Showing papers by "Zygmunt Kazimierczuk published in 1984"

Total synthesis of certain 2-, 6-mono- and 2,6-disubstituted-tubercidin derivatives. Synthesis of tubercidin via the sodium salt glycosylation procedure

Abstract: Direct glycosylation of the sodium salt of 4,6-dichloro- or 4,6-dibromo-2-methylthiopyrrolo[2,3-d]pyrimidine with 2,3,5-tri-O-benzoyl-D-ribofuranosyl bromide gave good yield of the corresponding N7-glycosylated pyrrolo [2,3-d]pyrimidine. The intermediate 4-amino-6-chloro-2-methylthio-7-beta-D-ribofuranosylpyrrolo[2,3-d] pyrimidine provided a new synthetic route to tubercidin, via 6-chlorotubercidin. 6-Chloro-2-methoxytubercidin was also obtained from 10 via the methylsulfone. Application of this glycosylation procedure to 4,6-dichloro- or 4,6-dibromo-2-methylpyrrolo [2,3-d]-pyrimidine also furnished the corresponding N7-glycosyl derivatives with beta-configuration. Dehalogenation of gave 2-methyl-tubercidin and bromination with bromine in a buffered solution gave 5,6-dihalo-2-methyltubercidin. Several new 2,6-disubstituted tubercidin derivatives were prepared from these glycosyl intermediates. This new sodium salt glycosylation procedure was found to be superior to other procedures for the total synthesis of these halogenated 7-deazapurine nucleosides.

Acyclonucleosides: acyclobenzimidazole nucleoside and nucleotide analogues and conformations of the acyclic chains by means of NMR spectroscopy.

Abstract: A number of acyclo nucleosides of benzimidazole derivatives has been synthesized, in which the benzimidazole ring includes substituents at C(5), C(6) and C(2). The acyclic chains which replace the sugar moiety are 2',3'-dihydroxypropyl, 2'-hydroxyethoxymethyl and 1',5'-dihydroxy-4'-hydroxymethyl-3'- oxypentyl -2' (R), each of which corresponds to some fragment of the ribose ring. 1H NMR spectroscopy has been employed to determine the conformations of these acyclic chains in solutions of fully deuterated dimethylsulfoxide and methanol, utilizing for this purpose vicinal proton-proton coupling constants, and the new Karplus relation developed by Haasnoot , de Leeuw & Altona ( Tetrahedron , 36, 2783-2792, 1980). The data thus obtained are compared with those available for the solid state from X-ray diffraction data, and should be applicable to other classes of acyclonucleosides . Nucleotides of the three types of acyclo benzimidazole nucleosides have also been prepared, and their susceptibilities to snake venom 5'-nucleotidase examined. In contrast to acycloG , the nucleoside analogues did not exhibit significant in vitro activity against herpes simplex virus type 1 or influenza virus.