Syntheses of 3,4- and 1,4-dihydroquinazolines from 2-aminobenzylamine

DÍAZ, JIMENA E; RANIERI, SILVIA; GRUBER, NADIA; ORELLI, LILIANA R

BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY

BEILSTEIN-INSTITUT

Año: 2017 vol. 13 p. 1470 - 1477

1860-5397

A straightforward strategy for the synthesis of dihydroquinazolines is presented, which allows for the preparation of 3,4- and 1,4-dihydroquinazolines with different substitution patterns from 2-aminobenzylamine (2-ABA) as common precursor. The required functionalization of both amino groups present in 2-ABA was achieved by different routes involving selective N-acylation and cesium carbonate-mediated N-alkylation reactions, avoiding protection/deprotection steps. The heterocycles were efficiently synthesized in short reaction times by microwave assisted ring closure of the corresponding aminoamides promoted by ethyl polyphosphate (PPE).