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Adducts of 2-arylsulfonyl-p-benzoquinones with imines of β-dicarbonyl compounds were obtained and their conversions to indole and benzofuran derivatives were studied.

1. The reaction of triethylsilylmethylamine with formaldehyde and sulfur yields in aqueous ethanol mainly triethylsilylmethyl isothiocyanate, and in benzene a mixture of that compound with N,N′-bis(triethylsilylmethyl)thiourea. In a similar reaction, bis(3-triethyl-silylpropyl)amine yields N,N,N′,N′-tetrakis(3-triethylsilylpropyl) thiourea, while bis(triethylsilylmethyl)amine yields a complex mixture of products. 2. The reaction of triethylsilylmethylamine with thiourea in the presence of ammonium sulfate yields N,N′-bis(triethylsilylmethyl)thiourea.

The dihydropyridazine ring undergoes contraction to a dihydropyrrole ring to give 1-phenyl-2-benzylideneaminodihydropyrrolo[3,4-b]indol-3-ones when 1-phenyldihydropyridazino[4,5-b]indol-4-ones are treated with aromatic aldehydes under acid catalysis conditions. The reaction mechanism consists in the formation of a (3-indolyl)phenylmethyl cation, which leads to opening of the pyridazine ring and subsequent development of a bond between the carbonium center and the amide nitrogen atom.

4-Hydroxybenzofuran derivatives were synthesized, and their reactions with bromine and nitric acid were studied.

Aromatic aldehydes react with amides of 1-methylindole-2-carboxylic acid under acid catalysis conditions to give 1-aryl-4-methyldihydropyrrolo[3,4-b]indol-3-ones. The intermediate 1-methyl-2-CONHR-3(α-X-benzyl)indoles, which are subsequently converted to the indicated cyclic compounds, were isolated. o-Acetyl derivatives were obtained by the action of acetic anhydride on derivatives of unsubstituted amides. Dihydropyrrolo[3,4-b] indol-3-ones were reduced by LiAlH4 to the corresponding dihydropyrrolo[3,4-b] indoles. A mechanism for the formation of dihydropyrrolo[3,4-b] indoles is proposed.

The corresponding 6-halo-substituted o-quinones were obtained by the action of nitric acid on 2-methyl(phenyl)-3-carbethoxy-4,6-dihalo-5-hydroxybenzofurans, whereas 2-methyl-3-carboxy-4,6-dibromo-5-hydroxybenzofuran is converted to the 4,6-dinitro derivative under similar conditions. The action of nitric acid on 2-methyl-3-carbethoxy-4-chloro-5-hydroxybenzofuran leads to replacement of the hydrogen in the 6 position by a nitro group. The reduction of o-quinones to the corresponding dihydroxy derivatives and reactions of quinones with amines are described.

It is shown that, in contrast to model structures with fixed amine and imine forms, the form and position of some of the signals in the PMR spectra of 4,4,6-trimethyl-2-phenylamino-4H-1, 3-thiazine derivatives depend on the temperature; this is associated with rotational isomerism about the nitrogen-heteroring bond, which is realized at a higher rate in the model derivative with an amine structure and is slowed down in the tautomeric derivatives owing to the formation of hydrogen bonds with solvent molecules (in deuteroacetone) or in dimeric associates (in deuterochloroform). According to data from the low-temperature spectra, the percentages of the syn and anti forms in acetone solutions are comparable. In chloroform solution, the equilibrium between the two rotational forms is shifted markedly to favor the anti isomer as the temperature is lowered because of the formation of cyclic dimeric structures.

We synthesized some new types of organosilicon monomers based on the hydrosilylation of 3-oxa-1,4-pentadiene and 1,5-hexadiene with silicofunctional alkylsilanes of type R3−nSiH(OC2H5)5 (n=1–3) and R2SiHCl. The halogenation of the monoaddition products gave the dibromo and dichloro derivatives.

A 4-oxotetrahydrobenzofuran derivative was obtained from 5-phenylcyclohexane-1,3-dione and phenacyl bromide, and dehydrogenation of the latter gave 2,6-diphenyl-4-hydroxybenzofuran. Some reactions of 2,6-diphenyl-4-hydroxybenzofuran and its derivatives were studied.

Aromatic aldehydes react with indole-2-carboxylic acid azides under acid catalysis conditions to give the corresponding 3-(α-halobenzyl)indoles, which react with aliphatic and aromatic amines to give the corresponding aminobenzylindoles. The latter undergo intramolecular cyclization to dihydropyrrolo[3,4-b]indoles at room temperature and are converted to dihydropyrimido[4,5-b]indoles through the Curtius rearrangement when they are heated to 80-110°C. Acetylation of the latter products gives N- and O-acetyl derivatives.

Die Umsetzung von Divinyl-sulfoxid (I) mit Trialkyl- silyl-alkanthiolen (II) verlauft zunachst vermutlich unter Bildung des Monoaddukts (III), das sich bei der Destillation zum Vinyl-(trialkylsilyl-alkyl)sulfid (IV) zersetzt.

A method for the preparation of substituted gramines, viz., 3-(α-aminobenzyl)-2-carbethoxyindoles, by alkylation of amines with 3-(α-halobenzyl)-2-carbethoxyindoles was developed. Ammonia, primary and secondary amines, and pyridine were used. Anhydronium bases, viz., 3-indolidenephenylmethanes, were isolated and characterized.

1. Trialkoxyalkanethiols have been synthesized by the reaction of chloroalkyltrialkoxysilanes with NaHS, as well as by the sodium-methoxide-catalyzed splitting of the thioacetates (RO)3Si(CH2)n·SCOCH3. 2. Bis(trialkoxysilylalkyl)sulfides have been synthesized by reacting chloroalkyltrialkoxysilanes with sodium sulfide.