PROCESS FOR PRPEPARING PZRAYOLE DERIVATIVES AND INTERMEDIATES PREPARED BY SAID PROCESS

摘要

The invention relates to a process for preparing pyrazole derivatives of the general formula I, used in the synthesis of pesticides which consists in reacting a cyanoacetate with a cyanide or a formaldehyde or formaldehyde precursor, reacting the intermediate of the formula (III), formed with a diazonium salt and finally cyclizating the intermediate of the formula V. The highly pure pyrazole derivatives are prepared directly without using the cyanohydrin formaldehyde and by avoiding the dimer formation.