反应详情

The product of step (a) (300 mg, 1.0 mmol) was dissolved in DMF (3 ml) and a solution of sodium dithionite hydrate added (500 mg, 2.9 mmol in 6 ml of H2O). The solution became warm and some solid precipitated out of solution. After stirring for 30 min at room temperature, 15 ml of H2O and 2N HCl were added. This mixture was extracted with EtOAc (2×30 ml), neutralised using 2N NaOH and re-extracted with EtOAc (2×30 ml). The combined EtOAc extracts were dried over MgSO4 and the solvent removed to give the crude product. This was purified on silica gel, eluting with CH2Cl2 /MeOH (98/2, v/v) to give the subtitle compound as colourless gum (190 mg, 74%). Rf 0.29 (hexane/ether 1/1, v/v). MS m/e 276 and 278 (MNH4+).

1. temperatureThe solution became warm
2. customsome solid precipitated out of solution
3. addition15 ml of H2O and 2N HCl were added
4. extractionThis mixture was extracted with EtOAc (2×30 ml)
5. extractionre-extracted with EtOAc (2×30 ml)
6. dry with materialThe combined EtOAc extracts were dried over MgSO4
7. customthe solvent removed
8. customto give the crude product
9. customThis was purified on silica gel
10. washeluting with CH2Cl2 /MeOH (98/2