合成了4个双功能方酰胺探针分子,其中1和3为新化合物,2和4为已知化合物,并通过核磁共振(1H NMR、13 C NMR)和高分辨质谱(HRMS)确认其结构。采用荧光光谱法,系统研究了这4个手性探针分子对Boc-苯丙氨酸、苯丙氨酸、苯甘氨酸、脯氨酸、缬...合成了4个双功能方酰胺探针分子,其中1和3为新化合物,2和4为已知化合物,并通过核磁共振(1H NMR、13 C NMR)和高分辨质谱(HRMS)确认其结构。采用荧光光谱法,系统研究了这4个手性探针分子对Boc-苯丙氨酸、苯丙氨酸、苯甘氨酸、脯氨酸、缬氨酸、酒石酸、扁桃酸和联二萘酚的荧光手性识别效果。通过组合筛选发现,探针分子4对缬氨酸有较好的识别效果。进一步的研究结果表明,探针分子4与缬氨酸的摩尔比为1∶2时,加入L-缬氨酸后,荧光光谱峰大幅蓝移,且荧光强度大幅减弱;加入D-缬氨酸后,荧光光谱没有变化,荧光强度比值(I D/I L)达到1.35。据此提出了探针分子4的叔胺基团和方酰胺基团分别通过静电作用和氢键作用各结合一分子L-缬氨酸的双手性中心识别机理。展开更多
Enantioselective chlorination of b-keto esters and amides catalyzed by squaramide-linked bisoxazoline ligand–Cu(OAc)2complexes was investigated. The corresponding chlorinated products were obtained in excellent yield...Enantioselective chlorination of b-keto esters and amides catalyzed by squaramide-linked bisoxazoline ligand–Cu(OAc)2complexes was investigated. The corresponding chlorinated products were obtained in excellent yields with moderate enantioselectivities. The effect of solvent, temperature, Lewis acid, and ligand structure on the reaction is discussed. This was the first investigation of catalytic asymmetric achlorination of b-keto amides. This study has highlighted that a simple chiral squaramide–oxazoline with cheap Cu(OAc)2 H2 O complexes can catalyze this chlorination.展开更多
Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invar...Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invariably very difficult and not always effective, and compounds that are amebicidic or amebistatic are frequently toxic and/or irritating for humans. Squaramides and polyamine derivatives have been demonstrated to have antitumor and antiprotozoal activity. The aim of this study was to investigate the activity of 5 squaramides and 5 acyclic polyamines against trophozoites and cysts of A. castellanii Neff. Amoebicidal activity against the trophozoites and cytotoxicity against Vero cells were evaluated with a colorimetric assay, using Alamar Blue?, and chlorhexidine digluconate was assayed as the reference drug. The squaramides 3 and 5 and the acyclic polyamine 6 appeared to be the most active against the trophozoites and their cytotoxicity was low, showing selectivity indexes of 28.3, 26, and 25.7, respectively, similar to the control drug, chlorhexidine digluconate (27.6). But only the squaramide 3 showed complete cysticidal activity at the concentrations of 100 and 200 μM, as the chlorhexidine digluconate. Further studies of the mechanism of action and in vivo assays are needed, but squaramide 3 could be used for developing novel therapeutic approaches against Acanthamoeba infections.展开更多
以廉价易得的方酸为原料,通过酯化,再与L-脯氨醇发生氨解反应,得到具有C2对称结构的手性L-脯氨醇方酰胺(分子式:C14H20N2O4),两步反应总收率67.5%.其结构经FT-IR、1 H NMR、13 C NMR、ESI-HRMS以及X-射线单晶衍射进行确证.该晶体属于斜...以廉价易得的方酸为原料,通过酯化,再与L-脯氨醇发生氨解反应,得到具有C2对称结构的手性L-脯氨醇方酰胺(分子式:C14H20N2O4),两步反应总收率67.5%.其结构经FT-IR、1 H NMR、13 C NMR、ESI-HRMS以及X-射线单晶衍射进行确证.该晶体属于斜方晶系,P212121空间群,晶胞参数:a=0.807 04(12)nm,b=0.901 36(13)nm,c=2.059 6(3)nm,α=β=γ=90.00°,V=1.498 2(4)nm3,Z=4,Dc=1.323g·cm-3,μ=0.100 mm-1,F(000)=640,最终残差因子R1=0.042 9,wR2=0.103 9.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.21072010 and 21272024)
文摘Enantioselective chlorination of b-keto esters and amides catalyzed by squaramide-linked bisoxazoline ligand–Cu(OAc)2complexes was investigated. The corresponding chlorinated products were obtained in excellent yields with moderate enantioselectivities. The effect of solvent, temperature, Lewis acid, and ligand structure on the reaction is discussed. This was the first investigation of catalytic asymmetric achlorination of b-keto amides. This study has highlighted that a simple chiral squaramide–oxazoline with cheap Cu(OAc)2 H2 O complexes can catalyze this chlorination.
文摘Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invariably very difficult and not always effective, and compounds that are amebicidic or amebistatic are frequently toxic and/or irritating for humans. Squaramides and polyamine derivatives have been demonstrated to have antitumor and antiprotozoal activity. The aim of this study was to investigate the activity of 5 squaramides and 5 acyclic polyamines against trophozoites and cysts of A. castellanii Neff. Amoebicidal activity against the trophozoites and cytotoxicity against Vero cells were evaluated with a colorimetric assay, using Alamar Blue?, and chlorhexidine digluconate was assayed as the reference drug. The squaramides 3 and 5 and the acyclic polyamine 6 appeared to be the most active against the trophozoites and their cytotoxicity was low, showing selectivity indexes of 28.3, 26, and 25.7, respectively, similar to the control drug, chlorhexidine digluconate (27.6). But only the squaramide 3 showed complete cysticidal activity at the concentrations of 100 and 200 μM, as the chlorhexidine digluconate. Further studies of the mechanism of action and in vivo assays are needed, but squaramide 3 could be used for developing novel therapeutic approaches against Acanthamoeba infections.