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Electrochemical reduction ofortho-nitroanilides in an aprotic medium has been studied by polarography and ESR. It has been shown that nitroanilide anion-radicals are formed at the first reduction wave potentials. The transfer of a second electron is accompanied by subsequent reactions (autoprotonation and homogeneous electron transfer), which occur in the bulk of the solution and lead to fairly stable intermediate anion-radicals ofortho-compounds.

The condensation of thiosemicarbazones with bromopyruvic acid gives thiazolylhydrazone hydrobromides, which were converted to the free bases. The question of the site of protonation was studied by PMR spectroscopy. The possibility of self-protonation in 4-carboxythiazolylhydrazone crystals is not excluded. The thiazolylhydrazones are brominated in the 5 position. Both cyclization to thiazolyltriazoles and the Chetteueya—Walker reaction are realized in the case of oxidation with lead tetraacetate.

The condensation of dichloromethyl tert-butyl ketone (1) with benzaldehyde, para-bromobenzaldehyde, and 2,4-dichlorobenzaldehyde under conditions for the Darzens reaction gives 1-aryl-1-chloro-4,4-dimethyl-2,3-pentanediones (2–4). In the case of nitrobenzaldehydes, the reaction products are 1-aryl-2-chloro-1,2-epoxy-4,4-dimethylpentanones (5 and 6), which isomerize to α-chloroketones (7 and 8) upon prolonged storage or heating at reflux in benzene.

The condensation of dichloromethyl tert-butyl ketone (1) with benzaldehyde, para-bromobenzaldehyde, and 2,4-dichlorobenzaldehyde under conditions for the Darzens reaction gives 1-aryl-1-chloro-4,4-dimethyl-2,3-pentanediones (2–4). In the case of nitrobenzaldehydes, the reaction products are 1-aryl-2-chloro-1,2-epoxy-4,4-dimethylpentanones (5 and 6), which isomerize to α-chloroketones (7 and 8) upon prolonged storage or heating at reflux in benzene.

The condensation of thiosemicarbazones with bromopyruvic acid gives thiazolylhydrazone hydrobromides, which were converted to the free bases. The question of the site of protonation was studied by PMR spectroscopy. The possibility of self-protonation in 4-carboxythiazolylhydrazone crystals is not excluded. The thiazolylhydrazones are brominated in the 5 position. Both cyclization to thiazolyltriazoles and the Chetteueya—Walker reaction are realized in the case of oxidation with lead tetraacetate.

1. By means of polarography and cyclic voltammetry it was shown that the degree of oxidation of the central atom in chelates of Co with α-hydroxylaminooximes was equal to three. A conversion scheme for the chelates during electrolysis at a dropping-mercury electrode in a medium of DMF was established, which involved the stepwise reduction of the central ion and of the oxime fragment of the ligand. 2. The kinetics of the first electron transfer were studied and indicated a quasireversible character of the reduction of the chelates.

1. A number of complexes of aryl- and acylhydrazones of benzaldehyde and salicylaldehyde have been synthesized. The composition and structure of these complexes have been established on the basis of the IR spectra and the data from elemental analysis. 2. In the case of the formation of the complexes with hydrazones, divalent copper, unlike the other metal ions studied, is capable of being reduced by the ligand. 3. Theα-hydroxyazone structure of the copper and nickel complexes of benzaldehyde benzoylhydrazone and the copper complexes of the salicylaldehyde acylhydrazones has been established. Here the enol hydrogen of theα-hydroxyazine structure is replaced by the metal, while in the complexes of the salicylaldehyde acylhydrazones with cadmium, manganese, iron, cobalt, and nickel the chelatization takes place with replacement of the phenol hydrogen.

1. Feasibility has been demonstrated for the use of the1H {31P} DHSD method in studying the structure of complexes of Ni(II) and Co (II) with hydrazones in solution. 2. It has been confirmed by means of1H DHSD that Co (II) and Ni (II), with the salicyloylhydrazone of acetone and the benzoylhydrazone of benzaldehyde, form complexes with coordination number 4; with the benzoylhydrazone of salicylaldehyde and with the salicyloylhydrazones of 2-pyridinealdehyde and benzaldehyde, they form complexes with coordination number 6. 3. It has been established by means of NMR that complexes of Co(II) with acylhydrazones having a planar square unit, are capable of coordinating oxygen molecules.

1. A study has been made of the IR and PMR spectra of arylhydrazones of benzoyl chlorides and arylhydrazones of benzaldehydes. The changes inν NH of the arylhydrazones of benzoyl chlorides when the change is made from solutions to crystals can be explained by realization of a weak intramolecular hydrogen bond (INTRAHB) NH...Cl in the crystals. 2. In the 2-nitrophenylhydrazones of benzoyl chloride and benzaldehyde, there is an NH...O(O2N) INTRAHB. In proton-acceptor solvents (dioxane, Me CN, DMSO, hexametapol), the arylhydrazones of benzoylchlorides and the arylhydrazones of aromatic aldehydes in which the NH does not participate in an INTRAHB form an intermolecular H-bond with the solvent. The character of the intermolecular interactions of the arylhydrazone of benzoyl chloride) or specific (phenylhydrazone of benzaldehyde). 3. X-ray structure analysis of the phenylhydrazone of benzaldehyde does not reveal any intermolecular contacts shorter than the sum of the van der Waals radii.

1. Oxygen adducts of cobalt chelates with benzaldehyde benzoyl- and salicyloylhydrazines have been synthesized for the first time and have been studied electrochemically in DMFA. 2. The kinetic nature of the chelate reduction current in the second wave is explained by the cleavage of the oxygen adduct during electrolysis, after transfer of the first electron. 3. The cyclic voltamperometric method has established the formation of intermediate complex particles with metal in the zero oxidation state.

1. Chemical polarization of1H nuclei in the products of the reaction of tert-butylmagnesium chloride with benzylidene chloride indicates a radical mechanism of the interaction. 2. The mechanism of the reaction includes a step of transfer of an electron from tert-butylmagnesium chloride to benzylidene chloride. The composition of the reaction products and the distribution of polarization in them are determined by the radical pairs α-chlorobenzyl-tert-butyl and tert-butyl-tert-butyl.

Energies of formation of complexes of hydrogen fluoride with compounds of tetracoordinated phosphorus, charge transfers in complexing, and other characteristics of these reactions calculated by CNDO/2 methods agree well with the measured values.

Upon electrochemical reduction in aprotic media, N,N-disubstituted hydrazones of benzaldehyde and benzoyl chloride undergo aminonitrile splitting.

1. Coordination compounds of Co, Cu, and Ni with acetone acylhydrazones have been obtained and their structures have been studied by physicochemical methods. Acetone benzoylhydrazone and its substituted derivatives coordinate with Co(II), Ni(II), and Cu(II) ions from, their acetates in theα-hydroxyazine form, and acetone salicyloylhydrazone coordinates with Ni(II) and Co(n) in the hydrazone form and with Cu(II) in theα-hydroxyazine form. 2. The stability constants of a number of complexes of acetone acylhydrazones in methanol have been calculated on the basis of their UV-spectroscopic characteristics.

The charge distribution in the unprotonated molecule is the determining factor in fixing basicities in the methylamine series. The high basicities in this series result from the fact that introduction of the CH3 group opens the possibility of the positive charge delocalization in the cation.

By drawing on measured values of dipole moments and Kerr constants and a study of vibrational spectra, it has been shown that the molecules of the symmetrical azines of the acetophenones exist as EE′ forms of the s-trans conformer, the angle of rotation of the azomethylidyne fragments around the N-N bond being 130±5° with the phenyl rings displaced out of the C=N bond planes by 35±5°.

1. The degree of oxidation of the metal ion in the chelates of Co, Pd, and Cu with α-hydroxylamine oximes is 2+ according to electrochemial and EPR data. 2. In the first stage of the electroreduction of the investigated chelates of Co with nioxime and of Cu with α-hydroxylamine oxime the degree of oxidation of the metal ion in the complex changes, while in the case of the other compounds the first electrons are probably accepted by mixed molecular orbitals, to which the ligand fragment makes the largest contribution. 3. The electrode reactions of the Co(II) and Pd(II) chelates with α-hydroxylamine oximes are complicated by the catalytic evolution of hydrogen from solutions containing proton donors.

We have already reported [1] the discovery of the anthelmintic activity of acylhydrazones of aromatic aldehydes. In continuation of this research , we studied the anthelmintic propert ies of a ser ies of N-unsubstituted hydrazones (I-HI), aryl(IV-VIII) and arylidenehydrazones of phthalazones (IX-XII), N-methyl-N(4-chloro-l-phthalazinyl)(XIII-XV) and N-methyl-N-(4-oxo-l-phthalazinyl)hydrazones of aromatic aldehydes (XVI-XVIII), as well as 2-methyl-4-chlorophthalazone (XIX) and N-methyl-N-(4-chloro-l-phthalazinyl)hydrazine (XX). (21 C1

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.

1. An x-ray diffraction study of benzoyl chloride phenylhydrazone was conducted. 2. The presence of a conjugated system in the molecule and very short intramolecular contacts, which, however, did not permit an unambiguous conclusion to be drawn on the intramolecular interactions, was established.

It is shown by means of the fixed-structure method, UV spectroscopy and dipolemoment method that the product of the reaction of 3,6-dichloropyridazine with hydrazine in solution in methanol and acetonitrile has the 3-chloro-6-hydrazinopyridazine structure.

On the basis of data obtained by methods of dipole moments and IR spectroscopy, it has been shown that these semicarbazones and thiosemicarbazones of aromatic aldehydes exist in solution in the EEE form, apparently stabilized by specific interaction NH2... N=C.

1. A mechanism for the electrochemical reduction of Co (III) complexes withα-amino acids is proposed, which involves a stepwise acceptance of one and two electrons by the depolarizer molecule, accompanied by an incorporated chemical stage. 2. By means of the ESR and electrochemical methods it has been shown that the nature of this stage is the elimination of one or two inner sphere ligands after addition of the first electron, which makes the first stage of the electrode process irreversible in character.

The products of condensation of 2-H-phthalazone hydrazones with carbonyl compounds in solution and in the crystalline form have phthalazone ylidenehydrazone (unsymmetrical azine) rather than phthalazinylhydrazone I structures, as has previously been assumed. 2-H-Phthalazone arylidenehydrazones exist in the EE′ form, and their analogs methylated in the 2-N position of the phthalazone ring exist in the ZE' form. Facile ZE' → ZZ' isomerization was noted for 2-methyl-4-chlorophthalazone ethylenehydrazone in halogen-containing solvents. Its unmethylated analog — 4-chlorophthalazone ethylenehydrazone (VIIIb) — is a mixture of geometrical isomers (EE'/EZ'=3∶1).

The center of formation of H-complexes of hydrazones with p-nitrophenol is the imine nitrogen atom. This direction of interaction is determined by the potential of the electrostatic field. Experimental values of the complex formation constants vary in proportion to the calculated values of the charge on the imine nitrogen atom.

1. Oxidation of the arylhydrazones of the acetylhalides by PbO2 leads to the formation of 1,3,4,6-tetraaryl-1,4-dihydro-1,2,4,5-tetrazines, which, in turn, form stable cation-radicals under electrochemical oxidation. 2. The stability of the dihydrotetrazine cation-radicals can be reduced, either by replacing the phenyl group at the nitrogen atom with a tosyl group or a hydrogen atom, or by replacing the phenyl groups at the carbon atoms with acetyl groups. 3. Substituents at the amine N atom are more influential than substituents at the C atoms in fixing the first wave potential for the electrochemical oxidation of 1,4-dihydro-1,2,4,5-tetrazine.

1. An orbital model has been developed for intramolecular interactions in hydrazones, based on competition of n-n and n-π interaction of the azomethine and amino groups. 2. Within the framework of the orbital model, an analysis has been made of the influence of steric hindrance on the degree of conjugation and on intramolecular charge transfer in hydrazone molecules.

1. The electrochemical reduction of some oximes and α-hydroxylaminooximes in a non-aqueous medium represents an irreversible four-electron process, involving kinetic limitations. 2. Difference between the electrochemical behavior of geometrical isomers of the oximes in a nonaqueous medium have been demonstrated.

1. Reaction of C,N-diphenylnitrilimines with benzaldehyde arylhydrazones has given new representatives of the arylidenebenzhydrazidines. 2. In solution, 1,4-diaryl-2-benzylidenehydrazidines have a nonplanar structure, and can exist in two conformational forms.

It was established on the basis of data from the UV and PMR spectra, the dipole moments, and the synthesis of fixed structures that the products of the condensation of phthalazone hydrazones with mesityl oxide have the structures of mixed phthalazone azines and mesityl oxide rather than the phthalazinylhydrazone structure that was previously assumed for them.

In theα,β-unsaturated aldehydes and ketones the s-trans and s-cis conformations differ in the character of the nonplanar deformational vibrations of the =CH bonds. The s-cis conformers are characterized by vibrations in the more high-frequency region of the spectrum than for the s-trans conformers.

1. The basicity constants of substituted benzaldehyde (BDMH) and acetophenone (ADMH) dimethylhydrazones in anhydrous acetonitrile are determined. 2. The amine nitrogen atom is the center of protonation in the dimethylhydrazones. 3. The effect of the substituents in the benzene ring on the reaction center is weakened 1.6-fold in the acoplanar ADMH molecules as compared to the BDMH molecules.

1. Protonation centers for alkyl-and arlhydrazones have been established from a study of UV spectra and comparison of calculated values of the energies of the protonated complexes. 2. Inversion of the protonation center occurs in the alkylhydrazones, but all of the phenylhydrazones protonate at the imine-nitrogen atom.

1. The aroylhydrazones with intramolecular hydrogen bonding exist in acylhydrazone form with a high degree of electron delocalization. 2. The preferred form in nonpolar solution is an equilibrium mixture of three conformers of the salicyloylhydrazones of several different aldehydes, these differing in the degree of rotation around the amide N-C bond and in the type of H-bonding (-OH...O=C or N-H...-OH).

Some new data and concepts relative to the individual steps of the mechanism of the Fischer-Arbuzov synthesis of indoles, including the role of catalysis and complexing, various anomalies during the process, as well as related reactions, are examined.

The molecular-crystal structure of 1-dimethylamino-4-chlorophthalazine was investigated by means of x-ray diffraction analysis. The dimethylamino group is turned about the Cr−N bond at an angle of 33.4 ° from the position that is optimal for its conjugation with the ring, and the nitrogen atom has a flattened trigonal-pyramidal conformation (the sum of the angles is 346.9 °); this is in agreement with NMR data on the low barrier to its rotation about the Cr−N bond.

1. The photoelectronic spectra of a number of organophosphorus compounds of the type of WPXYZ were obtained and interpreted for the first time. 2. The upper orbital is primarily localized on the pπ-orbitals of the W atom, participates in the bonding of WP, and has little conjugation with the orbitals of the unshared pairs of the substituents. Exceptions are nitrogen-containing substituents. 3. Series of atoms W with respect to decreasing influence on the ionization potentials of the UEP of the substituents XYZ were established: for nonnitrogen-containing substituents OP > SP > P, and for nitrogen-containing substituents SP > OP > P.

On the basis of VU and PMR spectroscopic data with the aid of the method of experimental structures and the method of dipole moments it was concluded that the products of the reaction of 1,4-dichlorophthalazine with ammonia, methylamine, and aniline in solutions and in the crystalline form exist primarily as Z conformers of the amino tautomeric form. Conversion to the tautomeric imino form was established for 1-phenylamino-4-chlorophthalazine in a number of solvents. The imines of 2-methyl-4-chlorophthalazine exist as the E isomers.

An increase in the resistance of the N-N bond to hydrogenolysis on Raney nickel in alkaline media is observed not only for 1,2,4-trisubstituted 3,5-dioxopyrazolidines but also for other types of 3,5-dioxopyrazolidines that are capable of enolization. 3,5-Dioxopyrazolidines that are capable of forming betaines also do not undergo hydrogenation in neutral ethanol. The use of the potentiometric method of Sokol'skii and Druz′ made it possible to establish very slight adsorption of the enolates and betaines on the catalyst surface. The decrease in adsorbability is explained by a decrease in the effective charges on the nitrogen atom of the heteroring; this is in agreement with the results of calculations of the enolate and enol by the Pariser-Parr-Pople method. An assumption regarding the greater aromatic character of the enolate as compared with the enol is expressed on the basis of a comparison of the bond lengths.

1. Electrochemical reduction of arylhydrazones of aromatic aldehydes begins with fragmentation at the N-N bond, whereas in the case of acylhdyrazones saturation of the azomethine bond precedes the fragmentation. 2. The contrast in the electroreduction of these types of hydrazones is determined by the difference in character of the lowest free MO of the hydrazone fragment; in acylhydrazones in contrast to arylhydrazones the orbital of the unshared pair of the amine nitrogen atom does not participate in the formation of this orbital.