methyl 5-(1,3-dioxoisoindol-2-yl)-4-oxopentanoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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. was refluxed for 7 hrs Following filtering the residue was washed with water the combined filtrates were evaporated to dryness on a rotary evaporator The residue was filtered dried over silica gel at 30° C. The crude product was dissolved in methanol (10 ml) Diethyl ether (150 ml) was added to stand 2 hrs The precipitate was filtered dried as before, to give 2.5 g (81%), mp 137-140° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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. was refluxed for 7 hrs Following filtering the residue was washed with water the combined filtrates were evaporated to dryness on a rotary evaporator The residue was filtered dried over silica gel at 30° C. The crude product was dissolved in methanol (10 ml) Diethyl ether (150 ml) was added to stand 2 hrs The precipitate was filtered dried as before, to give 2.5 g (81%), mp 137-140° C.