反应详情

To a stirred solution of 2-(2,3-dihydro-2-ethyl-4-oxo-4H-1-benzopyran-6-yl)propionic acid (10.0 g; 0.04 mol) in dry tetrahydrofuran (100 ml) at -20° C. was added triethylamine (4.05 g; 0.04 mol) followed by ethyl chloroformate (6.0 g; 0.056 mol). After 10 minutes the mixture was saturated with gaseous ammonia. It was then acidified with dilute hydrochloric acid, the organic solvent was removed in vacuo and the product was extracted with chloroform (4×80 ml). The combined extracts were washed with water (2×100 ml), brine (200 ml), and dried over MgSO4. Evaporation of the solvent and recrystallisation of the residue from ethyl acetate gave the title compound (wt=5.1 g). m.p. 148°-150° C.

1. customthe organic solvent was removed in vacuo
2. extractionthe product was extracted with chloroform (4×80 ml)
3. washThe combined extracts were washed with water (2×100 ml), brine (200 ml)
4. dry with materialdried over MgSO4
5. customEvaporation of the solvent and recrystallisation of the residue from ethyl acetate