... European Journal of Medicinal Chemistry. ... a Medicinal and Process ... This compound was obtained as solid in 62% yield, mp 158–162 °C; IR (KBr): ν max C O 1693 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ): δ 3.9 (dd, J = 2.0 and 16.0 Hz, 1H, 5-H A ), 4.2 (dd, J = 2.2 and 16.0 Hz, 1H, 5 ...