反应详情

To a stirring solution of acetylenic acid 3 (37 g, 188 mmol) in 1.1 L of methanol was added 2.2 mL of concentrated sulfuric acid, and the resulting reaction mixture was heated under reflux for 16 h. Upon cooling to room temperature, the reaction mixture was concentrated to one third volume in vacuo, diluted with 1 L of 2:1 hexanes/diethyl ether, and washed with 2×50 mL of saturated aqueous sodium bicarbonate. The combined aqueous washes were further extracted with 2×150 mL of diethyl ether, treated with 50 mL of brine, combined with the previous organic extract and dried sodium sulfate. Concentration in vacuo gave a biphasic residue that was partitioned with 500 mL of hexanes and 50 mL of brine. The aqueous layer was further extracted with 2×50 mL of hexanes, the combined organic layers were dried over sodium sulfate, concentrated in vacuo, and vacuum dried to give methyl ester 4 (38.2 g, 96%) a golden-brown oil:

1. customthe resulting reaction mixture
2. temperaturewas heated
3. temperatureunder reflux for 16 h
4. concentrationthe reaction mixture was concentrated to one third volume in vacuo
5. additiondiluted with 1 L of 2:1 hexanes/diethyl ether
6. washwashed with 2×50 mL of saturated aqueous sodium bicarbonate
7. extractionThe combined aqueous washes were further extracted with 2×150 mL of diethyl ether
8. additiontreated with 50 mL of brine
9. extractionorganic extract
10. concentrationConcentration in vacuo
11. customgave a biphasic residue that
12. customwas partitioned with 500 mL of hexanes and 50 mL of brine
13. extractionThe aqueous layer was further extracted with 2×50 mL of hexanes
14. dry with materialthe combined organic layers were dried over sodium sulfate
15. concentrationconcentrated in vacuo, and vacuum
16. customdried