Improved One-Step Procedure for the Preparation of 1-Substituted and 1,3-Disubstituted Uracils and 2-Thiouracils

Abstract

A convenient one-pot procedure for the synthesis of 1-substituted and 1,3- disubstituted uracils and 2-thiouracils consists of acylation of ureas, or thioureas with methyl 3,3-dimethoxypropanoate in the presence of a strong base, and acidic work-up. The yields range from 36 to 99%. In all cases, only one regioisomer is isolated.