反应详情

To a solution of 2-amino-9-(2,3,5-tri-O-benzyl-β-D-arabinofuranosyl)adenine (14.5 g, 26.2 mmol) in a mixture of 500 ml tetrahydrofuran and 1 l. of 48% fluoboric acid at -15° in a 4-l. beaker equipped with a mechanical stirrer was added dropwise in 20 min a saturated aqueous solution of NaNO2 (7.2 g, 105 mmol). The addition of NaNO2 (5.4 g, 78.6 mmol) was repeated three times after which none of the 2-aminoadenine remained (TLC). The fluoroboric acid was neutralized with 50% NaOH keeping the temperature between -40 and 0°. The solution was extracted four times with CHCl3 (300 ml, 250 ml, and two 200-ml portions). The CHCl3 extract was washed with saturated NaCl solution and then dried over MgSO4 before it was evaporated to dryness in vacuo. The residual oil was dissolved in a liter of ethanolic NH3 (saturated at 0° ), and the solution was allowed to stand for three days at 0° before it was evaporated to dryness. The residue was recrystallized from 100 ml EtOH; yield 4.7 g. Additional material was recovered from the filtrate by recrystallization and preparative TLC. The total yield was 5.8 g (40%).

1. customat -15°
2. custombeaker equipped with a mechanical stirrer
3. customthe temperature between -40 and 0°
4. extractionThe solution was extracted four times with CHCl3 (300 ml, 250 ml, and two 200-ml portions)
5. extractionThe CHCl3 extract
6. washwas washed with saturated NaCl solution
7. dry with materialdried over MgSO4 before it
8. customwas evaporated to dryness in vacuo
9. dissolutionThe residual oil was dissolved in a liter of ethanolic NH3 (saturated at 0° )
10. customwas evaporated to dryness
11. customThe residue was recrystallized from 100 ml EtOH
12. customAdditional material was recovered from the filtrate by recrystallization and preparative TLC