反应详情

A solution of 1.0 g of 4-methyl-2-(trityl-amino)-picolinic acid methyl ester (compound B1) in 35 ml of dry toluene is treated dropwise at −70° C. with 2.9 ml of a 1.5 M solution of diisobutylaluminium hydride in toluene. After 0.5 h 5 ml of diethylether and 2.9 ml of diluted aqueous acetic acid (20% strength) are added. After further 0.5 h the reaction mixture is warmed to room temperature and 29 ml of an aqueous solution of ammonia (25% strength) are added. The colorless precipitate is filtered off with suction and washed with toluene. The filtrate is extracted with brine, the organic phase is dried using sodium sulfate and concentrated to dryness. After purification of the crude product on silica gel (eluent: toluene/ethyl acetate 20:1) and evaporation of the eluents, 0.438 g of the title compound are obtained as a colorless, amorphous solid. M.p. 213° C. MS: 379.1 (MH+). TLC: Rf=0.66 (toluene/acetone 10:1).

1. filtrationThe colorless precipitate is filtered off with suction
2. washwashed with toluene
3. extractionThe filtrate is extracted with brine
4. customthe organic phase is dried
5. concentrationconcentrated to dryness
6. customAfter purification of the crude product
7. customon silica gel (eluent: toluene/ethyl acetate 20:1) and evaporation of the eluents, 0.438 g of the title compound
8. customare obtained as a colorless, amorphous solid