Synthesis of heterocyclic thiosulfonates

[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity.     

Synthesis of heterocyclic homotriptycenes

A series of novel heterocyclic homotriptycenes bearing furan, thiophene, and pyridine rings, 7a-f, were synthesized by intramolecular dehydration reactions of 10,10-dihetarylmethyl-9,10-dihydroanthracen-9-ols 6a-f. In the presence of acids, the secondary alcohols 6a-f show different reactions which depend on the electron densities of the attached heterocyclic rings. The initially formed carbenium ions react in an electrophilic substitution with electron-rich heterocycles. The formation of a transannular bridge (1,7-elimination) leads to homotriptycenes in high yields. When the heterocyclic ring has a moderate electron density, two competitive reactions exist, which afford 9-monosubstituted anthracenes by 1,4-elimination or 9,10-disubstituted anthracenes by a rearrangement, respectively. Electron-deficient heterocycles undergo a disproportionation to give hydrocarbons and ketones.     

Fluorosulfonyl-containing heterocyclic compounds

Hexafluoroisobutenylidene sulfate is a sulfotrioxidizing agent with respect to various olefins; methylenemethionic acid is formed in the case of ethylene, while the corresponding-sulfones are formed in the case of tetrafluoroethylene and vinylidene fluoride. 2,2-Difluoro-2-hydroxy-ethanesulfonic acid sultone is characterized by a capacity for anionotropic transformations; a number of sulfoacetic acid derivatives were obtained on the basis of this sultone.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 178–182, February, 1973.     

Investigation of heterocyclic quinones

Substitution of the methyl group by an amine residue to give 2,8-dipiperidino-4-hydroxy-quinazoline-5, 6-quinone occurs in the oxidative animation of 2-methyl-6-hydroxy-4-quinazolone in the presence of a Cu²⁺-piperidine complex. The possible mechanism of the reaction is discussed.See [1] for communication XX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1697–1699, December, 1973.     

Microwave-assisted conversion of aromatic heterocyclic nitriles to various heterocyclic molecules

Abstract

Dihydroimidazole (3a-c), dihydrooxazole (3d-f), benzoxazole (5a-c), benzothiazole (5d-f) and oxazolopyridine (7a-c) derivatives have been synthesized by condensation of various heterocyclic aromatic nitriles with diamine, aminoalcohal, aminophenol, aminothiophenol, and 3-aminopyridine-2-ol, respectively, under microwave irradiation and under solvent free conditions. This catalyst free and solvent free approach provided heterocyclic compounds in quantitative yields. Time taken for the condensation to occur is < 20 min.     

Polarography of heterocyclic compounds

The literature data on the principles of the electrochemical reduction of heteroethylene and heteroparaffin compounds (pyrazoline, diazepine, diaziridine, pyran, pyridazone, aziridine, oxaziridine, and other derivatives), cyclic anhydrides, imides, and hydrazides of acids on a dropping mercury electrode are correlated. In addition, the effect of substituents attached to the heterocyclic ring on the polarographic behavior of heterocycles is analyzed.     

Polyfluorinated heterocyclic compounds

The condensation of sodium acetoacetate ester with polyfluoroaromatic compounds proceeds according to a type of S-arylation with subsequent ring formation or deacetylation depending on the condition employed.For part III, see [5].     

Stereochemistry of heterocyclic compounds

Summary The stereochemistry of the reaction of 1-alkyl-4-piperidones with phenyllithium depends not only on steric factors, but also on the character of the nitrogen-attached alkyl group. The effect of alkyl groups is associated with fixation of the direction of the dipole of the nitrogen atom, as a result of which the predominant direction of reaction becomes that for which the free electron pair of the nitrogen and the C-O bond of the enolate ion then arising occupy antiparallel directions.     

Fluorosulfonyl-containing heterocyclic compounds

Salts of hexafluorodimethylmethionic andα-hydrohexafluoro-2-propane-2-sulfonic acids, the amide of the latter, and a number of sulfones containingα-hydrohexafluoroisopropyl, pentafluoroisopropenyl,Β,Β,Β-trifluoroethyl, and methyl groups were obtained by alkaline hydrolysis, alcoholysis, and ammonolysis of hexafluorodimethyl sulfonene trimer.     

Investigation of heterocyclic quinones

Oxidation of 4-substituted 2-phenyl-6-hydroxyquinazolines with oxygen in the presence of a Cu²⁺-secondary amine complex gave N-substituted 2-phenyl-4,8-diaminoquinazoline-5,6-quniones, which form diquinazolino[6,5-d:8,7-b]furan-7,8-quinones on acid hydrolysis.See [1] for communication XIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1403–1408, October, 1973.     

Polyfluorinated heterocyclic compounds

The treatment of 2-phenyl-4-carbomethoxy-6,7,8,9-tetrafluorobenz[f]oxazepin-1,3 (I), 3-benzamido-5,6,7,8-tetrafluorocoumarin (V), and α-benzamido-β-(2-hydroxy-3,4,5,6-tetrafluorophenyl)-acrylic acid (III) with a mixture of glacial acetic acid and a mineral acid gave (IV), the π-complex of 3-hydroxy-5,6,7,8-tetrafluorocoumarin (VII) and benzoic acid. Treatment of (IV) with acetic anhydride gave 3-acetoxy-5,6,7,8-tetrafluorocoumarin (VI) and benzoic acid. Treatment with diazomethane gave 3-methoxy-5,6,7,8-tetrafluorocoumarin (VIII) and methyl benzoate. IV was also obtained from an equimolar mixture of its components. A mechanism for the formation of IV from I is proposed.     

Polyfluorinated heterocyclic compounds

The treatment of 2-phenyl-4-carbomethoxy-6,7,8,9-tetrafluorobenz[f]oxazepin-1,3 (I), 3-benzamido-5,6,7,8-tetrafluorocoumarin (V), and -benzamido--(2-hydroxy-3,4,5,6-tetrafluorophenyl)-acrylic acid (III) with a mixture of glacial acetic acid and a mineral acid gave (IV), the -complex of 3-hydroxy-5,6,7,8-tetrafluorocoumarin (VII) and benzoic acid. Treatment of (IV) with acetic anhydride gave 3-acetoxy-5,6,7,8-tetrafluorocoumarin (VI) and benzoic acid. Treatment with diazomethane gave 3-methoxy-5,6,7,8-tetrafluorocoumarin (VIII) and methyl benzoate. IV was also obtained from an equimolar mixture of its components. A mechanism for the formation of IV from I is proposed.For part II, see [1].     

Siloxane-modified heterocyclic polymers

Fully aromatic, siloxane-modified polybenzimidazoles and polybenzoxazoles were prepared by a single-stage melt polymerization and characterized. These polymers, which have good solubility in pyridine and N-methylpyrrolidinone, undergo thermooxidative decomposition above 300°C. Model compounds for these two classes as well as polypyromellitimides were also prepared.     

Reaction of heterocyclic betaines. Synthesis of a new heterocyclic system

A new condensed heterocyclic system, viz., 1,3,7,9-tetra-oxo-2,8-diphenyl-6-formylpyrimido [3,4-a]pyrimido[4,5-dloxazine, was synthesized, and its electronic and PMR spectra were recorded. Factors that affect the orientation of nucleophilic substitution in betaines of the pyrimidine series with aliphatic amines are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 993–995, July, 1980.     

Magnetotropicity of five-membered heterocyclic molecules

Ab initio methods have been employed to obtain models for the current density field induced in the electrons of pentatomic cyclic molecules C₄H₄X, with X = CH₂, NH, O, S, PH, and AsH, in the presence of a static, homogeneous magnetic field normal to the plane containing the four ring carbon atoms. These models are expected to provide simple and valid tools to assess the magnetotropism of these compounds and to interpret their magnetic response.     

Stereochemistry of heterocyclic compounds

Summary On the basis of a number of chemical reactions, views are expressed on the possible steric structure of 1, 2, 5-trimethyl-4-ethyl-4-piperidinol isomers (I,, ), the corresponding acetylenic alcohols (II, ,), and certain piperidine derivatives obtained from them.     

Polynuclear heterocyclic compounds

Spectroscopic constants of dibenzoylenepyrans, dibenzoylene-1,4-dihydropyridine, and dibenzoylenepyridines are given. It is shown that the UV spectrum bands of dibenzoylenepyrans are slightly displaced when substituents are changed. Both in character and in band position the absorption curves for dibenzoylene-1,4-dihydropyridines differ from those of the simpler 1,4-dihydropyridines, and the maxima are displaced in a way depending on the substituents. On the other hand, the spectra of anyldibenzoylenepyridines are almost identical, and coincide with the spectrum of dibenzoylenepyridine.For Part XXI see [6].     

Enzymatic hydrolysis of heterocyclic nitriles

Chemoselective hydrolysis of heterocyclic nitriles can be achieved by an easy to use immobilized biocatalyst prepared from Rhodococcus sp. Pyrimidine-2-carbonitrile ( 2a ) and 3-chloropyridazine-4-carbonitrile ( 4a ) were converted into the corresponding amides while from 2-ethoxycarbonyl-4-pyridinecarbonitrile ( 1a ), 6-methylpyridazine-3-carbonitrile ( 3a ), 3-chloropyridazine-4-carbonitrile ( 4a ), 3-ethoxycarbonyl-4,5-dihydroisoxazole-5-carbonitrile ( 8a ), indole-3-carbonitrile ( 9a ) and indole-3-ylacetonitrile ( 10a ) the acids were formed.     

Fluorosulfonyl-containing heterocyclic compounds

When hexafluoroisobutenylidene sulfate is heated above 80°C, hexafluorodimethylketene is liberated and the inner anhydride of hexafluoro--pyrosulfoisobutyric acid (I) is formed. On storage, anhydride I is spontaneously isomerized to hexafluoroisobutenylidene pyrosulfate, which is converted to the mixed anhydride of pentafluoromethacrylic and fluoropyrosulfonic acids on heating above 130° for many hours. On heating above 160°, I is decarboxylated to give hexafluoropropane-2,2-disulfonic acid anhydride, which is inclined to isomerize to pentafluoropropene-2-pyrosulfonyl fluoride.See [1] for Communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No, 10, pp. 1321–1324, October, 1973.     

The thermolysis of heterocyclic aminimines

Aminimines derived from six heterocyclic tertiary amines were thermolyzed in t-butyl alcohol at ca. 80°. N-Methylindoline gave a good yield of the ring-opened product, and a double elimination on 1,4,4-trimethyl-piperidine gave 3,3-dimethyl-1,4-pentadiene. The aminimine derived from quinuclidine was stable to elimination under these conditions. Simple elimination products were not obtained from N-methyl-pyrrolidine, N-methylpiperidine, or N-methyltetrahydroisoquinoline.