反应详情

Lithium hydroxide monohydrate (87 mg) was added to a solution of N-isobutoxycarbonyl-2-[4-(2-[methoxycarbonyl]vinyl)phenyl]-N-(3-methoxy-5-methylpyrazin-2-yl)pyridine-3-sulphonamide (250 mg) in tetrahydrefuran (6.2 ml) followed by methanol (2.5 ml) and water (2.5 ml). The reaction mixture was stirred at ambient temperature for 18 hours then evaporated to dryness. The residue was dissolved in water (50 ml), washed with ethyl acetate (50 ml), acidified with 8% aqueous citric acid to pH 3-4 and extracted with ethyl acetate (100 ml). The organic layer was extracted with saturated sodium bicarbonate solution (50 ml) and the aqueous phase separated, acidified with 8% aqueous citric acid and extracted with ethyl acetate (3×30 ml). The combined organic extracts were dried (MgSO4) and evaporated to give 2-[4-(2-carboxyvinyl)phenyl]-N-(3-methoxy-5-methylpyrazin-2-yl)pyridine-3-sulphonamide (108 mg) as a solid, m.p. 233-235° C.: 1H NMR (d6 -DMSO): 2.2 (s, 3H), 3.8 (s, 3H), 6.55 (d, 1H), 7.35 (br s, 1H), 7.45 (d, 2H), 7.55-7.75 (m, 4H), 8.45 (dd, 1H), 8.8 (dd, 1H), 10.1 (br s, 1H); mass spectrum (+ve ESP) 427 (M+H)+.

1. customthen evaporated to dryness
2. dissolutionThe residue was dissolved in water (50 ml)
3. washwashed with ethyl acetate (50 ml)
4. extractionextracted with ethyl acetate (100 ml)
5. extractionThe organic layer was extracted with saturated sodium bicarbonate solution (50 ml)
6. customthe aqueous phase separated
7. extractionextracted with ethyl acetate (3×30 ml)
8. dry with materialThe combined organic extracts were dried (MgSO4)
9. customevaporated