A direct synthetic approach to uracil anhydrothionucleoside derivatives
摘要:
Direct conversion of peracylated N-1-(beta-D-glucopyranosyl)-2-thiouracil derivatives into the corresponding anhydrothionucleosides has been studied under various conditions including: gas-phase pyrolysis, heating without a solvent, and by heating in a solvent of high boiling point (DPE) in the presence of a base (DABCO) and reaction in a microwave reactor. Heating at 210-220 degrees C was found to give the best yield of a single isomer. The structures of the new anhydrothionucleosides were confirmed by NMR techniques. (C) 2009 Elsevier Ltd. All rights reserved.
A Facile Synthesis of 6-Aryl-5-cyano-1-(β-d-pyranosyl or β-d-furanosyl)-2-thiocytosines
摘要:
The treatment of a piperidinium salt of 6-aryl-5-cyano-2-thiouracil with an O-peracetyl-alpha -D-pyranosyl bromide produces a mixture of N1-(beta -D-pyranosyl)-2-thiouracil and its N1,S-2-disubstituted analog. By contrast, the reaction of a silyl derivative of the 2-thiouracil with an O-pcracetyl-beta -D-pyranose furnishes the mononucleoside selectively. Both the mononucleoside/dinucleoside mixture and pure mononucleoside undergo ammonolysis under mild conditions to give the P-D-nucleoside of 6-aryl-5-cyano-2-thiocytosine. The silyl method also provides an easy access to beta -D-ribosyl nucleosides. (C) 2000 Elsevier Science Ltd. All rights reserved.
The first direct ammonolysis of 2-thiouracil nucleosides to 2-thiocytosine nucleosides
作者:Lucjan Strekowski、Ibrahim M Abdou、Adel M.E Attia、Steven E Patterson
DOI:10.1016/s0040-4039(00)00712-7
日期:2000.6
Sugar-peracetylated 1-(beta-D-glucopyranosyl)-, 1-(beta-D-galactopyranosyl)-, and 1-(beta-D-xylopyranosyl)-6-aryl-5-cyano-2-thiouracils 2-4 and the corresponding 1-pyranosyl-2-(pyranosylthio)pyrimidines 5-7 undergo efficient ammonolysis (NH3/MeOH, 0-->23 degrees C, 16 h) to give the corresponding 1-(beta-D-pyranosyl)-6-aryl-5-cyano-2-thiocytosines. (C) 2000 Elsevier Science Ltd. All rights reserved.