反应详情

A mixture of 4.29 g (28.9 mmol) of 2-(aminomethyl)benzoxazole (PREPARATION 6) and 20 ml of ethyl formate is heated at 80° for 2 hr, after which the excess ethyl formate is removed under reduced pressure. The residue is chromatographed on silica gel (350 ml) eluting with methanol/dichloromethane (2/98), the appropriate fractions are pooled and concentrated to give the product, which is crystallized from dichloromethane/hexane to give the title compound, mp 98°-99°; MS (m/z) at 176; IR 1655, 1621, 1519, 1241, 750 cm-1 ; NMR (CDCl3) 4.81, 6.45, 7.36, 7.53, 7.70, 8.39 δ.

1. temperatureis heated at 80° for 2 hr
2. customafter which the excess ethyl formate is removed under reduced pressure
3. customThe residue is chromatographed on silica gel (350 ml)
4. washeluting with methanol/dichloromethane (2/98)
5. concentrationconcentrated
6. customto give the product, which
7. customis crystallized from dichloromethane/hexane