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An effective method has been developed for the synthesis of S,N- and S,N,O-containing cyclophanes by cyclothiomethylation reaction of primary amines with formaldehyde and aromatic dithiols. Benzene-1,2-dithiols were used in [1+2+1] cyclocondensation reaction that gave N-substituted 1,5,3-benzodithiazepines, while benzene-1,4-dithiol and 4,4'-dimercaptodiphenyl oxide participated in a [3+6+3] cyclocondensation reaction leading to cyclophanes.

The reactions of 3-acetoacetylchromen-2-one with mono- and binucleophilic reagents, under the action of microwave irradiation have been studied. It was shown that depending on the nucleophilicity of the reactant new heterocyclic systems were formed involving the oxo group of the substituent in position 3 of the heterofragment, its opening, or recyclization.

It was established that the direction of the reaction of 3-(1,3-dioxobutan-1-yl)-2H-chromen-2-one with bromine depends on the conditions under which it is carried out. In acidic media carbocyclization occurs with the formation of dihydroxanthylium bromide or hydroxyxanthene; in chloroform enolization of the carbonyl group with subsequent bromination and heterocyclization to substituted pyranochromene with the participation of the benzopyran-2-one fragment occurs.

It has been shown that 2-spiro(3-R-6,6-dimethyl-4-oxo-2,3,4,5,6,7-hexahydrobenzofuran)-2′-(5′, 5′-dimethylcyclohexane-1′,3′-diones) undergo conversions in reactions with ammonium acetate and hydrazine hydrate into substituted dihydropyridin-2-ones and tetrahydro-1,2-diazepin-7-ones respectively as a result of ring-opening of the spirodimedonyl fragment through the corresponding amides and hydrazides of δ-keto acids.

Published data and the authors' own experimental results on the reaction of aliphatic, semicyclic, and oxosemicyclic 1,5-diketones and alkylidene- and arylidene-2,2-dicyclanones with ammonia, ammonium acetate, and XNH2 derivatives, where X = Alk, Ar, OH, NH2, PhNH, ArCONH, and CHO, are reviewed. The characteristics and the relationships governing the transformations into azaheterocycles in relation to the nature of the reagents and the reaction conditions are discussed.

First time, benzopyran (I), urea (II), and aromatic aldehydes are used in the Biginelli reaction to synthesize the title compounds of type (IV) in a one-pot procedure.

Di(1-oxo-1,2,3,4-tetrahydro-2-naphthyl) sulfide has been obtained and its behavior towards hydrogen sulfide in situ, ammonium acetate, hydrazine hydrate, and hydrogen peroxide has been studied. The structure of the compounds synthesized was established by IR and by 1H and 13C NMR spectroscopy and by chromato-mass spectrometry.

Literature and characteristic experimental data correlated in the review concern the intramolecular cyclization by various means of substituted 1,5-diketones of the acyclic, semi-, and bicyclic series, proceeding to the formation of oxygen-containing heterocycles, such as pyrans, pyrylium salts, di- and tetrahydrofurans, and their condensed analogs, aroylfurans etc.

A comparative assessment was made of the reactivity of carbonyl-containing spirohydrochromans in their reaction with hydrogen sulfide under the conditions of acid catalysis. The special features of the structure of one of the obtained condensed spiro(thia)chromans are examined on the basis of the results from x-ray crystallographic analysis, the13C NMR spectra, and quantum-chemical calculations.

An unusual direction was found in the condensation of cyclohexanone and its Mannich base, leading to the formation of previously unknown polycyclic spirohydrochromans. The structure of the compounds was confirmed by13C NMR and mass spectrometry.

Research into the reactivity of carbonyl-substituted spirohydrochromans with hydrogen sulfide under the influence of protic and aprotic acids was continued for the case of 3,4,5,6,7,8-hexahydrospiro[chromene-2,1′-cyclohexan]-2-one. The general nature of the reactions was established. Complexes of copper(II) with substituted hydro(thio)chromans were obtained. The results from investigation of the antiphage activity of the synthesized compounds are presented.

Reaction of 5, 6-benzocyclohexan-l-one with formaldehyde in the presence of bases gives the Diels—Alder dimer of the intermediate 2-methylene-5, 6-benzocyclohexan-l-one and the expectedmethylenebis-Sexpectedmethylenebis-5, 6-benzocyclohexan-l-one. The optimal conditions for the formation of the dimer and its conversion into the hydroxy-.1, 6-diketone are found. The reactions of these products with H2S and acids are studied. The structures of the newly prepared compounds are confirmed by13C NMR.

Semicyclic 1,5-diketones of the 2-(3-oxopropyl)cyclohexane-1,3-dione series are capable of cyclization only in severe conditions on boiling in acetic anhydride to give substituted tetrahydrochromenones [1]. Salt formation is also difficult and takes place only with a donor substituent on C(1 ) of the aliphatic chain of the oxo compounds [2]. Reactions of analogous bicyclic oxo 1,5-diketones have not appeared in the periodic literature. We have shown for the first time that it is possible to aromatize the tetrahydroxanthene ring of 3,3-dimethyl-9(4,4-dimethyl-2,6-dioxocyclohexyl)-1,2,3,4-tetrahydro-9H-xanthen-1-one (1) under the influence of perchloric acid of boron trifluoride etherate with simultaneous polyacetalization of the 1,5-dicarbonyl unit into a hydroxytetrahydrochromen unit and formation of 8a-hydroxy-7,7,11,11-tetramethyl-13-oxo-6,7,8,8a,10,11,12,13octahydrochromeno[2,3,4-k,l]xanthen-5-ylium perchlorate (2) or tetrafluoroborate (3) respectively. The yields of the salts were 42.2 and 57.5% respectively. 5a-Hydroxy-3,3,7,7-tetramethyl-1H-2,3,4,5a,6,7,8,13b-octahydrobenzopyrano[2,3,4-k,l]xanthen-1-one (4) was isolated along with salts 2 and 3 (12.2 and 21.0% yield respectively). The formation of 4 permits the suggestion that polyacetalization precedes aromatization of the heterocyclic fragment of the substrate.