Ethyl 4-bromobutyrate → (+)[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5-yl)-oxy]butanoic acid

HRID 358274Notes

Reaction equation

[Cl:1][C:2]1[C:10]([Cl:11])=[C:9]2[C:5]([CH2:6][C:7]([CH:14]3[CH2:18][CH2:17][CH2:16][CH2:15]3)([CH3:13])[C:8]2=[O:12])=[CH:4][C:3]=1[OH:19].Br[CH2:21][CH2:22][CH2:23][C:24]([O:26]CC)=[O:25]>CN(C=O)C>[Cl:1][C:2]1[C:10]([Cl:11])=[C:9]2[C:5]([CH2:6][C:7]([CH:14]3[CH2:18][CH2:17][CH2:16][CH2:15]3)([CH3:13])[C:8]2=[O:12])=[CH:4][C:3]=1[O:19][CH:23]([CH2:22][CH3:21])[C:24]([OH:26])=[O:25]

Participants

Conditions

Temperature: 55 °C

Procedure

A mixture of (+) 6,7-dichloro-2-cyclopentyl-2,3-dihydro-5-hydroxy-2-methyl-1H-inden-1-one (14.25 g, 0.046 mole) potassium carbonate (12.5 g, 0.09 mole) and ethyl 4-bromobutanoate (17.5 g, 0.08 mole) in DMF (150 ml) is stirred at 55° C. for 4 hours then poured into ice water and extracted with ether, washed with water and the ether evaporated at reduced pressure. The residual oil is dissolved in acetic acid (150 ml) and 5% hydrochloric acid (50 ml), heated at 95° C. for 21/2 hours, cooled and treated with ie (50 g) to give 17.65 g of (+)[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5-yl)-oxy]butanoic acid which melts at 75°-77° C. [α]D25 (C=2, acetone)=+36.8°.

Workup

extractionextracted with ether
washwashed with water
customthe ether evaporated at reduced pressure
dissolutionThe residual oil is dissolved in acetic acid (150 ml)
temperature5% hydrochloric acid (50 ml), heated at 95° C. for 21/2 hours
temperaturecooled
additiontreated with ie (50 g)

Sources & evidence

ORD record: ord-cfe13803088d4712b3bba5d7947d844c
Source dataset: uspto-grants-1984_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04465850

Reaction notes

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