title: Synthesis and conformational analysis of 1,2-cis fused bicyclic α-d-galactofuranosyl thiocarbamate from per-O-tert-butyldimethylsilyl-β-d-galactofuranosyl isothiocyanate.
abstract: Per-O-tert-butyldimethylsilyl-α,β-d-galactofuranosyl isothiocyanate (4) was synthesized by the reaction of per-O-TBS-β-d-galactofuranose (1) with KSCN, promoted by TMSI. Upon O-desilylation (1,2-dideoxy-α-d-galactofuranoso)[1,2d]-1,3-oxazolidine-2-thione (6), the cis-fused bicyclic thiocarbamate was obtained as the only product. Conformational analysis, aided by molecular modelling, showed two stable twist forms ((3)T(4) and (4)T(O)) for the five-membered sugar ring in 6. In aqueous solution, the equilibrium favours the first conformation (3:1 ratio). On the other hand, this ratio decreases for less polar solvents.
authors.affiliation: CIHIDECAR-CONICET, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Pabellón II, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
authors.forename: Luciana
authors.initials: L
authors.lastname: Baldoni
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Stortz
authors.forename: Carla
authors.initials: C
authors.lastname: Marino
mesh_terms: D005690:Galactose / Q000031:analogs & derivatives* / Q000737:chemistry; D017879:Isothiocyanates / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D017646:Organosilicon Compounds / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D013859:Thiocarbamates / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D017879:Isothiocyanates; D017646:Organosilicon Compounds; D010080:Oxazoles; D013859:Thiocarbamates; D005690:Galactose