Enantiomeric forms of 9-(5-deoxy-beta-erythro-pent-4-enofuranosyl)adenine and a new preparation of 5-deoxy-D-lyxose

Abstract

Methyl 5-deoxy-5-iodo-2,3-O-isopropylidene-beta-D-ribofuranoside (3) was obtained in three steps from D-ribose. Exchange of the isopropylidene group for benzoate groups and acetolysis gave 1-O-acetyl-2,3-di-O-benzoyl-5-deoxy-5-iodo-D-ribofuranose which was coupled with 6-benzamidochloromercuripurine by the titanium tetrachloride method to afford the blocked nucleoside. Treatment with 1,5-diazabicyclo[5.4.0]undec-5-ene in N,N-dimethylformamide and removal of the blocking groups have 9-(5-deoxy-beta-D-erythro-pent-4-enofuranosyl)adenine (9). A similar route starting from methyl 5-deoxy-5-iodo-2,3-O-isopropylidene-alpha-D-lyxofuranoside (14) afforded the enantiomeric nucleoside, 9-(5-deoxy-beta-L-erythro-pent-4-enofuranosyl)adenine (20). Methyl 2,3-O-isopropylidene-alpha-D-mannofuranoside was treated with sodium periodate and then with sodium borohydride to give methyl 2,3-O-isopropylidene-alpha-D-lyxofuranoside (11). Acid hydrolysis afforded D-lyxose. Tosylation of 11 gave methyl 2,3-O-isopropylidene-5-O-p-tolylsulfonyl-alpha dp-lyxofuranoside (12) which was converted into 14 with sodium iodide in acetone. Reduction of 12 gave methyl 5-deoxy-2,3-O-isopropylidene-alpha-D-lyxofuranoside which was hydrolyzed to give 5-deoxy-D-lyxose.