Optimization details and limitations of a novel synthetic method of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives are herein disclosed. This synthesis consists of four steps that include a highly selective cyclization, and can be carried out from starting materials to target compounds without column chromatography purification. The high selectivity is