反应详情

A solution of 2.77 g of ethanethiol in 30 ml of 2-propanol was added to a mixture containing 7.7 g of 2,5-dichloro-4-pyridinecarbonitrile and 3.08 g of K2CO3 in 60 ml of 2-propanol at 0° C. The reaction mixture was allowed to warm to room temperature and then stirred for 4 days, after which it was poured onto 200 g of ice, stirred and extracted with CH2Cl2. Thin layer chromatography (using 10 percent ethyl acetate in hexane) disclosed the presence of three components. The CH2Cl2 solution was dried and concentrated to 25 ml and then diluted with 12.5 ml of hexane to give a crystalline material which was separated by filtration and identified as 2-chloro-5-ethylthio-4-pyridinecarbonitrile. The filtrate was concentrated and separated on a Water's Prep LC 500 instrument eluted with 2 percent ethyl acetate in hexane. Cuts of identical components were combined, evaporated and recrystallized to give 0.94 g (18%) of 5-chloro-2-ethylthio-4-pyridine-carbonitrile, (m.p. 103°-104° C.) and 3.33 g (64.5%) of 2-chloro-5-ethylthio-4-pyridinecarbonitrile (m.p. 112°-114° C.). The third component was identified as unreacted starting material.

1. stirringstirred
2. extractionextracted with CH2Cl2
3. dry with materialThe CH2Cl2 solution was dried
4. concentrationconcentrated to 25 ml
5. additiondiluted with 12.5 ml of hexane
6. customto give a crystalline material which
7. customwas separated by filtration
8. concentrationThe filtrate was concentrated
9. customseparated on a Water'
10. washeluted with 2 percent ethyl acetate in hexane
11. customevaporated
12. customrecrystallized