Synthesis of 3,5-disubstituted 1,2,4-oxadiazoles using ionic liquid-phase organic synthesis (IoLiPOS) methodology

New 3,5-disubstituted 1,2,4-oxadiazoles were synthesized in five steps by ionic liquid-phase organic synthesis (IoLiPOS) methodology. The strategy involved the preparation of amidoxime from the ionic liquid-phase bound arylnitrile. Addition of various carboxylic acid to the amidoxime produced the expected 3,5-disubstituted 1,2,4-oxadiazoles via the stable O-acyl amidoxime intermediate grafted on the ionic liquid-phase. The 1,2,4-oxadiazoles were easily cleaved by transesterification under mild reaction conditions in high purity with good overall yields. The structures of the intermediates in each step were verified by routine spectroscopic analysis (¹H, ¹³C NMR, and HRMS).     

Surfactant-assisted organic reactions in water. Effect of ultrasound on condensation reactions between active methylene compounds and arylaldehydes

A series of quaternary ammonium salts has been tested as phase transfer agents to promote condensation reactions in an aqueous solution of sodium hydroxide in the absence of any organic solvent. Methyltrioctylammonium chloride (Aliquat 336) emerges as the most efficient catalyst. Sonication of the reaction media has a poor but positive kinetic effect.     

An Improved One-Pot Method for the Preparation of 2-Substituted 1H-Perimidines

2-substituted 1H-perimidines are readily prepared, in high yields, by refluxing a mixture of sodium pyrosulfite, an aldehyde, and 1, 8-diaminonaphthalene in aqueous ethanol or N, N-dimethylformamide. The method is of wide applicability except from araldehydes bearing a strong electron-withdrawing group (-CN, -NO₂).     

Synthèse de 1H-pyrazolo[3,4-b] pyridines et de pyrazolo[1,5-a] pyrimidines

The reaction between an aminopyrazolone and a β-dicarbonyl compound has been studies. The orientation of the cyclo-condensation is dependent on the nature of each precursor.     

Liquid-phase synthesis of polyhydroquinoline using task-specific ionic liquid technology

A new strategy for the synthesis of polyhydroquinolines from task-specific ionic liquids (TSIL) as a soluble support was developed. The preparation of the polyhydroquinolines by a three-component reaction was achieved by using ionic liquid-phase bound beta-oxo esters. These starting functionalized esters were synthesized by a solventless transesterification without catalyst under microwave irradiation. The structure of the intermediates in each step was verified routinely by spectroscopic analysis, and after oxidation of the polyhydroquinolines grafted on the TSIL with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone or after cleavage (transesterification, saponification-acidification), the target compounds were obtained in good yields and high purities.     

Complete separation of the enantiomers of a tetraorganotin by chromatography on microcrystalline cellulose triacetate and fractional crystallization

Racemic methylneophylphenyltrityltin (1) could be resolved completely by chromatography on microcrystalline cellulose triacetate coupled with fractional crystallizations. The influence of temperature on the chromatographic separation of compound (1) and of t-butylmethylphenyltrityltin (2) is described.     

Organometallic compounds : LXIX. Synthesis and properties of the first chiral triorganostannyl-manganese complex

Methyl-1-naphthylphenylstannyltetracarbonyl(diphenyl-N-methyl-N-(S)-1-phenylethylaminophosphine)manganese (I) has been prepared by two different routes from racemic methyl-1-naphthylphenyltin chloride. Fractional recrystallizations yielded two diastereomeric fractions with fx205-1 = +40.3° and —71.4°, respectively, which have identical NMR and IR spectra.     

玉米醇溶蛋白/壳聚糖复合纳米微球的制备及性能研究

以生物相容性的玉米醇溶蛋白(Zein)和壳聚糖(Chitosan)为原料,利用溶剂-非溶剂相分离法成功制备了玉米醇溶蛋白/壳聚糖复合纳米微球(NSZ/CS),运用FT-IR、SEM和TEM等对复合纳米微球进行了表征。采用罗丹明B(RB)为模型药物分子,研究了复合纳米微球的药物释放性能。与玉米醇溶蛋白纳米微球(NSZ)相比,复合纳米微球NSZ/CS对RB和Dox·HCl的包封率显著上升,分别可达83.5%和75.3%。NSZ/CS对RB的累积释放量也大幅度提高。在模拟人工胃液和人工肠液中,NSZ/CS对RB释放36 h后,累积释放量分别为85.2%和95.4%。进一步将NSZ/CS用于负载抗癌药物盐酸阿霉素(Dox·HCl),发现Dox@NSZ/CS在p H=7.4的磷酸缓冲液(PBS)中的累积释放量达91.0%。复合纳米微球NSZ/CS有望作为水溶性药物载体应用于生物医药领域。     

掺杂LN晶体光折变效应及图象光存储特性

利用514.5nm和632.8nm波长的激光,研究了单掺杂Fe和双掺杂Ce∶Fe离子铌酸锂晶体的光折变二波耦合及光折变全息存储特性.实验结果表明生长态双掺杂Ce∶Fe与单掺杂Fe的LiNbO3晶体的光折变波耦合增益差异不明显,但双掺杂Ce∶Fe的LiNbO3晶体的图象存储和擦除特性明显得到改善.氧化态样品具有较大的透过率光谱范围和较好的图象存储质量;还原态样品具有较大的光折变二波耦合增益特性.