p-Toluenesulfonic acid → 2-(1,1-Dimethoxyethyl)thiazole

反応式

[S:1]1[CH:5]=[CH:4][N:3]=[C:2]1[C:6](=[O:8])[CH3:7].[CH:9](OC)(OC)[O:10]C.[C:16]1(C)C=CC(S(O)(=O)=O)=CC=1>CO>[CH3:16][O:8][C:6]([C:2]1[S:1][CH:5]=[CH:4][N:3]=1)([O:10][CH3:9])[CH3:7]

参加物

反応条件

温度: 50 °C

実験手順

To a solution of 1-Thiazol-2-yl-ethanone (7 g) in dry methanol (100 ml) was added trimethyl orthoformate (35 ml) and p-toluenesulfonic acid (10 g) and the resulting mixture was heated at 50° C. for 12 hours. The mixture was cooled to ambient and concentrated, partitioned between saturated sodium bicarbonate and diethyl ether (100 ml). The organic phase was removed and washed with saturated sodium bicarbonate and brine, dried (magnesium sulfate), filtered and concentrated to afford the sub-title compound as crude product. The product could be further purified if necessary by flash chromatography (20% ethyl acetate/petroleum ether) to afford the sub-title compound in quantitative yield as yellow oil (9.5 g); 1H NMR (400 Mhz, CDCl3) δ 1.75 (3H, s), 3.25 (6H, s), 7.3 (1H, s), 7.85 (1H, s); MS (ES+) 174.1 (M+1).