Toluene → t-butyl 3-bromo-4-methylbenzoate
Reaction equation
COC(OC)N(C)C.[Br:9][C:10]1[CH:11]=[C:12]([CH:16]=[CH:17][C:18]=1[CH3:19])[C:13]([OH:15])=[O:14].[C:20]1([CH3:26])[CH:25]=CC=C[CH:21]=1>>[Br:9][C:10]1[CH:11]=[C:12]([CH:16]=[CH:17][C:18]=1[CH3:19])[C:13]([O:15][C:20]([CH3:26])([CH3:25])[CH3:21])=[O:14]Participants
Conditions
- Temperature
- 75 °C
Procedure
Dimethylformamide dimethyl acetal (48 mL, 200 mmol) was added dropwise over 15 min to a suspension of 3-bromo-4-methylbenzoic acid (85%; 10.75 g, 42.5 mmol) in toluene (100 mL) at 70° C. The reaction was stirred at 70-80° C. for an additional 0.5 h, then was cooled, washed sequentially with water and 5% sodium bicarbonate, and dried (sodium sulfate). The mixture was filtered through a pad of silica gel, and the filter pad was washed with toluene. The filtrate was concentrated to afford the title compound (8.0 g, 69% ) as a yellow oil. TLC (toluene) Rf 0.68; 1H NMR (250 MHz, CDCl3) δ8.13 (d, J=1.7 Hz, 1H), 7.81 (dd, J=7.9, 1.7 Hz, 1H), 7.27 (d, J=7.9 Hz, 1H), 2.44 (3H), 1.59 (s, 9H); IR (CCl4) 1715, 1368, 1297, 1255, 1170, 1123, 1115 cm−1; MS(ES) m/e 273.0 [M+H]+, 271.0 [M+H]+, 214.8 (M+H−56)+.
Workup
- temperaturewas cooled
- washwashed sequentially with water and 5% sodium bicarbonate
- dry with materialdried (sodium sulfate)
- filtrationThe mixture was filtered through a pad of silica gel
- washthe filter pad was washed with toluene
- concentrationThe filtrate was concentrated
Sources & evidence
- ORD record
- ord-89643ac554324cc0b474780292f2c848
- Source dataset
- uspto-grants-2002_06
- Patent number
- US06403578B1
Reaction notes
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