6741-88-4Relevant articles and documents
High-throughput five minute microwave accelerated glycosylation approach to the synthesis of nucleoside libraries
Bookser, Brett C.,Raffaele, Nicholas B.
, p. 173 - 179 (2007/10/03)
The Vorbrueggen glycosylation reaction was adapted into a one-step 5 min/130 °C microwave assisted reaction. Triethanolamine in acetontrile containing 2% water was determined to be optimal for the neutralization of trimethylsilyl inflate allowing for direct MPLC purification of the reaction mixture. When coupled with a NH3/methanol deprotection reaction, a high-throughput method of nucleoside library synthesis was enabled. The method was demonstrated by examining the ribosylation of 48 nitrogen containing heteroaromatic bases that included 25 purines, four pyrazolopyrimidines, two 8-azapurines, one 2-azapurine, two imidazopyridines, two benzimidazoles, three imidazoles, three 1,2,4-triazoles, two pyrimidines, two 3-deazapyrimidines, one quinazolinedione, and one alloxazine. Of these, 32 yielded single regioisomer products, and six resulted in separable mixtures. Seven examples provided inseparable regioisomer mixtures of -two to three compounds (16 nucleosides), and three examples failed to yield isolable products. For the 45 single isomers isolated, the average two-step overall yield ± SD was 26 ± 16%, and the average purity ± SD was 95 ± 6%. A total of 58 different nucleosides were prepared of which 15 had not previously been accessed directly from glycosylation/deprotection of a readily available base.
Oxidative Transformations of Minor Components of Nucleic Acids. An Anomalous Reaction Course of Oxidation of N6,N6-Dialkyladenosines and Related Compounds with m-Chloroperoxybenzoic Acid
Endo, Takeshi,Zemlicka, Jiri
, p. 1887 - 1894 (2007/10/02)
Oxidation of N6-methyladenosine (1a) or the corresponding tribenzoate 1b with m-chloroperoxybenzoic acid gave N1-oxides 2a and 2b whereas N6,N6-dimethyladenosine tribenzoate (3a) afforded 2',3',5'-tri-O-benzoylinosine (4a) and N6-methyl-N6-formyl derivative 5.The N6,N6-diethyladenosine 3b and piperidine derivative 3c yielded only 4a, but N6,N6-dibenzyl compound 3d was not oxidized.N,N-Dimethyl-2,4-dinitroaniline (6a) was oxidized with m-chloroperoxybenzoic acid to give N-methyl-N-formyl derivative 7a, N-methyl-2,4-dinitroaniline (8a), N-oxide 10a, and only traces of 2,4-dinitrophenol (9a).By contrast, 2-(dimethylamino)-5-nitropyridine (6b) afforded 5-nitro-2-pyridone (9b) and N-demethylated N1-oxide 11. 2-(Dimethylamino)pyridine (6c) and 2-(methylamino)-5-nitropyridine (8b) gave the respective N2- and N1-oxides 10c and 11.The reaction of 6-chloropurine nucleosides 15a and 15b with N,N-dimethylhydroxylamine gave inosine 4a or 4b accompanied by a smaller amount of 3a or 3e. 2,4-Dinitrofluorobenzene (16) afforded O-(2,4-dinitrophenyl)-N,N-dimethylhydroxylamine (17).Mass spectra of compounds 10a, 10c, and 17 provided evidence for Meisenheimer rearrangement and subsequent cyclic transformation.The N-oxide 10a and hydroxylamino derivative 17 gave 2,4-dinitrophenol (9a), and N2-oxide 10c afforded fragments belonging to 2-pyridone (9c).Compound 17 is thermally stable whereas N-oxide 10a yielded at 100 deg C a mixture of 8a, 8b, 9a, and 17.
