An unprecedented tandem synthesis of fluorescent coumarin-fused pyrimidines via copper-catalyzed cross-dehydrogenative C(sp³)–N bond coupling

Abstract

An efficient, one-pot Cu-catalyzed tandem synthesis of fluorescent 1-benzyl-2-phenyl-1,2-dihydro-5H-chromeno[4,3-d]pyrimidin-5-ones from 4-chloro-3-formylcoumarin and benzylamines was developed by in situ intramolecular cross-dehydrogenative C(sp3)-N bond formation in moderate-to-good yields under ligand-free ambient conditions. This synthesis was easily scalable, and the generality of the substrates was established. These coumarin-fused pyrimidines exhibited interesting photo-physical properties and high quantum yields, and would be potential candidates for facilitating suitable studies in medicinal chemistry and materials science.

Copper-Catalyzed Synthesis of Coumarins. A Mini-Review

“…The use of two different benzylamines led to a mixture of cross-coupled and homo-coupled products. A plausible mechanism was proposed by the authors after some controlled experiments (Scheme 13) [57].…”

Progress in copper-catalysed/mediated intramolecular dehydrogenative coupling

“…The reaction was carried out between 4-halo-3-formyl coumarin and excess benzylamine, resulting in the formation of 1 : 2 adduct suitable for the dehydrogenative coupling. 25 First the reaction affords an aminocoumarin followed by condensation of the second benzylamine with the formyl group of coumarin (Scheme 25). The coumarin fused pyrimidine scaffolds are well known for antitumour, antitubercular, anti-inflammatory, anticancer, and antifungal activities.…”

Copper‐Catalyzed Cross‐Dehydrogenative Coupling Reactions

“…A Santhosh Kumari et al [49] The reaction was performed using 10 mol% CuI, equiv. K 2 CO 3 in DMF, at 80°C for 10-16 h under an air atmosphere (Scheme 45).…”

“…A novel and efficient synthesis of fluorescent 1-benzyl-2phenyl-1, 2-dihydro-5H-chromeno [4, 3-d]pyrimidine-5-ones (149) from benzylamine (148) and 4-chloro-3-formylcoumarin (147) via copper-catalyzed intramolecular in situ cross-dehydrogenative C(sp 3 )-N coupling reaction was well explored by Santhosh Kumari et al [49] The reaction was performed using 10 mol% CuI, equiv. K 2 CO 3 in DMF, at 80°C for 10-16 h under an air atmosphere (Scheme 45).…”