A Novel and Versatile Entry to Asymmetrically Substituted Pyrazines
摘要:
A novel and convenient procedure for the synthesis of asymmetrically tri- and tetrasubstituted pyrazines starting from para-methoxybenzyl-protected 3,5-dichloro-2(1H)-pyrazinones was elaborated. The key step is the conversion of the intermediate para-methoxybenzyl-protected thiopyrazinone upon treatment with MeI/I-2, into a pyrazine, rendering the chlorine in the C5-position susceptible to substitution. This approach entails the orthogonal introduction of the four substituents of the pyrazine scaffold. The application of microwave irradiation during different steps of the sequence has been shown to be highly valuable for speeding up reactions.
An Expeditious Route toward Pyrazine-Containing Nucleoside Analogues
作者:Sachin G. Modha、Jalpa C. Trivedi、Vaibhav P. Mehta、Denis S. Ermolat’ev、Erik V. Van der Eycken
DOI:10.1021/jo102089h
日期:2011.2.4
An improved and convenient methodology for the synthesis of asymmetrically substituted pyrazines starting from 3,5-dichloropyrazin-2(1H)-ones has been elaborated. Several nucleoside analogues have been synthesized containing the pyrazine core as the organic base coupled with the sugar via a triazole linkage. The beneficial effect of microwave irradiation throughout the sequence has been demonstrated.