反应详情

Compound 73 (32 gm, 0.1 mol) was added to a well stirred suspension of 2′, 3′-isopropylidene adenosine-5′-carboxylic acid (36.5 gm, 0.11 mol), DCC (24.5 gm, 0.118 mol), N-hydroxy-succinimide (11.87 gm, 0.11 mol) in DMF (200 ml), and was followed by the addition of diisopropyl ethylamine (40 ml, 0.22 mol) at room temperature. The reaction mixture became clear after the addition of diisopropyl ethylamine, and urea started precipitating after some time. The reaction was left at room temperature for 3 days. The white precipitate of urea was filtered and washed thoroughly with DMF. The filtrate was concentrated under vacuum to remove diisopropyl ethylamine, and then treated with acetic acid (2 eq.) to break the DCC complex. Again, the solid was filtered and discarded. The filtrate was concentrated under high vacuum at 60° C., and the residue was purified on the silica gel column using 8% CH3OH—CH2Cl2 to give a of 2′,3′-isopropylidene adenosine protected derivative of compound 130.

1. customstarted precipitating after some time
2. filtrationThe white precipitate of urea was filtered
3. washwashed thoroughly with DMF
4. concentrationThe filtrate was concentrated under vacuum
5. customto remove diisopropyl ethylamine
6. filtrationAgain, the solid was filtered
7. concentrationThe filtrate was concentrated under high vacuum at 60° C.
8. customthe residue was purified on the silica gel column