An elevated level of blood uric acid (hyperuricemia) is the underlying cause of gout. Xanthine oxidase is the key enzyme that catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid. Allopurinol, a widely used xanthine oxidase inhibitor is the most commonly used drug to treat gout. However, a small but significant portion of the population suffers from adverse effects of allopurinol that includes gastrointestinal upset, skin rashes and hypersensitivity reactions. Moreover, an elevated level of uric acid is considered as an independent risk factor for cardiovascular diseases. Therefore use of allopurinol-like drugs with minimum side effects is the ideal drug of choice against gout. In this study, we report the synthesis of a series of pyrimidin-5-one analogues as effective and a new class of xanthine oxidase inhibitors. All the synthesized pyrimidin-5-one analogues are characterized by spectroscopic techniques and elemental analysis. Four (6a, 6b, 6d and 6f) out of 20 synthesized molecules in this class showed good inhibition against three different sources of xanthine oxidase, which were more potent than allopurinol based on their respective IC₅₀ values. Molecular modeling and docking studies revealed that the molecule 6a has very good interactions with the Molybdenum–Oxygen–Sulfur (MOS) complex a key component in xanthine oxidase. These results highlight the identification of a new class of xanthine oxidase inhibitors that have potential to be more efficacious, than allopurinol, to treat gout and possibly against cardiovascular diseases.

血尿酸水平升高（高尿酸血症）是痛风的根本原因。黄嘌呤氧化酶是催化次黄嘌呤氧化为黄嘌呤然后变为尿酸的关键酶。别嘌醇是一种广泛使用的黄嘌呤氧化酶抑制剂，是治疗痛风的最常用药物。但是，一小部分人却遭受别嘌醇的不良影响，包括胃肠道不适，皮疹和超敏反应。此外，尿酸水平升高被认为是心血管疾病的独立危险因素。因此，使用副作用最小的类别嘌呤醇类药物是对抗痛风的理想药物选择。在这项研究中，我们报告了一系列有效的嘧啶5一类似物和一类新的黄嘌呤氧化酶抑制剂的合成。所有合成的嘧啶-5-酮类似物均通过光谱技术和元素分析进行​​表征。四（在该类别的20个合成分子中，图6a，6b，6d和6f）显示出对三种不同的黄嘌呤氧化酶的良好抑制作用，基于它们各自的IC ₅₀值，它们比别嘌呤醇更有效。分子建模和对接研究表明，分子6a与黄嘌呤氧化酶的关键成分钼－氧－硫（MOS）复合物具有很好的相互作用。这些结果突出了鉴定出一种新型的黄嘌呤氧化酶抑制剂，它比别嘌呤醇在治疗痛风和可能对抗心血管疾病方面更有效。