The invention concerns a new process for the preparation of biologically active 2-[(alkoxycarbonyl)amino]-5-(alkylthio)-1H-benzimidazoles of the formula (V) ##STR1## wherein R and R.sup.1 independently stand for alkyl having 1 to 3 carbon atoms. According to the invention compounds of the formula (V) are prepared by reacting carbamic acid alkyl esters of the formula (I) ##STR2## wherein R is as defined above, with (a) chlorosulfonic acid or (b) oleum to yield a sulfonic acid of the formula (II) ##STR3## wherein R is as defined above, and subsequently with a chlorinating agent, reducing a sulfonic acid chloride of the formula (III) ##STR4## wherein R is as defined above, obtained by process variant (a) or (b) and reacting a benzimidazole-thiol of the formula (IV) ##STR5## obtained, wherein R is as defined above, with an alkyl halide of the formula (VI) R.sup.1 -Hal (VI) wherein R.sup.1 is as defined above and Hal represents a halogen atom.
本发明涉及一种制备
生物活性2-[(烷氧羰基)
氨基]-5-(烷基
硫代)-1H-
苯并咪唑的新工艺,其
化学式为(V) ##STR1## 其中R和R.sup.1独立地代表具有1至3个碳原子的烷基。根据本发明,化合物(V)的制备是通过将
化学式(I)的
氨基甲酸烷酯与(a)
氯磺酸或(b)
油酸反应,得到
化学式(II)的
磺酸 ##STR3## 其中R如上所定义,然后与
氯化试剂反应,还原
化学式(III)的
磺酸氯化物 ##STR4## 其中R如上所定义,通过(a)或(b)的工艺变体得到,然后将
化学式(IV)的
苯并咪唑硫醇 ##STR5## 其中R如上所定义,与
化学式(VI)的烷基卤化物R.sup.1-Hal (VI)反应,其中R.sup.1如上所定义,Hal代表卤素原子。