反应详情

The cis methyl ester (14, 500 mg) was dissolved in methanol (5 ml) and stirred in a nitrogen atmosphere. A solution of NaOH in aqueous methanol (5 ml; 2.4 g NaOH in 30 ml water which was then diluted to 100 ml with methanol) was added and the mixture stirred for 24 hr at room temperature. The methanol was evaporated, water added, and then extracted with heptane (3×). The aqueous fraction was acidified to approximately pH 4 with dilute HCl, saturated with NaCl, and extracted with EtOAC (3×). The EtOAC extract was washed with water and dried over Na2O4, then evaporated in vacuo to give the cis-carboxylic acid (9, 0.35 g). A small aliquot was esterfied with diazomethane and analyzed by HPLC. Less than 1% of the trans isomer was present. The reaction was repeated on the remaining 400 mg. A total of 626 mg of the cis acid was obtained.

1. additionwas added
2. stirringthe mixture stirred for 24 hr at room temperature
3. customThe methanol was evaporated
4. additionwater added
5. extractionextracted with heptane (3×)
6. extractionextracted with EtOAC (3×)
7. extractionThe EtOAC extract
8. washwas washed with water
9. customdried over Na2O4
10. customevaporated in vacuo