Synthesis of substituted 4-aminothieno[2,3-d]-, 4-aminothieno[3,2-d]- and 4-aminothieno[3,4-d]pyrimidines

A study was carried out on the nucleophilic cleavage of the lactam bond in 4-amino(pyrrolidino, piperidino, morpolino)thieno[2,3-d]-, -[3,2-d]-, and -[3,4-d]pyrimido[1,2-b]isoquinolin-11-ones. This bond is readily cleaved upon heating in methanolic NaOH at reflux for 1-2 h to give previously unreported 4-amino-2-(o-carboxyphenylmethyl)thienopyrimidines. Replacement of the amine group by an OH group is possible under the reaction conditions, leading to the corresponding, already reported 2-(o-carboxyphenylmethyl)-4-oxothienopyrimidines. Prolonged refluxing (8-12 h) resulted in oxothienopyrimidines as the major products of the transformations of all the thienopyrimido-isoquinolinones studied. Biological activity predictions of these new products were compared in silico.

Zadorozhny A. V.
Chem. Heterocycl. Compd. 2012, 48 (7), 1028-1032
DOI: 10.1007/s10593-012-1095-y