K. B. Polyanskii

Synthesis and molecular structure of 2,3,4,5-tetrahydro-1H-3-benzazepine derivatives and dimethyl 4-cyano-2,3,6,7-tetrahydro-1H-3-benzazonine-5,6-dicarboxylate

A study was carried out on the direction of 1,2,3,4-tetrahydroisoquinolinium quaternary salt rearrangements by the action of base with or without dimethyl acetylenedicarboxylate. These quaternary salts containing a methylene group at the nitrogen atom, are converted in the presence of base through intermediate N-ylides into the Stevens rearrangement products, namely, tetrahydro-3-benzazepines. Upon the addition of dimethyl acetylenedicarboxylate as an electrophilic trap, this diester adds at the carbanion site of the ylide with subsequent recyclization of the piperidine fragment to give a 2-benzazonine derivative with an unusual 4,5-positioning of the olefin bond in the nine-membered heterocycle. An X-ray structural analysis established the molecular structures of 2-cyano-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine and dimethyl 4-cyano-2,3,6,7-tetrahydro-1H-3-benzazo-nine-5,6-dicarboxylate.

Rearrangements of N-ethoxycarbonylmethyl-1,2,3,4-tetrahydroquinolinium halogenalkylates effected by sodium hydride. Synthesis of 2,3,4,5-tetrahydro-1H-3-benzazepines

Quaternary salts obtained from N-alkyl-1,2,3,4-tetrahydroisoquinolines and ethyl haloacetates or diethyl bromomalonate under the action of sodium hydride in boiling 1,4-dioxane were converted into N-alkyl-N-ethoxycarbonyl-2,3,4,5-tetrahydro-1H-3-benzazepines in 49–60% yield. From the reaction mixture by column chromatography products of β-elimination by Hofmann reaction, 2-(N-methyl-N-ethoxycarbonylmethyl)-aminomethylstyrenes were also isolated (yield 0.6–16%).

Synthesis of pyrrolidines and tetrahydro-1H-azepines from 4-aryl-1-benzoyl(ethoxycarbonyl)methyl-1-methyl-1,2,3,6-tetrahydropyridinium halides

Abstract4-Aryl-1,2,3,6-tetrahydropyridinium quaternary salts which have a benzoylmethyl or ethoxycarbonylmethyl group on atom N-1 generate N-ylides when heated in the presence of NaH and they can rearrange in situ with contraction or expansion of the six-membered heterocycle to give substituted pyrrolidines (as a result of a [2,3]-sigmatropic rearrangement) or 1H-tetrahydroazepine derivatives (via Stevens rearrangement). The presence of an aryl substituent at position C-4 in the tetrahydropyridine ring allows to avoid the formation of elimination products and changes the direction of the reaction towards the preparation of the tetrahydroazepines.

Synthesis and molecular structure of 2,4,8a-triaryl-6-methylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines

Condensation of arylboronic acids with 4-hydroxy-3-(α-hydroxybenzyl)-1-methyl-4-phenylpiperidine afforded 2,4,8a-triarylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines. The molecular structure of 6-methyl-2,4,8a-triphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridine was established by X-ray diffraction analysis.

Oxidation reactions of azines: XIII. Synthesis, molecular structure, and oxidation reactions of 3-methyl-3,3′,4,4′,5,6-hexahydro-1′H,2H-spiro[benzo[f]isoquinoline-1,2′-naphthalen]-1′-one

The condensation of 3,4-dihydronaphthalen-1(2H)-one with methylamine and formaldehyde in acid medium gave N,N-bis(1-oxo-1,2,3,4-tetrahydronaphthalen-2-ylmethyl)methanamine hydrochloride which was converted into 3-methyl-3,3′,4,4′,5,6-hexahydro-1′H,2H-spiro[benzo[f]isoquinoline-1,2′-naphthalen]-1′-one by heating in 48% aqueous HBr or 50% H2SO4. Oxidation of the spiro compound with KMnO4 initially involved the methylene group of the allylamine fragment with formation of the corresponding lactam which then underwent cis-dihydroxylation at C4a and C10b. Oxidation of the same compound with KMnO4 in the presence of some CH acids (trifluoroacetone and 4-bromoacetophenone) or aromatic amines (4-fluoroaniline and 2-bromo-4-nitroaniline) afforded, respectively, 4-acylmethylidene or 4-arylimino derivatives via C-C or C-N cross-coupling at the 4-position.