反应详情

(a-2) To a solution of ethyl propiolate (1.2 ml, 12.0 mmole) in tetrahydrofuran (20 ml) was added at -65° C. under the argon atmosphere a solution of 2.0M lithium diisopropylamide in a mixed solvent of heptane-tetrahydrofuran-ethylbenzene (6.0 ml, 12.0 mole), and the mixture was stirred for 20 minutes. A solution of 4-methyl-2-nitrobenzaldehyde (1.65 g, 10 mmole) in tetrahydrofuran (10 ml) was added, and the reaction mixture was further stirred at 65° C. for 3 hours. To the reaction mixture was added a saturated aqueous ammonium chloride solution (20 ml) or a solution of acetic acid (13.0 ml, 220 mmole) in tetrahydrofuran (20 ml), followed by water, and the aqueous layer was extracted with ethyl acetate. The organic layer was washed with dilute hydrochloric acid, a saturated aqueous sodium hydrogen carbonate solution and a saturated aqueous saline in this sequence, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure to give ethyl 4-hydroxy-4-(4-methyl-2-nitrophenyl)-2-butynoate as an oil (2.60 g).

1. stirringthe reaction mixture was further stirred at 65° C. for 3 hours
2. extractionthe aqueous layer was extracted with ethyl acetate
3. washThe organic layer was washed with dilute hydrochloric acid
4. dry with materiala saturated aqueous sodium hydrogen carbonate solution and a saturated aqueous saline in this sequence, dried over anhydrous magnesium sulfate
5. customthe solvent was removed under reduced pressure