Triethyl orthoacetate → 7-Cyano-2-methyl-4-nitrobenzoxazole

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Reaction Steps

Compound 477B (0.360 g, 2.01 mmol) and triethyl orthoacetate (1.30 g, 8.04 mmol) were combined and heated at reflux under nitrogen for 1 h. The solvent was removed in vacuo and the resulting residue purified by flash chromatography eluting with 5% ether/CH2Cl2 to give 0.255 g (63%) of compound 477C as a brown solid. HPLC: 98.4% at 1.80 min (retention time) (YMC S5 ODS column, 4.6×50 mm, eluting with 10–90% aqueous methanol over 4 min containing 0.2% phosphoric acid, 4 mL/min, monitoring at 220 nm). MS (ES): m/z 204.28 [M+H]+.

Provenance & Evidence