THERMALLY STABLE POLYMERS CONTAINING 1,3,4-OXADIAZOLE UNITS OBTAINED FROM HUISGEN REACTION

Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble even in polar aprotic solvents such as DMSO and DMF.Relatively high inherent viscosity values（0.61-1.33 dL/g,in 0.125%H_2SO_4 at 25℃） were observed for these compounds.Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers have improved thermal stabilities.The glass transition temperature has not been observed in the fully aromatic polymers,but the polymers obtained from 5-[6-（1H-tetrazol -5-yl）hexyl]-lH-tetrazole（Ⅳ） showed very clear T_g.A model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compound was characterized by conventional spectroscopy methods.

6-三氮唑基甲氧基取代的2,4-二氨基嘧啶的合成

以2,4-二氨基-6-羟基嘧啶为原料,经氯代、溴代、亲核取代和Huisgen-Click共4步反应合成了标题化合物,其结构经1HNMR、13CNMR和MS表征,总收率为60%。

THERMALLY STABLE POLYMERS BASED ON 1,3,4-OXADIAZOLE RINGS

In the present work, new thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent. The obtained polymers are insoluble or slightly soluble in polar aprotic solvents such as DMSO and DMF. Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers had improved thermal stabilities. The model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compounds were characterized by conventional spectroscopic methods.

氯化胆碱-氯化亚铜在水相中催化炔与叠氮的环加成反应

采用氯化胆碱(ChCl)与CuCl加热制备ChCl-CuCl离子液体,并将所制离子液体作为一类高效催化剂用于水相中炔与叠氮的环加成反应得到1,2,3-三唑。实验结果表明,与ChCl-CuCl离子液体催化剂相比,没有形成离子液体的CuCl/ChCl的活性较差;该反应具有宽广的底物实用性,可用于芳香和杂环炔烃,产物的收率为91%~95%;与带有吸电子基团的炔烃相比,带有给电子基团的炔烃具有更好的反应活性;在反应研究的基础上,提出了相应的反应机理;ChCl作为配体和相转移催化剂可以有效地稳定和提高Cu(Ⅰ)的催化活性。

Antimalarial activity of a novel series of artemisinin-derived 1, 2, 3-triazole dimers

Objective: To obtain suitable artimisinin-based drug candidates with high antimalarial activity.Methods: Three different reaction schemes were used to synthesize a total of 15 artemisininbased compounds.The first synthetic scheme involved the synthesis of diazido aliphatic and aromatic compounds from commercially available dihalides and azido derivatives of artemisinin.The second scheme consisted of the reaction of dibromoaliphatic compounds with sodium azide in dimethylformamide which yielded the desired compounds.Artemisinin-based compounds on treatment with sodium azide and bromotrimethylsilane in dichloromethane produced the most potent compound GB-2.Another potent compound GB-1 was synthesized from artemisinin by treatment with alcohols in the presence of Aberlyst-15 in anhydrous dichloromethane.The third scheme involved the Huisgen 1,3-dipolar cycloaddition between the synthesized aliphatic and aromatic diazides and two alkyne derivatives of artemisinin to obtain the desired artemisinin dimers with average yields.Results: The best in vitro antiplasmodial activity was shown by the compound GB-2 registering IC_(50) value 0.066 μg/mL against chloroquine-sensitive and 0.865 μg/mL against chloroquineresistant strains of Plasmodium falciparum.It suppressed 59.0% parasitaemia in vivo of rodent malaria parasite Plasmodium berghei in Swiss albino model at 50 μg/kg body weight dosage.Molecular docking interactions of Plasmodium falciparum ATP6(PfATP6) protein revealed strong bonding of GB-2 with Thr255 residue which is likely to be the reason for excellent antimalarial activity of this compound.Conclusion: Two compounds GB-1 and GB-2 exhibited excellent in vitro antiplasmodial activity and fair in vivo antimalarial activity.Of the two, GB-2 showed better activity which could be attributed to its strong bonding interactions with Thr255 as evidenced from the molecular docking study.Study helped in identifying artemisinin analogues possessing good antimalarial properties and further research in structural alterations of the selected molecules should be carried out which may result in obtaining potent drug candidates against the malarial parasite.

Copper（Ⅱ） Acetylacetonate： An Efficient Catalyst for Huisgen- Click Reaction for Synthesis of 1,2,3-Triazoles in Water

An efficient and green copper（Ⅱ） acetylacetonate-catalyzed protocol for the Huisgen-click reaction in water at 100℃ has been established. The protocol was not only suitable for the reaction between organic azides and alkynes, but also suitable for one-pot three-component reaction among alkyl halides, NaN3 and alkynes.

基于Huisgen内盐的环化反应研究进展

发展高效、高选择性的有机合成方法是有机化学的一项重要研究内容.近年来,叔膦与偶氮二甲酸酯加成形成的Huisgen内盐在氮杂环化合物的合成上显示出独特的优越性和高效性,吸引了众多有机化学家的研究兴趣,基于Huisgen内盐的环化反应得以大量报道.根据亲电试剂的种类不同,综述了Husigen内盐与羰基化合物、缺电子烯烃、亚胺以及其他亲电试剂的环化反应.

Synthesis and Biological Activity of Novel 1-Substituted Phenyl（glycosyl）-4-{4-[（4,6-dimethoxy）pyrimidin-2-yl] Piperazin-l-yl}methyl-lH-1,2,3-triazoles

A series of novel 1-substituted phenyl or glycosyl 1,2,3-triazoles was designed and synthesized by azide-alkyne 1,3-dipolar cyeloaddition between 4,6-dimethoxy-2-[（4-prop-2-ynyl）piperazin-l-yl]pyrimidine and each of different azides catalysed by in situ generated Cu（I）. The O-acyl protecting groups on glycosyl 1,2,3-triazoles were removed by triethylamine in wet methanol. Their chemical structures were established on the basis of corresponding tH NMR, 13C NMR, MS and elemental analysis. The fungicidal activities of target compounds were evaluated in vitro against Fusarium omysporum, Physalospora piricola, Alternaria solani, Phytophthora capsici, Cercospora arachi- dicola and Gibberella zeae at 50 μg/mL. The bioassay results indicate that some of the compounds exhibited mode- rate but promising fungicidal activities. In particular, acetylated glucopyranosyl triazole displayed a good fungicidal activity against Physalospora piricola, which is equal to that of the positive control compound chlorothalonil.