Potassium Carbonate → Caleprunin B

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-hydroxy 4,5-dimethoxybenzaldehyde (2 g, 10.98 mmol) in butane-2-one (15 ml) added K2CO3 (6.07 g, 43.95 mmol) and then stirred at 0° C. for 10 min added bromoacetone (2.24 g, 16.47 mmol) and refluxed at 90° C. for 4 hr. After completion of the reaction butane-2-one was distilled off and water was added and extracted by ethylacetate twice. The EtOAc phase was dried over Na2SO4, Chromatography of the residue on silica gel (3:7 EtOAc/hexane) afforded the ketone A2 (1.69 g) in 70% yield pale yellow solid: 1H NMR (500 MHz, CDCl3) δ 7.29 (s, 1H), 7.04 (s, 1H), 6.98 (s, 1H), 3.94 (s, 3H), 3.90 (s, 3H), 2.30 (s, 3H) ppm. Mass: ESI [M+Na]+: 243.07; Elemental anal. calcd. for C12H12O4; C, 65.45; H, 5.49. found C, 65.20; H, 5.25.

Provenance & Evidence