Synthesis of 1-(3-Azido-2,3-dideoxy-4-C-hydroxymethyl-α-L-threo-pentofuranosyl)thymine, 1-(2,3-Dideoxy-4-C-hydroxymethyl-α-L-glycero-pentofuranosyl)thymine and 1-(2,3-Dideoxy-4-C-hydroxymethyl-α-L-glycero-pent-2-enofuranosyl)thymine

Abstract

1-(2-O-Acetyl-3,5-di-O-benzoyl-4-C-benzoyloxymethyl-α-L-arabinofuranosyl)thymine (II) was converted to 2,2'-anhydro derivative V by selective deacetylation, mesylation and treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene. Cleavage of 2,2'-anhydro ring in compound V with hydrogen chloride or bromide afforded the respective 2'-chloro and 2'-bromo derivatives VI and VII. Reaction of compound VII with Cu/Zn couple and subsequent debenzoylation led to 1-(2,3-dideoxy-4-C-hydroxymethyl-α-L-pent-2-enofuranosyl)thymine (IX). Catalytic hydrogenation of IX gave 1-(2,3-dideoxy-4-C-hydroxymethyl-α-L-glycero-pentofuranosyl)thymine (X). Dehalogenation of compound VI with tributyltin hydride and debenzoylation afforded 1-(2-deoxy-4-C-hydroxymethyl-α-L-erythro-pentofuranosyl)thymine (XII). Tritylation of compound XII, followed by mesylation, detritylation and nucleophilic substitution with azide furnished 1-(3-azido-2,3-dideoxy-4-C-hydroxymethyl-α-L-threo-pentofuranosyl)thymine (XXII).