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1.
Reaction of 3-hydrazonobutan-2-one oxime with aromatic aldehydes resulted in the formation of 1,2-bis(arylidene)hydrazine commonly referred as azine as an unexpected product, instead of expected product 3-(aryl)methylenehydrazonobutan-2-one oxime, which were subsequently oxidized to corresponding aromatic acids with an ecofriendly oxidizing agent iodobenzene diacetate. Azines and carboxylic acids were characterized by IR and NMR (1H, 13C, HMBC, and HMQC) studies. 相似文献
2.
Dionisia Sanz Rosa M. Claramunt Ibon Alkorta Goar Sánchez‐Sanz José Elguero 《Magnetic resonance in chemistry : MRC》2012,50(3):246-255
The structure of glibenclamide, 5‐chloro‐N‐(2‐{4‐[(cyclohexylamino)carbonyl] aminosulfonyl}phenyl) ethyl)‐2‐methoxybenzamide, an important antidiabetic drug, has been studied both in solution and in the solid state by a combination of NMR spectroscopy and theoretical calculations. The possibility that glibenclamide suffers a tautomerization under melting to afford a desmotrope was rejected. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
3.
Dionisia Sanz Rosa M. Claramunt François Mathey Ibon Alkorta Goar Sánchez-Sanz José Elguero 《Comptes Rendus Chimie》2013,16(10):937-944
This paper reports the study by NMR spectroscopy and ab initio methods of the structure of 3,4-dimethyl-1-cyanophosphole and its dimer. The dimer presents a P···P interaction of the pnictogen type due to the presence of σ-holes. NMR of the monomer was recorded in CDCl3 solution while NMR of the dimer corresponds to the solid state (CPMAS) experiments. The 2pJPP spin–spin coupling constant has not been measured, but calculated at the B3LYP level. AIM, NBO and ELF methodologies have been used to describe the electronic structure of the dimer. 相似文献
4.
Sanz D Claramunt RM Singh SP Kumar V Aggarwal R Elguero J Alkorta I 《Magnetic resonance in chemistry : MRC》2005,43(12):1040-1043
The combined use of 1H NMR spectroscopy with theoretical calculations of chemical shifts (GIAO) and coupling constants (B3LYP/6-311 ++G**) of a 5-hydroxy-5-trifluoromethyl-Delta2-isoxazoline has enabled solving the problem of the assignments of the diastereotopic protons in this compound. This result has been extended to 5-hydroxy-5-trifluoromethyl-Delta2-pyrazolines and the corresponding 5-trichloromethyl derivatives. 相似文献
5.
Vera L.M. Silva Artur M.S. Silva Rosa M. Claramunt Concepción López Dionisia Sanz Lourdes Infantes Ángela Martínez López Felipe Reviriego Ibon Alkorta José Elguero 《Tetrahedron》2019,75(48):130690
Tetrakis(1H-pyrazol-1-yl)methanes are very rare compounds of which only two are known: the unsubstituted 1 obtained classically by Hückel in 1937 from carbon tetrachloride and prepared again several times and the 3,5-dimethyl substituted 2 obtained serendipitously by Pombeiro in 2009. We have now extended this group to include four new derivatives 8, 9, 11 and 12 bearing methyl groups. The X-ray crystal structure of the four compounds has been determined. They have been studied by NMR both in solution (1H, 13C, 15N) and in the solid state (13C and 15N). DFT calculations of the six compounds (geometries, energies and absolute shieldings) have been used to discuss the experimental observations. 相似文献
6.
Marta Pérez Torralba Dionisia Sanz Rosa M. Claramunt Ibon Alkorta Christophe Dardonville José Elguero 《Tetrahedron》2018,74(29):3937-3942
Two samples of fosfomycin salts, the calcium and the disodium ones, were used to record their NMR spectra both in solution and in the solid state. The existence of fosfomycin in a neutral and two ionized structures (mono and dianion) was considered to interpret the spectra that were solved using the GIAO calculated chemical shifts of the minimum energy conformations. Although the starting materials were dianions, the spectra in solution show the presence of monoanions. 相似文献
7.
Sanz D Claramunt RM Saini A Kumar V Aggarwal R Singh SP Alkorta I Elguero J 《Magnetic resonance in chemistry : MRC》2007,45(6):513-517
Multinuclear magnetic resonance spectroscopy together with GIAO-DFT calculations allowed establishment of the structure of the products obtained by condensation of 3(5)-amino-4-phenyl-1H-pyrazole and beta-dicarbonyl compounds bearing a trifluoromethyl group. They are 3-phenyl-5-(R)-7-trifluoromethylpyrazolo[1,5-a]pyrimidines. 相似文献
8.
Rosa MarÍA Claramunt Dionisia Sanz Ibon Alkorta Jos Elguero Concepti
N Foces‐Foces Antonio L. Llamas‐Saiz 《Journal of heterocyclic chemistry》2001,38(2):443-450
We report the ab initio study of twenty‐four azolides derived from pyrrole, imidazole, pyrazole, both triazoles, tetrazole, pentazole, indole and carbazole bearing at the nitrogen atom the groups COMe, CHO, COCF3 and CO2Me. Theoretical values (isomerism, barriers, dipole moments, C=O stretching) are compared with experimental ones, when available, and also internally compared. A special effort has been devoted to the calculation of the absolute shieldings for the different nuclei present in azolides. At the level of calculation used (RHF/6‐311G**) the results are satisfactory. To complete the nmr data from the literature, some 1H, 13C, 15N, 17O and 19F chemical shifts have been determined. 相似文献
9.
Rosa M. Claramunt Dionisia Sanz Concepción López Elena Pinilla M. Rosario Torres José Elguero Pierre Nioche C. S. Raman 《Helvetica chimica acta》2009,92(10):1952-1962
The existence of polymorphism in parent indazolin‐3‐one (=1,2‐dihydro‐3H‐indazol‐3‐one; 1 ) is reported as well as an X‐ray and NMR CPMAS study establishing that its 7‐nitro derivative 2 exists as the 3‐hydroxy tautomer. Absolute shieldings calculated at the GIAO/B3LYP/6‐311++G(d,p) level were used to determine the tautomeric oxo/hydroxy equilibrium in solution, i.e., always the 1H‐indazol‐3‐ol tautomer predominates. 相似文献
10.