Hydrochloric Acid → 3,5-Diisopropoxybenzoic acid-1G

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Reaction Steps

Crude isopropoxybenzoate from above (compound E) was dissolved in 200 mL THF/H2O (1:1) in a 500 mL flask. Excess lithium hydroxide (10 g) was added and the reaction refluxed for over 48 hours. The mixture was cooled, acidified with HCl to pH 2, then extracted with several portions of diethyl ether. The organic layers were washed with brine, dried over MgSO4, and concentrated to a white solid in 55% yield over 2 steps: IR (cm−1): 3064, 2978, 2933, 2639, 1693, 1594, 1300, 1158, 1114, 1040, 767; 1H NMR (250 MHz, CD3OD): δ 1.30 (dd, J=2.3, 5.9 Hz, 12H), 4.59 (qn, J=6.2 Hz, 2H), 6.61 (t, J=2.3 Hz, 1H), 7.10 (d, J=2.5 Hz, 2H); 13C NMR (63 MHz, CD3OD): 22.2 (4C), 71.2 (2C), 109.8, 109.9, 133.8, 160.3 (2C), 169.7.

Provenance & Evidence