反应详情

A solution of 2-(2-cyanoethyl)malonic acid diethyl ester (24.2 g) in tetrahydrofuran (15 ml) was added to a suspension of sodium hydride (2.45 g) in tetrahydrofuran (30 ml) at 20° C. under nitrogen. To this was added 2-chloro-3-nitro-5-bromopyridine (22 g) and the mixture so obtained was heated to 93°-95° C. A small amount of tetrahydrofuran was allowed to distil off. The mixture was heated under reflux for 2.5 hr. The reaction mixture was poured into water and neutralised to pH 7 with concentrated hydrochloric acid. The aqueous phase was extracted with chloroform, dried (MgSO4) decolourised with charcoal and filtered through a silica column. The chloroform eluant was evaporated to yield an oil which slowly crystallised. The crystals were washed in petroleum ether (40°-60° C.) and dried to yield 4-(5-bromo-3-nitropyrid-2-yl)-4,4-bis(carbethoxy)butyronitrile (28 g) m.p. 58°-62° C.

1. customthe mixture so obtained
2. temperaturewas heated to 93°-95° C
3. customto distil off
4. temperatureThe mixture was heated
5. temperatureunder reflux for 2.5 hr
6. additionThe reaction mixture was poured into water and neutralised to pH 7 with concentrated hydrochloric acid
7. extractionThe aqueous phase was extracted with chloroform
8. dry with materialdried (MgSO4)
9. filtrationfiltered through a silica column
10. customThe chloroform eluant was evaporated
11. customto yield an oil which
12. customslowly crystallised
13. washThe crystals were washed in petroleum ether (40°-60° C.)
14. customdried