反应详情

Over a period of 1.5 hours, methyl lithium (531 ml. of a 2 molar solution, 1.06 M) is added under a nitrogen atmosphere to a rapidly stirring solution of 3,5-dibenzyloxybenzoic acid (175 g., 0.532 M) in ether (250 ml.)-tetrahydrofuran (1400 ml.) maintained at 15°-20° C. After stirring an additional 0.75 hour at 10°-15° C., water (600 ml.) is slowly added keeping the reaction temperature below 20° C. The aqueous layer is separated and extracted with ether (3×250 ml.). The organic phases are combined, washed with saturated sodium chloride solution (4×300 ml.), dried over sodium sulfate, and concentrated under vacuum to give an oil which slowly crystallized from isopropyl ether. The crude product is recrystallized from ether-hexane to yield 104.7 g. (59%) of product; m.p. 59°-61° C.

1. temperaturemaintained at 15°-20° C
2. customthe reaction temperature below 20° C
3. customThe aqueous layer is separated
4. extractionextracted with ether (3×250 ml.)
5. washwashed with saturated sodium chloride solution (4×300 ml.)
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated under vacuum
8. customto give an oil which
9. customslowly crystallized from isopropyl ether
10. customThe crude product is recrystallized from ether-hexane
11. customto yield 104.7 g