反应详情

To a mixture of dry ethyl acetate (1 l) and concentrated sulphuric acid (25 l, 0.469 mol) was added slowly, with stirring, dry pyridine (50 ml, 0.620 mol). The mixture was cooled and the precipitate of pyridinium sulphate produced was separated from the ethyl acetate by decanting, rinsed with a portion of dry ethyl acetate and vacuum dried at 60° C. to yield 85 g (100% yield) of product. The product (85 g, 0.480 mol) was dissolved in dry dimethylformamide (250 ml) to provide a 1.921M pyridinium sulphate solution, herein designated as pyridinium sulphate reagent. The reagent was stored in a hermetically sealed amber bottle over anhydrous calcium sulphate (25 g).

1. additionwas added slowly
2. temperatureThe mixture was cooled