A facile synthesis of novel pyrazolopyrimidine thioglycosides as purine thioglycoside analogues

作者：Abu Zaied Mamdouh A; Elgemeie Galal H^*

来源：Nucleosides Nucleotides & Nucleic Acids, 2018, 37(1): 67-77.

DOI：10.1080/15257770.2017.1419254

• Glycosides
• purine analogues
• thioglycosides
• mercaptopyrazolo[1,5-a]pyrimidine
• ketene dithioacetals
• activated nitriles
• carbohydrates

The easy, convenient and high yielding preparation of new thioglycosides incorporating mercaptopyrazolo[1,5-a]pyrimidine moieties from readily accessible starting materials has been reported. The main step of this protocol is the formation of 7-mercaptopyrazolo[1,5-a]pyrimidine-6-carbonitrile derivatives 4a-d by condensation of sodium 2-cyano-3-ethoxy-3-oxoprop-1-ene-1,1-bis(thiolate) 1 with 4-(aryldiazenyl)-1H-pyrazole-3,5-diamines 3a-d to form target compounds 4a-d, which coupled with tetra-O-acetyl-alpha-D-glycopyranosyl bromides 5a,b in the presence of basic medium to provide the corresponding product purine thioglycoside analogs 6a-h. Ammonolysis of the latter compounds 6a-d at ambient temperature for 10 minutes, led to the free glycoside derivatives 7a-h, which were obtained in approximately quantitative yields. Their structures were created based on the spectroscopic and elemental data.

• 出版日期2018