反应详情

A 23.8 g. portion of the product of Example 3 above was added to 600 ml. of tetrahydrofuran, 240 ml. of methanol and 40 ml. of 5 N sodium hydroxide. The mixture was stirred at ambient temperature for 60 hours, and then it was evaporated under vacuum. The residue was diluted to 400 ml. with water, and the solution was continuously extracted with diethyl ether for 8 hours. The aqueous phase was then filtered, cooled to below 10°, and acidified to pH 2 with methanesulfonic acid. It was then diluted to about 7 liters with water, and was extracted with diethyl ether. The aqueous layer was degassed under vacuum and made basic with sodium bicarbonate. The solids which precipitated were collected and vacuum dried, and purified by column chromatography on a 4.5×60 cm. column of silica gel, using as eluant a gradient composed of 2 liters of 1% methanol in chloroform phasing to 2 liters of 25% methanol in chloroform. Twenty ml. fractions were collected, and fractions 33 through 150 gave 13.5 g. of product, m.p. 146°-147° after crystallization from acetone. Its UV spectrum showed an absorption maximum at 290 nm. (32,500). The IR spectrum showed a maximum at 1607 cm.-1 attributable to the conjugated eneone system.

1. customit was evaporated under vacuum
2. additionThe residue was diluted to 400 ml
3. extractionwith water, and the solution was continuously extracted with diethyl ether for 8 hours
4. filtrationThe aqueous phase was then filtered
5. temperaturecooled to below 10°
6. additionIt was then diluted to about 7 liters with water
7. extractionwas extracted with diethyl ether
8. customThe aqueous layer was degassed under vacuum
9. customThe solids which precipitated
10. customwere collected
11. customvacuum dried
12. custompurified by column chromatography on a 4.5×60 cm
13. customfractions were collected
14. customfractions 33 through 150 gave 13.5 g
15. customof product, m.p. 146°-147° after crystallization from acetone