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Conditions for preparing acetophenone azine via the oxidative dimerization of acetophenone imine anion are investigated.

N,N-Disubstituted thioamides coupled with N-tosylhydrazones under Pd(TFA)2/tBuXPhos catalyst and NaOtBu, and the intermediates from palladium carbene migratory insertion containing β-hydrogen were trapped by intramolecular esters activated by BF3·Et2O ins

Cp*Co(III)-catalyzed direct C[sbnd]H amidation of azines has been developed. This conversion could proceed smoothly in the absence of external oxidants, acids or bases, with excellent regioselectivity and broad functional group tolerance. CO2 w

A simple and efficient copper-catalyzed tandem radical cyclization reaction has been discovered for the synthesis of triaryl [1,2,4]triazolo[1,5-a]pyridines from easily accessible azines and benzylidenmalononitriles. The new transformation involves multip

The Rh-catalyzed ortho-C-H carbenoid insertion reaction of diarylazines with diazo compounds has been developed. A wide range of ortho-substituted diarylazines have been obtained in moderate to high yields with high regioselectivity at room temperature. The hydrolysis of the products could release ketones or aldehydes, giving access to aromatic 1,5-keto-diesters as valuable synthons for further chemical transformations.

Photophysical properties of di-Schiff base compounds in the solution and solid states are explored. The di-Schiff bases with alkyl spacers (ethyl, butyl and hexyl) showed enhanced light emitting properties in the solid state, while quenching was observed for di-Schiff bases with a hydrazine spacer. The photoluminescence spectra and the crystal structure were compared with bis-pyridyl-ethyl-di-imine and bis-pyridyl-butyl-di-imine. The crystal structure analysis of the compounds rationalizes the observed results. The concentration dependent 1H-NMR and NOESY spectra showed the aggregation behaviour of the compounds.

[(THD-Dipp)AuOTf], supported by the strongly electron donating, sterically bulky THD-Dipp (1,3-bis(2,6-diisopropylphenyl)hexahydro-2H-1,3-diazepine-2-ylidene) seven-membered N-heterocyclic carbene ligand, efficiently promotes intermolecular addition of Ts- and Boc-hydrazine to arylalkynes under solvent-free conditions.

Described herein is a rhodium(III)-catalyzed coupling of aromatic ketazines or oximes with 2-vinyloxirane via directed C-H activation. This reaction proceeds efficiently under mild conditions with a low catalyst loading, especially in conditions with room temperature in the absence of additives for aromatic ketazines. A wide range of substituted substrates is supported and a possible mechanism is proposed according to the experimental results of kinetic isotopic effect, reversibility studies, and catalysis with rhodacycle intermediate c1.

A rhodium-catalyzed sequential oxidative C-H annulation reaction between ketazines and internal alkynes has been developed via C-H and N-N bond activation with air as an external oxidant, which led to an efficient approach toward isoquinolines with high atom efficiency at rt. Utilizing the distinctive reactivity of this catalysis, both N-atoms of the azines could be efficiently incorporated to the desired isoquinolines under very robust and mild reaction conditions.

A general and useful method for the synthesis of azines of aromatic aldehydes and ketones in good yields was elaborated. This reaction is carried out under solvent-free conditions and in the absence of catalyst to afford good yields of the relevant azines. The reaction is also environmentally friendly without the inconvenience of undesired by-products and has advantages over the previously reported methods. Products were characterized by the usual procedures (infrared, 1H NMR, and 13C NMR).

Differently substituted acetophenone azines on treatment with excess phosphorous oxychloride in N,N-dimethylformamide have found to yield three products in each case. An acceptable mechanism has been suggested for the formation of all the three products.

In an effective transformation, semicarbazones/thiosemicarbazones are smoothly converted into azines under microwave irradition. Oxadiazoles are also obtained from semicarbazones by reaction with bromine generated in situ via a grinding reaction in the solid phase. Taylor &Francis Group, LLC.

Three azines, two of them doubly labeled with 15N, have been studied by multinuclear magnetic resonance in solution and in the solid state. The spectral parameters obtained by iterative analyses have been compared with DFT/B3LYP calculated values (absolute shieldings and coupling constants). The agreement is generally good. Some anomalies have been discussed in relation to the structure of these compounds. Copyright

We report the reaction of hydrazine hydrate with carbonyl compounds in the presence of molecular iodine at 0-10°C, which affords symmetrical azines in excellent yields in 1 to 4 min without any adverse effect on other substituents. The reactions are rapid and chemoselective, afford excellent yields, and have high-purity products. The workup procedure is environmentally benign and does not require solvent extraction. Copyright Taylor & Francis Group, LLC.

Carbonyl compounds with freshly prepared hydrazinium formate successfully yielded the corresponding azines in excellent yields. In turn, azines were deprotected to the corresponding carbonyls using triethylammonium chlorochromate chemoselectively. Copyright Taylor & Francis Group, LLC.

Sterically congested cis- and trans-Δ3-1,3,4- selenadiazolines were isolated by one-pot reactions of ketone hydrazones with diselenium dibromide, which suggested the in situ formation of selone and diazoalkane intermediates. The thermolysis of these compounds gave symmetrical olefins, whereas oxidation afforded the corresponding azines. The reaction of acetophenone hydrazones with diselenium dibromide afforded 2,5- diarylselenophenes in moderate yields. The reaction proceeded through selone intermediates.

Ten new oxadiazoline sources of methoxy(oximino)carbenes were synthesized by exchanging the acetoxy group of 2-acetoxy-2-methoxy-Δ3-1,3, 4-oxadiazoline with an oximino group. The new compounds were characterized by means of spectroscopy and the formation of carbenes upon thermolysis of a few was demonstrated by means of interception with tert-butyl alcohol. The carbenes fragmented to form methoxycarbonyl and iminyl radicals.

An unprecedented reaction: Dinitrogen pincer Rh complexes react with azines in a moderately catalytic fashion by nonsymmetrical N-N bond cleavage to the corresponding nitriles and imines (see scheme).

The electrochemical behavior of a series of symmetrical and unsymmetrical aryl-substituted acetophenone azines (1-X/Y, where X and Y are 4-NO2, 4-CN, H, 3-OCH3, 4-OCH3, 4-CH3, and 4-N(CH3)2) was studied in acetonitrile and N,N-dimethylformamide (DMF) solution using cyclic voltammetry (CV). Compounds 1-X/Y, where neither X or Y are nitro substituents, undergo successive reduction to their radical anion (1-X/Y·-) and then dianion (1-X/Y2-), respectively. In all cases, the formation of the radical anion is completely reversible and the standard reduction potentials, E°1-X/Y/1-X/Y·- could be determined. The reversibility of the second electron transfer is substituent dependent with certain dianions sufficiently basic to be protonated under our conditions. Standard reduction potentials (E°1-X/Y/1-X/Y·-) for the formation of radical anions exhibit a large substituent effect with values differing by more than 0.66 V throughout the series going from 1-4-CN/4-CN to 1-4-OCH3/4-OCH3; similar substituent effects were determined for the formation of the dianion. The nitro-containing azines deviate from the above-mentioned behavior. With the exception of 1-4-NO2/4-NO2, they exhibit single electron waves that have values of E°1-X/Y/1-X/Y·- within 40 mV of each other and thus the reduction is not subject to the same substituent effect as the other azines. 1-4-NO2/4-NO2 exhibits an E° at a similar potential, but is a two-electron reversible wave with features indicative of a reduction system containing two localized, nonconjugated redox centers. The reduction potentials of all the aryl azines were correlated with Hammett σ parameters to look at variations in E°1-X/Y/1-X/Y·- vs SCE as a function of substituent. The small ρ values in combination with the other electrochemical data provide support for single bond character of the N-N bond and evidence for a lack of strong electronic communication between the two aryl centers through the azomethine bonds, especially for those systems with electron-withdrawing groups.

The reaction of aromatic and aliphatic azines with different ketene precursors, such as the acid chloride/Et3N system, alkoxychromium(0) carbenes, and free diphenyl ketene, gives N-imino-β-lactams in good to excellent yields, with good levels of cis,trans-selectivity. A wide variety of symmetrically-substituted azines derived from aldehydes and ketones are compatible with the Staudinger reaction. Chiral N-imino-β-lactams derived from symmetrically or unsymmetrically (mixed) chiral azines are also obtained in good yields as essentially single enantiomers (de > 95%). Different reaction intermediates, including hemiaminals, oxadiazols, and hydrazides have been isolated. Free diphenyl ketene forms Diels-Alder adducts and N-acylazadienes in addition to the previously reported N-imino-β-lactams. The usual reactivity of the β-lactam ring is modified in N-imino-β-lactams by the presence of the imino group. Thus, β-hydrazonoesters, N-alkylamino-β-lactams, and NH-β-lactams can be efficiently obtained by base-catalyzed 2-azetidinone ring opening, catalytic hydrogenation, and ozonolysis, respectively.

Photolysis of an intimate mixture of methyl(phenyl)diazirine and N-methylmaleimide in the absence of solvent permits the diazoalkane intermediate to be trapped, whereas the equivalent reaction in solution gives only cyclopropanated adducts.

Imine anions, generated by reaction of nitriles with organometallic reagents, are dimerized to form symmetrical azines through the use of CuI and t-butyl peroxybenzoate.

The bimolecular dimerization of phenyldiazomethane (1) and 1-diazo-1-phenylethane (2) to form the corresponding azines (3 and 4) is stereoselective for the E,Z isomer (>95:5 E,Z:E,E).The E,Z isomer can be isolated from the reaction of 2, and it can be observed but not isolated from the reaction of 1.Both (E,Z)-3 and -4 revert thermally to the more stable E,E isomer.The kinetic parameters of this process were determined for (E,Z)-4: Ea = 22.3 kcal/mol, log A = 11.2.The stereoselectivity is accounted for within the context of the accepted mechanism for azine formation via diazo compound dimerization.

Oxygenation of aromatic ketone hydrazones with Co(salen) in methanol resulted unexpectedly in oxidative degradation to give methyl benzoate derivatives.A mechanism involving nucleophilic attack by methanol on a diazo intermediate is discussed.