Peracetylated 6-thioguanosine (2) undergoes the so far unknown N-->S transglycosylation reaction to form a stable 9,S-6-bis(ribosyl) derivative (3) and N-2-acetyl-6-thioguanine (4). The reaction takes place at elevated temperatures with no catalyst, or in solution in the presence of acidic catalysts. The reversible 7 reversible arrow 9 isomerization, characteristic for guanosine and its analogs, has not been observed in this case.
Transglycosylation Reactions of 6-Thioguanine Acyclonucleosides
作者:Andrzej Manikowski、Jerzy Boryski
DOI:10.1080/15257770008045447
日期:2000.10
9-(2-Acetoxyethoxy)methyl-N-2-acetyl-6-thioguanine (2) undergoes two different transglycosylation reactions: i) the 7 reversible arrow 9 isomerization, which gives the respective 7-regioisomer (3) as the major product ii) the 9 reversible arrow S-6 glycosyl migration, which leads to a 9,S-6-disubstituted product (4). S-6-Methylation completely stopped the reversibility of transglycosylation.