反应详情

To 10 mL of concentrated sulfuric acid was added 2.31 g of [(2,6-difluorobenzoyl)amino]hydroxyacetic acid (prepared as for the known α-hydroxyhippuric acid from glyoxylic acid and 2,6-difluorobenzamide) and 2.50 g of S-([1,1'-biphenyl]4-yl) dimethylcarbamothioate, and this mixture was stirred for 2 h and poured over ice. The yellow precipitate was collected and washed with water, dissolved in ethyl acetate, and dried over magnesium sulfate. This solution was concentrated until a white precipitate formed, which was collected and washed with 50% ethyl acetate/hexane and dried to afford 2.07 of solid. To a solution of this solid in 15 mL of methanol was added 0.56 mL of thionyl chloride, and this mixture was stirred and heated at reflux for 3.5 h. After the addition of 16 mL of 1N NaOH to the reaction mixture, volatiles were removed on a rotary evaporator, and the residual mixture was extracted with ethyl acetate, and the extract was dried over magnesium sulfate. Concentration of the solution and addition of hexane produced a white solid, which was collected and dried to afford the named compound, 0.27 g. The remaining material was adsorbed onto silica gel, applied to a column of silica gel, and eluted with 60% ethyl acetate/hexane to afford an additional 1.04 g of the named compound. 1H-NMR(CDCl3, 300 MHz): δ3.0-3.2 (br d, 6H), 3.8 (s, 3H), 5.8 (d, 1H), 6.9-7.0 (m, 2H), 7.2 (br d, 1H), 7.4 (m, 1H), 7.5-7.6 (m, 8H).

1. additionpoured over ice
2. customThe yellow precipitate was collected
3. washwashed with water
4. dissolutiondissolved in ethyl acetate
5. dry with materialdried over magnesium sulfate
6. concentrationThis solution was concentrated until a white precipitate
7. customformed
8. customwhich was collected
9. washwashed with 50% ethyl acetate/hexane
10. customdried
11. customto afford 2.07 of solid
12. stirringthis mixture was stirred
13. temperatureheated
14. temperatureat reflux for 3.5 h
15. customwere removed on a rotary evaporator
16. extractionthe residual mixture was extracted with ethyl acetate
17. dry with materialthe extract was dried over magnesium sulfate
18. additionConcentration of the solution and addition of hexane
19. customproduced a white solid, which
20. customwas collected
21. customdried
22. customto afford the named compound, 0.27 g
23. washeluted with 60% ethyl acetate/hexane