反应制得3-氨基磺酰基噻吩-2-羧酸甲酯,进一步与光气反应转化为相应的异氰酸酯后与2-氨基-4-甲氧基-6-甲基-1,3,5-三嗪缩合制得噻吩磺隆。

Methyl-3-aminothiophene-2-carboxylate, which was obtained by cyclization reaction of 2,3-dichloropro-pionitrile and methyl 2-mercaptoacetate in presence of sodium methoxide, was used as starting material for preparation of methyl 3-aminosulfonylthiophene-2-carboxylate by sequential reactions of diazotization, chlorosulfonation and ammonia-tion in one-pot. Then methyl-3-aminosulfonylthiophene-2-carboxylate reacted with phosgene to give the corresponding isocyanate, which was subjected to a further condensation with 2-amino-4-methoxy-6-methyl-1,3,5-triazine to obtain the target product thifensulfuron-methyl.