Generalized structural and kinetic relationships for 1,2-shifts of a hydrogen atom in carbocations and neutral compounds

Dynamic PMR has been used in a kinetic study of degenerate rearrangement of 5,6-X₂-1-H-1, 2-dimethylacenaphthylenonium ions (X=CH₃, Br), accomplished by means of a 1,2-shift of the hydrogen atom. It has been found that the free energy of activation of the 1,2-shift of the H atom in the 5,6-X₂-1-H-1,2-dimethylacenaphthylenonium cation (X=H, CH₃, Br), in the 1-H-1,2-dimethylcyclopentyl cation, and in 5-H-1,2, 3,4,5-pentamethyl-1,3-cyclopentadiene exhibits a linear correlation with parameters characterizing the electron density on the atom to which the migrant is shifted.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1352–1358, June, 1991.     

Mechanism of lactic acid formation catalyzed by tetraamine rhodium(III) complexes

The transformation of methylglyoxal and of 1,3–dihydroxyacetone and glyceraldehyde into lactic acid can be catalyzed by cis- tetraaminediaquarhodium(III) complexes of ethane-1,2–diamine and of the macrocyclic racemic 5,5,7,12,12,14–hexamethyl-1,4,8,11– tetraazacyclotetradecane ligand. The detailed stoichiometry of this process has been investigated by isotopic labelling studies and 1H and 13C-n.m.r. spectroscopy.The suggested mechanism of the methylglyoxal transformation process involves bidentate substrate coordination, followed by an intramolecular 1,2–hydride shift in a resonance stabilized carbocation. The transformations of 1,3–dihydroxyacetone and glyceraldehyde are stoichiometrically more complicated, and rhodium(III) catalyzed conversion of 1,3–dihydroxyacetone into glyceraldehyde is observed. Ultimately both substrates are converted into coordinated lactate in which one hydrogen atom in the methyl group originates from the solvent water.     

Reactions of cyclic 1,3-dicarbonyl compounds with 1,2(1,4)-dihydro-1-methyl-2(4)-methylene-N-heterocycles. A new access to 6,12-methano-dibenz[d,g]-[1,3]oxazocinones

Summary The enamine-type methylene-N-heterocycles1–5 react with cyclic 2-ethoxymethylene-1,3-dicarbonyl compounds6 to give 2-[2-(hetarylidene)ethylidene]-1,3-dicarbonyl compounds7–14. The result of the reactions between 1,2-dihydro-1-methyl-2-methylene-quinoline (1a) and cyclic 1,3-dicarbonyl compounds depends on the nature of the dihydro intermediatesA/B. Dehydrogenation of keton intermediatesA results in 2-(1,2-dimethyl-4(1H)-quinolylidene)-1,3-dicarbonyl compounds17–21. Enol intermediatesB with 6-membered dicarbonyl ring form 6,12-methano-dibenz-[d,g][1,3]oxazocinones22–25.¹H NMR spectra and X-ray structure analysis prove the structure of23.

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Reaktionen cyclischer 1,3-Dicarbonylverbindungen mit 1,2(1,4)-Dihydro-1-methyl-2(4)-methylen-N-heterocyclen. Ein neuer Zugang zu 6,12-Methano- dibenz[d,g][1,3]oxazocinonen

Zusammenfassung Aufgrund ihres Enamincharakters reagieren die Methylen-N-heterocyclen1–5 mit cyclischen 2-Ethoxymethylen-1,3-dicarbonylverbindungen6 zu den 2-[2-(Hetaryliden)ethyliden]-1,3-dicarbonylverbindungen7–14. Das Ergebnis der Reaktionen zwischen 1,2-Dihydro-1-methyl-2-methylen-chinolin (1a) und cyclischen 1,3-Dicarbonylverbindungen hängt von der Natur der zwischenzeitlich entstehenden DihydroverbindungenA/B ab. Die Intermediat-KetoneA gehen durch Dehydrierung während der Reaktion in die 2-(1,2-Dimethyl-4(1H)chinolyliden)-1,3-dicarbonylverbindungen17–21 über. Die Intermediat-EnoleB mit sechsgliedrigem Dicarbonylring bilden in intramolekularer Reaktion die 6,12-Methano-dibenz[d,g][1,3]oxazocinone22–25, deren Struktur am Beispiel der Verbindung23 durch¹H-NMR sowie durch Röntgenkristallstrukturanalyse bewiesen wird.

     

Synthesis of benzothiazepines (review)

Methods for the preparation of benzothiazepines, which are grouped with respect to their structural features (1,2-, 1,3-, and 1,4-thiazepines), are correlated. Methods for the synthesis of compounds of each type are discussed in the case of the most thoroughly studied representatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1452, November, 1986.     

Acid-Catalyzed Rearrangements of 5,6-exo-Epoxy-7-oxabicyclo[2.2.1]hept-2-yl Derivatives. Migratory Aptitudes of Acyl vs. Alkyl Groups in Wagner-Meerwein Transpositions

In the presence of HSO₃F/Ac₂O in CH₂CL₂, 2-exo- and 2-endo-cyano-5,6-exo-epoxy-7-oxabicyclo[2.2.1]hept-2-yl acetates ( 6a , b ) gave products derived from the epoxide-ring opening and a 1,2-shift of the unsubstituted alkyl group (σ bond C(3)–C(4)). In contrast, under similar conditions, the 5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ( 6c ) gave 5-oxo-2-oxabicyclo[2.2.1]heptane-3,7-diyl diacetates 20 and 21 arising from the 1,2-shift of the acyl group. Acid treatment of 5,6-exo-epoxy-2,2-dimethoxy-7-oxabicyclo[2.2.1]heptane ( 6d ) and of 5,6-exo-epoxy-2,2-bis(benzyloxy)-7-oxabicyclo[2.2.1]heptane ( 6e ) gave minor products arising from epoxide-ring opening and the 1,2-shift of σ bond C(3)–C(4) and major products ( 25 , 29 ) arising from the 1,3-shift of a methoxy and benzyloxy group, respectively. Under similar conditions, 5,6-exo-epoxy-2,2-ethylenedioxy-7-oxabicyclo[2.2.1]heptane ( 6f ) gave 1,1-(ethylenedioxy)-2-(2-furyl)ethyl acetate ( 32 , major) and a minor product 33 , arising from the 1,2-shift of σ bond C(3)–C(4). The following order of migratory aptitudes for 1,2-shifts toward electron-deficient centers has been established: acyl > alkyl > alkyl α-substituted with inductive electron-withdrawing groups. This order is valid for competitive Wagner-Meerwein rearrangements involving equilibria between carbocation intermediates with similar exothermicities.     

Synthesis and structure of 1-(4-chlorophenyl)-3-(5-methyl-1, 3-dioxan-5-yl)-(1,2),(3,4)-diepoxybutane

The synthesis and X-ray structural study of 1-(4-chlorophenyl)-3-(5-methyl-1,3-dioxan-5-yl)-(1,2), (3,4)-diepoxybutane are described.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 715–718, April, 1995.     

Benchmarking the Fluxional Processes of Organometallic Piano-Stool Complexes

The correlation consistent Composite Approach for transition metals (ccCA-TM) and density functional theory (DFT) computations have been applied to investigate the fluxional mechanisms of cyclooctatetraene tricarbonyl chromium ((COT)Cr(CO)₃) and 1,3,5,7-tetramethylcyclooctatetraene tricarbonyl chromium, molybdenum, and tungsten ((TMCOT)M(CO)₃ (M = Cr, Mo, and W)) complexes. The geometries of (COT)Cr(CO)₃ were fully characterized with the PBEPBE, PBE0, B3LYP, and B97-1 functionals with various basis set/ECP combinations, while all investigated (TMCOT)M(CO)₃ complexes were fully characterized with the PBEPBE, PBE0, and B3LYP methods. The energetics of the fluxional dynamics of (COT)Cr(CO)₃ were examined using the correlation consistent Composite Approach for transition metals (ccCA-TM) to provide reliable energy benchmarks for corresponding DFT results. The PBE0/BS1 results are in semiquantitative agreement with the ccCA-TM results. Various transition states were identified for the fluxional processes of (COT)Cr(CO)₃. The PBEPBE/BS1 energetics indicate that the 1,2-shift is the lowest energy fluxional process, while the B3LYP/BS1 energetics (where BS1 = H, C, O: 6-31G(d′); M: mod-LANL2DZ(f)-ECP) indicate the 1,3-shift having a lower electronic energy of activation than the 1,2-shift by 2.9 kcal mol⁻¹. Notably, PBE0/BS1 describes the (CO)₃ rotation to be the lowest energy process, followed by the 1,3-shift. Six transition states have been identified in the fluxional processes of each of the (TMCOT)M(CO)₃ complexes (except for (TMCOT)W(CO)₃), two of which are 1,2-shift transition states. The lowest-energy fluxional process of each (TMCOT)M(CO)₃ complex (computed with the PBE0 functional) has a ΔG^‡ of 12.6, 12.8, and 13.2 kcal mol⁻¹ for Cr, Mo, and W complexes, respectively. Good agreement was observed between the experimental and computed ¹H-NMR and ¹³C-NMR chemical shifts for (TMCOT)Cr(CO)₃ and (TMCOT)Mo(CO)₃ at three different temperature regimes, with coalescence of chemically equivalent groups at higher temperatures.     

Lipids ofBryonia alba

The lipid composition of the roots ofBryonia alba (Cucurbitaceae) have been studied: It consists of fractions of 3-acyloxy-24-alkyl(alkenyl)-cholest-7-enes (I), triacylglycerols (II), 1,2-diacyl-3-monoglycopyranosyl-sn-glycerols (III), 1,2-diacyl-3-diglycopyranosyl-sn-glycerols (IV), 1,3-bis(3-sn-phosphatidyl)glycerols (V), 3-sn-phosphatidylethanolamines (VI), 3-sn-phosphatidylcholines (VII), and methyl esters of fatty acids (VIII). The amount of unsaturated fatty acids in the lipid fractions (I–VIII) is 60–94%, the main component being linolenic acid.A. L. Mndzhoyan Institute of Fine Organic Chemistry of the Academy of Sciences of the Armenian SSR, Erevan. Translated from Khimiya Pridodnykh Soedinenii, Vol. 6, pp. 781–785, November–December, 1980.     

Photochemistry of Solutions of Pt(II) Complexes with Salpn-1,2 and Salpn-1,3 Ligands

The results of a study of photochemical properties of Pt(II) complexes with tetradentate ligands, namely, methyl-N,N′-ethylene-bis(salicylideneimine) [Pt(Salpn-1,2)] and N,N′ -propylene-bis(salicylideneimine) [Pt(Salpn-1,3)] in acetonitrile, dichloromethane, ethanol, DMF, and DMSO solutions are discussed. The quantum yield of photochemical reactions of the corresponding Pt(II) complexes was found to decrease with the decreasing γ-acceptor properties of the ligands in a series Salen-Salpn-1,2-Salpn-1,3.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 612–617.Original Russian Text Copyright © 2005 by Ardasheva, Shagisultanova.     

Synthesis of ether-amines of propane-1,2-diol and their biological activity

An account is given of various routes for the synthesis of ether-amines of propane-1,2-diol from glycerol derivatives. It has been established that this series of compounds exhibits pharmacological activity and also a stimulating or inhibiting effect on the germinating capacity and the energy of germination of the seeds of agricultural crops. A definite relationship has been revealed between the structure and biological activity of ether-amines of propane-1,2-diol. Ether-amines of propanediol and unsymmetrical 1,3-diaminopropan-2-ols, and also their sulfur-containing analogs, containing residues of primary amines or hydrazine are convenient synthons for passing to heterocyclic systems: derivatives of 1,3-ozazolidine, 1,3-thiazolidine, and 3-methyl-5-pyrazolone. The possibility of obtaining new polycyclic systems by diene synthesis from 1,3-oxazolidine and 1,3-thiazolidine derivatives including furfural residues and also from 1,3,4-thiadiazole derivatives, using cyano and thiocyano derivatives of glycerol and thiosemicarbazide is discussed.Tadzhik State University (TGU), Dushanbe. Translated from Khimiya Prirodnykh Soedinenii, No. 5 pp. 649–654, September–October, 1997.     

Volumetric properties of dilute aqueous solutions of cobalt-amine-type salts. Part I. Densities at 25°C

The densities of dilute aqueous solutions of [CoL₃]X₃ [L=1,2-diaminoethane(en), 1,2-diaminopropane(pn), 1,3-diaminopropane(tn) X=Cl^–, Br^– and (ClO₄)^–] have been measured at 25°C from 0 to 5×10^–2m. The apparent molar volumes were calculated and extrapolated to infinite dilution. Ion-solvent interactions were detected from the change of the ionic partial molar volumes with concentration. These interactions depend both on the properties of the ion (polarization charge density at the surface, hydrophobic groups, etc.) and the characteristics and structure of the solvent.     

Über die Reaktion von Äthylketencarbonsäure-äthylester mit Benzalanilin

Zusammenfassung Dem vonStaudinger aus Äthylketencarbonsäureäthylester und Benzalanilin bei –20° dargestellten Addukt kommt die offenkettige, zwitterionische Struktur eines 4-Äthoxycarbonyl-1,2-diphenyl-2-azonia-1,3-hexadien-3-olats (3) zu.

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Reaction of ethyl 2-ethylketenecarboxylate with benzylidene aniline

The adduct obtained byStaudinger at –20° from ethoxycarbonyl ethyl ketene and benzylidene aniline has the open chain dipolar structure of 4-ethoxycarbonyl-1,2-diphenyl-2-azonia-1,3-hexadien-3-olate (3).

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Mit 1 Abbildung     

Investigation of the reaction products of the cyanation of methyl- and ethylferrocene

Conclusions Amides and nitriles of 1,2-, 1,3-, and 1.1'-methyl- and ethylfetrocenecarboxylic acids were produced.Translated from Izvestiya Akademii Nauk SSSR, Seria Khimicheskaya, No. 10, pp. 1897–1899, October, 1964     

Properties of a multiple bond conjugated with a pyridine ring

The composition of the products of the reaction of 2-vinylpyridine (I), 4-vinylpyridine (II), and 2-methyl-5-vinylpyridine (III) with piperylene and isoprene as well as the composition of catalysates obtained by dehydration of the isolated adducts were studied by means of gas-liquid chromatographic analysis. The reaction of I–III with isoprene forms only one 1,4-isomeric adduct, which gives the corresponding p-tolylpyridine on dehydrogenation. The reaction of I–III with piperylene, however, forms a mixture of 1,2- and 1,3-isomeric adducts, which give a mixture of the corresponding m-tolylpyridines on dehydrogenation; nation; in the case of I, the 1,2-isomer predominates in the mixture, while the 1,3-isomer predominates in the reaction with II and III.See [2] for Communication VIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1659–1662, December, 1970.     

Synthesis,reactions, and structures of 1,3- and 1,2-ditelluroles (review)

Data on methods for the synthesis of 1,3- and 1,2-di-telluroles and tetratellurofulvalenes and their reactions and structures are systematized and correlated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 291–304, March, 1991.     

Synthesis of New 3-Phenoxypropan-2-ols with Various Heterocyclic Substituents

1-Phenoxy-3-piperidinopropan-2-ol, 1-(5-methyl-1,3-benzothiazol-2-ylsulfanyl)-3-phenoxypropan-2-ol, 1-(2-hydroxy-3-phenoxypropyl)azepan-2-one, 1,1′-(6-chloro-1,3-benzothiazol-2-ylimino)bis(3-phenoxypropan-2-ol), 1-(1,3-benzothiazol-2-ylsulfanyl)-3-phenoxypropan-2-ol, 1,1′-(piperazine-1,4-diyl)bis(3-phenoxypropan-2-ol), and 1,3-bis(2-hydroxy-3-phenoxypropyl)barbituric acid were synthesized by condensation of 1,2-epoxy-3-phenoxypropane with the corresponding amines and thiols.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 70–72.Original Russian Text Copyright © 2005 by Mesropyan, Ambartsumyan, Avetisyan, Galstyan, Arutyunova.     

Mechanism of the conversion ofα,β-unsaturated aldehydes to esters of saturated acids under the action of cyanohydrins in the presence of tertiary amines

Conclusions The reaction of,-unsaturated aldehydes with cyanohydrins in the presence of tertiary amines, leading to esters of cyanohydrins, proceeds through the formation of the cyanohydrin of an,-unsaturated aldehyde, followed by intramolecular prototropic 1,3-shift (75–80%), the formation of a ketonitrile, and conversion of the latter to an ester.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 581–586, March, 1970.     

Preparation of N-phosphorylated 2-oxo-1,3-oxazolidines and 6-methyl-2-oxo-1,3-tetrahydrooxazine

Conclusions N-Phosphorylated 2-oxo-1,3-oxazolidines and 6-methyl-3-(diethoxyphosphinyl)-2-oxo-1,3-tetrahydro-oxazine were prepared by allowing N-(diethoxyphosphinyl)imidocarbonyl dichloride to react with ethylene glycol, 1,2-propylene glycol, and 1,3-butylene and 2,3-butylene glycols in the presence of triethylamine in a dioxane medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 396–399, February, 1970.     

Effect of the medium on the rate of the degenerate rearrangement of 1,2,3,4,5-pentamethyl-1,3-cyclopentadiene

Conclusions The rate of the 1,2 hydrogen atom shift in the degenerate rearrangement of 1,2,3,4,5-pentamethyl-1,3-cyclopentadiene is only slightly sensitive to variation in the medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimlcheskaya, No. 11, pp. 2622–2624, November, 1985.     

Reactions of phosphorylated allenes with dithiocarbamates

The addition of morpholino-, piperidino-, and N,N-diethyldithiocarbamate anions to 1,2-propadiene- and 1,2-butadienephosphonates proceeds on the electrophilic 1,2-double bond of the allene system with the formation of linear dithioesters. 1-Vinylallenylphosphonates add dithiocarbamate anions on the 1,3-conjugated system of multiple bonds, forming a mixture of stereoisomeric dithioesters with a diene structure.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 890–894, April, 1990.