Chemistry of indole

2-Methyl-5-vinylpyridine, which is usually of low reactivity, pyridylethylates the NH groups of pyrrole, indole and its homologs, carbazole,y- and -carbolines, etc. if the process is carried out in dimethyl sulfoxide containing alkaline agents.See [1] for communication XXXII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 207–212, February, 1973.     

Chemistry of indole

Under the influence of phosphorus oxychloride in an inert solvent, 1-aryl-2-acylhydrazines undergo intramolecular rearrangement to give 2-amino-3-alkylindoles. The latter are autooxidized in alkaline media to give 3-hydroxy-2-aminoindolenines or 3-hydroxy-2-iminoindolines. The structures of all of the compounds were proved by UV, IR, and PMR spectroscopy and also by mass-spectrometric data.See [1] for communication XXXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 511–515, April, 1973.     

Chemistry of indole

Under the influence of halide compounds of phosphorus, acetic acid -phenylhydrazides that have an alkyl group attached to at least one of the nitrogen atoms form 2-aminoindoles that do not have substituents in the 3 position. Similarly, 1-phenyl-2-acetylpyrazolidines are converted to 1,2,3,4-tetrahydropyrimido[1,2-a]indoles.See [1] for communication XXXV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 647–652, May, 1973.     

Chemistry of indole

By treating 1-alkylindolines with 1-benzoylpyrylium salts in the presence of Lewis acids, good yields of 1-alkyl-5-(pyrid-4 -yl) indolines can be obtained. 1-alkyl-5-benzoylindolines are side products. The structures of the reaction products were demonstrated by UV and IR spectra, thin-layer chromatography, and dehydrogenation to the corresponding pyridylindoles.For the previous paper see [1].     

Chemistry of indole

Bromination of various 5-hydroxyindole derivatives gives 6-bromo-5-hydroxyindole. Bromination in the 4 position is observed when the 6 position is occupied.See [1] for communication XXXIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 332–336, March, 1973.     

Chemistry of indole

The condensation of salts of 1-methyl-2-aminoindole with aldehydes in excess alkali gives Schiff bases, while salts of 1-methyl-3-arylidene-2-iminoindolines are obtained in the absence of alkali. The latter may give 12-aryl-5,7-dimethylindolo[2,3-b]--carbolines (I) on reaction with excess 1-methyl-2-aminoindole. Dihydro compounds (II) are formed as intermediates.See [1] for communication XXXI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1368–1373, October, 1972.     

Chemistry of indole

5-Methoxy-3-carbethoxyindoles are nitrated primarily in the 4 position. Replacement of the methoxy group by an acetoxy group leads to a change in orientation — only the 6 isomer is obtained. In the case of the similarly constructed 5-hydroxyindoles, monosubstitution cannot be accomplished under various conditions, and only the 4,6-dinitro derivative is formed. The synthesis of the corresponding amines by reduction of the nitro compounds is described.See [1] for communication XXXVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1646–1653, December, 1973.     

Chemistry of indole

,-Unsaturated ketones form pyrimido[1,2-a]indoles with 2-aminoindole, while 1-alkyl-2-aminoindoles under these conditions are converted to the corresponding -carbolines. The structures of the compounds obtained were confirmed by alternative synthesis.See [1] for communication XIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–64, January, 1971.     

Chemistry of indole

Condensation of 1-alkyl-2-aminoindoles with malonic ester gives -carbonyl derivatives which, on the basis of the their UV, IR, and NMR spectra, and their chemical properties, are assigned the 2-oxo-4-hydroxy--carboline structure.For Part XVIII, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1207–1211, September, 1970.     

Chemistry of indole

The nitration of indoles containing donor substituents in the 5- and 7-positions in strongly acidic media involves the protonated form and gives primarily compounds with a nitro group in the 6-position. The structures of the products were proved by PMR, UV, and mass spectrometry.     

Chemistry of indole

Nitration of 5- and 7-methyl-3-carbethoxyindoles leads to a mixture of 4- and 6-nitroindoles with predominance of the 4-nitro isomer.     

Chemistry of indole XLIII. New synthesis of benz(aminomethyl)indoles

Indolines are amidomethylated in the 6 position in acidic media. N-Acetylation changes the orientation to give the 5-substituted isomers. Dehydrogenation of the reaction products and subsequent hydrolysis make it possible to obtain 5-or 6-aminomethylindoles.     

Chemistry and pharmacology of analgesic indole alkaloids from the rubiaceous plant, Mitragyna speciosa

The leaves of a tropical plant, Mitragyna speciosa KORTH (Rubiaceae), have been traditionally used as a substitute for opium. Phytochemical studies of the constituents of the plant growing in Thailand and Malaysia have led to the isolation of several 9-methoxy-Corynanthe-type monoterpenoid indole alkaloids, including new natural products. The structures of the new compounds were elucidated by spectroscopic and/or synthetic methods. The potent opioid agonistic activities of mitragynine, the major constituent of this plant, and its analogues were found in in vitro and in vivo experiments and the mechanisms underlying the analgesic activity were clarified. The essential structural features of mitragynines, which differ from those of morphine and are responsible for the analgesic activity, were elucidated by pharmacological evaluation of the natural and synthetic derivatives. Among the mitragynine derivatives, 7-hydroxymitragynine, a minor constituent of M. speciosa, was found to exhibit potent antinociceptive activity in mice.     

The chemistry of indole

A number of amides of indole ketoacids are synthesized. 3-Carboxyacylindoles can be converted to the corresponding enol-lactones by treatment with acetic anhydride or acetyl chloride. Reaction of the lactones with ammonia or amines involves lactone ring opening, and this makes it possible to prepare some N-substituted or unsubstituted ketoacid amides. Deacylation can occur in the action of strong bases or high temperatures on indoleketoacids. Reaction of 2-(indolyl-3') benzoic acid with dimethyl sulfate proceeds in two ways: the NH group is methylated, and there is conversion to the corresponding indolenine, with subsequent methylation of the enol.For Part II see [1].     

The chemistry of indole

The synthesis of 2-substituted 3-acylindoles by various methods is described. It has been shown that branching both in the radical of the acyl group and in the substituent in position 2 creates hindrance for electrophilic attack.For Communication XVII, see [2].Probationer from Sofia University, Bulgaria.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 923–926, July, 1970.     

Synthesis of indole sulfonamides

A preparative method is reported for the synthesis of indole sulfonamides from 3-indolesulfonyl chlorides and certain amines.     

The chemistry of indole

In the reaction of 2-aminoindoles with -diketones, depending on the basicity of the medium, cyclization may take place with the participation of position 1 or 3 and the formation of the corresponding -carbolines, pyrimidoindoles, or mixtures of them.For Communication (XXXVI), see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1043–1046, August, 1973.     

The chemistry of indole

The opening of the pyrazolidine ring at the nitrogen-nitrogen bond in 1-arylpyrazolidine under the influence of acidic agents which leads to the formation of N-(3-aminoalkyl)indoles is described. The method enables one to obtain indoles with branched aminoalkyl radicals.For part XIII see [1].     

The chemistry of indole

The possibility of an electrophilic substitution reaction in the lilolidene series is shown. It is established that, when 2, 3-dimethyl-1, 7-trimethyleneindole (9, 10-dimethyl-9-lilolidene) is nitrated, the main product is the 5-nitro derivative with some of the 6-nitro isomer. The structure of the compounds obtained is established by the combined use of UV and NMR spectra. The conditions for the dehydrogenation of lilodines to lilolidenes are found. It is shown that the indoline system is dehydrogenated more readily than the tetrahydroquinoline system. The nitro compounds obtained are reduced to the corresponding amines by hydrazine hydrate in the presence of Raney nickel.