Process for synthesis of 7-hydroxy coumarins having substitutions in the 4-position

摘要

A process for synthesis of a compound of the formula: ##STR1## said process comprising the steps of (a) reacting 4-bromomethyl-7-methoxy coumarin with a malonic ester under conditions sufficient to achieve condensation of the ester to give the monoalkylated (2-bis(carbalkoxy)-2- R.sub.1 -1-ethyl) derivative; (b) removing one of the carbalkoxy groups from the product of step (a); (c) demethylation of the product of step (b) to give the 7-hydroxycoumarin compound; and (d) chemically modifying the remaining ester to yield a desired R.sub.2.