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3. Dimethylaminomethylene-��-D-xylo-hept-5-ulofuranurononitrile as building block in the synthesis of 'reversed' C-nucleoside analogues

Author

Hashmi, I.A., Feist, H., Michalik, M., Reinke, H., and Peseke, K.

Subjects
Pyrazolo[1,5-a]pyrimidines, Pyrimidines, 5-Aminopyrazoles, Reversed' C-Nucleoside Analogues, Benzo[4,5]imidazo[1,2-a]pyridine
Abstract

3-O-Benzyl-6-deoxy-1,2-O-isopropylidene-6-(dimethylaminomethylene) -��-D-xylo-hept-5-ulofuranurononitrile (1) was reacted with amidinium salts, S-methylisothiouronium sulfate, and guanidinium chloride, respectively, in the presence of bases to furnish the 4-(3-O-benzyl-1,2-O-isopropylidene- ��-D-xylo-tetrofuranos-4-yl)pyrimidine-5-carbonitriles 2 and the 4-(1,2-O-isopropylidene-��-D-glycero-tetr-3-enofuranos-4-yl) pyrimidine-5-carbonitriles 3, respectively. Treatment of 1 with ethyl 5-aminopyrazole-4-carboxylates yielded the ethyl 7-(3-O-benzyl-1,2-O- isopropylidene-��-D-xylo-tetrofuranos-4-yl)-6-cyanopyrazolo[1,5-a] pyrimidine-3-carboxylates 4 and the ethyl 7-amino-6-(3-O-benzyl-1,2-O- isopropylidene-��-D-xylo-pentofuranuronoyl)pyrazolo[1,5-a] pyrimidine-3-carboxylates 5, respectively. Reaction of 1 with 2-benzimidazolylacetonitrile in the presence of sodium methanolate afforded 1-amino-2-(3-O-benzyl-1,2-O-isopropylidene-��-D-xylo-pentofuranuronoyl) benzo[4,5]imidazo[1,2-a]pyridine-4-carbonitrile (6) and 1-amino-2-(3-deoxy-1,2- O-isopropylidene-��-D-glycero-pent-S-enofuranuronoyl)benzo[4,5]imidazo[1, 2-a]pyridine-4-carbonitrile (7). �� 2006 Verlag der Zeitschrift f��r Naturforschung.

Published
2006
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4. Synthesis of iso-C-nucleoside analogues from 1-(methyl 2-O-benzyl-4,6-O- benzylidene-3-deoxy-��-D-altropyranosid-3-yl)but-3-yn-2-ones

Author

Otero, I., Feist, H., Michalik, D., Michalik, M., Quincoces, J., and Peseke, K.

Subjects
Benz[4,5]imidazo[1,2-a]pyridine, Pyrazolo[1,5-a]pyrimidine, Glycosylalkynone, C-Nucleoside Analogues, 1,2-Dihydropyridin-2-one
Abstract

1-(Methyl 2-O-benzyl-4,6-O-benzylidene-3-deoxy-��-D-altropyranosid-3- yl)but-3-yn-2-one (3a) reacted with 3-amino-1H-1,2,4-triazole and 5-aminopyrazole-4-carboxylic acid derivatives in the presence of base to furnish the triazolo[1,5-a]pyrimidine (5) and the pyrazolo[1,5-a]pyrimidines (8a-d), respectively. Treatment of 1-(methyl 2-O-benzyl-4,6-O-benzylidene-3-deoxy- ��-D-altropyranosid-3-yl)-4-phenyl-but-3-yn-2-one (3b) with cyanacetamide, 2-cyano-N-(4-methoxyphenyl)acetamide und N-aryl-3-oxo-butyramides afforded the substituted nicotinonitriles (11a-d). Furthermore, reaction of 3b with 2-benzimidazolyl-acetonitrile yielded the benz[4,5]imidazo[1,2-a]pyridine-4- carbonitrile (13). Deprotection of 8d in two steps afforded the 2-amino-N-benzyl-5-(methyl 3-deoxy-��-D-altropyranosid-3-yl-methyl) pyrazolo[1,5-a]pyrimidine-3-carboxamide (10). Compounds 5 and 11d were treated with AcOH/H2O to furnish the 5-(methyl 2-O-benzyl-3-deoxy-��-D- altropyranosid-3-yl-methyl)[1,2,4]triazolo[1,5-a]pyrimidine (6) and the 3-acetyl-1,2-dihydro-1-(4-methoxyphenyl)-6-(methyl 2-O-benzyl-3-deoxy-��-D- altropyranosid-3-yl-methyl)-4-phenylpyridin-2-one (12), respectively.

Published
2005
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