Vanadametry

Summary A vanadametric method has been developed which has definite advantages over iodimetric assay and bromimetric assay for the estimation of isonicotinic acid hydrazide in tablets. The excepients such as lactose, glucose and starch do not interfere in the estimation of the hydrazide with vanadate. Unlike iodimetric and bromimetric assays, the vanadametric assay is rapid.See also Z. analyt. Chem. 160, 117 (1958).     

Determination of Nitrite via Reaction with Pyridine-4-Carboxylic Acid Hydrazide

Abstract

Nitrite is determined by its reaction with a measured but excessive amount of pyridine-4-carboxylic acid hydrazide in acid medium (when the two substances react in a 1:1 molar ratio) and evaluation of the surplus hydrazide by titration with chloramine-T in the presence of acidified potassium bromide, the end-point being shown by the decolorization of the methyl red indicator. Nitrate, copper(II), mercury(II), etc. are found not to interfere, and the determination of nitrite in the presence of diazotized aromatic amines is demonstrated.     

ONE-POT SYNTHESIS OF 1,2,4-TRIAZINES

ABSTRACT

1,2,4-Triazines have been prepared from the one-pot condensation reaction of acid hydrazide (1), ammonium acetate and dicarbonyl compounds (2) on the surface of silica gel in the presence of triethylamine under microwave irradiation.     

Facile and expedient synthesis and anti-proliferative activity of diversely pyrrolones bearing 1,3-diphenylpyrazole moiety

Abstract

A series of some pyrrolone derivatives were synthesized from the acid hydrazide, derived from a pyrazolyl-2(3H)-furanone, through treating with some carbonyl reagents such as 1-phenyl-3-(thiophen-2-yl)-1H-pyrazole-4-carbaldehyde, formic acid, lauroyl chloride, succinoyl chloride, propionic anhydride, as well as, ethoxymethylene malononitrile. All compounds were obtained in good yields and characterized by their microanalytical and spectral data. The synthesized products were evaluated for their in vitro antitumor activity against two human carcinoma cell lines (HCT-116 and MCF7) using doxorubicin as a reference drug by MTT assay. The results revealed that some compounds exhibited significant potency. Noteworthy, the N-propionyl hydrazide derivative was the most potent against both cell lines.     

Determination of Optimum Time and Temperature for the Reaction of Selected Conjugated 3-Ketosteroids with Isonicotinic Acid Hydrazide Reagent

Abstract

The reaction of selected conjugated 3-ketosteroids with isonicotinic acid hydrazide (INH) reagent in methanol was investigated. The Δ^{1, 4}?3-ketosteroids differed considerably from the Δ⁴ -3-ketosteroids with regard to the wavelength of maximum absorbance and to the reaction time and temperature required to attain maximum absorbance readings. Optimum conditions resulting in stable, maximum absorbance readings were determined experimentally for 17 standard compounds.     

系列新型硫杂杯[4]芳烃氮杂衍生物的合成

在对叔丁基硫杂杯[4]芳烃的下缘1,3位引入芳醛基, 合成了硫杂杯[4]二醛基衍生物2. 化合物2与苯胺、水杨酰肼、烟酰肼、异烟酰肼等通过席夫碱缩合反应得到新型硫杂杯[4]氮杂衍生物3a～3d, 产率分别为83%, 80%, 77%和79%. 化合物2与邻苯二胺、乙二酰肼、丙二酰肼、己二酰肼等通过“1＋1”分子间缩合得到新型1,3-桥联硫杂杯[4]氮杂衍生物4a～4d, 产率53%, 51%, 59%和66%. 新化合物的结构经IR, ¹H NMR, MS和元素分析等证实.     

新型多重氮杂杯[4]芳烃衍生物的合成

对叔丁基杯[4]芳烃-1,3-二醛基衍生物1与水杨酰肼、烟酰肼、异烟酰肼反应, 合成了具有开链结构新型杯[4]多重氮杂衍生物2a～2c, 产率分别为88%, 85%和90%. 化合物1与乙二酰肼、丙二酰肼、己二酰肼反应, 得到具有桥联结构的新型杯[4]多重氮杂衍生物3a～3c, 产率分别为86%, 89%和90%. 新化合物的结构经元素分析、质谱、核磁共振谱等表征证实, 杯[4]芳烃单元均为1,3-取代且采取锥式构象.     

Synthesis and Biological Activities of Novel 1,4-Bridged Bis-1,2,4-Triazoles,Bis-1,3,4-Thiadiazoles and Bis-1,3,4-Oxadiazoles

Abstract

The terephthalic acid hydrazide(1) reacted with phenyl/benzyl isothiocyanate2a,bto yield the corresponding bis-thiosemicarbazides4a,b,viaacid hydrolysis of the intermediate 3whereas cyclization of4gave the bis-1,2,4-triazoles 5,6and bis-1,3,4-thiadiazoles7,8. Similarly, compound 1reacted with phenyl isocyanate9to give the bis-semicarbazide10, which was cyclized to the bis-oxadiazole 11and/or bis-1,2,4-triazole12in POCl_ti3and NaOH respectively.     

Thermal degradation of polymethacrylic acid

The thermal degradation of polymethacrylic acid was found to have two separate decomposition regions. The first decomposition region, due to anhydride formation primarily, was caused by the conversion of polymethacrylic acid to polymethacrylic anhydride. This reaction followed first-order kinetics and had an activation energy of 40.5 kcal/mol. The second decomposition region was the thermal degradation for the corresponding polymethacrylic anhydride. In this region, the fragmentation of anhydride rings structure in polymethacrylic anhydride constitutes the major decomposition reaction with an activation energy of 37.4 kcal/mol. © 1992 John Wiley & Sons, Inc.     

Reactions of derivatives of phosphorylacetic acid hydrazides with 3,5-di-tert-butyl-4-hydroxybenzyl acetate

Abstract

To obtain new polyfunctional inhibitors of radical-chain oxidative processes, C- and N-benzylation of a number of phosphorylacetic acid hydrazide derivatives is realized in their reactions with 3,5-di-tert-butyl-4-hydroxybenzyl acetate. N-benzylation of mixtures of Z and E isomers of hydrazones of phosphorylacetic acid derivatives proceeds stereoselectively with the formation of only E_C=N isomers.     

Molecular brushes with long polyfluorene backbones and polymethacrylic acid side chains: Luminescent properties and self-organization in solutions

A series of molecular brushes with a polyfluorene (PF) backbone and polymethacrylic acid side chains of varying lengths were prepared by atom transfer radical polymerization. The structure and composition of the synthesized compounds were confirmed by ¹H NMR and IR spectroscopy. Effect of the length of the backbone on spectral and conformational parameters of the macromolecules in solutions was analyzed. The grafting density of side chains was about 90%. Spectral methods have been used to determine the dependence of side chain grafting on the luminescent properties of polymer solutions, including quantum yields. It was shown that an optimal length of polymethacrylic acid side chains provides solubility of the polymer brushes. Solutions of PF-graft-polymethacrylic acid complexes with the model substance curcumin were investigated. It was established that the molecular brushes containing curcumin form monomolecular micelles. Molecular brushes with zinc phthalocyanine, potential systems for photodynamic, and photothermal therapy, were studied.     

Facile Synthesis of Benzotriazines and Indoles by Ring-Scissions of α-Benzotriazol-1-yl Hydrazones

Abstract: α-(Benzotriazol-1-yl)hydrazones 2a-d and 13a-c were prepared by refluxing the corresponding α-(benzotriazol-1-yl)ketones with p-tosyl hydrazide or benzenesulfonyl hydrazide. Treatment of 2a-b with n-butyllithium in the presence of TMEDA gave benzotriazines 6a-b, while lithiation of 13a-c resulted in indole derivatives 16a-c, depending on the structure of the hydrazones.     

Synthesis and Biological Activity of 2-Hydroxy-N(5-methylene-4-oxo-2-aryl-thiazolidin-3-yl)-benzamide

2-Hydroxy benzoic acid hydrazide (1) undergoes facile condensation with aromatic aldehydes to afford the corresponding 2-hydroxy benzoic acid arylidene hydrazides (2a–h) in good yields. Cyclocondensation of compounds 2a–h with thioglycolic acid yields 2-hydroxy-N(4-oxo-2-aryl-thiazolidin-3-yl)-benzamides (3a–h). These 3a–h compounds are for the reacted with benzaldehyde in the presence of sodium ethanolate affords, giving 2-hydroxy-N(5-methylene-4-oxo-2-aryl-thiazolidin-3-yl)-benzamides (4a–h). The structures of these compounds were established on the basis of analytical and spectral data. All the newly synthesized compounds were evaluated for their antibacterial and antifungal activities.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and antitumor activity evaluation of some N-heterocycles derived from pyrazolyl-substituted 2(3H)-furanone

Pyrazolyl-substituted 2(3H)-furanone was allowed to react with different nitrogen nucleophiles such as hydrazine hydrate, ethylenediamine, ethanolamine, and anthranilic acid to give pyrrolone and benzoxazinone derivatives. The acid hydrazide 3 was reacted with some carbonyl compounds such as 4-chlorobenzaldehyde, chloroacetyl chloride, and acetic anhydride to give thiazolidinone, oxadiazole, and pyridazinone derivatives. Selected examples of the synthesized compounds were evaluated as anticancer agents against three types of carcinoma cell lines (HePG 2, HCT116, and PC3), using Doxorubicin as a reference drug. The result revealed that some of the new compounds showed high activities. Compound 6a was more potent than the standard drug. A docking study using MOE 2008.10 program was performed.     

Synthesis,Antimicrobial, and Anthelmintic Activities of Some New 3-Chlorobenzothiophene-2-Carbonylchloride Derivatives

3-Chlorobenzothiophene-2-carbonylchloride 1 was prepared from cinnamic acid and then converted into the acid hydrazide 2. Reaction of 3-chloro-1-benzothiophene-2-carbohydrazide 2 with the appropriate isothiocyanate yielded the substituted thiosemicarbazides 3a–b, which are cyclized into thioxotetrahydropyrimidine 4a–b, 1,3,4-thiadiazoles 5a–b, thiazolidine 6a–b, 1,3,4-oxadiazole 7a–b, triazoles 8a–b, 1,2,4-triazole substitutedthioate 9a–f, and 1,3-thiazolylidenes 10a–b, respectively. The structures of the newly synthesized compounds were elucidated on the basis of elemental analyses, IR, ¹H NMR, and mass spectral data and have been screened for antimicrobial and anthelmintic activities.     

Antianexiety activity of pyridine derivatives synthesized from 2-chloro-6-hydrazino-isonicotinic acid hydrazide

A series of oxadiazole pyridine derivatives were synthesized by using 2-chloro-6-hydrazinoisonicotinic acid hydrazide as starting material. Treatment of the hydrazide with carbon disulfide to afford the oxadiazole derivative, which was treated with 5-methyl-2-furancarbaldehyde, formic acid, acetic acid/acetic anhydride, or phthalic anhydride to yield the corresponding pyridinodiazoles and on imide. Condensation of the hydrazide with p-fluorobenzaldehyde in ethanol or acetic acid in the presence of sodium acetate afforded hydrazone and oxadiazole derivatives, which were acetylated and cyclized with acetic anhydride to N-acetyloxadiazole derivatives. The hydrazone was treated with acetic acid in the presence of sodium acetate, or bromine water/sodium acetate to give on oxadiazole, while it was cyclized with chloroacetyl chloride in the presence of TEA to oxoazetidinaminoisonicotinamide. Finally, condensation of the hydrazide with acid anhydrides in refluxing glacial acetic acid afforded the corresponding bisimide derivatives. The pharmacological screening showed that many of these obtained compounds have good antianexiety activity comparable to diazepam^® as positive control.     

Synthesis and antitumor activity evaluation of some novel pyrazolotriazine derivatives

6-Aminopyrazolo[1,2-a][1,2,4]triazine-4,8-dione derivative 3 was obtained upon the reaction of the acid hydrazide derivative 2a with ethyl cyanoacetate. The reactions of 3 with several electrophiles such as aldehydes, isatin, acetic anhydride, phenyl isocyanate, benzoyl isothiocyanate, and p-toluenesulfonyl chloride were studied. The structures of the newly synthesized compounds were established on the basis of IR, ¹H NMR, mass spectra, and elemental analyses. The antitumor activities of some selective compounds were examined against two cell lines as liver carcinoma cell line (HEPG-2) and human breast cancer cell line (MCF7).     

Efficient atom-economic one-pot multicomponent synthesis of benzylpyrazolyl coumarins and novel pyrano[2,3-c]pyrazoles catalysed by 2-aminoethanesulfonic acid (taurine) as a bio-organic catalyst

The present work describes eco-friendly multicomponent protocol for the synthesis in excellent yields of structurally diverse benzylpyrazolyl coumarin 5 (a–s) involving the reaction of 4-hydroxycoumarin, ethyl acetoacetate, hydrazine hydrate/phenyl hydrazine hydrate and aldehydes, also novel pyrano[2,3-c]pyrazole derivatives 8 (a–k) integrated by isonicotinic acid hydrazide from reaction of aldehyde, ethyl acetoacetate, malononitrile with isoniazid, employing water as a reaction medium and 2-aminoethanesulfonic acid (taurine) as the catalyst. This new methodology endowed the advantages such as short reaction time, recovery of catalysts after catalytic reaction and reusing them without losing their activity and alleviate of operation.     

Mixed ligand complexes of tungsten(VI) containing aroyl hydrazones and isothiocyanate

Five complexes [WO(NCS)₄L–L] (where L–L = benzoic acid[1-(Furan-2-yl)methylene]hydrazide(BFMH), benzoic acid[(thiophen-2-yl)methylene]hydrazide(BTMH), benzoic acid[1-(thiophen-2-yl)ethylidene]hydrazide(BTEH), benzoic acid(phenylmethylene)hydrazide(BPMH) and benzoic acid[1-(anisol-3-yl) methylene]hydrazide(BAMH)) have been prepared by reaction of ammonium tetraisothiocyanatodioxotungstate(VI) with the corresponding ligand in aqueous medium in the presence of hydrochloric acid. The complexes have been characterized by elemental analysis, molar conductivity, magnetic moment measurements, IR, electronic spectra, thermogravimetric analysis TGA/DTA and ¹H NMR.     

Effects of Some Phosphorylacetic Acid Hydrazides on Periferal Cholinegric Neurotransmission

Abstract

Cholinergic deficit has received considerable attention with respect to the development of therapeutic agents designed to ameliorate the cognitive symptomatology of the dementias. The influence of (2-chloroethoxy) (p-N,N- dimethylaminophenyl) phosphorylacetic acid hydrazide (CAPAH) and diphenylphosphorylacetic acid hydrazide (PHOSENAZID) on the processes of the synaptic transmission in the neuromuscular synapses of frog and rat was studied. Experiments revealed that the effectiveness of CAPAH was concentration- dependent: in low concentrations (10 - 100 nM) neuromuscular junction miniature end-plate currents (MEPC) were attenuated by 15 - 20 % (sensitising effect); at higher concentrations (0.1 mM) h4EPC amplitude was reduced. This effect was similar to that seen with blockers of the sodium channel component of the nicotinic receptor The HCI-salt of CAPAH also had a sensitising effect in low concentrations (1 - 10 nh4). By contrast, PHOSENAZID was not effective at low concentrations. These differences in the effects of CAPAH and PHOSENAZID on cholinergic neurotransmission appear dependent in changes in the phosphyl fragment of the molecule.