Lithium Hydroxide → 4-(2-Tert-butoxycarbonyl-ethyl)-3,5-dimethyl-benzoic acid

HRID 2047295Notes

Reaction equation

C[O:2][C:3](=[O:21])[C:4]1[CH:9]=[C:8]([CH3:10])[C:7]([CH2:11][CH2:12][C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])=[C:6]([CH3:20])[CH:5]=1.[Li+].[OH-]>C(O)C.C(O)(=O)CC(CC(O)=O)(C(O)=O)O>[C:16]([O:15][C:13]([CH2:12][CH2:11][C:7]1[C:8]([CH3:10])=[CH:9][C:4]([C:3]([OH:21])=[O:2])=[CH:5][C:6]=1[CH3:20])=[O:14])([CH3:19])([CH3:18])[CH3:17]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 4-(2-tert-butoxycarbonyl-ethyl)-3,5-dimethyl-benzoic acid methyl ester (10.8 g, 37.0 mmol) in ethanol (100 mL) a 2 M aq. solution of LiOH (50 mL) is added at 0° C. The turbid mixture is stirred at 0° C. for 30 min, then at rt for 4 h. The mixture is diluted with 10% aq. citric acid solution and extracted three times with diethyl ether. The combined org. extracts are dried over MgSO4, filtered and concentrated. The solid residue is suspended in diethyl ether/heptane, stirred at rt, and filtered. The slurry procedure in diethyl ether/heptane is repeated. The solid material is collected and dried under HV to give 4-(2-tert-butoxycarbonyl-ethyl)-3,5-dimethyl-benzoic acid (5.09 g) as a white crystalline powder; LC-MS: tR=0.95 min, [M+1]+=279.14; 1H NMR (CDCl3): δ 1.47 (s, 9H), 2.30-2.40 (m, 2H), 2.39 (s, 6H), 2.94-3.03 (m, 2H), 7.75 (s, 2H).

Workup

waitat rt for 4 h
extractionextracted three times with diethyl ether
dry with materialextracts are dried over MgSO4
filtrationfiltered
concentrationconcentrated
stirringstirred at rt
filtrationfiltered
customThe solid material is collected
customdried under HV

Sources & evidence

ORD record: ord-5ff4e50f9ac347fb94dc0a547f73e87c
Source dataset: uspto-grants-2013_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08592460B2

Reaction notes

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