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Heterocyclization of ethyl 2-acetyl(aroyl)-5-methylthieno[2,3-b]thiophene-3-acetates with hydrazine hydrate has been studied. A dependence of the reaction direaction on the nature of the substituent in the acyl fragment was established. The heterocyclization of ethyl 2-aroyl-5-methylthieno[2,3-b]thiophene-3-acetates leads to derivatives of thieno[3',2':4,5]thieno[2,3-d][1,2]diazepin-5-ones. The cyclization of ethyl 2-acetyl-5-methylthieno[2,3-b]thiophene-3-acetate with hydrazine hydrate forms a six-membered ring, viz. 2-aminothieno[3',2':4,5]thieno[2,3-c]pyridin-5(6H)-one.

A new synthetic approach to fused azepines was demonstrated on an example of the synthesis of 2-methyl-2,3,4,5-tetrahydro-1H-[1]benzothieno[2,3-c]azepine. The key stage of the synthesis is the formation of the azepine ring under the Eschweiler–Clark reaction conditions. The Gibbs energy of activation for the inversion of the azepine ring was determined by dynamic 1H NMR spectroscopy. Molecular modeling of the structure and estimation of the 1H and 13C NMR chemical shifts were performed for 2-methyl-2,3,4,5-tetrahydro-1H-[1]-benzothieno[2,3-c]azepine. The magnetic shielding tensors were calculated by the standard GIAO method using the B3LYP/6-31G(d,p)-optimized molecular geometry parameters. The solvent effect was taken into account in the PCM approximation. The calculated 1H and 13C NMR chemical shifts of 2-methyl-2,3,4,5-tetrahydro-1H-[1]-benzothieno[2,3-c]azepine are in good agreement with the experimental values observed in the spectra of its DMSO-d6 solution.

A number of new 1-substituted 5,10-dihydro[1,2]diazepino[4,5-b]indole-4(3H)-ones were synthesized, and their structural modification was performed to obtain previously unknown amino and fused triazolo derivatives.

1-Aryl-substituted tetrahydrothieno[3,2-с]pyridines easily undergo domino reactions with activated alkynes, giving good yields of the corresponding tetrahydrothieno[2,3-d]azocines. The reactions of 1-methyl-substituted tetrahydrothieno[3,2-с]pyridine were more complicated.

Acylation of 5-(benzothiophen-3-yl)pyrimidine-2,4,6(1H,3H,5H)-trione using acetic and propionic anhydride in the presence of 70% perchloric acid gave the 6-methyl(ethyl)-1,3-dioxo-1,2,3,4-tetra-hydro[1]benzothieno[3',2':4,5]pyrano[2,3-d]pyrimidin-5-ium perchlorates. Hydrolysis of the pyrano[2,3-d]pyrimidin-5-ium salts in aqueous alcohol solution gave 5-(2-acylbenzothiophen-3-yl)-pyrimidine-2,4,6(1H,3H,5H)-triones. Cyclocondensation of the latter with aromatic amine hydrochlorides produced 6-R-5-aryl-1,3-dioxo-1,2,3,4-tetrahydro[1]benzothieno[3',2':4,5]pyrido[2,3-d]-pyrimidin-5-ium chlorides. 6-R-5-Aryl-5,6-dihydro[1]benzothieno[3',2':4,5]pyrido[2,3-d]pyrimidine-1,3(2H,4H)-diones were synthesized by reduction of the pyrimidinium chlorides using sodium borohydride.

A study was carried out on the domino transformations of tetrahydrobenzofuro[2,3-c]pyridines and tetrahydrobenzofuro[3,2-c]pyridines by the action of activated alkynes in methanol and acetonitrile. This reaction is a new method for the synthesis of spiro[benzofuropyridines] showing acetylcholinesterase inhibition activity.

Novel 1-R-3,4-dihydro-5H-benzothieno[2,3-d][1,2]diazepin-4-ones have been prepared by the cyclization of 2-acyl(aroyl)benzo[b]thiophene-3-acetic acids or 1-R-benzothieno[2,3-c]pyr-3-ones with hydrazine hydrate.

A novel domino reaction of tetrahydrobenzofuro[3,2-c] or [2,3-c]pyridines with dimethylacetylene dicarboxylate (DMAD) or methyl propiolate (MP) resulted in the formation of spirobenzofuranpyridines in moderate yields. The spirobenzofuran derivatives reported may be considered analogs of the antifungal drug griseofulvin.

A series of previously unknown 2-([1]benzothieno[2,3-c]pyridin-1-yl)benzoic acids and 8,13b-dihydro-[1]benzothieno[2',3':3,4]pyrido[2,1-a]isoindol-5(7 H)-ones has been synthesized using domino reactions, taking place at the cyclization of 2-[3-oxo-4-(phenylsulfanyl)butyl]-1,3-isoindolinediones in polyphosphoric acid.

New 1-R-2-methyl-1,2,3,4-tetrahydrobenzothieno[2,3-c]pyridine derivatives have been obtained by cyclization of 2-(1-benzothiophen-3-yl)ethylamines with aromatic and heteroaromatic aldehydes in the presence of triisopropylchlorosilane.

A new strategy for the synthesis of the eight-membered heterocyclic skeleton of tetrahydro-quinazolino[3,2-c][2,3]benzodiazocin-15-ones, based on the Pictet–Spengler reaction of 3-amino-2-[2-(3,4-dimethoxyphenyl)ethyl]quinazolin-4(3H)-one with carbonyl compounds in acidic media, is proposed.

A series of new 3-substituted 6-(4-chlorophenyl)-9-methyl-12H-[1]benzofuro[3,2-e][1,2,4]triazolo[4,3-b][1,2]diazepines was synthesized from the corresponding bicyclic 1-(4-chlorophenyl)-3,5-dihydro-8-methyl-4H-[1]benzofuro[2,3-d][1,2]diazepin-4-one. The synthesis strategy makes use of silylation–amination as the key step, allowing a wide range of derivatives to be prepared. .

The cyclocondensation of (2-aroyl-1-benzofuran-3-yl)acetic acids and their methyl esters with hydrazine hydrate under various experimental conditions has been studied. Optimal conditions have been found for obtaining 1-aryl-3,5-dihydro-4H-1-benzofuro[2,3-d][1,2]diazepin-4-ones.

The reactivity of some new tetrahydrothienopyridines towards activated alkynes was investigated. A novel cascade cleavage-spiroannulation process, leading to the formation of previously unreported derivatives of 1′H-spiro[1-benzothiophene-3,4′-pyridine] was discovered and studied.

It has been shown that, on interacting 2-ethyl-3,3,5,5-tetramethyl- and 2-ethyl-1,3,3,5,5-pentamethyl-1,2,4,5-tetrahydro-3H-benz-2-azepines with ethyl propiolate in methanol, fission of the azepine ring occurs at the C(1)-N(2) bond involving a molecule of solvent. The indicated azepines do not react with acetylenedicarboxylic acid ester under these conditions.

On the interaction of 1-methyl-3-phenylbenzothieno[2,3-c]pyrilium perchlorate with primary and secondary amines and alkalis in aqueous media a product of cyclocondensation of 2-acetyl-3-phenacyl-benzo[b]thiophene – 2-[2-(1-benzoyl-4-methyldibenzothienyl-2)benzo[b]thienyl-3]phenyl-1-ethanone – was isolated in addition to the classical objects of recyclization.

The heterocyclization of 2-acetyl-3-indolylacetic acid hydrazones and its amides, in contrast to similar derivatives of phenylacetic acid, does not lead to 2,3-dihydro-2-oxo-5-R1-1H-[1,2]diazepino-[4,5-b]indoles but rather to 2-aminoindolo[2,3-c]pyridin-3(2H)-one or azines of 2-acetyl-3-indolyl-acetic acid. 2,3-Dihydro-2-oxo-5-R1-1H-[1,2]diazepino[4,5-b]indoles were obtained by the reaction of 1-alkylaminoacetylindolo[2,3-c]pyrilium perchlorates and of methyl esters of 2-acetyl- and 2-propionyl-3-indolylacetic acid with hydrazine hydrate.

The transformations of tetrahydrothieno[3,2-c]-and tetrahydrobenzothieno[2,3-c]pyridines in the reactions with acetylenedicarboxylic ester, alkyl propiolates, and acetylacetylene in alcohols were studied. Tetrahydrobenzothieno[3,2-d]azocines and 2-methoxyethyl-3-vinyl-aminoethylbenzothiophenes were synthesized.

It is shown that the expansion of the tetrahydropyridine fragment requires the presence of an aryl substituent at position 4 of the tetrahydrothieno[3,2-c]pyridines as it stabilizes the intermediate acyclic zwitterion.

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.

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 catalytic activity of several aliphatic amines in the liquid-phase oxidation of anthrone by molecular oxygen in dimethyl sulfoxide was studied. The kinetic data obtained were compared with the results of quantum-chemical calculations. The catalytic activity of aliphatic amines in the reaction under consideration was directly proportional to an increase in the absolute value of the heat of formation of the corresponding ammonium cation.

A new method is proposed for the production of substituted 3-phenacylbenzo[b]thiophenes by the intramolecular cyclization of 1-phenyl-4-phenylthio-1,3-butanediones in polyphosphoric acid. The analogous cyclization of 1-phenyl-4-(5-ethyl-2-thienylthio)-1,3-butanedione leads to 3-phenacyl-5-ethylthieno[2,3-b]thiophene. The acylation of substituted 3-phenacylbenzo[b]thiophenes and 3-phenacyl-5-ethylthieno[2,3-b]thiophene by the anhydrides of aliphatic acids in the presence of perchloric acid leads to 1-alkyl-3-phenylbenzothieno[2,3-c]pyrylium perchlorates and 2-ethyl-5-phenyl-7-methylthieno[2′,3′:5,4]thieno[2,3-c]pyrylium perchlorate. The action of ammonium acetate on the obtained salts gives the corresponding pyridine bases.

Acylation of 5-(benzothiophen-3-yl)pyrimidine-2,4,6(1H,3H,5H)-trione using acetic and propionic anhydride in the presence of 70% perchloric acid gave the 6-methyl(ethyl)-1,3-dioxo-1,2,3,4-tetra-hydro[1]benzothieno[3',2':4,5]pyrano[2,3-d]pyrimidin-5-ium perchlorates. Hydrolysis of the pyrano[2,3-d]pyrimidin-5-ium salts in aqueous alcohol solution gave 5-(2-acylbenzothiophen-3-yl)-pyrimidine-2,4,6(1H,3H,5H)-triones. Cyclocondensation of the latter with aromatic amine hydrochlorides produced 6-R-5-aryl-1,3-dioxo-1,2,3,4-tetrahydro[1]benzothieno[3',2':4,5]pyrido[2,3-d]-pyrimidin-5-ium chlorides. 6-R-5-Aryl-5,6-dihydro[1]benzothieno[3',2':4,5]pyrido[2,3-d]pyrimidine-1,3(2H,4H)-diones were synthesized by reduction of the pyrimidinium chlorides using sodium borohydride.

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.

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.

The reagent system DMF—Tips-Cl is used in a Pictet—Spengler reaction leading to title compounds (III).

A new strategy for the synthesis of the eight-membered heterocyclic skeleton of tetrahydro-quinazolino[3,2-c][2,3]benzodiazocin-15-ones, based on the Pictet–Spengler reaction of 3-amino-2-[2-(3,4-dimethoxyphenyl)ethyl]quinazolin-4(3H)-one with carbonyl compounds in acidic media, is proposed.

Condensation of benzo[b]furan-3(2H-one, benzo[b]thiophen-3(2H)-one and benzo[b]selenophen-3(2H)-one with dimedone gives 2-(3-heteryl)dimedones. Acylation of the latter leads to the corresponding tetracyclic pyrylium salts, from which condensed quinolines are obtained. Some condensed quinoline derivatives are obtained by reaction of 1-oxo-1,2,3,4-tetrahydroheterene[2,3-c]quinolines with sodium borohydride, hydrazine, and hydroxylamine.

A series of new 3-substituted 6-(4-chlorophenyl)-9-methyl-12H-[1]benzofuro[3,2-e][1,2,4]triazolo[4,3-b][1,2]diazepines was synthesized from the corresponding bicyclic 1-(4-chlorophenyl)-3,5-dihydro-8-methyl-4H-[1]benzofuro[2,3-d][1,2]diazepin-4-one. The synthesis strategy makes use of silylation–amination as the key step, allowing a wide range of derivatives to be prepared. .

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.

It has previously been shown that 5-o-chlorobenzyltetrahydrothieno[3,2-c]pyridines react with alkynes only in alcohols to form the products of cleavage of the tetrahydropyridine ring and involving molecules of the solvent and the products of debenzylation (N-vinyltetrahydrothienopyridines) [1]. 2-Trifluoroacetamidotetrahydrothieno[2,3-c]pyridines react readily with alkynes both in methanol and in acetonitrile to give a high yield of tetrahydrothieno[3,2-d]azocines [2]. 2-Acetamido-substituted thienopyridines react with alkynes in acetonitrile at 20oC to give modest yields (30-59%) of the thienoazocines. There occur in methanol simul-taneous processes of expansion and cleavage of the tetrahydropyridine fragment to form a mixture of the acetamido-substituted tetrahydrothieno[3,2-d]azocines and 2-acetamido-3-ethoxycarbonyl-4-(N-vinyl-N-R)aminoethyl-5-methoxymethylthiophenes [2]. Continuing our study of the dependence of the transformation of tetrahydrothienopyridines with activated alkynes we have shown, for the first time, that the tetrahydrobenzothieno[2,3-c]pyridines 1, 2 react with acetylene dicarboxylic ester (ADCE) in acetonitrile to form the spiro[benzothiophene-3,4'-pyridines] 3, 4 in 20-35% yields.

The reaction of 1,7-dimethyl-3(2H)-benzo[b]furo[2,3-c]pyridone with phosphoric acid amides gave 1,7-dimethyl-3-dimethylamino (morpholino)benzo[b]furo[2,3-c]pyridines. A method for the synthesis of 3-amino derivatives of 4-nitrobenzo[b]furo[2,3-c]pyridines, which consists in heating 1,7-dimethyl-4-nitro-3(2H)-benzo[b]furo[2,3-c]pyridone with hexamethyldisilazane and secondary or primary amines in pyridine, was developed.

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.