A series of dihydropyrimidine decorated phenothiazine and their derivatives 7 a‐7 i possessing a diverse range of functionalities such as isopropyl, methoxy, chloro, fluoro, nitro, naphthyl have been synthesized by adopting a multistep synthetic strategy and characterized using various physical and spectroscopic techniques. Preliminary antioxidant evaluation of all the molecules has been executed and exerted activity upto 69.34% (IC₅₀ 148 μM) with respect to the standard ascorbic acid. Computational studies of a representative molecule 7 a have also been executed and appropriate results are compared with the experimental ones. The optimized structure with their bonding features and vibrational frequencies of 7 a have been determined by employing DFT−B3LYP method with 6–311++G(d,p) basis set. The theoretically calculated and experimentally resulted vibrational frequencies of 7 a are in good harmony with each other. Further, the ¹H and ¹³C chemical shifts of 7 a have been calculated by the Gauge Independent Atomic Orbital (GIAO) technique and compared with the experimental ones.

中文翻译：

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二氢嘧啶花式吩噻嗪的合成，抗氧化评价，密度泛函理论研究

通过采用多步合成策略合成了一系列由二氢嘧啶修饰的吩噻嗪及其衍生物7 a-7 i，它们具有多种功能范围，例如异丙基，甲氧基，氯，氟，硝基，萘基，并使用各种物理和光谱技术进行了表征。已对所有分子进行了初步的抗氧化剂评估，并相对于标准抗坏血酸发挥了高达69.34％（IC ₅₀ 148μM）的活性。还进行了代表性分子7a的计算研究，并将适当的结果与实验结果进行了比较。具有键合特征和7 a的振动频率的优化结构通过使用具有6–311 ++ G（d，p）基集的DFT-B3LYP方法确定。从理论上计算出的和通过实验得出的7 a的振动频率相互之间非常协调。此外，已通过量规无关原子轨道（GIAO）技术计算了7 a的¹ H和¹³ C化学位移，并将其与实验值进行了比较。