反应详情

To dry methanol (285 mL) is carefully added K-tert.-butylate (28.28 g, 252 mmol) followed by hydroxylamine hydrochloride (15.0 g, 216 mmol). The suspension is stirred for 30 min before 4-hydroxybenzonitrile (8.58 g, 72 mmol) is added. The mixture is refluxed for 40 h, the solvent is evaporated and the residue is acidified by adding 2 N aq. HCl. The solution is extracted twice with DCM (100 mL). The aq. layer is basified by adding solid NaHCO3. The product precipitates, is filtered off, washed with water and dried to give 4,N-dihydroxy-benzamidine (7.6 g) as a brownish solid; 1H NMR (D6-DMSO): δ 9.57 (s, 1H), 9.33 (s, 1H), 7.48-7.42 (m, 2H), 6.74-6.68 (m, 2H), 5.62 (s, 2H).

1. additionis added
2. temperatureThe mixture is refluxed for 40 h
3. customthe solvent is evaporated
4. additionby adding 2 N aq. HCl
5. extractionThe solution is extracted twice with DCM (100 mL)
6. additionby adding solid NaHCO3
7. customThe product precipitates
8. filtrationis filtered off
9. washwashed with water
10. customdried