Alkylhydrazides and their protonated forms: Physical methods andab initio calculations

Фешин, В. П.; Kon'shin, M. Yu.; Radushev, A. V.; Фешина, Е. В.; Gusev, V. Yu.; Леснов, А. Е.; Karmanov, V. I.

doi:10.1007/bf01431104

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…The latter value is in good agreement with previous data reported for the higher hydrazides of aliphatic carboxylic acids [35], where dissociation constants of the molecules show little change with n in H(CH 2 ) n C(O)NHNH 2 (n = 5-12) and they are in the range 3.42(1)-3.78(1).…”

Section: Protonation Equilibria Of the Studied Ligandssupporting

confidence: 91%

“…Based on previous research associated with the possibility of O?N rearrangement [35][36][37][38] it can be concluded that the ligands: oxalodihydrazide, acethydrazide and formic hydrazide exist in two tautomeric forms (Scheme 1). Intramolecular proton transfer occurs between the enol (OH) form predominating in alkaline medium and the keto (NH) form predominating in an acidic environment [11,39].…”

Section: Protonation Equilibria Of the Studied Ligandsmentioning

confidence: 97%

“…In such an environment the molecule exists in the keto form. As the carbonyl oxygen has the lowest negative charge with respect to the N atoms, this is the least preferred site for attachment of a proton and C@O, and is hence not protonated [35]. Therefore, protonation is only possible for the amino and amide groups.…”

Section: Protonation Equilibria Of the Studied Ligandsmentioning

confidence: 98%

“…This continues until the ligand curve overlaps the acid curve (from pH 3.8 for oxalodihydrazide to pH 5.0 for acethydrazide) which denotes overall neutralization of the acid in the two solutions. In alkaline medium the carbonyl oxygen has the highest electron density [35] and the hydrazide exists in the enol form with AOAH, CAO and C@N groups (Scheme 1), where the proton in AOH is derived from the amide group [37]. Under these conditions (pH above 8.0) divergence of the ligand curve from the acid curve is caused by the evolvement of a proton from the ligand [13].…”

Section: Protonation Equilibria Of the Studied Ligandsmentioning

confidence: 99%

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The complexing properties of oxalodihydrazide, acethydrazide and formic hydrazide with Cu(II) in aqueous solution

Woźniczka

Szajdzińska‐Piętek

Jezierska

et al. 2017

Inorganica Chimica Acta

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Section: Protonation Equilibria Of the Studied Ligandssupporting

confidence: 91%

Section: Protonation Equilibria Of the Studied Ligandsmentioning

confidence: 97%

Section: Protonation Equilibria Of the Studied Ligandsmentioning

confidence: 98%

Section: Protonation Equilibria Of the Studied Ligandsmentioning

confidence: 99%

See 2 more Smart Citations

The complexing properties of oxalodihydrazide, acethydrazide and formic hydrazide with Cu(II) in aqueous solution

Woźniczka

Szajdzińska‐Piętek

Jezierska

et al. 2017

Inorganica Chimica Acta

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Oligonucleotide Analogues with Integrated Bases and Backbone. Part 20

Peifer

Giacomo

Schandl

et al. 2009

Helvetica Chimica Acta

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Hydrazide-and amide-linked oligonucleoside analogues with integrated bases and backbone were designed to allow for a rapid synthesis of long and water-soluble oligomers. The uracil-, cytosine-, and adenine-derived hydrazide building blocks 13 -15 were synthesized by nucleophilic substitution with the hydrazine 23 of the halides 19, 28, and 34, derived from the alcohols 18, 27, and 33, respectively, while the uracil-, cytosine-, and adenine-derived amide building blocks 45 -47 were synthesized by a Curtius degradation of the carboxylic acids 51, 56, and 61. These acids were obtained by Wittig reaction of the aldehydes 49, 53, and 58. The guanine-derived monomers 44 and 48 were synthesized by reductive cyclisation of the nitroso amides 38 and 63, respectively, resulting from acylation of the known 2,6diamino-4-(benzyloxy)-5-nitrosopyrimidine (37).Stacking of the nucleobases and the right geometry for Watson -Crick base pairing required adjusting the torsion angles k, x, and z from À 50, 180, and À 90 to À 70, þ 70, and À 1008, respectively ( Fig. 1, b ! c). We assumed that changing k and z from their energetically ideal values will result in only little torsional strain, and that the energy to be paid would be overcompensated by the H-bonds between the nucleobases [11] [25], and by base stacking [26]. However, calculations 7 ) to evaluate the energy to be paid for the adjustment of the torsion angle x from 1808 to þ 708 gave contradictory results 8 ). It is thus not possible to specify an overall energy value to be paid for the conformational transition from conformer b to c in Fig. 1.Modelling studies of various dimers suggested that stacking interactions depend on the sequence, and decrease in the order UA % UU % AA > AU. To evaluate the formation of duplexes between longer oligonucleotide analogues, we minimised the conformational energy of the octamer U 4 A 4 (Fig. 3) 9 ). The model suggested Watson -Crick-type base pairing and base stacking, with the hydrazide linker adopting a conformation with torsion angles k -z as deduced for the cyclic duplex (Fig. 1, c). The Helvetica Chimica Acta -Vol. 92 (2009) 1138. Model of the hydrazide-linked octamer U 4 A 4 . a) Side view. b) Top view. 7 ) Ab initio calculations using Spartan 06 and the 6-31G* basis set. 8 ) The conformational energies of N-methyl-2-(6-methyluracil-1-yl-)acetamide and N-methyl-2-(8methyladenine-9-yl-)acetamide were minimised, resulting in an energy minimum of x ¼ À 708 (cf. experimentally favoured: x ¼ 1808). The value of x ¼ 708, required for duplex formation, corresponds to a calculated energy maximum. 9 ) Amber* force-field calculation using Macromodel 7.0, with the H-bonds between the nucleobases constrained.

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Anti-oxidative reactivity and mechanism of formic hydrazide, acethydrazide and butyrohydrazide towards reduction of single electron oxidant iridium(IV)

Tian,

Fu,

Ren

et al. 2024

Journal of Molecular Liquids

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Alkylhydrazides and their protonated forms: Physical methods andab initio calculations

Cited by 4 publications

References 8 publications

The complexing properties of oxalodihydrazide, acethydrazide and formic hydrazide with Cu(II) in aqueous solution

The complexing properties of oxalodihydrazide, acethydrazide and formic hydrazide with Cu(II) in aqueous solution

Oligonucleotide Analogues with Integrated Bases and Backbone. Part 20

Anti-oxidative reactivity and mechanism of formic hydrazide, acethydrazide and butyrohydrazide towards reduction of single electron oxidant iridium(IV)

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