反应详情

L-threonine (11.9 g) is added to dioxane (125 ml) and 2N sodium hydroxide (50 ml). To the vigorously stirred solution, o-nitrophenylsulfenyl chloride (20.9 g) is added in ten equal portions over fifteen minutes, while 2N sodium hydroxide (60 ml) is slowly added dropwise. After five more minutes the reaction mixture is diluted with water (400 ml) and acidified to pH 2.5 with 10% potassium bisulfate. The organic layer is immediately extracted with ethyl acetate (three 200 ml portions), and the combined extracts are dried over sodium sulfate, and then concentrated to an oil. The product crystallizes on scratching (20.0 g). Recrystallization of 17 g from acetone/hexane affords 9.5 g of crystals, melting point 145°-148° C. which are stored in a freezer and used promptly.

1. additionis slowly added dropwise
2. extractionThe organic layer is immediately extracted with ethyl acetate (three 200 ml portions)
3. dry with materialthe combined extracts are dried over sodium sulfate
4. concentrationconcentrated to an oil
5. customThe product crystallizes
6. customRecrystallization of 17 g from acetone/hexane