ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Intensive studies on the diazomethane methylation of the common ribonucleosides uridine, cytidine, adenosine, and guanosine and its derivatives were performed to obtain preferentially the 2′-O-methyl isomers. Methylation of 5′-O-(monomethoxytrityl)-N2-(4-nitrophenyl)ethoxycarbonyl-O6-[2-(4-nitrophenyl)ethyl]-guanosine (1) with diazomethane resulted in an almost quantitative yield of the 2′- and 3′-O-methyl isomers which could be separated by simple silica-gel flash chromatography (Scheme 1). Adenosine, cytidine, and uridine were methylated with diazomethane with and without protection of the 5′ -O-position by a mono- or dimethoxytrityl group and the aglycone moiety of adenosine and cytidine by the 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) group (Schemes 2-4). Attempts to increase the formation of the 2′-O-methyl isomer as much as possible were based upon various solvents, temperatures, catalysts, and concentration of the catalysts during the methylation reaction.
Additional Material:
6 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19960790808
Permalink