Structural and spectral characterization of novel non-centrosymmetric 2,4-dintrobenzene derivative

Garipov

et al. 2014

Self Cite

A series of pyridoxine derivatives was investigated by (1) H and 2D nuclear overhauser enhancement spectroscopy (NOESY) NMR. The free energies of activation for the pyridyl-oxygen rotation of the 2,4-dinitrophenyl ether of the seven-membered acetals of pyridoxine were measured by dynamic NMR. A conformational exchange between the chair and twist forms of the seven-membered acetal ring was confirmed by dynamic NMR and STO3G computations.

“…The studied compounds have been reported as novel organic nonlinear optical (NLO) materials . These materials exhibit physicochemical properties suitable for second harmonic generation.…”

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Dynamic NMR study of cyclic derivatives of pyridoxine

Garipov

et al. 2014

Self Cite

“…Previous studies revealed some correlation between steric structure and reactivity of these compounds . Recently, we have investigated the conformational transformations of pyridoxine derivatives containing a seven‐membered acetal ring with a 2,4‐dinitrophenyloxy ortho‐substituent revealing properties of organic nonlinear optical materials . In this paper, we present the results of dynamic NMR study of 9‐(2,4‐dinitrophenyloxy)‐3,3,8‐trimethyl‐1,5‐dihydro‐[1,3]dioxepino[5,6‐с]pyridine and 9‐(2,4‐dinitrophenyloxy)‐3,8‐dimethyl‐3‐pentyl‐1,5‐dihydro‐[1,3]dioxepino[5,6‐с]pyridine.…”

Section: Introductionmentioning

confidence: 99%

Dynamic NMR study of dinitrophenyl derivatives of seven‐membered cyclic ketals of pyridoxine

Garipov

et al. 2015

Two pyridoxine derivatives containing a dinitrophenyl moiety were investigated by (1)H NMR spectroscopy. Conformational dynamics in solution were studied for each compound using dynamic NMR experiments. It was shown that both compounds studied are involved into two conformational exchange processes. The first process is a transformation of the seven-membered cycle conformation between the enantiomeric P-twist and M-twist forms, and the second is a rotation of the dinitrophenyl fragment of the molecules around the C-O bond. Energy barriers of both conformational transitions were determined.

“…In this paper, we present the results of dynamic NMR study of three new pyridoxine derivatives, a potent nonlinear optical materials: 3‐isopropyl‐8‐methyl‐6‐(2‐nitrophenyl)‐1,5‐dihydro‐[1,3]dioxepino[5,6‐c]pyridine‐9‐ol ( I ), 3,3,8‐trimethyl‐6‐(2‐nitrophenyl)‐1,5‐dihydro‐[1,3]dioxepino[5,6‐c]pyridine‐9‐ol ( II ), and 9‐(2,4‐dinitrophenoxy)‐3,3,8‐trimethyl‐6‐(2‐nitrophenyl)‐1,5‐dihydro‐[1,3]dioxepino[5,6‐c]pyridine ( III ) (Fig. ).…”

Section: Introductionmentioning

confidence: 99%

Stereodynamics of some pyridoxine derivatives

Баландина

et al. 2016

The conformational properties of three pyridoxine derivatives were studied by H dynamic NMR spectroscopy. Conformational exchange caused by a rotation of 2-nytrophenyl group around one single C-C bond, of 2,4-dinitrophenyl substituent around two single C-O bonds, and twist-twist transformations of the seven-membered ketal cycle was observed by NMR experiments at low temperatures. Meanwhile, the conformational exchange of the acetal ring remains fast in the NMR timescale even at 198 K. The energy barriers for all observed conformational exchange processes were determined by the lineshape analysis of dynamic NMR spectra. The activation barriers of the 2-nitrophenyl group rotation were almost the same for all studied compounds, about 40-41 kJ/mol. The energy barriers of the conformational exchange processes of the 2,4-nitrophenyl group and the ketal cycle increased significantly up to 10 kJ/mol in comparison with previously studied compounds with similar structure. Copyright © 2016 John Wiley & Sons, Ltd.