反应详情

Methyl 3-hydroxy-4-[N-hydroxyethanimidoyl]benzoate (250 mg, 1.19 mmole) is combined with triphenylphosphine (446 mg, 1.7 mmole) in 14 ml dry THF in a dry flask under nitrogen. The solution is treated slowly dropwise with N,N′-diethylazidodicarboxylate (268 mL, 1.7 mmole) in 10 ml dry THF. The reaction is stirred 4 h at rt. The volatiles are removed in vacuo and the residue is chromatographed over 30 g silica gel (230-400 mesh) eluting with 10% EtOAc/hexane. The appropriate fractions are combined and concentrated to provide 125 mg (55%) of methyl 3-methyl-1,2-benzisoxazole-6-carboxylate slightly contaminated (<10%) with methyl 4-acetyl-3-hydroxybenzoate. 1H NMR (CDCl3) δ 2.64, 4.00, 7.70, 8.01, 8.25 ppm.

1. customThe volatiles are removed in vacuo
2. customthe residue is chromatographed over 30 g silica gel (230-400 mesh)
3. washeluting with 10% EtOAc/hexane
4. concentrationconcentrated