Chemistry Department, Faculty of Science, Mansoura University, El-Gomhoria Street, Mansoura, 35516, Egypt.
Curr Org Synth. 2021 Oct 26;18(6):547-586. doi: 10.2174/1570179418666210509015108.
Pyrazolopyrimidines are a privileged class of 5-6 bicyclic systems with three or four nitrogen atoms, including four possible isomeric structures. The significance of this class of compounds is that they can be applied in medical and pharmaceutical fields due to their unlimited biological aptitude, hence it is the basic skeleton of several synthetic drugs. The current review aimed to highlight all the synthetic routes that have been applied to construct the pyrazolo[1,5-a]pyrimidine ring systems up to date. The sections in this study included the synthesis of pyrazolo[1,5- a]pyrimidines by condensation reactions of 5-aminopyrazoles with each of β-diketones, 1,5-diketones, β- ketoaldehydes, α-cyanoaldehydes, β-enaminones, enamines, enaminonitriles, ethers, with unsaturated ketones, unsaturated thiones, unsaturated esters, unsaturated dienones "1,2-allenic", unsaturated aldehydes, unsaturated imines, and unsaturated nitriles. The routes adopted to synthesize this class of heterocyclic compounds were extended for ring construction from acyclic reagents and multicomponent reactions under catalytic or catalyst-free conditions.
吡唑并嘧啶是一类具有三个或四个氮原子的五元至六元双环系统，包括四个可能的异构体结构。这类化合物的重要性在于它们由于具有无限的生物适应性而可以应用于医学和制药领域，因此它们是几种合成药物的基本骨架。本综述旨在强调迄今为止应用于构建吡唑并[1,5-a]嘧啶环系统的所有合成路线。本研究的章节包括通过 5-氨基吡唑与每种β-二酮、1,5-二酮、β-酮醛、α-氰基醛、β-烯胺酮、烯胺、烯胺腈、醚、不饱和酮、不饱和硫酮、不饱和酯、不饱和二烯酮“1,2-allenic”、不饱和醛、不饱和亚胺和不饱和腈的缩合反应合成吡唑并[1,5-a]嘧啶。为了合成这类杂环化合物，采用了从无环试剂和多组分反应在催化或无催化剂条件下进行环构建的方法。
