Metal-free radical C–H methylation of pyrimidinones and pyridinones with dicumyl peroxide
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry and Chemical Engineering, Soochow University, 199 Renai Street, Suzhou, China
Centre for Green Chemistry and Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, USA
Green Chem., 2017, Advance Article
A new method for free radical methylation of pyrimidinones and pyridinones with dicumyl peroxide (DCP) under metal-free conditions is introduced. A 50 g-scale reaction could be performed safely at the desired concentration. The reaction solvent and DCP derivative were readily recovered by distillation. The product was purified by crystallization to minimize the amount of waste.
Colorless solid, mp 258−260 °C, 73% yield (191 mg).
1H NMR (400 MHz, DMSO-d6): δ 12.85 (s, 1H), 8.17 (d, J = 7.1 Hz, 2H), 7.68 (d, J = 6.6 Hz, 2H), 7.53 (dd, J = 14.3, 6.8 Hz, 6H), 2.10 (s, 3H).
13C NMR (101 MHz, CDCl3): δ 161.15, 152.97, 138.68, 132.26, 131.62, 129.11, 129.02, 128.86, 128.15, 127.45, 119.09, 12.65.
HRMS (ESI-TOF) m/z: (M+H)+ Calcd for C17H15N2O 263.1184, found 263.1194.