排序方式: 共有17条查询结果,搜索用时 15 毫秒
1.
The reactions of cyclic aldo- and -methoxynitrones of the 2H-imidazole-1-oxide and 4H-imidazole 3-oxide series with isocyanates, phenyl isothiocyanate, N-phenylmaleimide, and dimethyl acetylenedicarboxylate were studied. The reactions give the corresponding 1,3-dipolar cycloaddition products. 2,2-Dimethyl-4-phenyl-2H-imidazole 1-oxide does not enter into a similar reaction with isocyanates or phenyl isothiocyanate. 相似文献
2.
3.
Nakka Mangarao Gajula Mahaboob BashaTadikonda Ramu Rayavarapu SrinuvasaraoSarakula Prasanthi Vidavalur Siddaiah 《Tetrahedron letters》2014
A facile and highly efficient synthesis of 3,4,5-trisubstituted 1,2,4-triazoles and 3,5-disubstituted 1,2,4-oxadiazoles from 2,2,2-trichloroethyl imidates using PEG as a solvent and employing PTSA as the catalyst under mild conditions is described. 相似文献
4.
N. Raouafi M. Freytag P. G. Jones M. L. BenKhoud 《Journal of chemical crystallography》2007,37(6):381-386
N-(1H-Benzimidazol-2-yl) propionimidic acid ethyl ester (1) reacts with benzylamine to yield the corresponding N-(1H-Benzimidazol-2-yl)-N′-benzyl proponamidine (2). The structure and conformation of the amidine 2 were determined by 1H and 13C NMR and X-ray diffraction. The product crystallizes in monoclinic system with space group P21/c, a = 10.7913 ?, b = 15.5164 ?, c = 9.1130 ?, β = 108.378° and Z = 4. In the crystal there are two N–HN hydrogen bonds, the first is intramolecular H-Bond links H4 to N1; the second one is intermolecular and it links H2 to N3
of a second molecule leading to inversion-related dimers. The X-ray results were compared with those obtained by semi-empirical and ab-initio calculations. 相似文献
5.
6.
7.
C. Wade Downey Alan S. FleisherJames T. Rague Chelsea L. SafranMegan E. Venable Robert D. Pike 《Tetrahedron letters》2011,52(37):4756-4759
Secondary amides undergo in situ silyl imidate formation mediated by TMSOTf and an amine base, followed by addition to acetal acceptors to provide N-acyl-N,O-acetals in good yields. An analogous, high-yielding reaction is observed with 2-mercaptothiazoline as the silyl imidate precursor. Competing reduction of the acetal to the corresponding methyl ether via transfer hydrogenation can be circumvented by the replacement of CY2NMe with 2,6-lutidine under otherwise identical reaction conditions. 相似文献
8.
《Analytical letters》2012,45(7):1439-1449
Abstract In this work, the (R)‐N,N,N‐trimethyl‐2‐aminobutanol‐bis(trifluoromethanesulfon)imidate chiral ionic liquid was first used in chromatography and exhibited a excellent chiral recognition ability in high performance capillary electrophoresis (HPCE), high performance liquid chromatography (HPLC), and capillary gas chromatography (CGC), which also showed for the first time that chrial ionic liquid was an effective chiral selector in HPCE and HPLC. The compounds that have been separated using this chiral ionic liquid at least included alcohol, amine, acid, and amino acid, et al. enantiomers. As the chiral ionic liquid can be easily synthesized from relatively inexpensive materials, it should have a great potentiality for chiral separation in chromatographic science. 相似文献
9.
Samudranil Pal 《Journal of Chemical Sciences》2002,114(4):417-430
The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. Two types of
aroylhydrazones derived from aroylhydrazines and ortho-hydroxy aldehydes or 2-pyridine-carboxaldehyde have been used. The
characterization of the complexes has been performed with the help of various physico-chemical techniques. Solid state structural
patterns have been established by X-ray crystallography. In the solid state, structural varieties of these complexes are seen
to range from monomeric, dimeric, polymeric and one-dimensional self-assembly via hydrogen bonds and π-π interactions. EPR
spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination
geometry and magnetic characteristics of these complexes. 相似文献
10.
In the flash vacuum thermolysis of methyl N-acyl imidates, the loss of methanol is consistent with the intermediacy of an N-acylketenimine. Recombination and further reactions may lead to the array of products observed in these thermal reactions. An attempt to trap the intermediate N-acylketenimine by an intramolecular [2 + 2] cycloaddition was unsuccessful. 相似文献