ClC(Cl)(Cl)C(OC(=O)C(Cl)(Cl)Cl)=O.CS(C)=O.[C:18]([Si:22]([C:49]1[CH:54]=[CH:53][CH:52]=[CH:51][CH:50]=1)([C:43]1[CH:48]=[CH:47][CH:46]=[CH:45][CH:44]=1)[O:23][CH:24]1[CH:28]([CH2:29][OH:30])[O:27][CH:26]([N:31]2[CH:36]=[CH:35][C:34](=[O:37])[NH:33][C:32]2=[O:38])[CH:25]1[O:39][C:40](=[O:42])[CH3:41])([CH3:21])([CH3:20])[CH3:19].C(N(CC)CC)C>ClCCl.C(OCC)(=O)C>[C:18]([Si:22]([C:49]1[CH:54]=[CH:53][CH:52]=[CH:51][CH:50]=1)([C:43]1[CH:44]=[CH:45][CH:46]=[CH:47][CH:48]=1)[O:23][CH:24]1[CH:28]([CH:29]=[O:30])[O:27][CH:26]([N:31]2[CH:36]=[CH:35][C:34](=[O:37])[NH:33][C:32]2=[O:38])[CH:25]1[O:39][C:40](=[O:42])[CH3:41])([CH3:19])([CH3:20])[CH3:21]To a mixture of trichloroacetic anhydride (1.5 eq.) and dimethylsulfoxide (2.0 eq.) in dichloromethane at −78° C. is added a solution of Compound 9 in dichloromethane. After 30 minutes, triethylamine (4.5 eq.) is added. Subsequently, the mixture is poured into ethyl acetate, washed with water and brine, dried over anhydrous sodium sulfate, and evaporated to dryness. The resulting material is carried into the next step without further purification. This procedure has been used to prepare the related 4′-C-α-formyl nucleosides (Nomura, M., et. al., J. Med. Chem. 1999, 42, 2901-2908).
読み込み中…