REACTION OF ADENINE NUCLEOSIDES, TOSYLATED IN THE CARBOHYDRATE MOIETY, WITH LITHIUM TRIETHYLBOROHYDRIDE

Article abstract of DOI:10.1016/S0040-4020(01)89533-8

The reaction of lithium triethylborohydride with the 2',3'-di-O-p-tolylsulphonyl derivatives of 9-β-D-ribofuranosyladenine, 9-β-D-arabinofuranosyladenine, 9-β-D-xylofuranosyladenine and 9-β-D-lyxofuranosyladenine was studied.The reaction of 2',3'-di-O-p-tolylsulphonyladenosine with LiEt3BH gave 9-(3-deoxy-β-D-threo-pentofuranosyl)adenine.This rearrangement reaction was used for the synthesis of 9-(3,5-dideoxy-β-D-threo-pentofuranosyl)adenine in one step from 2',3',5'-tri-O-p-tolylsulphonyladenosine in 58percent yield.The p-tolylsulphonyl group in the 2'-"up" configuration of unprotected adenine nucleosides was preferentially attacked by LiEt3BH giving S-O-bond scission.This was shown by the formation of 9-(3-deoxy-β-D-threo-pentofuranosyl)adenine from 2',3'-di-O-p-tolylsulphonyl-9-β-D-arabinofuranosyladenine and by the formation of 9-β-D-lyxofuranosyladenine from 2'-O-p-tolylsulphonyl-9-β-D-lyxofuranosyladenine with LiEt3BH. 9-β-D-Lyxofuranosyladenine was synthesized from 3',5'-di-O-benzoyl-9-β-D-xylofuranosyladenosine in 88percent yield using a triflate displacement reaction.