Aprotic Acids Research Articles

Technological Aspects of Dicarboxylic Acids Esterification in the Presence of Aprotic Catalysts

The investigation results of the regularities of diesters of aliphatic dicarboxylic acids obtained in the presence of aprotic catalysts - Lewis acids - have been generalized. The effect of catalysts (metal salts) nature and concentrations, reagents nature and ratio, water content in them, as well as the influence of reaction temperature on the technological characteristics of esterification process have been determined. The technological aspects of the process have been examined in the presence of aprotic acids. The investigated catalysts may be reused in the technological process.

2-ARYLAZO-1-VINYLPYRROLES: OLIGOMERIZATION IN THE PRESENCE OF PROTIC AND APROTIC ACIDS

2-Arylazo-1-vinylpyrroles react with protic (CF 3 COOH, HCl) and aprotic (BF 3 ) acids forming deeply colored oligomeric products consisting of soluble (in benzene, chloroform) and insoluble fractions with yields amounting to 73%. According to the data from 1 H NMR and IR spectroscopy oligomerization takes place mainly at the 1-vinyl group with partial involvement of the pyrrole ring. The process is accompanied by capture of the catalyzing acids by the azo group, leading to strong polarization of the elementary unit with transfer of positive charge to the pyrrole ring, which thus becomes capable of further transformations with cross-linking of oligomeric chains. The obtained oligomers possess electric conductivity of 10 −13 -10 −9 S/cm, which is increased to 4.8·10 −6 S/cm when the products are iodinated with iodine vapor. Authors: M. V. Markova, E. Yu. Shmidt, L. V. Morozova, I. V. Tatarinova, G. F. Prozorova, A. I. Mikhaleva, and B. A. Trofimov. English translation in Chemistry of Heterocyclic Compounds , 2012, 48 (2), pp 280-286 http://link.springer.com/article/10.1007/s10593-012-0987-1

2-Arylazo-1-vinylpyrroles: oligomerization in the presence of protic and aprotic acids

2-Arylazo-1-vinylpyrroles react with protic (CF3COOH, HCl) and aprotic (BF3) acids forming deeply colored oligomeric products consisting of soluble (in benzene, chloroform) and insoluble fractions with yields amounting to 73 %. According to the data from 1H NMR and IR spectroscopy oligomerization takes place mainly at the 1-vinyl group with partial involvement of the pyrrole ring. The process is accompanied by capture of the catalyzing acids by the azo group, leading to strong polarization of the elementary unit with transfer of positive charge to the pyrrole ring, which thus becomes capable of further transformations with cross-linking of oligomeric chains. The obtained oligomers possess electric conductivity of 10−13-10−9 S/cm, which is increased to 4.8∙10−6 S/cm when the products are iodinated with iodine vapor.

A terminal nickel(ii) anilide complex featuring an unsymmetrically substituted amido pincer ligand: synthesis and reactivity

This work describes preparation and reaction chemistry of a terminal nickel(II) anilide complex supported by an unsymmetrically substituted diarylamido diphosphine ligand, [N(o-C(6)H(4)PPh(2))(o-C(6)H(4)P(i)Pr(2))](-) ([Ph-PNP-(i)Pr](-)). Treatment of NiCl(2)(DME) with H[Ph-PNP-(i)Pr] in THF at room temperature produced [Ph-PNP-(i)Pr]NiCl as green crystals in 82% yield. Salt metathesis of [Ph-PNP-(i)Pr]NiCl with LiNHPh(THF) in THF at -35 °C generated cleanly [Ph-PNP-(i)Pr]NiNHPh as a greenish blue solid. The anilide complex deprotonates protic (e.g., PhOH and PhSH) and aprotic (e.g., trimethylsilylacetylene, phenylacetylene, and acetonitrile) acids in benzene at room temperature to give quantitatively [Ph-PNP-(i)Pr]NiX (X = OPh, SPh, C≡CSiMe(3), C≡CPh, CH(2)CN). In addition, [Ph-PNP-(i)Pr]NiNHPh also behaves as a nucleophile to react with acetyl chloride to yield [Ph-PNP-(i)Pr]NiCl and N-phenylacetamide quantitatively. Carbonylation of [Ph-PNP-(i)Pr]NiNHPh with carbon monoxide affords cleanly the carbamoyl derivative [Ph-PNP-(i)Pr]Ni[C(O)NHPh]. The relative bond strengths of Ni-E in [Ph-PNP-(i)Pr]NiEPh (E = NH, O, S, C≡C) are assessed and discussed.

Reactivity and electronic structure of the ground and excited states of oxazole, 2-phenyloxazole, and 2-phenylthiazole

The relationship of the electronic structure, of oxazole, 2-phenyloxazole, and 2-phenylthiazole to the properties of the electronic excited states and transitions is examined. Spectral properties of these compounds in the free state (no effect from external perturbations) and in complexes with the proton and aprotic acids are measured and calculated by quantum-chemical PPP/S (π-approximation), and INDO/S (sp-basis) methods. Features of the electronic excitation of the atoms and the vibronic interaction of bonds in the singlet and triplet states are examined for a change of the various structural forms of azoles, which determine their spectral fluorescence properties and reactivity. Possible direction control of reactions and optimized syntheses of new compounds with given properties are discussed based on a study of the properties of the ground and excited states.

Soluble aromatic polyamide and polyimides derived from di(aminophenyl) acetylenediurea

New aromatic polyamide and polyimides were prepared from di(aminophenyl)acetylenediurea. In addition, model compounds were synthesized and their IR spectra were in agreement with those of the corresponding polymers. The polymers were amorphous and readily soluble in polar aprotic solvents (DMF, NMP, DMSO) and certain acids (H2SO4, CCl3COOH). The hydrophilicity of polyamide was estimated by measuring the isothermal water absorption. The polyamide softened at 260°C but no softening was observed for polyimides. The glass transition temperatures of polymers were determined by the TMA method and they were in the range of 235–310°C. The polymers were stable up to 359–404°C in N2 or air and afforded char yields of 53–65% at 800°C in N2. © 1996 John Wiley & Sons, Inc.

Properties and antiphage activity of condensed hydro(thio)chromans and their copper complexes

Research into the reactivity of carbonyl-substituted spirohydrochromans with hydrogen sulfide under the influence of protic and aprotic acids was continued for the case of 3,4,5,6,7,8-hexahydrospiro[chromene-2,1′-cyclohexan]-2-one. The general nature of the reactions was established. Complexes of copper(II) with substituted hydro(thio)chromans were obtained. The results from investigation of the antiphage activity of the synthesized compounds are presented.

Electrophilic activation of carbon dioxide. Preparation of vinylacetic acid from CO2 and allyltrimethylsilane

The search for fundamentally new methods to activate the carbon dioxide molecule and involve it in various reactions attracts special attention. In this respect, the problem of the possible use of Lewis acids and protic superacids has been repeatedly discussed in the literature. However, no actual results in this field have been obtained until recently. Now the authors can report the first example of direct electrophilic activation of the CO{sub 2} molecule by aprotic Lewis acids under mild conditions.

Polyamides containing olefinic bonds

AbstractThe reaction of 2,5‐dimethylpiperazine with a double molar amount of maleic anhydride afforded a new unsaturated dicarboxylic acid that was characterized by IR and 1H‐NMR spectroscopy. It was condensed with various aromatic diamines by the phosphorylation method to yield polyamides bearing olefinic bonds. They were readily soluble in polar aprotic solvents and certain acids. The DTA traces of polyamides showed exotherms above 250°C attributable to their cross‐linking through the olefinic bonds and a partial thermal degradation. Evidence for the cross‐linking of polyamides attained during their heat‐curing was obtained from the IR spectra of the uncured and cured samples. Thermal stabilities of cured (at 300°C for 15 h) polyamides were evaluated by TGA and isothermal gravimetric analysis. They were stable up to 321–336°C in N2 or air and afforded an anserobic char yield of 61–71% at 800°C. © 1993 John Wiley & Sons, Inc.

Cellulose sorbents obtained by the action of Lewis acids

Abstract

ChemInform Abstract: Adamantane‐2‐spiro‐3′‐diazirine in Reactions with Protic and Aprotic Acids.

AbstractThe title compound (I), on treatment with protic acids such as conc.

Basicity of metal carbonyl complexes: XIX. Co substitution in azacymantrene and reactions of (η 5-C 4H 4N)Mn(CO) 2PPh 3 with electrophiles. X-ray crystal structure of [(PPh 3)(CO) 2Mn(η 5-C 4H 4N)] 2PdCl 2

A convenient method for substituting a CO ligand in azacymantrene, (η 5- C 4H 4N)Mn(CO) 3 (I), by the interaction of I with PPh 3 in the presence of Me 3NO has been found. The reactions of (η 5-C 4H 4N)Mn(CO) 2PPh 3 (II) with electrophiles were studied. The nitrogen atom of the η-pyrrolyl ligand was shown to be the site having the largest basicity with respect to the proton (protonation in CF 3CO- OH/CH 2Cl 2) and aprotic acids (Zn, Cd, Hg, Al, Ga, Sn, Pd salts) in II. The structure of the trinuclear complex [(PPh 3)(CO) 2Mn(η 5-C 4H 4N)] 2PdCl 2 was established by an X-ray study: the crystals are monoclinic, a 9.0165(5), b 15.748(1), c 16.179(1) Å, β 103.37(1)°, Z = 2, space group P2 1/ c; the palladium coordination environment is square-planar, PdN 2.033(2) and PdCl 2.306(1) Å.

ChemInform Abstract: NITRO DERIVATIVES OF THE THIOPHENE SERIES. 3. STUDY OF THE NITRATION OF THIOPHENE α,β‐UNSATURATED KETONES IN THE PRESENCE OF PROTONIC AND APROTIC ACIDS

Chemischer InformationsdienstVolume 12, Issue 44 Preparative Organic Chemistry ChemInform Abstract: NITRO DERIVATIVES OF THE THIOPHENE SERIES. 3. STUDY OF THE NITRATION OF THIOPHENE α,β-UNSATURATED KETONES IN THE PRESENCE OF PROTONIC AND APROTIC ACIDS YU. D. CHURKIN, YU. D. CHURKINSearch for more papers by this authorL. V. PANFILOVA, L. V. PANFILOVASearch for more papers by this authorA. S. SHASHKOV, A. S. SHASHKOVSearch for more papers by this authorK. YA. BURSHTEIN, K. YA. BURSHTEINSearch for more papers by this author YU. D. CHURKIN, YU. D. CHURKINSearch for more papers by this authorL. V. PANFILOVA, L. V. PANFILOVASearch for more papers by this authorA. S. SHASHKOV, A. S. SHASHKOVSearch for more papers by this authorK. YA. BURSHTEIN, K. YA. BURSHTEINSearch for more papers by this author First published: November 3, 1981 https://doi.org/10.1002/chin.198144114Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue44November 3, 1981 RelatedInformation

Basicity of carbonyl complexes of metals. 14. Reactions of benzene-chromium-dicarbonyltriphenyl-phosphine with aprotic acids

1. The complex C6H6Cr(CO)2(PPh3) reacts with aprotic acids HgCl2 and SnCl4 at the chromium atom, which is the part of the molecule with the highest basicity. 2. The formation of adducts is accompanied by an increase in the frequencies νCO and a change in their intensities.

Nitro derivatives of the thiophene series. 3. Study of the nitration of thiophene ?,?-unsaturated ketones in the presence of protic and aprotic acids

The nitration of 4-(5-R-2-thienyl) but-3-en-2-ones (R = H, CH3, C2H5) with a nitrating mixture and group I and III metal nitrates in concentrated sulfuric and trifluoroacetic acids, as well as in the presence of aluminum chloride, was investigated. Nitration with a nitrating mixture and potassium, sodium, lithium, copper, and aluminum nitrates in sulfuric acid takes place in the heterocyclic ring to give a mixture of nitro ketones. Nitration in trifluoroacetic acid and in the presence of aluminum chloride proceeds with the formation of a single α-nitro ketone. The structures of the substances obtained were proved by means of the IR and PMR spectra. A possible mechanism of the reaction is discussed.

Basicity of transiton metal carbonyl complexes : XIII. Reactions of the π-cyclopentadienyl complexes of molybdenum and tungsten with aprotic acids

The aprotic acids HgCl2 and SnX4 (X  Cl, Br) react with the π-complexes C5H5M(CO)(NO)(L) (II, M  Mo W; L  PPh3) by attack at the metal center. With HgCl2 complexes II yield stable neutral 1:1 adducts CpM(CO)(NO)(L)HgCl2(III). In the case of SnCl4, complexes II initially produce the ionic 1:2 adducts [CpM(CO)(NO)(L)(SnCl3)]+SnCl5-(IV) which, as a result of oxidative elimination of CO, turn into the neutral complexes CpM(NO)(L)(SnCl3)(Cl)(V). In reactions of II with SnBr4 the corresponding CpM(NO)(L)(SnB3)(Br) complexes are formed directly. The formation of III–V is accompanied by a considerable increase of the frequencies ν(CO) and ν(NO). The structures of the complexes IV (M  Mo) and V (M  Mo) have been established by an X-ray structure analysis.

Basicity of transition metal carbonyl complexes : XII. Reactions of C 5H 5M(CO)(NO)(PPh 3) Complexes (M  Mo, W) with aprotic acids

The aprotic acids HgCl 2 and SnCl 4 react with the complexes C 5H 5Mo(CO)(NO)(PPh 3) (M  Mo, W) by electrophilic attack at the transition metal centre. In the case of SnCl 4 the initial reaction is followed by elimination of Cl -. This reaction can be viewed as a S N displacement of chloride by the transition metal centre.

Basicity of transition metal carbonyl complexes : XI. Reactions of C 5H 5Mn(CO) 2L with stannic chloride and structure of reaction products

Adducts of 1 : 2 composition were obtained by reacting C 5H 5Mn(CO) 2L complexes (L = tertiary phosphines, AsPh 3 and SbPh 3) with stannic chloride. The crystal and molecular structure of C 5H 5Mn(CO) 2PPh 3 · 2SnCl 4 was established by X-ray structural analysis. It has an ionic structure that corresponds to formula [C 5H 5Mn(CO) 2(PPh 3)(SnCl 3)] +SnCl 5 −. The coordination environment of the manganese atom is a distorted square pyramid with a C 5H 5 ligand at the apex. Using IR spectroscopy it was established that in certain cases a mixture of two isomers is formed in solution. In C 5H 5Mn(CO) 2L complexes the central manganese atom is the site of attack by aprotic acids and is the most basic site of the molecule.

Basicity of carbonyl complexes of transition metals : X . Interaction of (π-C 5H 5)Mn(CO)(Ph 2PCH 2CH 2PPh 2) with aprotic acids in solution

The interaction of CpMn(CO)(Ph 2PCH 2CH 2PPh 2) with some aprotic acids in solution has been studied by infrared, electronic and ESR spectroscopy and electroconductivity. It is shown, that reactions with π-acids and some π-complexes such as CpTiX 3, CP 2MCl 2 (M  Ti, Zr, Hf, V) take place with oxidation of the manganese atom electron transfer to the acceptor molecule and the formation of the cation-radical of the donor molecule. It is also shown that an increase in the oxidation state of the Mn atom occurs in the reactions with halides of Al, Ti, Sn and Hg and the structure of the products is discussed. Less basic complexes CpMn(CO) 3, Et 5C 5Mn(CO) 3 and Et 5C 5Mn(CO) 2PPh 3 are not oxidised in the presence of tetracyanoethylene but form charge-transfer complexes.

Formation of free radicals in acid-catalyzed decomposition of di-tert-butyl peroxide

Di-tert-butyl peroxide under the influence of protic and aprotic acids is converted to isobutylene and tert-butyl hydroperoxide. The formation of free radicals occurs as the result of the acid-catalyzed homolysis of the hydroperoxide.