Preliminary communication : Development of an incremental system for the prediction of the nematic-isotropic phase transition temperature of liquid crystals with two aromatic rings

It is possible to express the transition temperature nematic-isotropic (TNI) for nematogens with just two aromatic ring systems as the sum of incremental values of substructural elements, denoted as substituents and bridging moieties. Of the 1426 mesogens that can be constructed by the elements for which the increments have been given, the TNI values of most can be predicted to within 10 C, the only notable exception being the 1,2-diphenylethenes.     

Metal Salts of Dinitro‐, Trinitropyrazole,and Trinitroimidazole

The syntheses of alkali and earth alkaline dinitropyrazolate (DNP), trinitropyrazolate (TNP), and trinitroimidazolate (TNI) salts are reported. Additionally, copper trinitroimidazolate was synthesized. Their characterization by NMR spectroscopy, mass spectrometry, elemental analysis, and vibrational spectroscopy is reported as well. Crystal structures of compound Ba(DNP)₂ ( 9 ), which crystallizes with one molecule of methanol and ethyl ether as well as of compounds Sr(TNP)₂ · 3H₂O ( 12 ), Ba(TNP)₂ · 3H₂O ( 13 ), and LiTNI · 3H₂O ( 14 ) were determined. The energetic and thermal properties were measured as well. Green‐ and red‐burning pyrotechnic formulations containing barium salts 9 and 13 as well as strontium salts 8 and 12 serving as colorants are tested. Additionally, formulations using Sr(TNP)₂ · 3H₂O ( 12 ) and Ba(TNP)₂ · 3H₂O ( 13 ) as the oxidizer and colorant at the same time were examined. The formulations were investigated with regard to their combustion behavior and performances such as burn time, dominant wavelength, spectral purity, luminous intensity, and luminous efficiency. The sensitivities towards ignition stimuli and the decomposition temperatures were determined as well.     

Influence of trans-cis photoisomerizations of solubilized compounds on transition temperatures in the system cetyltrimethylammonium bromide-water: Light-induced phase transitions

Transition temperatures (TN1) from the nematic lyotropic liquid-crystalline phase to the isotropic phase were measured for the system cetyltrimethylammonium bromide (CTAB) water in the presence of small amounts of 3-stilbene carboxylic acid (3SC), 4-stilbene carboxylic acid (4SC) and Δ2/2'-bi-(2H-l,4-benzothiazine) (BT). TNI, increases as a function of trans-3SC or trans-4SC concentration, ranging from 01 to 08 wt %, by up to 12°C. A further increase in TNI between 2 and 5°C can be achieved by photochemically converting the solubilized trans stilbene derivatives to the cis isomers. Irradiation of a trans-3SC containing sample at a temperature just above TNl leads to a light-induced phase transition to the lyotropic liquid-crystalline phase. Solubilization of trans-BT causes a slight decrease of TNI while photoisomerization to cis-BT increases T_NI by 1°C.     

Synthesis and Reactivity of Unsaturated Bisphosphonium Salts

Abstract

The synthesis of 1, 2 vinylene bisphosphonium salts 1 has now been enlarged to the vinylogous 1, 4-butadienylene bisphosphonium salts 2. The salts 2, a new class of unsaturated disalts, have also been prepared through a two-step isomerisation of acetylenic salts. New aspects of the reactivity of salts 1 and the comparative study of salts 2 (selective cleavage reactions of P-C bonds and reactions with nucleophiles having a mobile hydrogen) are described. This reactivity allows the preparation of new series of phosphonium salts substituted by heteroatomic groups.     

1-(N-Acylamino)alkyltriphenylphosphonium salts as synthetic equivalents of N-acylimines and new effective α-amidoalkylating agents

1-(N-Acylaminoalkyl)triphenylphosphonium salts 2a-f on reaction with DBU in MeCN are transformed into 1-(N-acylaminoalkyl)amidinium salts 3a-f. Amidinium salts 3d-f with a proton at the β-position undergo slow tautomerization into the corresponding enamides 6d-f. The same 1-(N-acylamino)alkyltriphenylphosphonium salts 2d-f in the presence of Hünig’s base are transformed directly into the corresponding enamides. Phosphonium salts 2, amidinium salts 3, and enamides 6 react with dialkyl malonates in the presence of DBU to give the corresponding amidoalkylation products. α-Amidoalkylation of dialkyl malonates is not observed in the presence of (i-Pr)₂EtN, yet proceeds well under these conditions with more acidic nucleophiles, for example, phthalimide or benzyl mercaptan.     

Regioselective Synthesis of Substituted Triazolium Salts via 1,3-Dipolar Cycloaddition Reactions

The regioselectivity of 1,3-dipolar cycloaddition reactions of 1-aza-2-azoniaallene salts with ,-unsaturated nitriles such as acrylonitrile or cyclohexylidene acetonitrile afforded only 1,2,4-triazolium salts via addition to the nitrile group, while the other expected pyrazolium salts were not observed. Moreover, 1-aza-2-azonia-allene salts reacted with other competitive systems such as -iminonitrile derivatives yielding only triazolium salts via addition to the nitrile and not to the imino group. Treatment of cumulene with 3-pyridylnitrile afforded the pyridinium salt. However, 2,3-dimethyl-5-(2,6-dimethoxyphenyl)-[1,2,4]triazole could be prepared from cumulene and 2,6-dimethoxybenzonitrile. Some reactions of nitriles with 1-aza-2-azonia-allene salts prepared from 1,2,3-indantrione and 9-acetylphenanthrene are discussed.     

Regioselective Synthesis of Substituted Triazolium Salts <Emphasis Type="Italic">via</Emphasis> 1,3-Dipolar Cycloaddition Reactions

Summary. The regioselectivity of 1,3-dipolar cycloaddition reactions of 1-aza-2-azoniaallene salts with ,-unsaturated nitriles such as acrylonitrile or cyclohexylidene acetonitrile afforded only 1,2,4-triazolium salts via addition to the nitrile group, while the other expected pyrazolium salts were not observed. Moreover, 1-aza-2-azonia-allene salts reacted with other competitive systems such as -iminonitrile derivatives yielding only triazolium salts via addition to the nitrile and not to the imino group. Treatment of cumulene with 3-pyridylnitrile afforded the pyridinium salt. However, 2,3-dimethyl-5-(2,6-dimethoxyphenyl)-[1,2,4]triazole could be prepared from cumulene and 2,6-dimethoxybenzonitrile. Some reactions of nitriles with 1-aza-2-azonia-allene salts prepared from 1,2,3-indantrione and 9-acetylphenanthrene are discussed.     

On interpretation of a missing spectral band; IR spectra of acidic salts of benzohydroxamic acid

Using solid benzohydroxamic acid (BHA) as a model compound for its salts, a broad absorption at 2730 cm(-1) was generally agreed to represent the nu(OH) band of the OH... ON bonds. The absence of nu(OH) band in the IR region 3600-1700 cm(-1) was taken to indicate the absence of OH groups in the solid salts. The same argument and conclusion was erroneously accepted for lithium (LiBHA) and potassium (KBHA) salts of BHA which are not "normal" but acid salts and do contain OH groups. X-ray diffraction results allow explanation of this discrepancy. The lithium and potassium acid salts have much shorter OH... ON bridges (O...O distances of 247 and 245 pm, respectively) than the model compound (258 pm). Accordingly, the nu(OH...O) bands in the acidic salts are shifted into the crowded 1600-700 cm(-1) interval. Obviously, interpretation of a missing spectral band in terms of molecular structure can be misleading when the models do not include all possible structural variations.     

Synthesis of 2, 6-dicyclohexyl-substituted pyrylium salts

2, 6-Dicyclohexyl-substituted pyrylium salts are synthesized by condensing hexahydrobenzoyl chloride with isobutene, isomeric pentenes, diisobutene, and -methylstyrene. Treatment of the resultant pyrylium salts with ammonia converts them into the corresponding pyridine salts.     

Reaction of 4-ethoxychromylium salts with some amines

The reactions of 4-ethoxychromylium salts with some amines were studied. It was shown that o-hydroxyarylpyrazoles and chromone phenylhydrazones, respectively, are formed by the reaction of these salts with hydrazine and phenylhydrazine. The action of primary aromatic amines leads to replacement of the 4-ethoxy group by a 4-arylamino group, while the reaction of the 4-ethoxychromylium salts with N,N-diethylaniline gives 4-ethoxy-4-diethylaminoflavylium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1112–1114, August, 1971.     

ANTIBACTERIAL ACTIVITY OF SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS GRAFTED ON "GEL-TYPE" STYRENE-DIVINYLBENZENE COPOLYMERS*

1.INTRODUCTIONThesynthesisofpolymer-supported"onium"salts(ammoniumandphosphonium)(1~5(wasdiscussedindetailduetothewidefieldofutilizationas:polarstationaryphasesforanionchromatography(6(,polymericreagentsfortrans-quaternizationreactions(7,8(,phase-transfercatalysts(9~13(andpolycationicbiocides(14~17(.Manychemicalmaterialssuchasozone,liquidchlorine,sodiumhydrochloride,s.a.,havebeenlargelyusedtosterilizeairandwater.Suchmaterialsrequirespecialequipmentandcarelessusemaycauseenvironmentalpolluti…     

Ethynyl carbonium ions. 2. Reactions of 4-ethynylpyrylium perchlorates with alcohols and nitrogen-containing nucleophiles

Derivatives of -alkoxy- and -(phenylamino)styrylpyrylium salts, the hydrolysis of which leads to phenacylpyrylium salts and 4-benzoylmethylenepyrans, are formed in the reaction of 4-phenylethynylpyrylium salts with alcohols and aromatic amines. Ethynyl-substituted pyridines and pyridinium salts were synthesized by the action of ammonium acetate and methylamine, benzylamine, and butylamine. A -methylaminostyryl-1-methyl-substituted pyridinium salt is formed with excess methylamine.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 299–306, March, 1990.     

Powder X-ray diffraction study of the double complexes [M(NH3)5Cl][M"Cl4] as precursors of metal powders (M = Ir,Rh, Co; M" = Pt,Pd)

According to the results of powder X-ray diffraction study of the complex salts of composition [M(NH₃)₅Cl][M"Cl₄] (M = Ir, Rh, or Co and M" = Pt or Pd), the anhydrous salts crystallize in the orthorhombic system (space group Pnma) and are isostructural to the [Ir(NH₃)₅Cl][PtCl₄] complex studied previously. The unit cell parameters of the resulting salts were refined. The metal powders, which were obtained by thermal decomposition of these salts under an atmosphere of hydrogen, were studied by powder X-ray analysis.     

Ambidentate reactivity of 3-azapyrylium systems in nucleophilic attack reactions

It has been shown that recyclization of 4-acylmethyl-3-azapyrylium salts under the influence of primary amines affords 4-(-hydrozystyryl)pyrimidinium salts, which, upon further heating with the amine, are recyclized to form 4-acylaminopyridinium salts. It has been established that nucleophilic attack of 6-acylmethyl-substituted 3-azapyrylium salts in aqueous NaOH solution leads to functionally substituted pyridines. By means of MNDO quantum-chemical calculations with an accounting for solvation effects, in a continuum model, it has been shown that two directions of nucleophilic attack of the azapyrylium ring — at positions 2 and 6 — are equally probable.Rostov State University. Scientific-Research Institute of Physical and Organic Chemistry, Rostov State University, Rostov-on-Don 344010. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–700, May, 1994. Original article submitted April 18, 1994.     

α-Ferrocenylalkylation of 1,5-Disubstituted Tetrazoles and Certain Transformations of Reaction Products

The reaction of -hydroxyferrocenylalkyl derivatives and vinylferrocene with 1,5-disubstituted tetrazoles in methylene chloride-aqueous acid HX (X = BF4, ClO4) two-phase systems gives a mixture of 1,3,5- and 1,4,5-trisubstituted tetrazolium salts, the fraction of the 1,3,5-isomers prevailing. The synthesized salts are readily dealkylated under the action of bases to give the above starting compounds. Heating of 3(4)-(ferrocenylmethylene)-1,5-pentamethylenetetrazolium and 3(4)-(ferrocenylmethylene)-2-methyl-1-phenyltetrazolium tetrafluoroborates in anhydrous methanol or ethanol in the presence of catalytic amounts of alkali gives rise to ferrocenylcarbinol ethers. Other nuclephiles (pyridine, triphenylphosphine, sodium thiocyanate, sodium p-toluenesulfinate, dibenzoylmethane) also react with the above tetrazolium salts, forming ferrocenylmethylation products. Heating of equimolar amounts of 3(4)-(ferrocenylmethylene)-1,5-pentamethylenetetrazolium or 3(4)-(ferrocenylmethylene)-2-methyl-1-phenyltetrazolium perchlorates with mercury(II) perchlorates in anhydrous ethanol results in mercuration of the starting tetrazolium salts, involving hydrogen substitution in the methylene or methyl groups bound to tetrazolium carbon atoms. The condensation of the same salts with p-N,N-(dimethylamino)nitrosobenzene, leading to azomethine formation, occurs under similar conditions.     

Synthesis and complexing properties of a chiral macrocyclic molecular receptor with convergent binding sites

Two novel hosts: 15-crown-5 and N-benzyl-aza-15-crown-5 incorporating a boron-containing D-mannopyranosidic unit form more stable cascade complexes with (S)-amino acid sodium or potassium salts than with the respective (R)-enantiomers. Complexes with sodium salts are more stable than the corresponding complexes with potassium salts as revealed by variable-temperature NMR measurements. Strong non-bonded interaction between the sugar unit and the -substituents of the amino acids results in enantiomeric differentiation and destabilization of the complex. Complex formation is interpreted in terms of ion-pair inclusion by macrocyclic ring and nitrogen-boron interaction.     

Intramolecular "hydroiminiumation and -amidiniumation" of alkenes: a convenient, flexible, and scalable route to cyclic iminium and imidazolinium salts

Addition of a stoichiometric amount of HCl to alkenylaldimines, -formamidines, and -amidines results in the protonation of the sp2-nitrogen atom. The resulting alkenylaldiminium, -formamidinium, and -amidinium salts can be isolated and fully characterized, including single-crystal X-ray diffraction studies. Heating solutions of these salts induces ring closure cleanly and regioselectively via formal "exo" addition of the nitrogen-hydrogen bond to the pendent carbon-carbon double bond, affording the corresponding cyclic aldiminium, dihydroisoquinolinium, and imidazolinium salts. Of special interest, novel 4,4-disubstituted imidazolinium salts are accessible via this synthetic route. Similarly, addition of phosgene to alkenyl ureas and alkenyl amides, followed by gentle heating, cleanly affords C-chloro imidazolinium, and cyclic C-chloro iminium salts, respectively. Treatment of the latter with tetrakis(triphenylphosphine)palladium allows for the preparation of the first transition-metal complex bearing a cyclic arylaminocarbene as ligand. Deuterium labeling experiments suggest that the mechanism of the hydroiminiumation and -amidiniumation reactions involves an intramolecular proton transfer to the double bond in the rate-determining step. This novel synthetic methodology gives access to a variety of N-heterocyclic carbene (NHC) and cyclic alkyl- and arylaminocarbene (CAAC) precursors.     

Products of the reaction of the bases of cyanine dyes with silver ions

The reaction of 2-[3-(3-alkyl-2-benzothiazolylidene)propenyl]benzothiazole,-pyridine, and -quinoline with silver ions in various solvents was studied. In anhydrous methanol, chloroform, and acetonitrile the indicated bases of cyanine dyes reduce silver ions with the liberation of acid in an amount equivalent to the silver metal formed, and the bases are partially converted to the salts. Similar reaction products are obtained by electrolysis of solutions of them in methanol and acetonitrile at the potentials established for them. It was established that the unstable salts of their N-oxides are formed in the presence of water in the reaction of the bases with silver salts; the products of the transformations of the N-oxides were identified.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 761–766, June, 1979.     

Pyranyltriphenylphosphonium salts

The reaction of pyrylium salts having a free or position with triphenylphosphine has given pyranylphosphonium salts. 2,4,6-Trisubstituted pyrylium salts do not react with triphenylphosphine. The properties and IR spectra of the compounds synthesized are discussed.