反应详情

A mixture of 2-(2,2-dimethylpropionyl)thiophene (21.45 g), 2,2-dimethylpropane-1,3-diol (14.63 g), and a catalytic amount of p-toluenesulphonic acid in benzene (100 ml) was heated at reflux for 44 hours using a Dean and Stark apparatus. The mixture was cooled, diluted with ether (150 ml), and washed with saturated aqueous sodium hydrogen carbonate solution. The organic phase was then dried (MgSO4) and decolourised with activated charcoal. The solvent was removed by evaporation to give 2-t-butyl-5,5-dimethyl-2-(thien-2-yl)-1,3-dioxane (B) as a white solid (31.9 g, 98% yield); NMR: 0.57(s, 3H), 1.0(s, 9H), 1.21(s, 3H), 3.36(m, 2H), 3.62(d, 2H), 6.9(dd, 1H), 7.01(dd, 1H), 7.3(dd, 1H); mass spectrum (chemical ionisation) 255 (M+H)+.

1. temperatureat reflux for 44 hours
2. temperatureThe mixture was cooled
3. washwashed with saturated aqueous sodium hydrogen carbonate solution
4. dry with materialThe organic phase was then dried (MgSO4)
5. customThe solvent was removed by evaporation