3′-Selective modification of a 4′,5′-didehydro-5′-deoxy-2′,3′-epoxyuridine using nucleophiles
摘要:
1-(2,3-Anhydro-5-deoxy-4,5-didehydro-alpha-(L)-erythro-pent-4-enofuranosyl)uracil 4 was obtained by the treatment of 5 '-iodo-2 ',3 '-epoxyuridine 5 with LiHMDS in excellent yield. The pyrimidine nucleoside 4 possesses quite unique vinyl epoxide moiety within the molecules. The reactions of 4 with a variety of nucleophiles gave 3 '-substituted pyrimidine nucleosides without the formation of the corresponding 2 '-substituted isomers. In the case of NaN3 or PhSH, the corresponding 5 '-adduct was obtained as a minor product together with the expected 3 '-adduct. (c) 2005 Elsevier Ltd. All rights reserved.
Formation of 4’,5’-Didehydro-5’-deoxy-3’-O-methyluridine via Regioselective Nucleophilic Addition of Methoxide Anion to 2’,3’-Anhydro-5’-dehydro-5’-iodouridine
摘要:
Treatment of 2',3'-anhydro-5'-deoxy-5'-iodouracil (1) with sodium methoxide regioselectively provided 4',5'-didehydro-5'-deoxy-3'-O-methyl-uridine (2) as the sole product via 4',5'-didehydro-5'-deoxy-2',3'-epoxyuridine (6) as an intermediate.