1-Substituted imidazoles was ozonolyzed cleanly without any complicated procedures into the corresponding N-acylamides, which were regarded to be much useful derivatives of either amines or acyl compounds.
通过在不同溶剂中结晶来研究外消旋咪唑-1基琥珀酸衍生物的多态性,这是一系列以前用作核磁共振光谱的细胞外 pH 探针的化合物。单酯,(±)-3-(乙氧基羰基)-2-(咪唑-1-基)丙酸,分别在无水乙醇(I型)或水(II型)中重结晶时显示两种不同的多晶型物。这两种形式已通过光学显微镜、粉末 X 射线衍射分析和热重分析进行表征。多晶型物 I 和 II 也可以通过固态 CP-MAS C NMR 光谱进行区分。
(+/-)-2-Imidazol-1-ylsuccinic esters were synthesized by thermal addition of imidazole to either fumaric or maleic esters. Acceleration of the reaction was achieved, in some cases, using microwave heating. These esters underwent an easy regioselective hydrolysis, under neutral conditions, to give the corresponding half-esters: (+/-)-3-(alkoxycarbonyl)-2-imidazol-1-ylpropionic acids, through either BAC(3) or BAL(1) mechanisms. Kinetic studies in H2O and D2O as well as O-18 and O-17 labeling experiments supported the proposed mechanism. The results of these hydrolyses, which depended on the nature of the alcohol moiety, were compared with those obtained with some imidazol-1-ylacetate analogues or with (+/-)-2-pyrazol-1-yl- and benzimidazol-1-ylsuccinic esters. In general, imidazolylsuccinic esters hydrolyzed faster than the homologous derivatives from pyrazole or benzimidazole.
Synthesis of multicarboxylic acid appended imidazolium ionic liquids and their application in palladium-catalyzed selective oxidation of styrene
作者:Xuehui Li、Weiguo Geng、Jixiang Zhou、Wei Luo、Furong Wang、Lefu Wang、Shik Chi Tsang
DOI:10.1039/b702573d
日期:——
A series of multicarboxylic acid appended imidazolium ionic liquids (McaILs) with chloride [Cl]– or bromide [Br]– as anions have been synthesized and characterized. Deprotonation of these ionic acids gives the corresponding zwitterions. Re-protonation of the zwitterions with strong Brønsted acids gives a series of new ionic acid-adducts, many of which remained as room-temperature ionic liquids. A new catalytic system, McaIL/PdCl2 for the selective catalytic oxidation of styrene to acetophenone with hydrogen peroxide as an oxidant has been attempted. In the presence of McaILs, it is found that the quantity of palladium chloride PdCl2 used can be greatly reduced while the activity (TOF) and selectivity towards acetophenone are enhanced sharply. It is also shown that the catalytic properties of this system could be finely tuned through the molecular design of the McaILs. The best TOF value obtained so far is 146 h–1 with 100% conversion of styrene at 93% selectivity to acetophenone. In addition, the catalytic activity has been maintained for at least ten catalytic cycles.
1-Substituted imidazoles was ozonolyzed cleanly without any complicated procedures into the corresponding N-acylamides, which were regarded to be much useful derivatives of either amines or acyl compounds.
Polymorphism of racemic imidazol-1yl succinic acid derivatives. Suitable probes for extracellular pH by magnetic resonance spectroscopic imaging (MRSI).
作者:Paloma Ballesteros、Carmen Ubide-Barreda、Mª Luisa Rojas、Pedro José Martínez de Paz、Valeria Righi
DOI:10.3998/ark.5550190.0012.314
日期:——
The polymorphism of racemic imidazol-1ylsuccinic acidderivatives, a series of compounds previously used as extracellularpHprobes for NMR spectroscopy, is investigated by crystallization in different solvents. The mono-ester, (±)-3-(ethoxycarbonyl)-2-(imidazol-1-yl) propionic acid, shows two different polymorphs when recrystallized in absolute ethanol (Form I) or water (Form II), respectively. These
通过在不同溶剂中结晶来研究外消旋咪唑-1基琥珀酸衍生物的多态性,这是一系列以前用作核磁共振光谱的细胞外 pH 探针的化合物。单酯,(±)-3-(乙氧基羰基)-2-(咪唑-1-基)丙酸,分别在无水乙醇(I型)或水(II型)中重结晶时显示两种不同的多晶型物。这两种形式已通过光学显微镜、粉末 X 射线衍射分析和热重分析进行表征。多晶型物 I 和 II 也可以通过固态 CP-MAS C NMR 光谱进行区分。