NMR-spektroskopische Untersuchungen an Derivaten des 2,4-Dichlorphenoxyessigs�urehydrazids

Himmelreich, Uwe; Tschwatschal, F.; Borsdorf, Rolf

doi:10.1007/bf00814150

Cited by 15 publications

(2 citation statements)

References 8 publications

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“…For calculating ΔG { , the singlets of 7a-H and i-H in the 1 H-NMR spectra of N3 are chosen and the data are listed as below: It can be seen that the obtained ΔG { values are comparable to the ΔG { values of the conformation exchange at the single bond of N-C(O) (68-71 kJ/mol) of similar compounds [28,29], and therefore, the two observed structures are two conformers due to the hindered rotation around the hydrazide N-C(O) single bond, but they are not two geometrical isomers at the hydrazone N¼CH double bond. It has been pointed out that hydrazones derived from aldehydes and substituted hydrazides are present in the solution in the E-configuration at N¼CH bond [30]; in DMSO-d 6 , the major compound is E N-C(O) E N¼C isomer and the minor compound is Z N-C(O) E N¼C isomer [28,29]. Thus, it is clearly demonstrated that the two sets of resonance signals in the NMR spectra of the examined hydrazide-hydrazones are caused by the E N-C(O) E N¼C and Z N-C(O) E N¼C isomers.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and NMR Spectroscopic Characteristics of a Series of Hydrazide‐Hydrazones Containing Furoxan Ring Derived from Isoeugenoxyacetic Acid

Định

Lan²,

Trang

et al. 2012

Journal of Heterocyclic Chem

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A novel hydrazide, 2‐methoxy‐4‐(3‐methyfuroxan‐4‐yl)‐5‐nitrophenoxyacetylhydrazine, was prepared from isoeugenoxyacetic acid. The hydrazide was condensed with aromatic aldehydes to give a series of 20 hydrazide‐hydrazones incorporating the furoxan ring. The structure of obtained compounds was determined by analytical and spectral data. It was demonstrated that the two sets of resonance signals in the 1H‐NMR and 13C‐NMR spectra of the examined hydrazide‐hydrazones are caused by EN–C(O) and ZN–C(O) conformers. The energy barriers for the conformation exchange were determined by 1H‐NMR‐measurement at various temperatures. Among seven tested hydrazide‐hydrazones, four compounds exhibit inhibition activities in vitro on human epidermis carcinoma (KB‐cell) with IC50 = 47, 68, 79, and 103 μg/mL.

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Section: Resultsmentioning

confidence: 99%

Synthesis and NMR Spectroscopic Characteristics of a Series of Hydrazide‐Hydrazones Containing Furoxan Ring Derived from Isoeugenoxyacetic Acid

Định

Lan²,

Trang

et al. 2012

Journal of Heterocyclic Chem

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“…The hydrazones of aromatic aldehydes can exist as Z/E geometrical isomers about the CQN bond of the hydrazone moiety, as well as cis/trans amide conformers 23,[25][26][27] (Fig. 2).…”

Section: Characteristic Stretching Vibrations Observed In the Ftir Sp...mentioning

confidence: 99%

Synthesis and NMR and mass spectrometric study of ammonioacetohydrazones of formylphenylboronic acids as novel ionic prospective sugar receptors

et al. 2015

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Controlled Release of Volatile Aldehydes and Ketones from Dynamic Mixtures Generated by Reversible Hydrazone Formation

Levrand¹,

Fieber²,

Lehn³

et al. 2007

Helvetica Chimica Acta

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Delivery systems generated by reversible hydrazone formation from hydrazine derivatives (see Fig. 1) and carbonyl compounds in H 2 O efficiently increase the long-lastingness of volatile aldehydes and ketones (R 1 R 2 C¼O) in various perfumery applications. The hydrazones are usually obtained in an (E) configuration at the imine double bond (NHN¼C) and, in the case of aliphatic acylhydrazones R'COÀNHÀN¼CR 1 R 2 (R' ¼ alkyl), as syn and anti conformers with respect to the amide bond (COÀNHN). An average free-energy barrier of ca. 78 kJ/mol was determined for the amide-bond rotation by variable-temperature 1 H-NMR measurements ( Fig. 2). In the presence of H 2 O, the hydrazone formation is entirely reversible, reaching an equilibrium composed of the hydrazine derivative, the carbonyl compound, and the corresponding hydrazone. Kinetic measurements carried out by UV/VIS spectroscopy showed that the same equilibrium was reached for the formation and hydrolysis of the hydrazone. Rate constants are strongly pH-dependent and increase with decreasing pH ( Table 1). The influence of the hydrazine structure on the rate constants is less pronounced than the pH effect, and the presence of surfactants reduces the rate of equilibration (Tables 1 and 3). The full reversibility of the hydrazone formation allows to prepare dynamic mixtures by simple addition of a hydrazine derivative to several carbonyl compounds. Dynamic headspace analysis on dry cotton showed that the presence of a hydrazine derivative significantly increased the headspace concentrations of the different carbonyl compounds as compared to the reference sample without hydrazine ( Table 4). The release of the volatiles was found to be efficient for fragrances with high vapor pressures and low H 2 O solubility. Furthermore, a special long-lasting effect was obtained for the release of ketones. The simplicity of generating dynamic mixtures combined with the high efficiency for the release of volatiles makes these systems particularly interesting for practical applications and will certainly influence the development of delivery systems in other areas such as the pharmaceutical or agrochemical industry.

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NMR-spektroskopische Untersuchungen an Derivaten des 2,4-Dichlorphenoxyessigs�urehydrazids

Cited by 15 publications

References 8 publications

Synthesis and NMR Spectroscopic Characteristics of a Series of Hydrazide‐Hydrazones Containing Furoxan Ring Derived from Isoeugenoxyacetic Acid

Synthesis and NMR Spectroscopic Characteristics of a Series of Hydrazide‐Hydrazones Containing Furoxan Ring Derived from Isoeugenoxyacetic Acid

Synthesis and NMR and mass spectrometric study of ammonioacetohydrazones of formylphenylboronic acids as novel ionic prospective sugar receptors

Controlled Release of Volatile Aldehydes and Ketones from Dynamic Mixtures Generated by Reversible Hydrazone Formation

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