Dichotomy in the reactivity of 2-methyltetrahydroquinazoline 1-oxides towards aldehydes: An unprecedented condensation with simultaneous reduction of the N-oxide fragment

摘要

An unusual condensation reaction of 2-methyltetrahydroquinazoline N-oxides with aromatic aldehydes was found. The reaction of 4-cyano substituted heterocycles as well as the use of microwave irradiation for 4-morpholinyl substituted heterocycles resulted in the condensation engaging the methylene group of the tetrahydroquinazoline fragment with simultaneous deoxygenation of the N-oxide. A preparative approach towards previously unknown pyrimidine-containing conjugated molecules was developed based on this process. (C) 2020 Elsevier Ltd. All rights reserved.