title: 7-Functionalized 7-deazapurine ribonucleosides related to 2-aminoadenosine, guanosine, and xanthosine: glycosylation of pyrrolo[2,3-d]pyrimidines with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose.
abstract: [reaction: see text] The Silyl-Hilbert-Johnson reaction as well as the nucleobase-anion glycosylation of a series of 7-deazapurines has been investigated, and the 7-functionalized 7-deazapurine ribonucleosides were prepared. Glycosylation of the 7-halogenated 6-chloro-2-pivaloylamino-7-deazapurines 9b-d with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (5) gave the beta-D-nucleosides 11b-d (73-75% yield), which were transformed to a number of novel 7-halogenated 7-deazapurine ribonucleosides (2b-d, 3b-d, and 4b-d) related to guanosine, 2-aminoadenosine, and xanthosine. 7-Alkynyl derivatives (2e-i, 3e-h, or 4g) have been prepared from the corresponding 7-iodonucleosides 2d, 3d, or 4d employing the palladium-catalyzed Sonogashira cross-coupling reaction. The 7-halogenated 2-amino-7-deazapurine ribonucleosides with a reactive 6-chloro substituent (18b-d) were synthesized in an alternative way using nucleobase-anion glycosylation performed on the 7-halogenated 2-amino-6-chloro-7-deazapurines 13b-d with 5-O-[(1,1-dimethylethyl)dimethylsilyl]-2,3-O-(1-methylethylidene)-alpha-D-ribofuranosyl chloride (17). Compounds 18b-d have been converted to the nucleosides 19b-d carrying reactive substituents in the pyrimidine moiety. Conformational analysis of selected nucleosides on the basis of proton coupling constants and using the program PSEUROT showed that these ribonucleosides exist in a preferred S conformation in solution.
authors.affiliation: Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie, Universität Osnabrück, Barbarastr. 7, D-49069 Osnabrück, Germany. frank.seela@uni-osnabrueck.de
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Peng
mesh_terms: D000241:Adenosine / Q000737:chemistry*; D000586:Amination; D000838:Anions / Q000737:chemistry; D001372:Aza Compounds / Q000737:chemistry*; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D006031:Glycosylation; D006151:Guanosine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009005:Monosaccharides / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry; D011687:Purines / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D012263:Ribonucleosides / Q000737:chemistry*; D014970:Xanthines
chemical_list: C511842:1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose; D000838:Anions; D001372:Aza Compounds; D009005:Monosaccharides; D011687:Purines; D011743:Pyrimidines; D012263:Ribonucleosides; D014970:Xanthines; D006151:Guanosine; D010165:Palladium; C005893:xanthosine; D000241:Adenosine; C030986:pyrimidine; C030985:purine