Benzoin acetate → Oxazole, 2-methyl-4,5-diphenyl-

HRID 1753717Notes

Reaction equation

[C:1]([O:4][CH:5]([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)[C:6](=O)[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1)(=O)[CH3:2].[NH2:20]C(N)=S>CN(C=O)C.ClCCl>[CH3:2][C:1]1[O:4][C:5]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[C:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[N:20]=1

Participants

Conditions

Temperature: 160 °C

Procedure

2-Oxo-1,2-diphenylethyl acetate 24 (0.20 g, 0.79 mmol) was dissolved in DMF (10 mL). Thiourea was then added and the reaction was refluxed (160° C., oil bath) under nitrogen atmosphere. As the reaction progressed, the color changed from colorless to a light yellow-orange and had an odorous smell. The reaction was monitored by TLC and when complete, the reaction mixture was dissolved in dichloromethane (40 mL) and then washed with water (3×30 mL). The dichloromethane layer was separated and dried over anhydrous sodium sulfate. Removal of the drying agent by filtration and rotary evaporation of the solvent gave a crude oil that was purified by flash chromatography on silica gel (dichloromethane) to provide 25 (74%): Rf: 0.098 (hexane/ethyl acetate, 2:1); FTIR 2920.50; 1220.30; 1502.00, 1588.24 cm−1; 1H NMR (400 MHz, CDCl3) δ: 2.617 (s, 3H); 7.25-7.66 (m, 10H, aromatic); 13C NMR (100 MHz, CDCl3) δ 160.35, 145.41, 134.82, 126.46-132.14, 13.92; HRMS calcd for C16H13NO (M+H)+ 236.1075, Found: 236.1077.

Workup

washwashed with water (3×30 mL)
customThe dichloromethane layer was separated
dry with materialdried over anhydrous sodium sulfate
customRemoval of the drying agent
filtrationby filtration and rotary evaporation of the solvent
customgave a crude oil that
customwas purified by flash chromatography on silica gel (dichloromethane)

Sources & evidence

ORD record: ord-dfc22bd7daf34ef78351b34a5a09ea22
Source dataset: uspto-grants-2015_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09167820B2

Reaction notes

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