Acetic Acid → Ethyl 4-hydroxy-4-(4,5-dimethoxy-2-nitrophenyl)-2-butynoate

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Reaction Steps

1.5 N butyl lithium (26.8 ml, 40.2 mmol) was added to a solution of diisopropylamine (6.0 ml, 42.8 mmol) in tetrahydrofuran (75 ml) under an argon atmosphere at −78° C. The mixture was stirred for one hr. Ethyl propiolate (3.4 ml, 33.5 mmol) and a solution of 4,5-dimethoxy-2-nitrobenzaldehyde (5.0 g, 23.7 mmol) in tetrahydrofuran (50 ml) were added thereto in that order, and the mixture was stirred at −78° C. for additional 1.5 hr. A solution of acetic acid (7.0 ml, 122 mmol) in tetrahydrofuran (20 ml) was added thereto, followed by addition of water. The mixture was extracted with ethyl acetate. The organic layer was washed with dilute hydrochloric acid, water, a saturated aqueous sodium hydrogencarbonate solution, and saturated brine solution in that order. The organic layer was then dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to give ethyl 4-hydroxy-4-(4,5-dimethoxy-2-nitrophenyl)-2-butynoate as an oil (8.59 g) The resultant ethyl 4-hydroxy-4-(4,5-dimethoxy-2-nitrophenyl)-2-butynoate was dissolved in toluene (80 ml).

Provenance & Evidence