In this study, a novel catalyst based on layered double hydroxides (LDHs) attached by hexamethylene‐1,6‐diisocyanate (HMDI) and citric acid (LDHs‐g‐HMDI‐Citric acid) is reported and used to increase the yield of biurets synthesis. Biuret derivatives 5a–n were prepared by reaction of several phenyl allophanates (3a–d), which prepared from the reaction of phenyl chloroformate and urea derivatives (2a–d), with variously substituted amines (4a–g) in the presence of LDHs‐g‐HMDI‐Citric acid as a reusable heterogeneous catalyst at reflux condition for 60–180 min. These biurets (5a–n) were evaluated for human immunodeficiency virus type‐1 (HIV‐1) protease inhibitory activity by HIV‐1 p24 antigen ELISA kit and six of them (5n, 5i, 5j, 5 m, 5f, and 5a) showed moderate activity on HIV‐1 virus with IC₅₀ values ranging from 55 to 100 μM compared with the azidothymidine as the reference drug (IC₅₀ = 0.11 μM). Results of the in vitro test and docking study were in good correlation.

中文翻译：

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使用（LDHs-g-HMDI-柠檬酸）作为绿色可回收催化剂合成缩二脲衍生物作为潜在的HIV-1蛋白酶抑制剂

在这项研究中，报告了一种新型催化剂，该催化剂基于六亚甲基-1,6-二异氰酸酯（HMDI）和柠檬酸（LDHs-g-HMDI-柠檬酸）连接的层状双氢氧化物（LDHs），并用于增加缩二脲的收率合成。双缩脲衍生物5a – n是通过在LDHs存在下，几种脲基甲酸酯苯基酯（3a – d）与氯代甲酸苯酯和脲衍生物（2a – d）与各种取代的胺（4a – g）反应制备的。 -g-HMDI-柠檬酸作为可重复使用的非均相催化剂，在回流条件下持续60-180分钟。这些缩二脲（5a – n）已通过HIV-1 p24抗原ELISA试剂盒评估了人类1型免疫缺陷病毒（HIV-1）蛋白酶抑制活性，其中6种（5n，5i，5j，5m，5f和5a）对HIV具有中等活性‐1病毒，与作为参考药物的叠氮胸苷相比，IC ₅₀值在55至100μM之间（IC ₅₀ = 0.11μM）。该结果在体外试验和对接研究是在良好的相关性。