24807-04-3Relevant academic research and scientific papers
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.
Nucleoside Syntheses, XXII. Nucleoside Synthesis with Trimethylsilyl Triflate and Perchlorate as Catalysts
Vorbrueggen, Helmut,Krolikiewicz, Konrad,Bennua, Baerbel
, p. 1234 - 1255 (2007/10/02)
The novel Lewis acids (CH3)3SiOSO2CF3 (5), (CH3)3SiOSO2C4F9 (6), and (CH3)3SiClO4 (4) are highly selective and efficient Friedel-Crafts catalysts for nucleoside formation from silylated heterocycles and peracylated sugars as well as for rearrangements of persilylated protected nucleosides.With basic silylated heterocycles these new catalysts give much higher yields of the natural N-1-nucleosides than with SnCl4.
