PYRAZOLESULFONYLUREA DERIVATIVE, ITS PRODUCTION AND SELECTIVE HERBICIDE COMPRISING THE SAME DERIVATIVE

摘要

PURPOSE:To obtain a new 5-substituted pyrazole derivative useful as an intermediate for herbicides having the selectivity for important crops. CONSTITUTION:The compound of formula I (A is lower alkyl or phenyl; B is H or lower alkyl; R1 is H or lower alkyl; J is mercapto, sulfenamoyl or benzylthio), e.g. ethyl 5-mercapto-1-methylpyrazole-4-carboxylate. This exemplified compound is obtained by reacting ethyl 5-hydroxy-1-methylpyrazole-4- carboxylate with phosphorus oxychloride and then reacting the resultant 5-chloro derivative with hydrogen sulfide. A new pyrazolesulfonylurea derivative of formula II capable of manifesting excellent herbicidal effects with a smaller amount of the chemical than that of a conventional herbicide can be obtained from this compound of formula I.