Showing papers on "Hydrazone published in 1977"

Azo Dye Tautomeric Structures Determined by Laser-Raman Spectroscopy

Abstract: Raman spectra of a number of azo dye structures have been analyzed. In azonaphthol and azopyrazol dyes, hydroxyazo to ketohydrazone tautomerizations, —N=N—C=C—OH →← —HN—N=C—C=O were observed in aqueous basic and acidic media. Observations of azo and ring vibrations, as well as hydrazone (C=N plus C=O) bands, were made. It was noted that the azo-anions (examined at pH 12) convert to the protonated neutral hydrazone (keto) form in aqueous acid (run at pH 2). Infrared spectra were used to confirm the presence of the C=O group in keto-tautomeric forms.

Oxidation by singlet oxygen of arylazonaphthols exhibiting azo–hydrazone tautomerism

Abstract: Self-sensitised and Methylene Blue-sensitised photo-oxidation of 4-arylazo-1- and 1-arylazo-2-naphthols gives 1,4- and 1,2-naphthoquinone, respectively, via the reaction of singles oxygen with the hydrazone tautomeric forms. The reactivity in both cases decreases with increasing electron-withdrawing strength of substituents in the aryl ring.

Hindered rotation about the metal–nitrogen bond in trans-dichlorodihydrazonepalladium(II) complexes and X-ray crystal structure of trans-bis(acetone methylphenylhydrazone)dichloropalladium(II)

Abstract: The complexes trans-[PdCl2L2][L = Me2CN–NMePh (L1); Et2CN–NMePh (L2); PrnMeCN–NMePh (L3); MeHCN–NMePh (L4); Me2CN–NMe2(L5); or MeHCN–NMe2(L6)] have been prepared by reaction of the hydrazone ligands with [PdCl2(NCPh)2]. The crystal and molecular structure of trans-[PdCl2(Me2CN–NMePh)2] has been determined from three-dimensional X-ray data. The complex crystallizes in the monoclinic space group P21/n with two molecules in a cell of dimensions a= 18.83(3), b= 7.53(2), and c= 7.76(2)A, β= 89.1(5)°. The palladium atom lies at a centre of symmetry; consequently the four ligating atoms, i.e. the two chloride ions and the two imino-nitrogens of the hydrazones, are located rigorously in a plane passing through the central metal. The co-ordination plane is nearly perpendicular to the plane containing the non-hydrogen atoms of the hydrazone skeleton Me2CN–N. Significant bond distances are Pd–Cl 2.298(4) and Pd–N 2.047(2)A. Another isomeric structure of this complex can be obtained by 180° rotation about the Pd–N bond of one of the two hydrazone ligands. This isomer is not centrosymmetric but contains a plane of symmetry which is perpendicular to the co-ordination plane and passes through the Cl–Pd–Cl axis. Both these isomers exist in equilibrium in solution for all the prepared complexes. Values of free energies of activation for the interconversion process have been obtained from temperatures of coalescence of the n.m.r. signals; they vary from 58 to 89 kJ mol–1 with the nature of the ligand substituents. In particular, complexes of hydrazones derived from aldehydes (L4 and L6) have ΔG‡ 10–14 kJ mol–1 lower than those of analogous hydrazones derived from ketones (L1–L3 and L5); complexes of hydrazones derived from methylphenylhydrazine (L1–L4) have ΔG‡ 17–21 kJ mol–1 lower than those of analogous hydrazones derived from dimethylhydrazine (L5 and L6).

Chemistry of polydentate ligands. Part 1. Condensation reactions of aldehydes and ketones with 6,6′-dihydrazino-2,2′-bipyridylnickel(II) perchlorate

Abstract: The complex 6,6′-dihydrazino-2,2′-bipyridylnickel(II) perchlorate has been prepared and its reactivity as a macrocyclic precursor investigated. This complex does not undergo cyclisation on reaction with acetone and other α-methyl ketones, or aldehydes, but preferentially forms a series of stable bis(hydrazone) complexes. The metal-free ligands have been isolated and manifest imino–azo tautomerism. This tautomerism has been studied by n.m.r. spectroscopy and evidence is presented for the formation of azo-hydroperoxide compounds.

Acetone picolinoyl hydrazone complexes of some first row transition metal ions

Abstract: Acetone picolinoyl hydrazone (APH) complexes of the types M(APH)Cl2nEtOH and M(APH-H)22EtOH (where M = manganese(II), iron(II), cobalt(II), nickel(II), or copper(II); n = 0 or 2) have been prepared and their nature and structures studied by molar conductance, molecular weight determination, thermal degradation, magnetic susceptibility, electronic and i.r. spectral measurements. Spin-free octahedral geometry has been proposed for all the complexes except Mn(APH)Cl2 and Co(APH)Cl2 for which tetrahedral geometry has been suggested.

Kinetics and product orientation in oxidation of aldehyde 2,4-disubstituted phenylhydrazones by lead tetra-acetate; hydrazone azo tautomers

Abstract: Oxidation of aliphatic aldehyde phenylhydrazones containing ortho-substituents (NO2, Br, or Me) in the N-phenyl ring with lead tetra-acetate-gives significant yields of α-unsubstituted azo-acetates which are azo tautomers of hydrazones. With aromatic aldehyde derivatives the product-orienting influence of the ortho-substituent in the N-phenyl ring was negated or reduced by the aromatic methine substituent. Kinetic measurements were made on series of aliphatic aldehyde 2,4-dinitrophenylhydrazones and 2-bromo-4-nitrophenylhydrazones. Strong steric effects (δ 0.83) for methine substituents were detected for the 2,4-dinitrophenylhydrazone series. The relative influences of the 2-NO2 and 2-Br substituents on the rates were examined. The 2-NO2 group had an exceptionally large rate-retarding effect. The mechanism of the reaction is discussed.

Use of Porous Polymer Containing Hydrazide Groups for Selective Removal of Carbonyl Compounds in Gas Chromatography

Abstract: An evaluation of a porous polymer containing hydrazide groups as a subtractor for aldehydes and ketones in gas chromatography was described Reactive species were subtracted in the gas phase due to the formation of hydrazone derivatives on the polymer and could be identified by their absence in the chromatograms The proposed stationary phase had selectivity for aldehydes and ketones, while alcohols, esters, ethers, halides, hydrocarbons and water showed no effect

Structure and Characterization of Copper(II) and Nickel(II) Complexes with 3-Acetyl-5,6-dimethylpyridazine Hydrazone, the Condensation Product of Biacetyl and Hydrazine

Abstract: Copper(II) and nickel(II) complexes, MLX2·nH2O (L=C16H24N8; X=Cl−, Br−, NO3−, ClO4−, BF4−; n=0, 2), were obtained by reacting diacetyl with hydrazine in the presence of a metal ion and characterized. The condensation product L was found to be 3-acetyl-5,6-dimethylpyridazine hydrazone. The molecular structure of NiL(ClO4)2·2H2O has been determined, the configuration around the nickel(II) ion being a distorted octahedron.

Interception of a metallo-intermediate in the oxidation of a bis-hydrazone: reactions of benzil (toluene-p-sulphonyl)hydrazones with lead(IV) and mercury(II) acetates

Abstract: Oxidation of benzil bis(toluene-p-sulphonyl)-hydrazone with mercuric acetate or lead tetra-acetate gave 4,5-diphenyl-1,2,3-triazol-1-yl-toluene-p-sulphon-amide; an unstable hydrazono–mercury acetate intermediate was isolated from the oxidation and comparative evidence for a subsequent diazo intermediate is presented.

1-Substituted phenyl-4(1H)-pyridinone hydrazones and composition therewith for treatment of coccidiosis

Abstract: Novel 1-substitutedphenyl-4(1H)-pyridinone hydrazones are prepared by reacting 1-substitutedphenyl-4(1H)-pyridinone hydrazone with substituted benzaldehydes. The novel hydrazones are useful as anticoccidial agents.

[On structure-activity relationships of N'methyl-N'-beta-chloroethyl-benzaldehyde hydrazones (author's transl)].

Abstract: The inhibition of uridine and thymidine in Ehrlich ascites cells is a basic property of the methylhydrazone structure and is reinforced by introducing a beta-chloroethyl group. This was shown by variation of the substituents at the N'-nitrogen atom of N'-methyl-N'-beta-chloroethyl-benzaldehyde hydrazone. Probably this action is due to an ethylenimmonium intermediate. This is derived from the observation that substituents which increase the nucleophilic property of the N'-nitrogen atom show a greater inhibitory effect in vitro. The therapeutic effect, however, is not enhanced when tested on the solid Ehrlich ascites tumor of mice. A better therapeutic effect resulted from introduction of chlorine atoms in positions 3 and 4 of the ring which inhbiits as well a probable metabolic hydroxylation of the ring.

A spectrophotometric assay of histaminase activity based on the hydrazone derivative of imidazole acetaldehyde with 2,4-dinitrophenylhydrazine.

Abstract: The activity of histaminase by using histamine as a substrate was spectrophotometrically estimated as the hydrazone derivative of imidazole acetaldehyde with 2, 4-dinitrophenylhydrazine (DNP). The measurement of enzyme activity in pig kidney was based on oxygen consumption in the presence of histamine by means of oxygen electrode, and the assay based on hydrazone derivative was performed with a spectrophotometer. In determination of oxygen consumption, there was a remarkable difference in the patterns of activities under the conditions of incubation temperature of 38°and 60°. The maximum activity of histaminase at 60°was about 2.4 times higher than that at 38°when the concentration of histamine was 10-4M. By measuring the absorbance of the hydrazone derivative of imidazole acetaldehyde formed in the presence of 3×10-4M histamine at 60°, it could be compared with oxygen consumption proportional to an increased amount of enzyme. Isooctane extractable hydrazones and unreacted DNP disturbed markedly the spectrophotometric assay, but these substances could be removed by use of a mixed solvent of isooctane and CHCl3. If aldehyde compound is formed over 1 μM/min or if oxygen is consumed over 15μM/min even in the incubation temperature of 38°, it is indicated that hydrazone derivative of aldehyde compound can be spectrophotometrically detected and that the assay method can be applied to the measurement of histaminase activity.

Process for forming carbonnphosphorus bond

Abstract: PURPOSE:The bond between phosphorus and carbonyl carbon of aldehyde or ketone ketone is formed in high yield by the addition of phosphine derivatives with hydrazone derivatives obtained by the reaction of hydrazine derivatives with aldehydes or ketones.

High barrier to rotation about the Pd–N bond in trans-dichloro-dihydrazonepalladium(II) complexes

Abstract: Newly synthesized trans-[PdCl2(R1R2CN1–N2R3R4)2] complexes have a high Pd–N1 rotational barrier which, in solution, gives rise to two isomers depending on the relative orientations of the hydrazone molecules with respect to each other (symmetrical in one isomer and asymmetrical in the other).

Basicities and ionization potentials of the hydrazones

Abstract: 1. Potentiometric titration in anhydrous acetonitrile has been used to calculate basicity factors (pK a values) for various hydrazones; protonation energies for the same compounds have been calculated by the CNDO/2 method. 2. It has been found that the values of pK a and the vertical ionization potential change regularly and antibatically in the hydrazone and azine series. 3. The basicities of the hydrazone amine and imine nitrogen atoms are almost identical in value, and, as a result, protonation center shift is observed in this series.

Derivatives of 4(7)-methyl- and 5,6-dimethyl-benzimidazolyl-2-mercaptoacetic acids.

Abstract: Esters, hydrazides and hydrazones of the in title mentioned acids were prepared and screened for tuberculostatic activity. The strongest activity (MIC at 15-6 mug/cm3) was shown by hydrazide 4 and its hydrazone 4a.

Investigation of the direction of the Fischer cyclization of arylhydrazones that are derivatives of hexahydrobenz[e]indene cyclization of a piperidine-2,3-dione 3-hydrazone

Abstract: The cyclization of the piperidine-2,3-dione 3-hydrazone obtained from the three-ring steroid BCD fragment proceeds with the primary formation of a p-substitution product. According to the PMR spectral data, the ratio of the para and ortho isomers is 3.3∶2.

Hindered rotation about the metal-nitrogen bond in trans-dichlorodihydrazonepalladium(ii) complexes and x-ray crystal structure of trans-bis(acetone methylphenylhydrazone)dichloropalladium(ii)

Abstract: The complexes trans-[PdCl2L2][L = Me2CN–NMePh (L1); Et2CN–NMePh (L2); PrnMeCN–NMePh (L3); MeHCN–NMePh (L4); Me2CN–NMe2(L5); or MeHCN–NMe2(L6)] have been prepared by reaction of the hydrazone ligands with [PdCl2(NCPh)2]. The crystal and molecular structure of trans-[PdCl2(Me2CN–NMePh)2] has been determined from three-dimensional X-ray data. The complex crystallizes in the monoclinic space group P21/n with two molecules in a cell of dimensions a= 18.83(3), b= 7.53(2), and c= 7.76(2)A, β= 89.1(5)°. The palladium atom lies at a centre of symmetry; consequently the four ligating atoms, i.e. the two chloride ions and the two imino-nitrogens of the hydrazones, are located rigorously in a plane passing through the central metal. The co-ordination plane is nearly perpendicular to the plane containing the non-hydrogen atoms of the hydrazone skeleton Me2CN–N. Significant bond distances are Pd–Cl 2.298(4) and Pd–N 2.047(2)A. Another isomeric structure of this complex can be obtained by 180° rotation about the Pd–N bond of one of the two hydrazone ligands. This isomer is not centrosymmetric but contains a plane of symmetry which is perpendicular to the co-ordination plane and passes through the Cl–Pd–Cl axis. Both these isomers exist in equilibrium in solution for all the prepared complexes. Values of free energies of activation for the interconversion process have been obtained from temperatures of coalescence of the n.m.r. signals; they vary from 58 to 89 kJ mol–1 with the nature of the ligand substituents. In particular, complexes of hydrazones derived from aldehydes (L4 and L6) have ΔG‡ 10–14 kJ mol–1 lower than those of analogous hydrazones derived from ketones (L1–L3 and L5); complexes of hydrazones derived from methylphenylhydrazine (L1–L4) have ΔG‡ 17–21 kJ mol–1 lower than those of analogous hydrazones derived from dimethylhydrazine (L5 and L6).

Hydrazone dithiophosphates and phosphonates and use thereof as insecticides

Abstract: Novel insecticidal compounds have the general structural formula ##STR1## in which each of R and R 2 is an alkyl or alkoxy group and each R 1 and R 3 is an alkoxy group.

Phosphorus-nitrogen compounds. 20. thiophosphorus hydrazones

Abstract: Six pyridine-2-carboxaldehyde, one pyridine N-oxide 2-carboxaldehyde, and five diketone thiophosphoric hydrazones, three thiophosphoric hydrazides, and two cupric chelates were synthesized. The chelates and nine of the hydrazones were tested against Ehrlich ascites carcinoma. Seven of these latter agents were administered concurrently with either cupric and/or ferrous salts to mice bearing this tumor. The greatest activity was found with the chelate, cimethyl pyridine-2-carboxyaldehyde phosphorothioic hydrazone-copper (1:1). The hydrazone portion of this chelate also formed a ligand-copper (2:1) complex. Although all of the hydrazones but one were inactive when evaluated alone, the concurrent injection of cupric ion increased survival times by an avoli alkaline phosphatase was found to be inhibited by two thiosemicarbazones in a manner similar to that previously reported by these agents against alkaline phosphatase derived from Sarcoma 180-6-thiopurine resistant ascites cells. None of the 14 hydrazides or hydrazones tested against E. coli enzyme displayed significant inhibition.

Photographic elements in which gelatin silver halide layers contain polymers with semicarbazone or alkoxy carbonyl hydrazone groups

Abstract: Abrasion marks by dry-friction and the tendency of producing pressure-scratches in photographic materials is reduced by incorporating in the gelatin silver halide emulsion layers polymeric compounds containing recurring units with semicarbazone or alkoxy carbonyl hydrazone groups in the side-chains. These recurring units are represented by one of the formulae: ##STR1## wherein: A is a single bond or --CONH-alkylene-, --COO-alkylene-, or phenylene, B is a single bond or alkylene, R 1 is hydrogen or methyl, R 2 is hydrogen, phenyl or lower alkyl (1-4 C), R 3 is --NH--COOR or ##STR2## wherein R is lower alkyl (1-4 C) and each of R 4 , R 5 and R 6 is hydrogen or lower alkyl (1-4 C).

Application of Pschorr reaction to N-(o-aminobenzoyl)-benzyl and phenethyl amines and to N-(o-aminophenylacetyl) anilines

Abstract: Decomposition of the diazonium chloride from N-(o-aminobenzoyl)-N-methylbenzylamine led to the formation of 3-benzyl-3, 4-dihydrobenzo-triazin-4-one (8), N-benzoylbenzylamine (11), N-benzylphthalimidine (13) ando-diphenic acid N-methyl amide (14), the last one presumably through the intermediary, the expected dibenzazepinone 16 From the analogue, N-(o-aminobenzoyl)-4-methoxybenzyl amine (4), triazinone 10 and N-benzoyl-4-methoxybenzyl amine (12) were obtained Application of Pschorr reaction to N-(o-aminobenzoyl)-N-methyl-β-(4-methoxyphenyl) ethyl amine (23) afforded 2-methoxy-7-methyl-5, 6, 7, 8- tetrahydrodibenzo (c, e) azocin-8-one (26), with an interesting conformation From N-(o-aminophenylacetyl)-p-methoxyaniline were obtained under these conditions, indazole-3-carboxylic acidp-anisidide (35) and N-[2-(4-methoxyphenyl carbamoylmethyl) phenyl]-1-(p-methoxyphenyl) isatin-β-hydrazone (37) The structure of 37 was deduced from spectral data and hydrolysis to the acid 42 Diazotisation of N-(o-aminophenylacetyl)-1, 2, 3, 4-tetrahydroquinoline (47) led to the formation of tetrahydroquinoline (49) ando-hydroxyphenyl acetic acid (50) presumably through the salicylamide 48 A similar reaction on N-(o-aminophenylacetyl) tetrahydroisoquinoline (52) gave the benzofurandione hydrazone 55, besides tetrahydroisoquinoline Oxindole 45 and benzofuranone 56 were likely precursors for 37 and 55 respectively Salicylamides 5, 7, 24 and 34 were byproducts in the Pschorr reaction