Dexibuprofen → Ibuprofen, (+-)-

HRID 1769303Notes

Reaction equation

[CH3:1][C@H:2]([C:13]([OH:15])=[O:14])[C:3]1[CH:8]=[CH:7][C:6]([CH2:9][CH:10]([CH3:12])[CH3:11])=[CH:5][CH:4]=1>CCCCCCC>[OH:15][C:13]([CH:2]([C:3]1[CH:4]=[CH:5][C:6]([CH2:9][CH:10]([CH3:11])[CH3:12])=[CH:7][CH:8]=1)[CH3:1])=[O:14]

Participants

Conditions

Temperature: 220 °C

Procedure

Heptane is removed as stream 18, FIG. 1, by distillation in an evaporator at atmospheric pressure from a mixture [stream 15, FIG. 1] containing S(+)-ibuprofen (0.1912 moles, 39.43 g), R(-)-ibuprofen (0.5136 moles, 105.95 g), and heptane (ca. 390 g). During the distillation, water [30 g, stream 17] is injected into the base of the evaporator to help strip out the last traces of heptane and to minimize formation of ibuprofen ethyl ester. The molten evaporation residue [stream 33], which consists essentially of ibuprofen with an S/R ratio of 27/73, is first racemized by being heated under nitrogen at 220° C. for four (4) hours and is then distilled at about 220° C., 10 mm HgA in an evaporator to provide a distillate [stream 19] of substantially pure racemized ibuprofen (0.6907 moles, 142.48 g, S/R ratio of 47:53) and an undistilled residue [stream 20, 2.91 g] for incineration as a waste stream. Racemized ibuprofen distillate [stream 19] is recycled to the first crop crystallization of crude S(+)-ibuprofen lysinate.

Workup

customHeptane is removed as stream 18, FIG. 1, by distillation in an evaporator at atmospheric pressure from a mixture [stream 15, FIG. 1]
distillationDuring the distillation, water [30 g, stream 17]
customis injected into the base of the evaporator
customThe molten evaporation residue [stream 33], which
distillationis then distilled at about 220° C.
custom10 mm HgA in an evaporator

Sources & evidence

ORD record: ord-324afa9e89bf4d4cbd17a3b1c7980f2c
Source dataset: uspto-grants-1995_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05380867

Reaction notes

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