长链亲脂性氮氧自由基HPN衍生物的设计合成及对缺氧小鼠存活的影响

Design,synthesis and anti-hypoxia activity of HPN derivatives containing lipophilic long chains

目的:设计合成长链取代的2-(4′-羟基苯基)-4,4,5,5-四甲基咪唑烷-1-氧基-3-氧化物(HPN)衍生物,以增强HPN的抗缺氧活性。方法:以乙腈为溶剂、碳酸钾为缚酸剂,60℃反应条件下将HPN分别与6-溴己醇、6-溴己酸乙酯和6-溴己烷进行烷基化反应得到3个长链亲脂性HPN衍生物1、3和5;衍生物1在氢氧化钠甲醇/水体系下经过水解反应得到衍生物2;以二氯甲烷为溶剂,N,N′-二异丙基碳二亚胺为脱水剂,HPN与己酸进行酯化反应,得到衍生物4。采用红外光谱、电子顺磁共振和高分辨质谱表征衍生物1~5的结构,高效液相色谱法检测衍生物的纯度,计算油水分配系数(logP值)评估衍生物的脂溶性,并通过缺氧小鼠常压密闭缺氧实验和急性减压耐受实验考察HPN及衍生物1~5的抗缺氧活性。结果:5个衍生物的结构经红外光谱、电子顺磁共振和高分辨质谱分析确认,产率均在92%以上,纯度均在96%以上。衍生物1~5的logP值分别为2.78、2.00、2.04、2.88和3.10,均高于HPN(0.97);在给药剂量为0.3 mmol/kg时均能显著延长常压密闭缺氧小鼠的生存时间,并将急性减压缺氧小鼠的死亡率分别下降至60%、70%、60%、70%、40%。结论:衍生物1~5的合成方法简便,产率较高,且在剂量较小的情况下,仍然表现出类似或优于HPN的抗缺氧活性,其中衍生物5的活性最佳。

Objective:To design and synthesize long-chain substituted 2-[(4′-hydroxyethoxy)phenyl]-4,4,5,5-tetramethyl-2-imidazoline-1-oxyl 3-oxide(HPN)derivatives with enhanced anti-hypoxic activity.Methods:HPN derivatives 1,3,5 containing lipophilic long chains were synthesized via the alkylation of HPN with 6-bromohexan-1-ol,ethyl 6-bromohexanoate or 6-bromohexane,respectively using acetonitrile as the solvent and K2CO3as the acid-binding agent at 60℃.Derivative 2 was synthesized via hydrolysis reactions of derivative 1 in the Na OH/CH3OH/H2O system.Using dichloromethane as the solvent and N,N′-diisopropylcarbodiimide as the dehydrating agent,HPN underwent esterification with hexanoic acid to obtain derivative 4.The structures of derivatives 1-5 were characterized by infrared spectroscopy,electron paramagnetic resonance and high resolution mass spectrometry.The purities of derivatives were detected by high performance liquid chromatography,and the lipid solubilities of derivatives were evaluated by calculating the oil-water partition coefficients(logP).Anti-hypoxia activities of HPN and its long-chain lipophilic derivatives1-5 were evaluated using normobaric hypoxia test and acute decompression hypoxia test.Results:The structures of the derivatives were confirmed by infrared spectroscopy,electron paramagnetic resonance and high resolution mass spectroscopy.The yields of target derivatives were all above 92%,and the purities were all above 96%.The logPvalues of derivatives 1-5 were 2.78,2.00,2.04,2.88 and 3.10,which were higher than that of HPN(0.97).Derivatives 1-5 significantly prolonged the survival time of mice at the dose of0.3 mmol/kg in normobaric hypoxic test and reduced the mortality rate of acute decompression hypoxic mice to 60%,70%,60%,70%and 40%,respectively.Conclusions:The synthesis of derivatives 1-5 is convenient,and the yield is high.The synthesized derivatives especially derivative 5 show anti-hypoxic activity similar to or better than HPN at lower doses.