Evidences of strong C-H...O bond in an o-carboranyl beta-lactoside in solution

In this communication, the presence of a persistent intramolecular C-H....O bond in solution, has been evidenced by NMR spectroscopy and theoretical calculations. The molecules under study were o-carboranyl beta-glycoside derivatives, in which, the donor group was the activated CH of the carboranyl residue and the acceptor atom was the glycosidic oxygen. The strength of the interaction and the geometry of the atoms involved were determined by ab initio calculations.     

Reactions of 2,3-diferrocenylcyclopropenone with methyllithium and phenyllithium

Reactions of 2,3-diferrocenylcyclopropenone with methyllithium and phenyllithium afford products of the nucleophilic opening of the three-membered ring, viz., α,β-unsaturated ketones (cis-3,4-diferrocenylbut-3-en-2-one and cis-2,3-diferrocenyl-1-phenylprop-2-enone) and allylic alcohols (cis-3,4-diferrocenyl-2-methylbut-3-en-2-ol and cis-1,1-diphenyl-2,3-diferrocenylprop-2-en-1-ol). The insertion product of a methyl(diferrocenyl)vinylcarbenoid into a σ-bond of the starting compound, viz., 2,3,4-triferrocenyl-4-(1-ferrocenyl-2-oxopropyl)cyclobutenone, along with intramolecular ortho-alkylation products, viz., 2,3-diferrocenylindanone and 2,3-diferrocenyl-2-hydroxyindanone, were also isolated. X-ray diffraction data for triferrocenylcyclobutenone and 2,3-diferrocenyl-2-hydroxyindanone are presented.     

A product of the reaction of bis(methylcarboranyl)chlorophosphine with methylcarboranyllithium

Conclusions 1. An x-ray crystallographic structural study has shown that each phosphorus atom in penta(methyl-o-carboranyl)diphosphine is attached to two o-carboranyl rings directly through a carboranyl carbon atom, while the third ring is attached through a methylene group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2346–2348, October, 1979.The authors thank V. F. Sizyi and Yu. S. Nekrasov for taking and interpreting the mass spectra.     

Spectroscopic study of 1-cyanoacetyl-2-alkylhydrazines and their ring isomers — 1-alkyl-5-amino-3-pyrazolones

The structures of 1-cyanoacetyl-2-alkylhydrazines and their ring isomers, viz., 1-alkyl-5-amino-3-pyrazolones, to which they are readily cyclized, were investigated by IR, UV, and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 516–519, April, 1981.     

Indole derivatives. 129. Reaction of 5-vinylindole with brominating agents

The bromination of 5-vinylindole at two reaction centers, viz., the carbon-carbon multiple bond of the vinyl group and the pyrrole ring, was realized. In the case of the reaction with pyridinium bromide perbromide it was shown that the pyrrole ring is the most reactive with respect to electrophilic agents. It was established that the introduction of an electron-acceptor acetyl group into the pyrrole ring leads to a decrease in the reactivity of the pyrrole ring, and bromination takes place at the double bond.See [1] for communication 128.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 325–328, March, 1987.     

Pyrido[2,3-c]furoxan as a probable intermediate in the reaction of 2-nitro-3-azidopyridine with amines

Two parallel reactions, viz., cyclization of 2-nitro-3-azidopyridine to pyrido-[2,3-c]furoxan, which is aminated in the 6 position of the pyridine ring with opening of the furoxan ring, and reduction of the azido group to form 2-nitro-3-aminopyridine, occur in the reaction of 2-nitro-3-azidopyridine with amines. It was established that pyrido[2,3-c]furoxan reacts with amines in aqueous media in the 1-oxide form.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 654–657, May, 1981.     

Ring-chain isomerism of imines of N-monosubstituted 2-benzoylbenzenesulfonamides

Imines of N-monosubstituted 2-benzoylbenzenesulfonamides or their ring isomers, viz., 3-amino-3-phenylbenzoisothiazoline 1,1-dioxides, were synthesized by condensation of the dilithium derivatives of N-monosubstituted benzenesulfonamides with benzonitrile. Interconversions of the isomers were realized for the N-phenyl derivative. The introduction of bulky isopropyl or tert-butyl substituents at the sulfonamide nitrogen atoms stabilizes the open structure. The ring isomers of the N-acylimines, viz., 3-acylamino-3-phenylbenzoisothiazoline 1,1-dioxides, are formed exclusively in the acylation of both the open and ring isomers.Communication 6 from the series Ring-Chain Transformations with the Participation of a C=N Group. See [1] for Communication 5.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1209–1213, September, 1981.     

Sigma complexes in the pyrimidine series. 2. σ Complexes of 5-nitropyrimidine and methoxy-substituted 5-nitropyrimidines with the acetone anion

The corresponding σ complexes of the Meisenheimer type, viz., anions of the potassium salts of 6H-5-nitro-6-acetonylpyrimidines, were obtained and isolated in the reaction of 5-nitro-, 5-nitro-4-methoxy-, 5-nitro-2-methoxy-, and 5-nitro-2,4-dimethoxypyrimidines with acetone in the presence of potassium hydroxide. The structures of the complexes were proved by means of the PMR, IR, and UV spectra. It is shown that the acetone anion in all cases adds to the methoxy-unsubstituted position of the pyrimidine ring, whereas nucleophilic attack takes place at the C₄ atom when the 2 and 4 positions are free. See [1] for communication 1. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–242, February, 1980.     

Cyclization of n-alkylazinium cations with bisnucleophiles. 5. Cyclic adducts and recyclization products in the reactions of benzodiazinium cations with imido esters

The reaction of imido esters that contain an active methylene group with four isomeric benzodiazinium cations, viz., the 1-methylquinoxalinium, 2-methylcinnolinium, 3-methylquinazolinium, and 2-methylphthalazinium cations, was investigated. The 1-methylquinoxalinium cation reacts with imido esters via a scheme involving anionic [3^– +2]-cycloaddition to form tetrahydropyrrolo[2,3-b]quinoxalines. The 2-methylcinnolinium cation forms an adduct with an annelated pyrrole ring. Under the influence of imido esters, the 3-methylquinazolinium cation undergoes recyclization to a 2,3-disubstituted quinoline. The 2-methylphthalazinium cation is inert in this reaction.See [1] for Communication 4.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1549–1553, November, 1981.     

Complexation of Macrocyclic Compounds with Silver Ions in Surfactant Media

This paper is a report on the complexation studies of silverions with certain water soluble crown ethers viz., 15-crown-5,18-crown-6, cyclam, diaza 15-crown-5 and certain water insolublecrown ethers viz., benzo 15-crown-5, dibenzodiaza 15-crown-4,dibenzyldiaza 18-crown-6 in some nonionic surfactants viz.,polyoxyethylated alkyl phenol (TX 100), polyoxyethylene (20)sorbiton monolaurate (Tween 20), polyoxyethylene (20) sorbitonmonoleate (Tween 80) and polyoxyethylated glyco monolaurylether (Brij 35) by potentiometry. In addition, conductometry wasalso used to study the complexation of oxa crown ethers to comparethe results obtained by potentiometry, which were found to be ingood agreement with each other. The complexation studies indicate1:1 complex formation between the silver ion and macrocycle, thelog_ML ⁿ⁺ values being in the range 1 to 9.     

Synthesis of o-bisazo-1H-pyrazoles and study of their cyclization to give compounds with a 1,2,4-triazine ring

The reactivities of o-hydroxyarylazo-1H-pyrazoles in reactions involving the formation of a 1,2,4-triazine ring in alkaline and acidic media as a function of the character of the substituent in the 4 position of the 1H-pyrazole and the temperature were studied. o-Hydroxyarylazo-1H-pyrazoles and o-hydroxyarylbisazo-1H-pyrazoles, as well as condensed 1,2,4-triazines, were synthesized by diazo coupling of diazotized 5-amino-3-methyl-1R-pyrazoles and o-aminoazobipyrazoles with azo components, viz., 2,3-dihydroxynaphthalene, 1-methyl-3-hydroxyindole, 3-methyl-1-phenyl-5-pyrazolone, and 5-amino-3-methyl-1R-pyrazoles. Azo compounds that undergo ring closure to a triazine ring with the liberation of water when solutions are heated are obtained in the case of 2,3-dihydroxynaphthalene; only azo and o-bisazo compounds were synthesized in the case of 5-aminopyrazoles. An o-bisazo compound that is converted to a triazine when the hydroxy group is replaced by chlorine was isolated in the case of 5-pyrazolone; only a triazine was obtained with 1-methyl-3-hydroxyindole. The compounds obtained were characterized by their IR, UV, PMR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 805–812, June, 1979.     

Reaction of cycloheptanone with concentrated sulfuric acid

Treatment of cycloheptanone or 2-cycloheptylidenecycloheptanone with concentrated sulfuric acid, leads to self-condensation accompanied by intramolecular rearrangement and cyclization to give substituted tetrahydrofurans, viz. 2-methyl-2, 3-cyclohexano-4, 5-cyclohepteno-(⁵)-2, 3, 4, 5-tetrahydrofuran and 2-methyl-2, 3-cyclohexano-5-hydroxy-4, 5-cycloheptano-2, 3, 4, 5-tetrahydrofuran. Self-condensation of ketones with 6-membered rings under the action of concentrated sulfuric acid, proceeding via carbonium ions, and accompanied by contraction to a 5-membered ring, is also characteristic of cycloheptanone, the 7-membered ring of which isomerizes to a 6-membered one.     

Synthesis of spiro oxirane derivatives of the decahydroquinoline series

It was established that 1-methyl-, 1-ethyl-, 1,2-dimethyl-, and 1,2,2-trimethyl-4-oxiranyl-trans-decahydro-4-quinolols undergo isomerization under the influence of aqueous or alcohol solutions of sodium hydroxide, barium hydroxide, and thiourea with migration of the oxide ring to give the corresponding spiro epoxy compounds. A comparison of the IR spectra of the spiro epoxy compounds with the spectra of alternative products, viz., the corresponding keto alcohols, showed that keto alcohols are not formed under the given reaction conditions. The indicated conclusions are confirmed by the IR, PMR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 72–77, January, 1982.     

Reactivity of cycloalkanes in hydrogen abstraction with different acceptors

The reactions of some acceptors (^?CH₃, ^?OOH, ^?CCl₃, O₃, and Br^?) with saturated cyclic hydrocarbons, viz., cyclohexane, cycloheptane, and cyclooctane were studied by the DFT methods based on B3LYP and PBE0 functionals, the method based on the double hybrid functional B2PLYP, a combined ONIOM approach (CCSD:B3LYP)) and the coupled-cluster method (CCSD) using the 6-31+G**, aug-cc-pVDZ, Midi-X, and SVP basis sets. A specific feature of these reactions is that their rates depend on the excess ring energy, although no ring opening occurs in all cases.     

Synthesis and structure of 6-substituted 9-(2-ethoxy-1,3-dioxan-5-yl)purines

The reaction of 4-chloro-5-amino-6-(1,3-dihydroxy-2-propyl)aminopyrimidine with excess ethyl orthoformate gave a cyclic acetal, viz., 6-chloro-9-(2-ethoxy-1,3-dioxan-5-yl)purine, amination of which yielded 6-amino-9-(2-ethoxy-1,3-dioxan-5-yl)purine. The presence of two configurational isomers with a diaxial orientation of the purine ring and the ethoxy group in the trans isomer and an equatorial orientation of the ethoxy group in the cis isomer was established for these compounds by ¹H and ¹³C NMR and IR spectroscopy. The three-dimensional structure of trans-6-chloro-9-(2-ethoxy-1,3-dioxan-5-yl)purine was determined by an x-ray difraction study, and the trans-diaxial orientation of the purine ring and the ethoxy group was confirmed; it is shown that the dioxane ring is in an anti conformation relative to the purine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 976–983, July, 1979.     

Amide acetals in the synthesis of pyridothienopyrimidines

Methyl 3-amino-4-arylaminothieno[2,3-b]pyridine-2-carboxylates containing various substituents in the benzene ring were synthesized by the Thorpe-Ziegler reaction of 4-arylamino-2-chloropyridine-3-carbonitriles with methyl thioglycolates. The influence of the substituent in the benzene ring, acetal structure, the solvent and the process temperature on the reactions of obtained compounds with amide acetals was studied. It was established that reactions with dimethylacetamide dimethylacetal in toluene smoothly results in amidine derivatives, viz., methyl 4-arylamino-3-[1-(dimethylamino)ethylidene]aminothieno[2,3-b]pyridine-2-carboxylates, regardless of the substituent in the benzene ring. Analogous reaction of p-fluoroderivative with dimethylacetamide dimethylacetal in refluxing anhydrous ethanol leads to intramolecular cyclocondensation to produce substituted pyridothienopyrimidines, viz., 5H-1-thia-3,5,8-triazaacenaphthenes, in good yields. Amidine derivatives were the major products in the case of the coupling of aminothienopyridines with dimethylformamide dimethylacetal under the same conditions. A new approach to the synthesis of substituted pyridothienopyrimidines, viz., 3H-1-thia-3,5,8-triazaacenaphthylenes, based on the prolonged heating of methyl 4-arylamino-3-[1-(dimethylamino)ethylidene]aminothieno[2,3-b]pyridine-2-carboxylates in the excess of acetic anhydride was elaborated. Putative mechanisms of the processes concerned are given.     

Mersicarpine, an unusual tetracyclic dihydroindole alkaloid incorporating a seven-membered imine ring

A novel dihydroindole derivative, viz., mersicarpine, incorporating a novel tetracyclic carbon skeleton, containing a seven-membered imine ring, was obtained from a Malayan Kopsia species. The structure was established by spectroscopic analysis and a possible biogenetic pathway from a leuconolam precursor is presented.     

Anhydro bases of 3-pyridylindoles

The reactions of quaternary salts of 3-pyridyl- and benzopyridylindoles with alkali proceed via two pathways, viz., deprotonation, the products of which are anhydro bases, and dealkylation of the pyridine ring, as a consequence of which the corresponding nonquaternized bases are formed. The reactions are interpreted from a quantum-chemical point of view.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 959–964, July, 1980.     

Fused polycyclic nitrogen-containing heterocycles 24. Three-component condensation of diethyl 2,4,6-trioxoheptanedicarboxylate with salicylaldehydes and ammonium acetate as a new method for the synthesis of 7- and 9-substituted benzo[e]pyrano[4,3-b]pyridines

The three-component condensation of diethyl 2,4,6-trioxoheptanedicarboxylate with salicylaldehyde and its 3,5-dichloro-, 3-methoxy-, and 5-methoxy-substituted derivatives in EtOH in the presence of ammonium acetate affords tricyclic products, viz., tetrahydrobenzo[e]-pyrano[4,3-b]pyridines. In the reaction with 3-nitrosalicylaldehyde, the intramolecular closure of the pyran ring does not occur due to the deactivation of the hydroxy group by the nitro group, and this reaction stops at the formation of the monocyclic product, viz., tetrahydropyridin-4-one.     

Mesogenic benzothiazole derivatives with methoxy substituents

Two new mesogenic homologous series containing 6-methoxybenzothiazole ring at the terminus of the molecule, viz. 2-(4′-n-alkoxyphenylazo)-6-methoxybenzothiazoles and 2-[4′-(4″-n-alkoxy-benzoyloxy) phenylazo]-6-methoxybenzothiazoles were synthesized. In series I,n-butyloxy to n-tetradecyloxy derivatives exhibit nematic mesophase. Smectic A mesophase commences from then-dodecyl-oxy derivative as a monotropic phase and is retained up to the last member synthesized. All the members of series II exhibit enantiotropic nematic mesophase. The mesomorphic properties of the present series are compared with other structurally related series to evaluate the effect of the benzothiazole ring and the methoxy substituent on mesomorphism. This paper was presented at the 10th National Conference on Liquid Crystals held at Bangalore during 9–11 October 2003