An expeditious catalyst-free heteroannulation reaction for imidazo[1,2-a]pyridines/pyrimidines/pyrazines was developed in green solvent under microwave irradiation. Using H₂O-IPA as the reaction medium, various substituted 2-aminopyridines/pyrazines/pyrimidines underwent annulation reaction with α-bromoketones under microwave irradiation to provide the corresponding imidazo[1,2-a]pyridines/pyrimidines/pyrazines in excellent yields. The synthetic methodology appears to be very simple and superior to the already reported procedures with the high abundance of commercial reagents and great ability in expanding the molecular diversity. The present synthetic sequence is visualized as an environmentally benign process which allows the introduction of three points of structural diversity to expand chemical space with excellent purity and yields. The anti-inflammatory and antimicrobial activities of the derivatives were evaluated. Screening results uncovered three derivatives with strong inhibition of albumin denaturation and two derivatives were active on Proteus and Klebsiella bacteria. These positive bioassay results implied that the library of potential anti-inflammatory agents could be rapidly prepared in an ecofriendly manner, and provided new insights into drug discovery for medicinal chemists.

中文翻译：

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在绿色溶剂中微波辐射下通过无催化剂环化反应有效获得咪唑并[1,2- a ]吡啶/吡嗪/嘧啶

微波辐射下，在绿色溶剂中开发了咪唑并[1,2- a ]吡啶/嘧啶/吡嗪的快速无催化剂杂环化反应。以H ₂ O-IPA为反应介质，在微波辐射下，将各种取代的2-氨基吡啶/吡嗪/嘧啶与α-溴酮进行环化反应，得到相应的咪唑并[1,2- a]。]吡啶/嘧啶/吡嗪，收率极高。合成方法似乎非常简单并且优于已报道的方法，具有高度丰富的商业试剂和强大的扩展分子多样性的能力。本合成序列可视为对环境有益的过程，该过程允许引入三点结构多样性以优异的纯度和收率扩大化学空间。评价了衍生物的抗炎和抗微生物活性。筛选结果发现了三种抑制白蛋白变性的衍生物，其中两种衍生物对变形杆菌和克雷伯菌具有活性细菌。这些积极的生物测定结果表明，可以以生态友好的方式快速制备潜在的抗炎药库，并为药物化学家提供了有关药物发现的新见解。