title: 2',3'-Dideoxy-3'-C,2'-N-[(3R,5R)-5-ethoxy-carbonyl-2-methyl-1, 2-isoxazolidine]-ribothymidine.
abstract: The title compound, C15H21N3O7, is a thymidine derivative with a tetrahydroisoxazole (THI) ring fused to the sugar ring at the 2'- and 3'-C atoms. The thymine base is in an anti conformation [chi = -122.5 (3) degrees] while the ribose moiety has C2'-exo,C3'-endo (3T2) conformation with a highly flattened sugar ring [P = -5.8, tau m = 13.1 degrees]. The molecule contains a pseudo-twofold axis on the C2'-C3' bond with the ethyl ester group acting as the base and the N-methyl group acting as the 5'-hydroxyl group in a nucleoside. The THI ring fused to the furanose has a C3'-endo,C4'-exo (3T4) conformation [P = 4.18, tau m = 19.3 degrees]. The ethyl ester moiety is disordered with respect to two conformations, the population of the major form being 87.4 (8)% and that of the minor form 12.6 (8)%.
authors.affiliation: Department of Chemistry, Ohio State Univeristy, Columbus 43210, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Burkhart
authors.forename: A
authors.initials: A
authors.lastname: Papchikhin
authors.forename: J
authors.initials: J
authors.lastname: Chattopadhyaya
authors.forename: M
authors.initials: M
authors.lastname: Sundaralingam
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007555:Isoxazoles / Q000737:chemistry*; D015394:Molecular Structure; D013936:Thymidine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C096579:2',3'-dideoxy-3'-C,2'-N-(5-ethoxycarbonyl-2-methyl-1,2-isoxazolidine)ribothymidine; D000998:Antiviral Agents; D007555:Isoxazoles; D013936:Thymidine