Derivatives of 1,1,2,2-tetraaminoethane: I. Condensation of 1,2-diacetoxy-1,2-bis(acylamino)ethanes with nitrogen-containing nucleophiles

Reaction of 1,2-diacetoxy-1,2-bis(acylamino)ethanes with acetamide and urethane gave rise to 1,2-bis(acetylamino)-1,2-bis(acylamino)ethanes and 1,2-bis(acylamino)-1,2-bis(ethoxycarbonylamino)ethanes respectively. Condensation products were isolated of reactions between 1,2-diacetoxy-1,2-bis-(acylamino)ethanes with acetonitrile, diaminofurazan, and 4-phenylfurazan-3-ylamine.     

Mild template synthesis of copper(II)-containing macrocyclic compounds in the CuII–1,2-diaminoethanedithione-1,2–ethanedione-1,2 and CuII–1,2-diamino-ethanedithione-1,2–butanedione-2,3 triple systems into Cu2[Fe(CN)6]-gelatin-immobilized matrix implantates

The complexing processes in the Cu^II–1,2-diaminoethanedithione-1,2–ethanedione-1,2 and Cu^II–1,2-diaminoethanedithione-1,2–butanedione-2,3 triple systems occuring in the copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous alkaline solutions (pH~12) containing 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-1,2 under room temperature, and between MCl₂, 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-1,2 in the ethanol solutions, upon heating up to ~80 °C, have been studied. In both systems indicated, template synthesis occurs in the gelatin-immobililized matrix but does not occur in the ethanol solution. As a result of template synthesis, macrocyclic Cu^II chelates with 2,7-dithio-3,6-diazaoctadien-3,5-dithioamide-1,8 and its 4,5-dimethylsubstituted derivative are formed in the gelatin-immobililized matrix. 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-2,3 are the ligand synthons in the processes indicated.     

Rhodium-Mediated Stoichiometric Synthesis of Mono-, Bi-, and Bis-1,2-Azaborinines: 1-Rhoda-3,2-azaboroles as Reactive Precursors

A series of highly substituted 1,2-azaborinines, including a phenylene-bridged bis-1,2-azaborinine, was synthesized from the reaction of 1,2-azaborete rhodium complexes with variously substituted alkynes. 1-Rhoda-3,2-azaborole complexes, which are accessible by phosphine addition to the corresponding 1,2-azaborete complexes, were also found to be suitable precursors for the synthesis of 1,2-azaborinines and readily reacted with alkynyl-substituted 1,2-azaborinines to generate new regioisomers of bi-1,2-azaborinines, which feature directly connected aromatic rings. Their molecular structures, which can be viewed as boron-nitrogen isosteres of biphenyls, show nearly perpendicular 1,2-azaborinine rings. The new method using rhodacycles instead of 1,2-azaborete complexes as precursors is shown to be more effective, allowing the synthesis of a wider range of 1,2-azaborinines.     

Chemistry of 1,2-diphospholide anions and 1,2-diphospholes

The main trends in the chemistry of 1,2-diphosphacyclopentadienes (1,2-diphospholes) and their derivatives 1,2-diphosphacyclopentadienide anions (1,2-diphospholide anions) were systematized, analyzed, and generalized. Methods for the generation of 1,2-diphospholide anions and their reactions with organic and organoelement electrophiles, as well as with transition metal complexes, were considered. Particular attention was paid to the cycloaddition reactions of 1-alkyl-1,2-diphospholes to obtain polycyclic chiral phosphines. A comparative analysis of the reactivity of 1,2-diphospholes and 1,2-diphospholide anions with respect to other representatives of phosphacyclopentadienes and phosphacyclopentadienide anions was carried out. The potential of application of 1,2-diphosphacyclopentadiene derivatives for the design of materials with magnetic, catalytic, and optical properties was shown.

     

Reactions of azoles with tetrachloro-1,2-difluoroethane and 1,2-dichlorodifluoroethylene

Tetrachloro-1,2-difluoroethane reacted with pyrazole and imidazole sodium salts to give mixtures of the corresponding N-(1,2,2-trichloro-1,2-difluoroethyl) derivatives and (E)-1,2-difluoro-1,2-dihetarylethenes. (E)-1,2-Difluoro-1,2-di(3,5-dimethyl-1H-pyrazol-1yl)ethene was also obtained as a result of replacement of chlorine atoms in 1,2-dichloro-1,2-difluoroethene. Analogous reaction with more nucleophilic imidazole involved replacement of not only chlorine but also fluorine atoms in 1,2-dichloro-1,2-difluoroethene, yielding tetraimidazolyl-substituted ethylene.     

Thermody namic functions of 1,2-alkanediols in dilute aqueous solutions

The heat capacities of binary aqueous solutions of 1,2-ethanediol, 1,2-propanediol and 1,2-butanediol were measured at temperatures ranging from 283.15 to 338.15 K by differential scanning calorimetry. The partial molar heat capacities at the infinite dilution were then calculated for the respective alkanediols. For 1,2-ethanediol or 1,2-propanediol, the partial molar heat capacities at the infinite dilution of increased with increasing temperature. In contrast, the partial molar heat capacities of 1,2-butanediol at the infinite dilution decreased with increasing temperature. Heat capacity changes by dissolution of the alkanediols were also determined. Heat capacity changes caused by the dissolution of 1,2-ethanediol or 1,2-propanediol were increase with increasing temperature. On the other hand, heat capacity changes caused by the dissolution of 1,2-butanediol are decrease with increasing temperature. Thus our results indicated that the structural changes of water caused by the dissolution of 1,2-butanediol differed from that of the two other alkanediols. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reversible redox behavior between stannole dianion and bistannole-1,2-dianion

The reversible redox behavior between the stannole dianion and the bistannole-1,2-dianion is demonstrated. Reaction of the stannole dianion with oxygen (1 eq) gives the 1,2-bistannole-1,2-dianion which is a tin-analogue of the cyclopentadienyl anion in 94% yield. Reaction of the stannole dianion with ferrocenium tetrafluoroborate (1 eq) also gives the 1,2-dianion. The 1,2-bistannole-1,2-dianion has a nonaromatic nature as evidenced by X-ray and NMR analysis. Reduction of the 1,2-dianion with lithium gives the starting dianion.     

1,2-Epoxycarotinoide. 3. Mitteilung. Isolierun von 1,2-Epoxy-1,2-dihydrolycopin aus Tomaten

1,2-Epoxycarotenoids: Isolation of 1,2-Epoxy-1,2-dihydrolycopene from Tomatoes The optically active, 1,2-epoxy-1,2-dihydrolycopene was isolated from tomatoes. Its constitution was established by comparison with the racemic synthetic compound.     

Straightforward access to pyrazines, piperazinones, and quinoxalines by reactions of 1,2-diaza-1,3-butadienes with 1,2-diamines under solution, solvent-free, or solid-phase conditions

The preparation of tetrahydropyrazines, dihydropyrazines, pyrazines, piperazinones, and quinoxalines by 1,4-addition of 1,2-diamines to 1,2-diaza-1,3-butadienes bearing carboxylate, carboxamide, or phosphorylated groups at the terminal carbon and subsequent internal heterocyclization is described. The solvent-free reaction of carboxylated 1,2-diaza-1,3-butadienes with the same reagents affords piperazinones, while phosphorylated 1,2-diaza-1,3-butadienes yield phosphorylated pyrazines. The solid-phase reaction of polymer-bound 1,2-diaza-1,3-butadienes with 1,2-diamines produces pyrazines.     

Crystal clear structural evidence for electron delocalization in 1,2-dihydro-1,2-azaborines

The first examples of "pre-aromatic" 1,2-dihydro-1,2-azaborine heterocycles have been structurally characterized, enabling the direct comparison of delocalized bonds of 1,2-dihydro-1,2-azaborines to their corresponding formal double and single bonds in nonaromatic systems. The crystallographic data provide an unprecedented look into the structural changes that occur in six-membered BN-heterocycles on their road to aromaticity, and they establish with little ambiguity that 1,2-dihydro-1,2-azaborines possess delocalized structures consistent with aromaticity.     

Polymeric organosilicon system VIII. Synthesis of poly[(disilanylene)diethynylene] with highly conducting properties

The reaction of bis(trimethylsilyl)butadiyne with 2 equiv. of methyllithium, followed by 1,2-dichloro-1,2-dimethyldiphenyl- or 1,2-dichloro-1,2-diethyldimethyldisilane gives poly[(1,2-dimethyldiphenyldisilanylene)diethynylene] (II) or poly[(1,2- diethyldimethyldisilanylene)diethynylene] (III), respectively. Films of II and III become conducting when treated with SbF₅ vapor.     

The first one-pot oxidative 1,2-acetoxysulfenylation and 1,2-disulfenylation of Baylis-Hillman alcohols in an ionic liquid

The first example of tandem oxidation and 1,2-acetoxysulfenylation/1,2-disulfenylation of Baylis-Hillman (BH) alcohols to afford 1,2-acetoxysulfides/1,2-dithioethers is reported. The reaction involves oxidation of BH alcohols with IBX in [bmim]Br to give β-ketomethylene compounds in situ followed by CuI-imidazole-catalyzed 1,2-acetoxysulfenylation with an organodisulfide and acetic acid under air to afford vicinal acetoxysulfides in excellent yields with complete regioselectivity. In the absence of the Cu(I) catalyst, 1,2-disulfenylation takes place to give vicinal dithioethers in 81-90% yields.     

Polyfluoro-1,2-epoxy-alkanes and -cycloalkanes. Part I. Preparation of some polyfluoro-1,2-epoxycyclohexanes

Polyfluorocyclohexenes with hydrogen, bromine, and methoxy substituents yielded the corresponding 1,2-epoxides when treated with aqueous sodium hypochlorite containing some acetonitrile. 4,5-Dibromooctafluoro-1,2-epoxycyclohexane was debrominated with zinc dust to give a mixture of octafluoro- and 4H-heptafluoro-1,2-epoxycyolohex- 4-ene. Decafluoro- and 4,5-dibromo-octafluoro-1,2-epoxycyolohexane gave with potassium fluoride in acetonitrile the corresponding potassium perhalogenocyclohexyloxides; heating these gave the analogous cyclohexanones, and treatment with methyl iodide the methyl ethers. The unsaturated 1,2-epoxides also gave methyl ethers on treatment with KF, followed by methylation.     

Reaktion von Bis(methylzink)‐1,2‐dipyridyl‐1,2‐bis(tert‐butyldimethylsilylamido)ethan mit Triisopropylsilylphosphan und ‐arsan

Reaction of Bis(methylzinc)‐1,2‐dipyridyl‐1,2‐bis(tert‐butyldimethylsilylamido)ethane with Triisopropylsilylphosphane and ‐arsane The reaction of bis(methylzinc)‐1,2‐dipyridyl‐1,2‐bis(tert‐butyldimethylsilylamido)ethane ( 1 ) with triisopropylsilylphosphane gives the three‐nuclear complex [1,2‐dipyridyl‐1,2‐bis(tert‐butyldimethylsilylamido)ethane]trizinc‐bis(μ‐triisopropylsilylphosphanediide) ( 2 ). Two zinc atoms show the coordination number of four whereas the third metal center is located between the two phosphorus atoms with a bent P–Zn–P‐moiety. The reaction of 1 with triisopropylsilylarsane proceeds analoguesly, however, we were not able to isolate analytically pure [1,2‐dipyridyl‐1,2‐bis(tert‐butyldimethylsilylamido)ethane]trizinc‐bis(μ‐triisopropylsilylarsanediide) ( 3 ).     

Ultrasonic-enhanced Stereoselective Debromination of vic-Dibromides to Alkenes with Metallic Zinc Powder in Aqueous Media

IntroductionThe protection/deprotection procedures play avery important role in organic syntheses[1,2 ] .Car-bon- carbon double bond functional groups are oftenprotected during reactions because of their reactivi-ty.A variety of protecting methods,such as halo-genation,epoxidation and the method of usingC5H5Fe( CO) 2 BF4as the blocking group have beenrecommended for this purpose[3 _ 5] .Among themethods,protection/deprotection of olefins viabromination/debromination is more popular,sim-pler…     

Theoretical determination of chromophores in the chromogenic effects of aromatic neurotoxicants

We report the first computational study of the chromophores responsible for the chromogenic effects of aromatic neurotoxicants containing a 1,2-diacetyl moiety in their oxidation metabolites. A series of ab initio electronic structure calculations was performed on two representative aromatic compounds, 1,2-diacetylbenzene (1,2-DAB) and 1,2-diacetyl tetramethyl tetralin (1,2-DATT), the putative active metabolites of the neurotoxic aromatic hydrocarbon compounds 1,2-diethylbenzene (1,2-DEB) and acetyl ethyl tetramethyl tetralin (AETT), and on the products of their possible reactions with proteins that result in chromogenic effects. The electronic excitation energies determined by three different computational approaches were found to be consistent with each other. The calculated results are consistent with the conclusion/prediction that the chromogenic effects of 1,2-DAB (or 1,2-DEB) and 1,2-DATT (or AETT) could result from ninhydrin-like reactions, rather than the formation of pyrrole-like compounds. Our pK(a) calculations further indicate that the chromophore, i.e., the product of the ninhydrin-like reaction showing the blue color, is deprotonated in neutral aqueous solution. The corresponding protonated structure has a different color as it absorbs in the blue region of the visible spectrum, and its chromogenic contribution would be significant in solution at low pH.     

TBAF-mediated reactions of 1,1-dibromo-1-alkenes with thiols and amines and regioselective synthesis of 1,2-heterodisubstituted alkenes

An efficient synthesis of trisubstituted alkenes including 1,2-heterodisubstituted alkenes has been described. Reactions of thiols and amines with 1,1-dibromo-1-alkenes in the presence of TBAF·3H(2)O afford (Z)-2-bromovinyl sulfides and (Z)-2-bromovinyl amines regio- and stereoselectively. The reaction proceeds under catalyst-free conditions with high efficiency. The coupling reactions of the obtained products bearing bromine atoms with phenylacetylene and phenylboronic acid gave trisubstituted alkenes in good to excellent yields. Cross-coupling with various N, O, S, and P nucleophiles selectively generated 1,2-N,O, 1,2-N,S, 1,2-S,P, 1,2-S,S, and 1,2-S,O heterodisubstituted alkenes.     

Domino reactions of 1,2-diimidoyl-1,2-dichloroethanes. Synthesis of 3-imino-1,2-dithia-3h-cyclopent-4-enes, 3-amino-2-thioxo-2,5H-pyrrol-5-ones, 2,3-diamino-4-thioxo-4H-thiopyrans, and 6-imino-6H-1,3-oxazines

The reaction of mono- and dilithiated ethyl thioglycolate with 1,2-diimidoyl-1,2-dichloroethanes, aza-analogues of oxalyl chloride, afforded (depending on the reaction conditions) 3-imino-1,2-dithia-3H-cyclopent-4-enes, 3-amino-2-thioxo-2,5H-pyrrol-5-ones, and 2,3-diamino-4-thioxo-4H-thiopyrans. The reaction of the dianion of ethyl hippurate with 1,2-diimidoyl-1,2-dichloroethanes afforded 6-imino-6H-1,3-oxazines.     

On Condensation Reactions of Aceanthrene Quinone: Novel Heterocycles

Summary.  It was found that aceanthrene quinone can be condensed with ethylenediamine, 1,2-diaminobenzene, 4-nitro-1,2-diaminobenzene, 1,2-diaminoanthrene quinone, and 4,5,6-triaminopyrimidine derivatives to give aceanthryleno[1,2-b]pyrazine and aceanthryleno[1,2-g]pteridine derivatives. Condensation of aceanthrene quinone with 2-aminoguanidine, semicarbazide, and thiosemicarbazide yielded aceanthryleno[1,2-e]triazines, condensation with 6-hydrazinopyrimidine derivatives gave 3,4-aceanthrylenopyrimido[4,5-c]pyridazines. Reaction of aceanthrene quinone with 2-cyanoethanoic acid hydrazide afforded 10,11-dihydro-10-oxo-aceanthryleno[1,2-c]pyridazine-9-carbonitrile. Treatment of aceanthrene quinone with malononitrile and hydrazine hydrate resulted in 10-aminoaceanthryleno[1,2-c]pyridazine-9-carbonitrile. The antibacterial effects of the prepared compounds were tested. Three of the compounds were tested against 60 cancer types. Received May 6, 2001. Accepted June 5, 2001     

Reaction of perfluorinated 1-ethyl-, 1,1-diethyl-, and 1,2-diethylcyclobutabenzenes with pentafluorobenzene in SbF<Subscript>5</Subscript>

Perfluoro(1-ethyl-1,2-dihydrocyclobutabenzene) reacts with pentafluorobenzene in SbF5 to give perfluoro(1-ethyl-2-phenyl-1,2-dihydrocyclobutabenzene). Analogous reaction of a mixture of perfluoro(1,1-diethyl-1,2-dihydrocyclobutabenzene) and perfluoro(1,2-diethyl-1,2-dihydrocyclobutabenzene) leads to the formation (after hydrolysis of the reaction mixture) of perfluorinated 7-phenyl-8,8-diethylbicyclo[4.2.0]octa-1,4,6-trien-3-one, 1,1-diethyl-2-(4-oxocyclohexa-2,5-dienylidene)-1,2-dihydrocyclobutabenzene, and 2-(pent-2-en-3-yl)benzophenone (from the 1,1-isomer) and perfluorinated (E)-1,2-diethyl-1-phenyl-1,2-dihydrocyclobutabenzene, 7,8-diethyl-8-phenylbicyclo[4.2.0]octa-1,4,6-trien-3-one, and 1-[2-(1-phenylprop-1-en-1-yl)-phenyl]propan-1-one (from the 1,2-isomer).