反应详情

Guanidine·HCl (2.66 g, 27.8 mmol) was added to a solution of NaOMe (sodium methoxide) (1.50 g, 27.8 mmol) in absolute EtOH (180 mL). The mixture was stirred at 20°-23° C. for 15 minutes before 5 (2.00 g, 13.9 mmol) was added. After a 24-hour reflux period with rapid stirring, TLC (cyclohexane-EtOAc, 1:1) showed absence of 5. The solid filtered from the cooled mixture was washed on the funnel with H2O and EtOH; yield 95% (2.45 g). A sample of this material (1.0 g) was stirred with near-boiling Me2SO (dimethyl sulfoxide) (250 mL), and the slightly cloudy solution was filtered (Celite) to give a clear, pale-yellow filtrate which was then concentrated by evaporation in vacuo (to about 60 mL). Addition of EtOH (200 mL) gave 7 as a light yellow solid (880 mg); 1H NMR (Me2SO-d6) δ6.97 (2, NH2), 7.84 (s, NH2), 8.87 and 8.91 (two d, 5-H and 7-H, J=2 Hz).

1. additionwas added
2. filtrationThe solid filtered from the cooled mixture
3. washwas washed on the funnel with H2O and EtOH
4. filtrationthe slightly cloudy solution was filtered (Celite)
5. customto give a clear, pale-yellow filtrate which
6. concentrationwas then concentrated by evaporation in vacuo (to about 60 mL)
7. additionAddition of EtOH (200 mL)