scispace - formally typeset
Search or ask a question
Topic

Hydrazone

About: Hydrazone is a research topic. Over the lifetime, 4853 publications have been published within this topic receiving 65160 citations. The topic is also known as: hydrazone.


Papers
More filters
Journal ArticleDOI
TL;DR: It was concluded that all condensations/cycloeliminations, except with hydrazine itself, were more effective with catalysts or higher reaction temperatures.
Abstract: An efficient and selective method for the synthesis of spiro-fused (C5)-isoxazolino-(C4)-pyrazolones (C) is reported. The process consists of utilizing the Baylis−Hillman reactionor a quicker, stepwise MAC procedureto give I followed by 1,3-dipolar cycloaddition and Swern oxidation to give β-ketoesters H, which were condensed with hydrazine derivatives to provide hydrazones that underwent cycloelimination. These novel spiro-fused (C5)-isoxazolino-(C4)-pyrazolones were confirmed by spectroscopic analysis as well as single-crystal X-ray of 5. We also concluded that all condensations/cycloeliminations, except with hydrazine itself, were more effective with catalysts or higher reaction temperatures. For example, TiCl4 was an efficient catalyst for hydrazone formation and cycloelimination with methylhydrazine, while phenyl-, benzyl-, and (4-methoxyphenyl)hydrazine reacted effectively without catalyst in refluxing xylene.

30 citations

Journal ArticleDOI
TL;DR: All structural kinds of hydrazones, having at least one hydrogen atom on nitrogen, are prone to autoxidation; however, there are marked differences in the rate of the reaction, leading mostly to the formation of alpha-azohydroperoxides.
Abstract: Autoxidation of hydrazones is a generally occurring reaction, leading mostly to the formation of α-azohydroperoxides. All structural kinds of hydrazones, having at least one hydrogen atom on nitrogen, are prone to autoxidation; however, there are marked differences in the rate of the reaction. Hydrazones of aliphatic ketones are 1−2 orders of magnitude more reactive than analogous derivatives of aromatic ketones. Even less reactive are the hydrazones of chalcones, which function also as efficient inhibitors of autoxidation of other hydrazones. These differences can be attributed to the reduction of the rate of the addition of oxygen to a hydrazonyl radical, which is a reversible reaction. In the case of conjugated ketones, it becomes endothermic, making this elementary step slow down and the chain termination reactions become important. Substituents influence the stability of hydrazonyl radicals and, consequently, the bond dissociation energies of the N−H bonds. In acetophenone phenylhydrazones, the subst...

30 citations

Journal ArticleDOI
TL;DR: In silico, in vitro and in vivo investigations of ZE-4b, Ze-4c,ZE-5a and ZE -5b prove their antiplatelet and anticoagulant potential and can be used as lead molecules for further development.
Abstract: In the present study, a series of new hydrazone and sulfonamide derivatives of 1,2,4-triazole were synthesized. Initially three 4-substituted-5-(2-pyridyl)-1,2,4-triazole-3-thiones ZE-1(a–c) were treated with ethyl chloroacetate to get the corresponding thioesters ZE-2(a–c), which were reacted with hydrazine hydrate to the respective hydrazides ZE-3(a–c). The synthesized hydrazides were condensed with different aldehydes and p-toluene sulfonylchloride to furnish the target hydrazone derivatives ZE-4(a–c) and sulfonamide derivatives ZE-5(a–c) respectively. All the synthesized compounds were characterized by FTIR, 1HNMR, 13CNMR and elemental analysis data. Furthermore, the new hydrazone and sulfonamide derivatives ZE-4(b–c) and ZE-5(a–b) were evaluated for their antiplatelet and anticoagulant activities. ZE-4b, ZE-4c, ZE-5a and ZE-5b inhibited arachidonic acid, adenosine diphosphate and collagen-induced platelets aggregation with IC50 values of 40.1, 785 and 10.01 (ZE-4b), 55.3, 850.4 and 10 (ZE-4c), 121.6, 956.8 and 30.1 (ZE-5a), 99.9, 519 and 29.97 (ZE-5b) respectively. Test compounds increased plasma recalcification time (PRT) and bleeding time (BT) with ZE-4c being found most effective, which at 30, 100, 300 and 1000 µM increased PRT to 84.2 ± 1.88, 142 ± 3.51, 205.6 ± 5.37 and 300.2 ± 3.48 s and prolonged BT to 90.5 ± 3.12, 112.25 ± 2.66, 145.75 ± 1.60 s (P < 0.001 vs. saline group) respectively. In silico docking approach was also applied to screen these compounds for their efficacy against selected drug targets of platelet aggregation and blood coagulation. Thus in silico, in vitro and in vivo investigations of ZE-4b, ZE-4c, ZE-5a and ZE-5b prove their antiplatelet and anticoagulant potential and can be used as lead molecules for further development.

30 citations

Journal ArticleDOI
TL;DR: Simultaneous treatment with all mixed forms of the polymeric derivatives of doxorubicin significantly increased antitumor efficacy after application of monoconjugates, suggesting a synergizing effect that could be used in designing new doxorbicin-containing therapeutic systems.
Abstract: The cytostatic effects of polymeric conjugates based on N-(2-hydroxypropyl)methacrylamide copolymers (PHPMA) and containing doxorubicin bound through amide and hydrazone bonds (mixed conjugates) were compared with the cytostatic effects of monoconjugates containing drug bound through an amide or hydrazone bond. One group of mixed conjugates was formed from two comonomers containing doxorubicin bound to the methacryloyl group through a spacer and an amide (DOXAM) or hydrazone (DOXHYD) bond via copolymerization with HPMA. A second group of mixed conjugates was formed from two different interconnected HPMA copolymers, one containing DOXAM and the other DOXHYD, forming a high-molecular-weight branched structure. The third mixed polymeric system was a simple mixture of monoconjugates DOXAM−PHPMA and DOXHYD−PHPMA. Simultaneous treatment with all mixed forms of the polymeric derivatives of doxorubicin significantly increased antitumor efficacy after application of monoconjugates, suggesting a synergizing effect ...

30 citations

Journal ArticleDOI
TL;DR: A detailed mechanism for the adduct I formation in WT has been proposed that is consistent with the mechanism proposed for the oxidation of substrate by CAOs but addresses some key differences in the active site chemistry of hydrazine inhibitors and substrate amines.
Abstract: 2-Hydrazinopyridine (2HP) is an irreversible inhibitor of copper amine oxidases (CAOs) 2HP reacts directly at the C5 position of the TPQ cofactor, yielding an intense chromophore with lambda(max) approximately 430 nm (adduct I) in Escherichia coli amine oxidase (ECAO) The adduct I form of wild type (WT-ECAO) was assigned as a hydrazone on the basis of the X-ray crystal structure The hydrazone adduct appears to be stabilized by two key hydrogen-bonding interactions between the TPQ-2HP moiety and two active site residues: the catalytic base (D383) and the conserved tyrosine residue (Y369) In this work, we have synthesized a model compound (2) for adduct I from the reaction of a TPQ model compound (1) and 2HP NMR spectroscopy and X-ray crystallography show that 2 exists predominantly as the azo form (lambda(max) at 414 nm) Comparison of the UV-vis and resonance Raman spectra of 2 with adduct I in WT, D383E, D383N, and Y369F forms of ECAO revealed that adduct I in WT and D383N is a tautomeric mixture where the hydrazone form is favored In D383E adduct I, the equilibrium is further shifted in favor of the hydrazone form UV-vis spectroscopic pH titrations of adduct I in WT, D383N, D383E, and 2 confirmed that D383 in WT adduct I is protonated at pH 7 and stabilizes the hydrazone tautomer by a short hydrogen-bonding interaction The deprotonation of D383 (pKa approximately 97) in adduct I resulted in conversion of adduct I to the azo tautomer with a blue shift of the lambda(max) to 420 nm, close to that of 2 In contrast, adduct I in D383N and D383E is stable and did not show any pH-dependent spectral changes In Y369F, adduct I was not stable and gradually converted into a new species with lambda(max) at approximately 530 nm (adduct II) A detailed mechanism for the adduct I formation in WT has been proposed that is consistent with the mechanism proposed for the oxidation of substrate by CAOs but addresses some key differences in the active site chemistry of hydrazine inhibitors and substrate amines

30 citations


Network Information
Related Topics (5)
Aryl
95.6K papers, 1.3M citations
91% related
Ligand
67.7K papers, 1.3M citations
90% related
Alkyl
223.5K papers, 2M citations
90% related
Ruthenium
40.1K papers, 996.5K citations
88% related
Supramolecular chemistry
25.1K papers, 878.4K citations
88% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023230
2022455
2021122
2020152
2019158
2018153