Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. <b>VIII</b>. Synthesis of ethyl and methyl 2,4‐disubstituted 5‐pyrimidinecarboxylates

Abstract

Abstract Reaction of ethyl or methyl 2‐dimethylaminomethylene‐3‐oxoalkanoates with N‐C‐N dinucleophiles such as guanidine, acetamidine or benzamidine afforded in high yields the relative esters of 4‐substituted 2‐amino‐, 2‐methyl‐ or 2‐phenyl‐5‐pyrimidinecarboxylic acids, respectively. These esters were hydrolyzed to the corresponding carboxylic acids, which were converted by heating to 4‐substituted 2‐pyrimidinamines, 2‐methyl or 2‐phenylpyrimidines, respectively, generally in excellent yields. The 4‐unsubstituted ethyl 2‐amino‐, 2‐methyl‐ and 2‐phenyl‐5‐pyrimidinecarboxylates were obtained in moderate yields by reaction of the above dinucleophiles with ethyl 2,2‐diformylacetate. These esters were hydrolyzed and the corresponding acids (with the exception of the 2‐methyl derivative) were decarboxylated to give 2‐pyrimidinamine and 2‐phenylpyrimidine in satisfactory yields.