Synthesis of phosphonic esters containing heterocyclic radicals

Abstract

1. In presence of sodium alkoxides, dialkyl phosphites add to coumarin and 4-methylcoumarin with formation of esters of hydrocoumarin-4-yl- and 4-methylhydrocoumarine-4-yl-phosphonic acids, respectively. 2. Experiments on the addition of diethyl phosphite to 2,6-dimethyl-4H-pyran-4-one and of diethyl phosphorodithioate to coumarin did not give positive results.