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Stereoselective Synthesis of Indazole 2′‐Deoxy‐β‐ D ‐ribonucleosides: Glycosylation of the Nucleobase Anion
Author(s) -
Seela Frank,
Bourgeois Werner
Publication year - 1991
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19910740209
Subject(s) - chemistry , indazole , anomer , nucleobase , glycosylation , stereochemistry , stereoselectivity , protonation , adenosine deaminase , medicinal chemistry , catalysis , ion , organic chemistry , enzyme , dna , biochemistry
The glycosylation of indazolyl anions derived from 4a , b with 2‐deoxy‐3,5‐bis‐ O ‐(4‐methylbenzoyl)‐α‐ D ‐ erythro ‐pentofuranosyl chloride ( 5 ) is described. The reaction was Stereoselective – exclusive β‐ D ‐anomer formation – but regioisomeric N 1 ‐ and N 2 ‐(2′‐deoxy‐β‐ D ‐ribofuranosides) ( i.e. 6a and 7a , resp., and 6b and 7b , resp.) were formed in about equal amounts. They were deprotected to yield 8a , b and 9a , b . Compound 1 , related to 2′‐deoxyadenosine ( 3 ), and its regioisomer 2 were obtained from 8b and 9b , respectively, by catalytic hydrogenation. The anomeric configuration as well as the position of glycosylation were determined by 1D NOE‐difference spectroscopy. The first protonation site of 1 and 2 was found to be the NH 2 group. The N ‐glycosylic bond of 1 H ‐indazole N 1 ‐(2′‐deoxyribofuranosides) is more stable than that of the parent purine nucleosides. Compound 1 is no substrate for adenosine deaminase.