Hydrazino Group Research Articles

Hydrazino-containing Zr-MOF for enhanced Lewis acid-base catalysis of CO2 fixation into cyclocarbonate

Developing an effective catalyst for converting CO2 into high-value chemicals is greatly desirable but remains a big hurdle. Herein, Zr-MOF derivative-bearing hydrazino groups were synthesized by mixing the ligands of terephthalic acid and 4-hydrazinobenzoic acid (HBA), resulting in UiO-66-HBA as heterocatalyst for epoxide cycloaddition with CO2. Compared to UiO-66, the optimal UiO-66-HBA0.2 displayed outstanding activity for epichlorohydrin cycloaddition, with 96.03 % cyclocarbonate yield under 0.1 MPa CO2 at 70 ℃. The great activity of UiO-66-HBA0.2 was attributed to the synergistic cooperation of Lewis base offered by HBA moiety and Lewis acid originated from Zr6 clusters, which was affirmed by NH3/CO2-temperature-programmed desorption experiments and CO2 adsorption isotherms. Moreover, UiO-66-HBA0.2 exhibited excellent stability and great substrate compatibility. In addition, a possible mechanism for catalyzing CO2 conversion into cyclocarbonate was suggested. This study provides an effective way to design functionalized MOFs-based heterocatalysts for CO2 utilization.

New Quinoline Derivatives and their Antimicrobial Potential Against Candida Albicans and Staphylococcus Aureus

AbstractAntimicrobial resistance is a pressing global health concern, demanding the development of novel antimicrobial agents. Quinoline derivatives emerge as promising candidates with their diverse chemical structures and recognized bioactive properties. This study aimed to investigate the antimicrobial potency of newly synthesized quinoline derivatives against Candida albicans and five bacterial strains, which are responsible for various infections and have exhibited varying degrees of antibiotic resistance. A series of quinoline derivatives were synthesized through simple structural modifications, such as the inclusion of nitro, amino, and hydrazino groups, or using the molecular hybridization strategy, involving the combination of quinoline and 1,2,3‐triazoles. None of the compounds showed promising activity against the bacterial strains. However, a promising fungistatic effect was observed against C. albicans. In this test, two of the compounds showed lower MIC values than fluconazole (25 μg/mL). In addition, the most promising compounds showed high affinity for the enzyme lanosterol 14 alpha demethylase, due to the low energy values found (−7.6 and −8.2 kcal/mol). Our study offers new avenues for future drug development in the fight against antimicrobial resistance.

Stepwise and site-selective enzymatic introduction of multiple functional groups to turn-on multiple fluorescence in long DNA strands

We have developed a stepwise and site-specific method, employing DNA polymerase, for the introduction of many functional groups into long DNA strands. With this approach, we developed three novel fluorescence turn-on systems that respond specifically to amino, alkynyl, and hydrazino groups in oligonucleotide strands. These systems operate when adding fluorescence precursors (i.e., ylidenmalonitrile enamine, azidopyrene, and diethylsalicylaldehyde), each of which exists in its turned-off state in the absence of the specific reactions. MALDI-TOF mass spectrometry confirmed the site-specific introduction of these functional groups and their post-synthetic reactions with the fluorescence precursors. We also applied this method to incorporate several functional groups into long DNA strands; for example, we demonstrate the stepwise and site-specific introduction, mediated by several enzymes, of multiple functional groups at 18 different positions in a 144mer DNA. Multiple fluorescence turn-on was possible when this long DNA containing 18 functional groups encountered the fluorescence precursors. In a cellular study, we observed three different fluorescence turn-on processes, exhibiting blue, green, and red fluorescence signals, when using this post-synthetic approach.

Self-Repairing Tin-Based Perovskite Solar Cells with a Breakthrough Efficiency Over 11.

The development of tin (Sn)-based perovskite solar cells (PSCs) is hindered by their lower power conversion efficiency and poorer stability compared to the lead-based ones, which arise from the easy oxidation of Sn2+ to Sn4+ . Herein, phenylhydrazine hydrochloride (PHCl) is introduced into FASnI3 (FA = NH2 CH  NH2 + ) perovskite films to reduce the existing Sn4+ and prevent the further degradation of FASnI3 , since PHCl has a reductive hydrazino group and a hydrophobic phenyl group. Consequently, the device achieves a record power conversion efficiency of 11.4% for lead-free PSCs. Besides, the unencapsulated device displays almost no efficiency reduction in a glove box over 110 days and shows efficiency recovery after being exposed to air, due to a proposed self-repairing trap state passivation process.

N-Hydroxyphthalimide catalyzed hydrazination of polyethylene glycol

In this work, N-hydroxyphthalimide (NHPI) was used as catalyst to cleave CH bonds in polyethylene glycol (PEG) backbones to generate carbon free radicals that reacted with the NN bonds of di-tert-butyl azodicarboxylate (DBAD) to form CN grafts (PEG-g-DBAD). Subsequently, the tert-butoxycarbonyl (-Boc) groups of PEG-g-DBAD were removed by treating with trifluoroacetic acid (TFA) to obtain hydrazino functionalized PEG (PEG-g-NHNH2). The structure of functionalized PEG was confirmed by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR), elemental analysis and size exclusion chromatography (SEC). Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied to investigate thermal stability and crystallization properties of the functionalized PEG. The synthesized PEG-g-NHNH2 could be used to toughen epoxy resin (EP). The results of mechanical testing and SEM images indicated that the compatibility between PEG backbones and EP has been improved due to the existing of hydrazino groups. The grafted hydrazine groups could also react with 2-bromoisobutyryl bromide (BIBB) to obtain PEG-g-BIBB which initiated the polymerization of (methyl) methacrylate (MMA) by ARGET-ATRP. Thus, we presented a methodology with high efficiency for hydrazination of PEG under mild condition, and the functionalized PEG might have many potential applications.

ПОХІДНІ 4-ГІДРАЗИНОХІНОЛІНУ ТА ЇХ БІОЛОГІЧНА АКТИВНІСТЬ (ОГЛЯД ЛІТЕРАТУРИ)

The analysis of the literature about the biological activity of 4-hydrazinoquinolines derivatives was carried out. The variety of actions of this class of organic compounds was depicted. The most promising compounds are the ones that are associated with antimycobacterial and antimalarial activity. It is found out that the presence of substituents in the 6-th and / or 8-th position of the quinoline system increases, and in position 5 and 7 – reduces antimalarial and antibacterial activity. Studies have shown that 4-hydrazinequinolines have a fairly high toxicity, and the maintenance of electron-donating substituents leads to an increase in toxicity by 3-7 times. Their toxicity also increases in the series H <K <Na, which is associated with an increase in solubility in the above-mentioned compounds. 4-hydrazinoquinolines have a pronounced antioxidant effect, by blocking the hydrazino group on the α-ketoglutaric acid residue, the antioxidant effect is reduced, which is also due to their poor solubility in the media. Quinolinohydrazones have been investigated as transcriptase inhibitors, a retrovirus conversion enzyme. The inhibitory activity of the obtained compounds decreases in the series M-MulV> RAV-2> HIV-1. The cytotoxicity of these compounds was evaluated by means of Mosman’s analysis on a J774 cell line infected with BGC (bacille Calmette-Guerin). During this analysis, at R1 = 4-OMe, it was found to be non-cytotoxic to host cells at effective concentrations (MIK 2.5 mg / ml) to inhibit M. Tuberculosis growth. The effect of disodium salt of 2-methylquinolin-4-yl-hydrazone α-ketoglutaric acid on the synthesis of pigment in pigment-producing bacteria of the genera Pseudomonos and Serratia was studied. The maximum effect was observed at a concentration of 100 mg / L. Pigment-stimulating ability is enhanced in proportion to the concentration of 2-methyl-4-yl-hydrazone α-ketoglutaric acid in the culture medium (this trend is shown for cultures of Ps. Fluorescens iodinum, Pseudomonos fluorescens, S. Marcescens). The studied substances can be considered as the basis for the creation of new biologically active compounds.

Biologically and chemically important hydrazino-containing imidazolines as antioxidant agents

Biologically and chemically useful hydrazinoimidazolines were evaluated as antioxidant and antihaemolytic agents. 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH•), galvinoxyl radical (GOR), nitric oxide (NO) and hydrogen peroxide (H2O2) scavenging assays, ferric ions reducing power assay, and ex vivo model of rat erythrocytes exposed to 2,2′-azobis(2-methylpropionamidine)dihydrochloride (AAPH) or H2O2 were used. The most potent DPPH• scavengers proved to be hydrazinoimidazolines 3, 2, and 4, revealing excellent antiradical effects – superior or comparable to that of all antioxidant standards used. Moreover, these molecules showed strong NO neutralising potencies – better to that of ascorbic acid (AA) (3), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) (3 and 2), butylated hydroxytoluene (BHT) (3 and 2), and butylated hydroxyanisole (BHA) (3, 2, and 4). Compound 4 was also effective in GOR scavenging. The excellent scavenger of GOR, NO, and H2O2 proved to be structure 5, with the potency superior or comparable to the majority of antioxidant standards used. In turn, compound 9 was effective in H2O2 and GOR neutralisation. All hydrazinoimidazolines revealed the reducing power that is higher than BHT. Moreover, the protective effects of most test compounds on oxidatively stressed erythrocytes were observed. Some structure–activity relationships were disclosed. A significance of the primary hydrazino group on antioxidant effects was confirmed. The most likely DPPH• and GOR scavenging mechanisms for test compounds were propound. Among all the investigated molecules, hydrazinoimidazolines 5, 3, 2, 4, and 9, due to their excellent or good antiradical activities, can represent promising antioxidant candidates with prospective utility for prevention of diseases related to reactive oxygen/nitrogen species.

Ionic Liquid-Promoted Synthesis of Novel Chromone-Pyrimidine Coupled Derivatives, Antimicrobial Analysis, Enzyme Assay, Docking Study and Toxicity Study.

Herein, we report an environmentally friendly, rapid, and convenient ionic liquid ([Et3NH][HSO4])-promoted facile synthesis of ethyl 4-(6-substituted-4-oxo-4H-chromen-3-yl)-6-methyl-2-thioxo/oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives 4(a–f) and 4-(6-substituted-4-oxo-4H-chromen-3-yl)-6-methyl-2-thioxo/oxo-1,2,3,4-tetrahydropyrimidine-5- carbohydrazide derivatives 6(a–f). All the synthesized derivatives 4(a–f) and 6(a–f) were evaluated for their in vitro antifungal and antibacterial activity, by method recommended by National Committee for Clinical Laboratory Standards (NCCLS). The compound 6c bearing a fluoro group on the chromone ring and oxygen and a hydrazino group (–NHNH2) on the pyrimidine ring, was found to be the most potent antibacterial compound amongst the synthesized derivatives. The compound 6f bearing a methoxy group (–OCH3) on the chromone ring and sulphur group on the pyrimidine ring, was found to exhibit equipotent antifungal activity when compared with the standard drug miconazole. A d-alanine-d-alanine ligase (DdlB) enzyme assay study and an ergosterol extraction and quantitation assay study were performed to predict the mode of action of the synthesized compounds. A molecular docking study was performed to predict the binding interactions with receptors and mode of action of the synthesized derivatives. Further, analysis of the ADMET parameters for the synthesized compounds has shown that these compounds have good oral drug-like properties and can be developed as oral drug candidates. To establish the antimicrobial selectivity and safety, the most active compounds 6c and 6f were further tested for cytotoxicity against the human cancer cell line HeLa and were found to be non-cytotoxic in nature. An in vivo acute oral toxicity study was also performed for the most active compounds 6c and 6f and the results indicated that the compounds are non-toxic in nature.

Сyclization of 1-amino-2-hydrazinobenzimidazole treated with carbon disulfide. Synthesis of 9-amino-2,9-dihydro-3Н-[1,2,4]triazolo[4,3-а]benzimidazole-3-thione and its derivatives

1-Amino-2-hydrazinobenzimidazole when treated with carbon disulfide underwent a regioselective cyclization involving the hydrazino group to form 9-amino-2,9-dihydro-3Н-[1,2,4]triazolo[4,3-а]benzimidazole-3-thione. Being an N-amine this compound gives Schiff bases with aromatic aldehydes, and as thione in DMF at a temperature not exceeding 60°С it is successfully alkylated, particularly by functionalized alkylating agents, affording the corresponding sulfanylmethyl derivatives. In boiling DMF, as it is demonstrated by an example of benzyl chlorides, NNH2 group also undergoes alkylation that unexpectedly results in 4-benzylidenamino-3-benzylsulfanyltriazolobenzimidazoles.

Azolo[1,4]diazepines: the methods of synthesis and structural modification

The literature relating to the methods of synthesis and chemical transformations of azolo[1,4]diazepines (pyrazolo-, imidazo-, triazolo-, isoxazolo-, oxazolo-, isothiazolo- and thiazolodiazepines) currently known have been generalized and systematized. Their role as important substances for the design of compounds with a great pharmacological potential has been noted. The methods of synthesis of pyrazolo[3,4-e][1,4]diazepines, pyrazolo[4,3-e][1,4]diazepines and tri- and tetracyclic pyrazolo[1,4]diazepines based on formation of the diazepine ring in most cases due to transformations of multifunctional pyrazole derivatives have been described in detail. A significant emphasis is focused on the structural functionalization of pyrazolo[1,4]diazepines; this functionalization is a powerful tool to design attractive synthetic and biological derivatives. On the examples of 7-hydroxypyrazole[3,4-e][1,4]diazepines the effect of the reaction conditions, electronic and steric parameters, which control the processes of functionalization of the diazepine nucleus with SH-, NH- and C- nucleophilic reagents, is described. The synthetic potential of 7-arylpyrazole[4,3-e][1,4]diazepin-4-ones as key structures for their direct functionalization in position 4 with chloro-, methylthio-, amino- and hydrazino groups is shown. The methods of preparation and some chemical transformations of imidazo[1,4]diazepines, in particular imidazo[4,5-e][1,4]diazepin-8-ones and 5,8-diones, which in recent years attract great attention of researchers, have been analyzed.

Microwave and Quantum Chemical Study of Intramolecular Hydrogen Bonding in 2-Propynylhydrazine (HC≡CCH2NHNH2).

The microwave spectrum of 2-propynylhydrazine (HC≡CCH2NHNH2) was investigated in the 23-124 GHz spectral interval. The spectra of two conformers denoted I and II were assigned. I is the lower-energy form, and relative intensity measurements yielded an internal energy difference of 3.0(4) kJ/mol between I and II. The spectra of the ground and five vibrationally excited states were assigned for I, whereas only the spectrum of the ground vibrational state was assigned for II. Both I and II are each stabilized simultaneously by two intramolecular hydrogen bonds. The first of these hydrogen bonds is formed between the hydrogen atom of the -NH- part of the hydrazino group, and the second internal hydrogen bond is formed between one of the hydrogen atoms of the -NH2 part. The π-electrons of the triple bond is thus shared by these two hydrogen atoms. The shortest contact between a hydrogen atom of the hydrazino group and the π-electrons of the ethynyl group is found in lower-energy conformer I. The conformational properties of 2-propynylhydrazine were explored by MP2/cc-pVTZ and CCSD/cc-pVQZ calculations. The CCSD method predicts that seven rotameric forms exist for this compound. Five of these rotamers are stabilized by internal hydrogen bonding. The simultaneous sharing of the π-electrons of the triple bond by two hydrogen atoms occurs only in Conformers I and II, which are predicted to be the two forms with the lowest energies, with I 2.52 kJ/mol lower in energy than II. The effective rotational constants of the ground vibrational states of I and II were predicted by a combination of MP2 and CCSD calculations, whereas centrifugal distortion constants and vibration-rotation constants were calculated by the MP2 method. The theoretical spectroscopic constants are compared with the experimental counterparts. It is concluded that more refined calculations are necessary to obtain complete agreement.

Hydrazino-methoxy-1,3,5-triazine Derivatives' Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution.

The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT), 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT), and 2,4,6-tridydrazino-1,3,5-triaizne (TH3) on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT) gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%). The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS) measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH3, DMeHT and DHMeT) were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH3, DMeHT and DHMeT behaved as mixed type inhibitors.

Microwave and Quantum Chemical Study of Intramolecular Hydrogen Bonding in 2-Propenylhydrazine (H2C═CHCH2NHNH2).

The microwave spectrum of 2-propenylhydrazine (H2C═CHCH2NHNH2) was studied in the 12-61 and 72-123 GHz spectral regions. A variety of intramolecular hydrogen bonds between one or more of the hydrogen atoms of the hydrazino group and the π-electrons are possible for this compound. Assignments of the spectra of four conformers, all of which are stabilized with intramolecular hydrogen bonds are reported. One hydrogen bond exists in two of these conformers, whereas the π-electrons are shared by two hydrogen atoms in the two other rotamers. Vibrationally excited-state spectra were assigned for three of the four conformers. The internal hydrogen bonds are weak, probably in the 3-6 kJ/mol range. A total of about 4400 transitions were assigned for these four forms. The microwave work was guided by quantum chemical calculations at the B3LYP/cc-pVTZ and CCSD/cc-pVTZ levels of theory. These calculations indicated that as many as 18 conformers may exist for 2-propenylhydrazine and 11 of these have either one or two intramolecular hydrogen bonds. The four conformers detected in this work are among the rotamers with the lowest CCSD electronic energies. The CCSD method predicts rotational constants that are very close to the experimental rotational constants. The B3LYP calculations yielded quartic centrifugal distortion constants that deviated considerably from their experimental counterparts in most cases. The calculation of vibration-rotation constants and sextic centrifugal distortion constants by the B3LYP method were generally found to be in poor agreement with the corresponding experimental constants.

Preferential binding of E. coli with type 1 fimbria to D-mannobiose with the Manα1 → 2Man structure.

Manα1 → 2Man, Manα1 → 3Man, Manα1 → 4Man, and Manα1 → 6Man were converted to the glycosylamine derivatives. Then, they were mixed with monobenzyl succinic acid to obtain their amide derivatives. After removing the benzyl group by hydrogenation, the succinylamide derivatives were coupled with the hydrazino groups on BlotGlyco™ beads in the presence of water-soluble carbodiimide. d-Mannobiose-linked beads were incubated with fluorescence-labeled Escherichia coli with type 1 fimbria, and the number of the fluorescent dots associated with the beads was counted in order to determine the binding preference among d-mannobiose isomers. The results showed that the bacteria bind strongly to Manα1 → 2Man1 → beads, Manα1 → 3Man1 → beads, Manα1 → 4Man1 → beads, and Manα1 → 6Man1 → beads, in order. In the presence of 0.1 M methyl α-d-mannopyranoside, most of the bacteria failed to bind to these beads. These results indicate that E. coli with type 1 fimbria binds to all types of d-mannobiose isomers but preferentially to Manα1 → 2Man disaccharide.

Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH2CH2NHNH2).

The microwave spectrum of (2-fluoroethyl)hydrazine (FCH2CH2NHNH2) was studied in the 11-123 GHz spectral region to investigate the ability of the hydrazino group to form intramolecular hydrogen bonds acting as a proton donor. This group can participate both in five-member and in six-member internal hydrogen bonds with the fluorine atom. The spectra of four conformers were assigned, and the rotational and centrifugal distortion constants of these rotameric forms were determined. Two of these conformers have five-member intramolecular hydrogen bonds, while the two other forms are without this interaction. The internal hydrogen bonds in the two hydrogen-bonded forms are assumed to be mainly electrostatic in origin because the N-H and C-F bonds are nearly parallel and the associated bond moments are antiparallel. This is the first example of a gas-phase study of a hydrazine where the hydrazino functional group acts as a proton donor in weak intramolecular hydrogen bonds. Extensive quantum chemical calculations at the B3LYP/cc-pVTZ, MP2/cc-pVTZ, and CCSD/cc-pVQZ levels of theory accompanied and guided the experimental work. These calculations predict the existence of no less than 18 conformers, spanning a CCSD internal energy range of 15.4 kJ/mol. Intramolecular hydrogen bonds are predicted to be present in seven of these conformers. Three of these forms have six-member hydrogen bonds, while four have five-member hydrogen bonds. The three lowest-energy conformers have five-member internal hydrogen bonds. The spectrum of the conformer with the lowest energy was not assigned because it has a very small dipole moment. The CCSD relative energies of the two hydrogen-bonded rotamers whose spectra were assigned are 1.04 and 1.62 kJ/mol, respectively, whereas the relative energies of the two conformers with assigned spectra and no hydrogen bonds have relative energies of 6.46 and 4.89 kJ/mol.

Facile method for the synthesis of silver nanoparticles using 3-hydrazino-isatin derivatives in aqueous methanol and their antibacterial activity

IntroductionA new method for preparation of silver nanoparticles (AgNPs) based on using hydrazino-isatin derivatives in an aqueous methanol reaction medium is reported here. AgNPs were prepared using silver nitrate solubilized in a water core as the source of silver ions and 3-hydrazino-isatin derivatives (3-hydrazino-isatin [IsH] and 1-benzyl-3-hydrazino-isatin [BIsH]) solubilized in methanol core as a reducing agent. The proposed method is effective, rapid, and convenient. X-ray diffraction (XRD), energy dispersive X-ray analysis, scanning electron microscope (SEM) and transmission electron microscopy (TEM) were used for characterization of the AgNPs. The TEM micrographs confirmed that the nanopowders consist of well-dispersed agglomerates of grains with a narrow size distribution of 18–21 nm and 17–20 nm. The AgNPs, as well as BIsH, showed high antimicrobial and bactericidal activity against the Gram-positive Bacillus subtilis and Gram-negative Micrococcus luteus and Proteus vulgaris, as well as antifungal activities against Saccharomyces cerevisiae. On the other hand, they were not effective against the Gram-negative Escherichia coli.PurposeA simple, effective, rapid, and convenient chemical reduction method for the synthesis of AgNPs in an aqueous methanol reaction medium using hydrazino-isatin derivatives and studying their antibacterial effect.ResultsIsH and BIsH are remarkably powerful reductants for Ag+ ions in an aqueous methanol medium, which could be considered as a simple chemical reduction method for formation of AgNPs. The AgNP formation depends on the solubility of the hydrazino-isatin derivatives. BIsH gave more AgNPs than IsH, as observed from XRD. The formation of AgNPs is attributed to the adsorption of hydrazine derivatives and/or interparticle interaction on the surface of AgNP through electrostatic interactions between the lone pair electrons of the hydrazino group (C=N-NH2) and the positive surface of AgNPs. AgNPs and BIsH showed high antimicrobial and bacterial activity.ConclusionIn summary, it is shown that IsH and BIsH are remarkably powerful reductants for Ag+ ions in an aqueous methanol medium. BIsH gave more AgNPs than IsH, as observed from XRD due to better solubility of the BIsH than IsH in aqueous-methanol. The formation of AgNPs is attributed to the adsorption of hydrazine derivatives and/or interparticle interaction on the surface of AgNPs through electrostatic interactions between the lone pair electrons of the hydrazino group (C=N-NH2) and the positive surface of AgNPs. The AgNps as well as BIsH ligand showed high antimicrobial and bactericidal activity.

Nitrogen-rich salts based on 5-hydrazino-1H-tetrazole: a new family of high-density energetic materials

High-density energetic salts that contain nitrogen-rich anions and the 5-hydrazino-1H-tetrazolium cation were synthesized. All salts were fully characterized by vibrational spectroscopy (IR), multinuclear (1H, 13C) NMR spectroscopy, elemental analysis, differential scanning calorimetry (DSC), and impact sensitivity. Four compounds were characterized by single X-ray diffraction. The results show that the extensive hydrogen bonding interactions between the cations and anions form a complex 3D network, which contributes greatly to the high density of the 5-hydrazinotetrazolium salts. It was also found that the incorporation of hydrazino groups into a heterocyclic ring increases the heat of formation and overall nitrogen content of the entire molecule. Some of these salts exhibit reasonable physical properties, such as good thermal stability (Td = 173.7–198.6 °C), reasonable impact sensitivities (IS = 4–40 J), and excellent specific impulses (Isp = 196.1–288.7 s). In addition, detonation properties of the energetic salts obtained with EXPLO 5.05 identify them as competitively energetic compounds, and in some cases are superior to those of HMX.

Enamino esters in the synthesis of heterocyclic systems. Transformation of diethyl acetone-1,3-dicarboxylate into poly-substituted 1,2,7,8-tetrahydro-2,7-naphthyridine-4-carboxylates

A simple three step synthesis of aminosubstituted 1,2,7,8-tetrahydro-2,7-naphthyridine-4- carboxylates is described. Ethyl (3-cyano-6-ethoxy-2-oxo-1,2-dihydropyridin-4-yl)acetate 3, formed by the condensation of diethyl acetone-1,3-dicarboxylate with malononitrile, was transformed with N,N-dimethylformamide dimethylacetal (DMFDMA) into (E)-ethyl 2-(3- cyano-6-ethoxy-2-oxo-1,2-dihydropyridin-4-yl)-3-(dimethylamino)propenoate 4. In further reaction the dimethylamino group was substituted with amino, hydroxy or substituted hydrazino group, followed by cyclisation to afford substituted 1-amino-7,8-dihydro-2,7-naphthyridine-4- carboxylate 6b, 1-imino-7,8-dihydro-1H-pyrano(3,4-c)pyridine-4-carboxylate 8, and 1-imino-2- aminosubstituted 1,2,7,8-tetrahydro-2,7-naphthyridine-4-carboxylates 13a-i.

Synthesis and structure of catena cadmium complex with 2-hydroxo-1-naphthaldehyde thiosemicarbazono tetradentate ligand

The title ligand (H2L) and its complex [CdL(py)2]py (L= C12H9N3OS dianionic) have been synthesized and characterized. The complex structure determination indicates that Cd( II ) atom has a distorted octahedral coordination geometry. As an unusual tetradentate ligand, one L2 chelates one Cd( II ) atom using the O, S atoms and one N atom of the hydrazino group while its another N atom links to the neighbouring Cd atom. The bridging hydrazono groups extend the compound into a catena chain. The naphthoxy rings of each neighboring unit are alternatively arranged at opposite sides of the chain, and the ring planes on the same side are parallel.

Spectroscopic and structural studies of 6,6′-bis(N-methylhydrazine)-2,2′-bipyridine and its mononuclear copper(II) complex

The tetradentate ligand, 6,6′-bis(N-methylhydrazine)-2,2′-bipyridine (L) and its mononuclear copper(II) complex [Cu(L)](ClO4)2] (1) have been synthesized and characterized. The crystal structures of L and 1 have been determined by single-crystal X-ray diffraction. Both crystallize in the centrosymmetric monoclinic space group with crystallographic inversion symmetry. The ligand adopts a planar transoid configuration in the solid state. In 1, the Cu(II) is six-coordinate octahedral, defined by N4O2 donors from ligand and two perchlorates. The molecular units are connected by intermolecular H-bonds between the hydrazino group of the one unit and coordinated perchlorate of the neighboring two units via N–H ··· O to furnish a 2-D network. Coordinated perchlorates also form an intramolecular H-bond with hydrazine influencing the crystal packing.