The preparation of the benzo[4,5]cyclohepta[1,2-b]pyrazine and benzo[4,5]cyclohepta[1,2-b]quinoxaline systems

Benzo[4,5]cyclohepta[1,2-b]quinoxaIine 2 , benzo[4,5]cyclohepta[1,2-b]pyrazine 3a and benzo[4,5]cyclohepta[1,2-b]quinoxaline 4 were prepared from 4,5-benzotropolone and 1,2-phenylenediamine, ethylenediamine and 1,2-diaminocyclohexane, respectively. Compound 3a was methylated to 3b .     

Synthesis of benzo[g]quinoline derivatives

The synthesis of 4-aminobenzo[g]quinoline has been effected by the following three methods: 1) replacement of the halogen in 4-chlorobenzo[g]quinoline by an amino group; 2) dehydrogenation of the oxime of 1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline; 3) direct condensation of 1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline with ammonia.     

Synthesis of benzo [g]quinoline derivatives

The IR spectra of linear benzoquinoline derivatives at 700–900, 1400–1700, and 2800–3600 cm^–1 are discussed, and the characteristic frequencies are related to the peculiarities of the structures of the synthesized compounds.See [1] for communication VIIITranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 367–372, March, 1972.     

Synthesis of benzo[g]quinoline derivatives

It has been established that the cyclization of -(2-carboxy-3-naphthylamino)propionic acid into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]quinoline takes place with the participation of acetic anhydride and an alkali metal acetate. In the absence of the alkali metal acetate cyclization takes place in a different direction. A mechanism for this reaction has been proposed as taking place through the formation of an internal mixed anhydride, which decomposes under the reaction conditions into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]-quinoline and carbon dioxide.For part V, see [1].     

Synthesis of benzo[g]quinoline derivatives

The electronic spectra of linear benzo[g]quinoline, its 4-substituted derivatives, and some hydrogenated derivatives are examined and discussed.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 662–665, May, 1972.     

Synthesis of benzo[g]quinoline derivatives

A method for the synthesis of 3-substituted benzo[g]quinolin-4-ones by the condensation of 1,2,3,4-tetrahydrobenzo[g]quinolin-4-one with aromatic aldehydes in an alkaline medium has been developed. It has been found that the first stage of the reaction is the formation of the corresponding benzylidene derivative, which then isomerizes into the more stable benzyl derivative. The structure of the 3-substituted benzo[g]quinolin-4-ones obtained, as existing in the tautomeric oxo form, is confirmed by their IR and UV spectra.For Communication VI, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinii, Vol. 6, No. 6, pp. 798–801, June, 1970.     

Synthesis of benzo[g]quinoline derivatives

4-Amino-substituted benzo[g]quinolines have been synthesized for the first time by the condensation of 4-oxo-1,2,3,4-tetrahydrobenzo[g]-quinoline with amines. This reaction is characterized by the addition of the amine, the splitting out of water, and the complete aromatization of the initial hydrogenated heterocyclic system. The UV spectra of the compounds obtained are similar to those of 4-amino-substituted quinolines, their maxima being displaced somewhat into the long-wave region.For part III, see [2].     

Synthesis of benzo[g]quinoline derivatives

In the condensation of 1, 2, 3, 4-tetrahydro-4-oxobenzo[g]quinollne with ammonia, which leads to the formation of 4-aminobenzo[g]quinoline, the by-products are benzo[g]quinoline (V) and 1, 2, 3, 4-tetrahydrobenzo]quinoline (VI), which are also obtained from 1, 2, 3, 4-tetrahydro-4hydroxybenzo[g]quinoline by its dehydration and the subsequent disproportionation of the dihydrobenzo[g]quinoline formed.For communication II, see [1].     

New heterocyclic systems. Benzo[4,5]cyclohepta[1,2-b]pyrrole and benzo[5,6]cyclohepta[1,2-f]pyrrolizidine derivatives

The synthesis of the polycyclic pyrrole acetic acids 9e, 13e and 13g by multistep processes from 1-bromo-4-phenylbutan-2-one ( 6c ) is reported. An instance of the use of the 2-chloroethyl moiety as a pyrrole nitrogen protecting group is described. The α-methylaminoketone ( 6e ) was synthesised by a novel two step process from 6c and methyl N-methylformimidate ( 12 ).     

Synthesis of benzo[g]quinoline derivatives. XI. 2,4-Diamino-substituted benzo[g]quinolines

Previously unknown 2,4-diamino-substituted benzo[g]quinolines were synthesized from 2,4-dihydroxybenzo[g]quinoline.     

Pyrido[1,2-b] indazole and its derivatives

A new route to pyrido[1,2-b]indazole and its derivatives is described and the nitration of the parent compound is reported. The formation of δ-carbolines as byproducts is discussed.     

Investigations of substituted benzofuran-3-carboxylates,benzo[1,2-b:4,5-b']difurans and benzo[1,2-b:4,3-b']difurans

The Michael addition of ethyl acetoacetate to benzoquinone, toluquinone, and chlorobenzo-quinone leads to formation of substituted 5-hydroxybenzofuran-3-earboxylates and linear benzo-[1,2-b:4,5-b']difurans. The previously reported structural proof for the benzodifurans obtained from chlorobenzoquinone and toluquinone, although correct in the conclusion, is shown to be invalid. Proof of the linear benzodifuran structures was obtained by comparison of the uv spectra with authentic angular benzo[1,2-b:4,3-b']difurans.     

Synthesis, properties, and structures of benzo[1,2-b:4,5-b']bis[b]benzothiophene and benzo[1,2-b:4,5-b']bis[b]benzoselenophene

Employing two consecutive cyclization reactions, benzo[1,2-b:4,5-b']bis[b]benzochalcogenophenes, which are pi-extended heteroarenes, were efficiently synthesized. Their electronic and crystal structures were elucidated on the basis of UV-vis spectra, electrochemical measurements, and X-ray structural analyses.     

Synthesis of 3H[1,2]diazepino[5,6-b]indole and 3H[1,2]diazepino[4,5-b]indole derivatives

The synthesis of two new derivatives of 3H[1,2]diazepino[5,6-b]indole, 5 and 11 , and one new derivative of 3H[1,2]diazepino[4,5-b]indole, 16 , are described. Compound 5 was obtained by the reaction of methyl 2-(3-methoxycarbonyl-1-methylindole)acetate 2 , with hydrazine. Compound 11 was obtained in two ways from ethyl 2-(1-methylindole)acetate ( 8 ) by formylation and reaction with hydrazine. Compound 16 was obtained treating 3-(2-ethoxycarbonylindole)acetonitrile ( 14 ) with hydrazine.     

1,2,5-Thiadiazolo[3,4-b]pyrazines

1,2,5-Thiadiazolo[3,4-b]pyrazine and its derivatives were prepared. Nucleophilic displacements of halogen atoms on the nucleus were reported.     

Nitration of benzo[g]isoquinoline and its methyl-substituted derivatives

Di- and trinitro derivatives are formed in the nitration under mild conditions (0–5 °C) of benzo[g]isoquinoline and its analogs with a methyl substituent in the pyridine and phenylene rings. The principal reaction products contain a nitro group in the meso position (attached to the C₅ atom) and in the phenylene ring. The structures of the nitro derivatives obtained and the position of the nitro groups in the molecules were proved by means of the PMR, IR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1658–1661, December, 1981.