Control of cyanobacteria harmful algal blooms remains a global challenge. In the present study, a series of novel 2-cyclopropyl-4-aminopyrimidine hydrazones were designed and synthesized as potential algicides. Compounds 4a, 4b, 4h, 4j, 4k, 4l, and 4m showed potent inhibition against Synechocystis sp. PCC6803 (median effective concentration, EC₅₀ = 1.1 to 1.7 μM) and Microcystis aeruginosa FACHB905 (EC₅₀ = 1.2 to 2.0 μM), more potent than, or comparably with, copper sulfate (PCC6803, EC₅₀ = 1.8 μM; FACHB905, EC₅₀ = 2.2 μM) and prometryne (PCC6803, EC₅₀ = 12.3 μM; FACHB905, EC₅₀ = 7.2 μM). Compound 4k exhibited algicidal activity in an expanded culture system, and was less toxic than copper sulfate to zebrafish. Electron microscope analyses showed that 4k damaged cyanobacterial cells and decreased the number of thylakoid lamellae. Transcriptomic and qPCR analyses suggest that 4k interfered photosynthesis-related pathways. Treatment with 4k significantly decreased the maximum quantum yield of photosystem II and the photosynthetic electron transfer rate, and the resulting reactive oxygen species damaged thylakoid membranes and photosystem I. The results suggest that 4k is a potential lead for further development of effective and safe algicides.

控制蓝藻有害藻华仍然是一项全球性挑战。在本研究中，设计并合成了一系列新型 2-环丙基-4-氨基嘧啶腙类化合物作为潜在的杀藻剂。化合物4a、4b、4h、4j、4k、4l和4m显示出对集胞藻的有效抑制作用。PCC6803（中位有效浓度，EC ₅₀  = 1.1 至 1.7 μM）和铜绿微囊藻FACHB905（EC ₅₀  = 1.2 至 2.0 μM），比硫酸铜（PCC6803，EC ₅₀  = 1.8 μM；FACHB905，EC ）更有效或相当₅₀ = 2.2 μM) 和扑草净 (PCC6803, EC ₅₀  = 12.3 μM; FACHB905, EC ₅₀  = 7.2 μM)。化合物4k在扩大的培养系统中表现出杀藻活性，并且对斑马鱼的毒性低于硫酸铜。电子显微镜分析表明，4k破坏了蓝藻细胞并减少了类囊体薄片的数量。转录组学和 qPCR 分析表明4k干扰了与光合作用相关的途径。4k处理显着降低了光系统 II 的最大量子产率和光合电子转移率，产生的活性氧破坏了类囊体膜和光系统 I。结果表明4k是进一步开发有效和安全的杀藻剂的潜在先导。