Herein described the synthesis and antiviral evaluation of a novel series of morpholine and thio-morpholine coupled imidazo[2,1-b]thiazoles. The three-step reaction sequence involving the condensation of 1,3-dichloroacetone with thiourea followed by coupling with morpholine and thiomorpholine and finally cyclization with substituted α-bromoacetophenones yielded the desired imidazothiazoles 7(a–l). Screening of all the new compounds for their in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells, resulted in two potent analogs, 7d (IC₅₀: 1.1 μM, C₅₀: >300 μM, SI = 273) and 7e (IC₅₀: 2.0 μM, C₅₀: >300 μM, SI = 150), with a favorable toxicity profile and are the best anti-influenza hit analogs for further structural optimization.

中文翻译：

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新型咪唑并[2,1-b]噻唑与吗啉和硫代吗啉偶联的合成及其抗病毒活性

本文描述了一系列新型吗啉和硫代吗啉偶联咪唑并[2,1- b ]噻唑的合成和抗病毒评价。三步反应顺序包括 1,3-二氯丙酮与硫脲缩合，然后与吗啉和硫代吗啉偶联，最后与取代的 α-溴苯乙酮环化，得到所需的咪唑并噻唑7(a–l)。在 MDCK 细胞中筛选所有新化合物针对流感病毒 A/Puerto Rico/8/34 (H1N1) 的体外抗病毒活性，结果产生了两种有效的类似物 7d（IC 50 _： 1.1 μM，C ₅₀：>300 μM） , SI = 273) 和7e (IC ₅₀ : 2.0 μM, C ₅₀ : >300 μM, SI = 150)，具有良好的毒性特征，是进一步结构优化的最佳抗流感病毒类似物。