反应详情

A stirred mixture of methyl 5-phthalimido-4-oxopentanoate (4.0 g, 14.5 mmol) [Z. Naturforsch. 41B, 1593-94 (1986)] and 48% hydrobromic acid (40 ml) was refluxed for 7 hrs, then cooled to room temperature and stored overnight in a refrigerator. Following filtering the residue was washed with water and the combined filtrates were evaporated to dryness on a rotary evaporator and titrated with diethyl ether (2×25 ml). The residue was filtered and dried over silica gel at 30° C. and 15 mm Hg in a drying pistol. The crude product was dissolved in methanol (10 ml) and 2-propanol (30 ml). Diethyl ether (150 ml) was added and the mixture was allowed to stand 2 hrs. The precipitate was filtered and dried as before, to give 2.5 g (81%), mp 137-140° C.

1. temperaturewas refluxed for 7 hrs
2. filtrationFollowing filtering the residue
3. washwas washed with water
4. customthe combined filtrates were evaporated to dryness on a rotary evaporator
5. filtrationThe residue was filtered
6. customdried over silica gel at 30° C.
7. dissolutionThe crude product was dissolved in methanol (10 ml)
8. additionDiethyl ether (150 ml) was added
9. waitto stand 2 hrs
10. filtrationThe precipitate was filtered
11. customdried as before,
12. customto give 2.5 g (81%), mp 137-140° C.