PROCESS FOR THE PREPARATION OF INTERMEDIATES USEFUL IN THE PREPARATION OF PYRANYL CYANOGUANIDINE DERIVATIVES

摘要

PROCESS FOR THE PREPARATION OF INTERMEDIATES USEFUL IN THE PREPARATION OF PYRANYL CYANOGUANIDINE DERIVATIVES A process for preparing compounds of the formula <IMG> where a, b, c, R1, R2, and R3 are as defined herein including the step of alkylating a phenol of formula II <IMG> with an acetylene of formula III <IMG> where X is chlorine; bromine; -OC(O)-R5, where R5 is alkyl, aryl or <IMG> substituted aryl; or-OCO2R6, where R6 is alkyl or <IMG> , in the presence of a catalytic amount of a cuprous or cupric salt. The compounds of formula I are intermediates useful in the preparation of pyranyl cyanoguanidine derivatives.