- Novel Desulphurization of Thiourea Derivatives by Alkaline Autoxidation
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Autoxidation of 1,3-disubstituted thioureas in the presence of oxygen and tertiary butoxide in tertiary butanol afforded the corresponding ureas in good yields together with small amounts of the corresponding guanidines while the same treatment of benz- or naphth-imidazole-2-thiones gave the parent imidazoles and the 2-sulphonic acids.
- Kim, Yong Hae,Kim, Hyung Jin,Yon, Gyu Hwan
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- Mechanistic insights into N - N bond cleavage in catalytic guanylation reactions between 1,2-diarylhydrazines and carbodiimides
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Cleavage of the N - N bond in 1,2-diarylhydrazine was achieved through an alkyllithium-catalyzed guanylation reaction of 1,2-diarylhydrazine with carbodiimide, affording guanidine and azo compounds. This N - N bond cleavage via thermal rearrangement was d
- Xu, Ling,Wang, Yu-Chen,Ma, Wangyang,Zhang, Wen-Xiong,Xi, Zhenfeng
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- INVESTIGATION OF THE THERMOLYSIS OF 5-METHYL-1-PHENYLTETRAZOLE BY COMBINED DERIVATOGRAPHY AND MASS SPECTROMETRY
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The thermolysis of 5-methyl-1-phenyltetrazole was studied at 20-350 deg C by derivatography and mass spectrometry, and it was shown that thermal decomposition proceeds with the elimination of a molecule of nitrogen and is accompanied by skeletal rearrangement of the intermediately formed nitrene to 2-methylbenzimidazole or migration of the methyl group to the nitrogen atom with the formation of methylphenylcarbodiimide (MPCD).In addition, symmetrical dimethyl- and diphenylcarbodiimides, methylphenylguanidines, and aniline are formed.It is assumed that the formation of these compounds in pyrolyzate is due to polymerization of MPCD and subsequent thermal destruction of the polymerization products.A scheme for the thermolysis of 5-methyl-1-phenyltetrazole is proposed.
- Klyuev, N. A.,Shurukhin, Yu. V.,Konchits, V. A.,Grandberg, I. I.,Rusinov, V. L.,et al.
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- Molecular structure and acid/base properties of 1,2-dihydro-1,3,5-triazine derivatives
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It is shown that guanidine and its N,N-dimethyl-derivative react with substituted carbodiimides, affording hitherto unknown 1,2-dihydro-1,2,3-triazine derivatives. The structures of three novel compounds of this type and their perchlorate salts were elucidated by spectroscopic (IR, 1H and 13C NMR and 15N solid-state NMR) and X-ray diffraction methods. The acid/base properties were also determined experimentally and by using DFT calculations with the B3LYP functional. The most basic compound was found to be dihydrotriazine 3, the basicity of which with the pKa value of 23.3 is of the same order of magnitude as that of tetramethylguanidine. Acidity measurements revealed that all the compounds studied are very weak acids with pKa values in the range of 25.8-30.8 pKa units in acetonitrile. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Trukil, Vjekoslav,Ilovic, Ivica,Matkovic-Alogovic, Dubravka,Saame, Jaan,Leito, Ivo,Ket, Primo,Plavec, Janez,Eckert-Maksic, Mirjana
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- O-Iodoxybenzoic acid mediated oxidative condensation: Synthesis of guanidines using 1,-3-disubstituted thiourea precursors
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An efficient and mild oxidative condensation procedure using o-iodoxybenzoic acid and triethylamine or ammonia as base has been developed for the synthesis of guanidines starting from easily synthesizable 1,3-disubstituted thioureas and amines or ammonia.
- Dangate, Prasad S.,Akamanchi, Krishnacharya G.
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p. 6765 - 6767
(2013/01/15)
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- Synthesis and some transformations of (dialkoxy)arylimidophosphinoylformamidines
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Dialkyl hydrogen phosphites add reversibly to dicyclohexylcarbodiimide, forming N,N'-dicyclohexylformamidines.Similar addition products derived from phenylphophoramidites and diphenylcarbodiimide are converted on heating or on prolonged storage at room temperature into 1-dialkoxyphosphino-1,2,3-triphenylguanidines together with other products; their hydrolysis gives anilidophosphates and diphenylformamidine, and under the action of dithiophosphoric acids they lose both alkyl groups, yielding zwitterionic anilido(formamidinio)phosphonates.
- Kamalov, R. M.,Khailova, N. A.,Al'fonsov, V. A.,Pudovik, M. A.
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- Benzenetellurinic Mixed Anhydrides as Mild Oxidizing Agents
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Three benzenetellurinic mixed anhydrides. i. e. benzenetellurinyl acetate, trifluoroacetate, and trifluoromethanesulfonate, have been found to be mild oxidizing agents for various substrates such as thiol, phosphine, acyloin, α-hydroxy ester, catechol, hydroquinone, thiourea, and thioamide.The reactions towards the last two substrates are highly chemoselective, depending on both the reagent and substrate.
- Fukumoto, Takahiro,Matsuki, Toshiaki,Hu, Nan Xing,Aso, Yoshio,Otsubo, Tetsuo,Ogura, Fumio
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p. 2269 - 2272
(2007/10/02)
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- Photochemical Reactions of Primary Aromatic Amines with Chloromethanes in Solution. II. The Products and Mechanisms of Partial Reactions of Aniline in Tetrachloromethane, Chloroform and Dichloromethane
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Major products of photochemical reactions of aniline in tetrachloromethane, chloroform and dichloromethane have been isolated and identified.The mechanisms of partial reactions have been discussed. - Keywords: Photochemical Reactions, Primary Aromatic Amines, Chloromethanes
- Boszczyk, Wojciech,Latowski, Tadeusz
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p. 1589 - 1592
(2007/10/02)
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- Exchange, Elimination, and Ring Opening Reactions of 2,3-Dihydrobenzimidazothiadiazoles and 3H-Benzimidazodithiazoles
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The reactions of benzimidazothiadiazol-3(2H)-ones (1) with isocyanates, isothiocyanates, carbon disulphide, aryl cyanates, acetylenedicarboxylates, and enamines, with exchange of the isocyanate component of (1), to give the corresponding condensed benzimidazole derivatives (1)-(6) are described.Under more severe conditions the 1-benzothiazol-2-yl-1,3-dihydrobenzimidazole-2-thiones (7) were obtained from aromatic isothiocyanates.Thermolysis of the thiadiazoles (1) led to the triazine derivative (12) with elimination of isocyanate and sulphur, and in the presence of phenols to the 2-aryloxybenzimidazoles (13).With amines and CH-acidic compounds, the S,N bond in compound (1) was cleaved to give benzimidazol-2-ylsulphenamides (14), and the ω-substituted methylthiobenzimidazoles (17) and (18).With cyanide ion, insertion into the S,N bond of compound (1) to furnish the thiadiazine (22) took place.The dithiazoles (2) were fragmented by amines to give 1,3-dihydrobenzimidazole-2-thione and guanidine with loss of sulphur; reaction with cyanide ion then gave the dibenzimidazothiadiazine (25).
- Martin, Dieter,Tittelbach, Franz
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p. 1007 - 1014
(2007/10/02)
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- Novel Desulphurization of 1,3-Disubstituted Thioureas by Superoxide Anion (O2*-): One-step Synthesis of 1,2,3-Trisubstituted Guanidines from 1,3-Disubstituted Thioureas
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Treatment of 1,3-diarylthioureas with superoxide anion (O2*-) at 20 deg C in tetrahydrofuran or acetonitrile resulted in the formation of 1,2,3-triarylguanidines in excellent yields.
- Kim,Yong Hae,Yon, Gyu Hwan
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p. 715 - 716
(2007/10/02)
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- Orthoamides, XXXVIII. - Contributions to the Chemistry of Orthocarbonic Acid Esters and α,α,α-Trialkoxyacetonitriles
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The reactivity of the orthocarbonates 4 and the nitriles 1 has been investigated.Carboxylic acids are esterified by 4b. Orthocarbonates 4c-f and 9b are prepared by transesterification of 4b.Mixed substituted orthocarbonates 8c-f are obtained from the nitriles 1a,b.The nitriles 2a and 3a react with alkali alcoholate in alcohol to yield the orthocarbamic acid esters 13a,b. Spirocyclic orthocarbonates 17a-d are prepared from 4b and 1,2 or 1,3-dioles, respectively. The reaction of phenol with 1b affords the mixed substituted orthocarbonate 18a. Catechol is converted by 1a into the orthocarbonate 20a.Reactions of 4b with amines and ami ne derivatives are studied. In the course of these investigations guanidines 21, imidocarbonic acid esters 22a-c, 30, carbamic acid esters 25, ureas 26, the isourea derivative 29, as well as the 1,3,4-oxadiazole 31 are prepared. The mechanism of these reactions is discussed. Imidocarbonic acid esters 22d-f, 38, N-cyanocarbamates 39, and isoureas 37 can be prepared from 1b and amines or amine derivatives. 2a as well as 13b react with cyanamide to give the N-cyanoisourea 40. Ureas 26 are formed in the reaction of 1a,b with secondary amines at elevated temperatures.The guanidinium cyanide 41a can be obtained by reaction of pyrrolidine with 1b in ether, whereas under similiar conditions from 1a and pyrrolidine the amidine 42 is produced. o-Aminophenol, o-phenylenediamine and anthranilic acid are cyclized by 4b or 1b to afford the heterocyclic compounds 43-45. α- and β-amino acids are transformed by 4b or 1b into the N-(ethoxycarbonyl)amino acid esters 46 and 47, respectively.
- Kantlehner, Willi,Maier, Thomas,Loeffler, Wolfgang,Kapassakalidis, Joanis J.
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p. 507 - 529
(2007/10/02)
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- EINE CARBEN-METALLBINDUNG IN -NICKELABICYCLEN
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The complex (Ph3P)Ni(PhNCNPh) (II) is formed from (Ph3P)2Ni(PhNCNPh) (I) in toluene at 60 deg C.II can also be prepared directly from (COD)2Ni, Ph3P and PhNCNPh (45percent yield). (COD)2Ni reacts with diarylcarbodiimides in THF to give (ArNCNAr)3Ni(THF) (VIII).The structure of VIIIa (Ar = phenyl) has been determined by X-ray crystallography.The molecule is shown to contain a nickela bicyclic group in which the carbodiimide molecules are linked to form a 2,5,8-h3-carbene ligand.Some properties and reactions of II and VIII are described.
- Hoberg, Heinz,Burkhart, Georg,Krueger, C.,Tsay, Y. -H
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p. 343 - 352
(2007/10/02)
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