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Reaction of 2-acyl-6-methylbenzo[b]furan-3-acetic acids and their derivatives such as amides and esters with hydrazine does not give expected 1-alkyl-5H-benzofuro[2,3-e]diazepin-4-ones ones but results in 2-amino-7-methyl-2H-benzo[4,5]furo[2,3-c]pyridin-3-ones or (3-R-6-methylbenzo[b]furan-2-yl)alkyl ketone azines.

Condensation of hetarene carboxaldehydes with phthalide gave 2-(3-hydroxy-1-oxoinden-2-yl)benzo[b]furan and 2-(3-hydroxy-1-oxoinden-2-yl)-5-ethylthieno[2,3-b]thiophene. Starting from hetaryl acetic acids gave 3-(3-hydroxy-1-oxoinden-2-yl)benzo[b]furan and 3-(3-hydroxy-1-oxoinden-2-yl)benzo[b]thiophene. Acylation of 3-hydroxy-1-oxoinden-2-yl-substituted heterocycles using acetic anhydride in the presence of 70% HClO4 leads to the formation of pentacyclic pyrilium salts. Pentacyclic indenopyridines are prepared by treating the pyrilium salts with ammonia. The reaction of the carbonyl group in the indenopyridines with hydroxylamine, hydrazine hydrate, and in reduction using NaBH4 has been studied.

The isomerization of 9-propargylcarbazole in alcoholic alkali leads to the product of dimerization of 9-allenylcarbazole, 1,2-bis(9-carbazolylmethylene)cyclobutane, the structure of which was established by X-ray diffraction analysis.

We have studied the reactions of benzothieno[2,3-c]pyrylium salts with primary amines. We have shown that recyclization occurs in two directions, and whether benzothieno[2,3-c]pyridinium salts or 1-aminodibenzothiophenes are formed is determined by the nature of the primary amine.

The acylation of benzo[b]furan-, benzo[b]thiophene, and indolyl-3-acetic acid arylamides using acetic anhydride in the presence of 70% perchloric acid occurs at the α-position of the heterocycle to give 2-acetylbenzo[b]furan-, 2-acetylbenzo[b]thiophene, and 2-acetylindolyl-3-acetic acid arylamides. Depending on the amount of perchloric used in the reaction they undergo cyclodehydration to 3-arylamino-1-methylhetero[2,3-c]pyrilium salts and to N-aryl-1-methyl-3(2H)hetero[2,3-c]pyridones.

Oximes of 3-ethoxycarbonyl-4-halo(methoxy)phenyl-2,7,7-trimethyl-5-oxo-5,6,7,8-tetrahydroquinolines are converted in polyphosphoric acid (PPA) into 3'-ethoxycarbonyl-4',7',7'-trimethyl-4-oxo-2',6',7',8'-tetrahydrospiro(cyclohexa-2,5-diene-1,2'-pyrrolo[4,3,2-d,e]quinoline). An X-ray structural analysis has been carried out on one of the synthesized compounds.

Transformations of oximes of 4-aryl-2,7,7-trimethyl-5-oxo-5,6,7,8-tetrahydroquinolines in PPA have been studied. It is shown that the reaction, depending on substituent at position 4 of quinoline ring, can occur in three directions: aromatization of the saturated ring (Semmler-Wolff aromatization), formation of azepinones - normal products of Beckmann rearrangement, and formation of pyridoacridines.

The site of electrophilic substitution in benzo[b]thieno- and benzo[b]furo[2,3-c]pyridines has been determined using the nuclear Overhauser effect and by a method based on the difference in reactivity of the isomeric products.

The nitration products of benzo[b]thieno[2,3-c]pyridines were used in the synthesis of new fused tetracyclic heterocyclic systems, which are structural analogs of natural ellipticine and olivicine alkaloids. Closure of the pyridine ring gives products only with linear ring fusion. This behavior was explained using the steric strain-stability principle and complete optimization of the structure of these products with a PCMODEL program and MMX force field in conjunction with the π-electron approximation.

Treatment of 4-aryl-5-aminopyrazoles and 2-aryl-3-amino-maleimides with tris(morpholino)methane gives N-azolyl formamidines which are converted upon heating in trifluoroacetic acid to polycondensed heterocycles with isoquinoline and indolo[2,3-c]pyridine structural fragments.

Treatment of N-phenyl-2-(1-R-indol-3-yl)succinimides with acetyl perchlorate leads to acylation of the benzene ring of the indole substituent.

Novel unusual double recyclization of both pyrrole and pyrylium cores of 5-alkyl-7,8-dimethoxy-2-phenylbenzo[d]pyrrolo[3,2-b]pyrylium perchlorate by nucleophiles is described, which regardless of the nucleophile (ammoniumcarbamate, triethylamine, sodium acetate, HCI in methanol), results in 5-alkyl-7,8-dimethoxy-2-phenylfuro[2,3-c]isoquinoline. The structure of 5-methyl-7,8-dimethoxy-2-phenylfuro[2,3-c]isoquinoline was established from X-ray diffraction analysis.

Nitration, bromination, thiocyanation, and acylation of 1, 7-dimethyl-3(2H)-benzo[b]furo[2, 3-c]pyridone were investigated. It was shown that either the 4-nitro- or the 4,6-dinitro derivative is formed as a function of the nitration conditions. Bromination with bromine and thiocyanation with dithiocyanogen yields a bromo derivative at position 4. The product of substitution at the C(6), atom is obtained in acylation with acetyl chloride, and the product of substitution at atoms C(4) and C(6) is obtained with benzoyl chloride. The results of the calculations were generalized in the MNDO approximation.

A study has been made of thenitrationand bromination of 1-oxo-3,3,6-trimethyl-1,2,3,4-tetrahydrobenzo[bjfuro-, benzo[b]thieno-, and indolo[2,3-c]quinolines. It has been shown that the nitration is directed to the benzene ring (position 10). Bromination by molecular bromine takes place at the 6-CH3 group of the pyridine fragment and yields a mixture of the corresponding nwnobromomethyl and dibromomethyl derivatives, whereas a dimethylacetamide-bromine complex bronzinates the methylene group in position 2, forming the α-bromoketone. The Schmidt reaction of 1-oxo-3,3,6-trimetliyl-1,2,3,4-tetrahydrobenzo[b]furo-, benzol[b]thieno-, and indolo[2,3-c]quinolines have been investigated, as well as conversions of their oximes under conditions of the Beckmann rearrangement.

It has been shown that the nitration and acylation of substituted benzo[b]furo[2,3-c]pyridines proceeds exclusively at position 6 of the benzene ring. If position 6 is blocked by a substitutnt, the product of monosubstitution at the C(8) atom is formed. The molecules that were investigated have been calculated in the MNDO approximation.

It was shown that benzo[c]pyrilium salts containing an acceptor group at position 4 react with benzylamine to form intermediate N-benzylisoquinolinium salts which then undergo conversion to 2-benzyl-6-benzylaminoisoquinolinium cations and napthylamines.

The reaction of acyl perchlorates with 1 phenacylskatole affords the previously unknown 1-R-lamethyl-3phenylindolo[2,1-c1-1,4oxazinium salts, which undergo recyclization by the action of ammonia to the corresponding indolo[2,1-alpyrazines. It is found that the salts (R = CHj, CZHS) also form dimers of their anhydro bases. The perchlorate (R = Ph) is converted to indolo[2,141-1, 2, S-triazepine by the action of hydrazine.

A study was carried out on the nitration of substituted benzo[b]thieno[2,3-c]pyridines. Depending on the conditions, either one nitro group is introduced at C(6) or two nitro groups are introduced at C(6) and C(8). If C(6) is blocked, a mixture of products is formed.

Benzo[c]pyrylium salts that contain an acetyl, cyano, or ethoxycarbonyl group in the 4 position of the pyrylium ring were synthesized by the reaction of 3-(3,4-dimethoxyphenyl)pentane-2,4-dione and α-(3,4-dimethoxyphenyl)acetoacetonitrile and ethyl α-(3,4-dimethoxyphenyl)acetoacetate, as well as ethyl α-(3,4-dimethoxyphenyl)benzoylacetate, with acyl perchlorates. It is shown that α-(3,4-dimethoxyphenyl)acetoacetonitrile ethyleneketal is converted to 3-amino-4-acetylbenzo(c)pyrylium salts under these conditions.

The reaction of acyl perchlorates with 1 phenacylskatole affords the previously unknown 1-R-lamethyl-3phenylindolo[2,1-c1-1,4oxazinium salts, which undergo recyclization by the action of ammonia to the corresponding indolo[2,1-alpyrazines. It is found that the salts (R = CHj, CZHS) also form dimers of their anhydro bases. The perchlorate (R = Ph) is converted to indolo[2,141-1, 2, S-triazepine by the action of hydrazine.

A study has been made of thenitrationand bromination of 1-oxo-3,3,6-trimethyl-1,2,3,4-tetrahydrobenzo[bjfuro-, benzo[b]thieno-, and indolo[2,3-c]quinolines. It has been shown that the nitration is directed to the benzene ring (position 10). Bromination by molecular bromine takes place at the 6-CH3 group of the pyridine fragment and yields a mixture of the corresponding nwnobromomethyl and dibromomethyl derivatives, whereas a dimethylacetamide-bromine complex bronzinates the methylene group in position 2, forming the α-bromoketone. The Schmidt reaction of 1-oxo-3,3,6-trimetliyl-1,2,3,4-tetrahydrobenzo[b]furo-, benzol[b]thieno-, and indolo[2,3-c]quinolines have been investigated, as well as conversions of their oximes under conditions of the Beckmann rearrangement.

Treatment of N-phenyl-2-(1-R-indol-3-yl)succinimides with acetyl perchlorate leads to acylation of the benzene ring of the indole substituent.