An Efficient Synthesis of Tetrahydoropyrido[4,3-d]pyrimidine Derivatives

Abstract

An efficient route has been developed for the synthesis of tetrahydoropyrido[4,3-d]pyrimidines which are useful in treating allergic, inflammatory and hyperproliferative skin diseases. The route features a quite unique conversion of an enaminonitrile to a tetrahydropyridopyrimidine using carbon dioxide in the presence of DBU (1,8-diazobicyclo[5.4.0]undec-7-ene). The intermediate is transformed to the desired drug substance in a few additional steps. This process is not only general but also expected to apply for the large scale synthesis.