2,4,5-Trimethylbenzoic Acid → HCID 22117219, compound

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Reaction Steps

A solution of the product of step (i)(36.7 g) in tetrahydrofuran (300 ml) was added dropwise to a stirred solution of lithium diisopropylamide (235 ml of a 2.0M solution in heptane) at 10-20° C. The mixture was allowed to warm to room temperature and stirred for 30 minutes then cooled to -20° C. A solution of 3-methylbenzylbromide (36.2 ml) in tetrahydrofuran (100 ml) was added dropwise over 20 minutes. The mixture was allowed to warm to room temperature and stirred for 45 minutes before quenching with 2M HCl and adding ethyl acetate. The organic phase was washed with brine, dried (MgSO4) and concentrated under reduced pressure to 200 ml. Isohexane (200 ml) was added and the crystallised unreacted starting material filtered off. The filtrate was evaporated and the residue partitioned between 2M sodium hydroxide and isohexane. The aqueous phase was acidified to pH 1 with 2M HCl and extracted with dichloromethane. The extract was dried (MgSO4) and evaporated under reduced pressure. Used directly in the next step.

Provenance & Evidence