Oxalyl chloride → 2-p-Tolylbenzo[d]oxazole-4-carboxamide

HRID 415171Notes

Reaction equation

C(Cl)(=O)C(Cl)=O.[C:7]1([CH3:25])[CH:12]=[CH:11][C:10]([C:13]2[O:14][C:15]3[C:16](=[C:18]([C:22](O)=[O:23])[CH:19]=[CH:20][CH:21]=3)[N:17]=2)=[CH:9][CH:8]=1.O.[NH3:27]>ClCCl>[C:7]1([CH3:25])[CH:12]=[CH:11][C:10]([C:13]2[O:14][C:15]3[C:16](=[C:18]([C:22]([NH2:27])=[O:23])[CH:19]=[CH:20][CH:21]=3)[N:17]=2)=[CH:9][CH:8]=1

Participants

Conditions

Temperature: 50 °C

Procedure

Oxalyl chloride (0.04 g, 0.3 mmol) was slowly added to a solution of 2-p-tolylbenzo[d]oxazole-4-carboxylic acid (0.064 g, 0.25 mmol) in dichloromethane (10 mL) with stirring. The reaction mixture was warmed to 50° C. for 4 hr and then cooled to 25° C. The solution was condensed in vacuum and then slowly added to 28% ammonia water (10 mL) and a solid precipitated out immediately. The mixture was warmed to 50° C. and stirred for another 2 hr. Water (20 mL) was added to the mixture and the slurry was cooled to 25° C. The product was filtered and the cake was washed with water, dried to afford 44 mg 2-p-tolylbenzo[d]oxazole-4-carboxamide as a solid (yield 69.8%). 1H-NMR (400 MHz, DMSO-d6) δ 2.46 (s, 3H), 6.01 (s, 1H), 7.34-7.36 (d, J=7.6 Hz, 2H), 7.43-7.47 (t, J=8.0 Hz, 1H), 7.71-7.73 (d, J=8.0 Hz, 1H), 8.15-8.18 (m, 3H), 9.02 (s, 1H); LC-MS (ESI) m/z 253 [M+1]+.

Workup

temperaturecooled to 25° C
customcondensed in vacuum
customa solid precipitated out immediately
temperatureThe mixture was warmed to 50° C.
stirringstirred for another 2 hr
additionWater (20 mL) was added to the mixture
temperaturethe slurry was cooled to 25° C
filtrationThe product was filtered
washthe cake was washed with water
customdried

Sources & evidence

ORD record: ord-c71f23b292ef42dcbe5dfc3fa33e0836
Source dataset: uspto-grants-2012_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08088760B2

Reaction notes

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