Lewis Acid-Mediated Ring Contraction of 2,4-Diaryl-2,3-dihydro-1H-1,5-benzodiazepines: Access to 2-Aryl-1-styrylbenzimidazoles

2,4-Diaryl-2,3-dihydro-1H-1,5-benzodiazepines readily undergo a ring contraction to generate 2-aryl-1-styrylbenzimidazoles in the presence of some Lewis acids. Copper acetate shows high efficiency compared with other Lewis acids. The ring contraction includes Lewis acid-catalyzed intramolecular addition, ammonium-induced ring-opening of the generated four-membered azetidine ring, deprotonation, and amine-promoted nucleophilic styryl 1,2-shift and elimination. Copper acetate serves as Lewis acid, base, and oxidant. The current reaction provides an efficient method for the convenient synthesis of 2-aryl-1-styrylbenzimidazole derivatives from readily available 2,4-diaryl-2,3-dihydro-1H-1,5-benzodiazepines.     

Manganese(III)-mediated intermolecular cyclization reactions of alkenes and active methylene compounds

The reactions of 1,1-diphenylethene, 1,1-bis(4-chlorophenyl)ethene, 1,1-bis(4-methylphenyl)ethene, and 1,1-bis(4-methoxyphenyl)ethene with 3,5-diacetyl-2,6-heptanedione in the presence of manganese(III) acetate in acetic acid at 80° yielded 4,6-diacetyl-8,8-diaryl-1,3-dimethyl-2,9-dioxabicyclo[4.3.0]non-3-enes (41-48%), 5-acetyl-2,2-diaryl-6-methyl-2,3-dihydrobenzo[b]furans (20–21%), 3-acetyl-5,5-diaryl-2-methyl-4,5-dihydrofurans (5–10%), and benzophenones (3–7%). Similarly, the reactions of 1,1-diarylethenes with dimethyl 2,4-diacetyl-1,5-pentanedioate or diethyl 2,4-diacetyl-1,5-pentanedioate gave the corresponding 4,6-bis(alkoxycarbonyl)-8,8-diaryl-1,3-dimethyl-2,9-dioxabicyclo[4.3.0]non-3-enes in moderate yields.     

Chemical properties of 2,2,4-trisubstituted 2,3-dihydro-1H-1,5-benzodiazepines

Acetylation and nitrosation of 2,4-diaryl-2-methyl-2,3-dihydro-1H-1,5-benzodiazepines take place at the azomethyne nitrogen. Reduction is stereoselective.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1122–1126, August, 1987     

Reactions with pyrrolidine-2,4-diones,I. New synthesis of pyrano[2,3-c]pyrrole and pyrrolo[3,4-b]pyridine systems

The synthesis of some substituted 4-hydroxy-2,5,6,7-tetrahydro-pyrano[2,3-c]pyrrole-2,5-diones (5) and 4-hydroxy-1,2,6,7-tetrahydro-5H-pyrrolo[3,4-b]pyridine-2,5-diones (6) by reacting 1,5-diaryl-pyrrolidine-2,4-diones (1) and 1,5-diaryl-1,5-dihydro-4-amino-2H-pyrrol-2-ones (3) with bis-2,4,6-trichlorophenyl malonates (4) is described.Dedicated to Prof. Dr. Dr. h. c.O. Kratky, Graz, on the occasion of his 80th birthday.     

Synthesis and pancreatic lipase inhibitory activities of some 1,2,4-triazol-5(3)-one derivatives

In this study, starting from 4-amino-5-(4-chlorobenzyl)-2,4-dihydro-3H-1,2,4-triazole-3-one ( 1 ), the 4-Amino-5-(4-chlorobenzyl)-2-undecyl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 2 ) was first synthesized and this compound was converted to Schiff base derivatives ( 3a-e ). In the second step of the study, the 2-[3-(4-chlorobenzyl)-5-oxo-1-undecyl-1,5-dihydro-4H-1,2,4-triazole-4-yl]-acetohydrazide ( 6 ), which was used as a key product in the synthesis of many heterocyclic compounds was synthesized in four steps, and then this compound was converted into methylidene acetohydrazide ( 7a-e ), thiosemicarbazide ( 8a-e ), and 1,2,4-triazole-5-thione ( 9a-e ) derivatives. Also, in the last part of the study, 1,2,4-triazole-5-thione derivatives were changed into Mannich bases ( 10a-b ) bearing a 4-phenylpiperazine ring. These new compounds were tested with regard to pancreatic lipase (PL) inhibition activity, and compound 3b , 3d , 7d , 8d , and 9d showed a considerable anti-lipase activity at various concentrations. The activity of compounds 7b (IC₅₀ = 1.45 ± 0.12 μM) was the highest in terms of IC₅₀, comparable to that of orlistat, a well-known PL inhibitor used as an antiobesity drug.     

Synthesis of Some New Thiazoles and Pyrazolo[1,5-a]pyrimidines Containing an Antipyrine Moiety

Ethyl 2-{2-[4-(2,3-dimethyl-5-oxo-1-phenyl-3-(pyrazolin-4-yl)]-2-cyano-1-(phenylamino)vinylthio}-acetate, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]2-(4-oxo-3-phenyl-(1,3-thiazoilidin-2-ylidene))ethanenitrile, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-2-(4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))ethanenitrile, 2-(5-acetyl-4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))-2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]ethanenitrile, and ethyl 2-(cyano(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)methylene)-2,3-dihydro-4-methyl-3-phenylthiazole-5-carboxylate were synthesized by treatment of 2-(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)-3-mercapto-3-(phenylamino)-acrylonitrile with appropriate halo ketones or halo esters. Also, 4-{2-[5,7-dimethyl-2-(phenylamino)(7a-hydropyrazolo[1,5-a]pyrimidin-3-yl](1,-thiazol-4-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one derivatives were synthesized via reaction of 4-{2-[5-amino-3-(phenylamino)pyrazolin-4-yl](1,3-thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one with β-diketone or β-keto ester. All synthesized compound were established by elemental analysis, spectral data, and alternative synthesis whenever possible.     

Synthesis of 1,2-diaryl-2-imidazolines

Polyphosphoric acid and N-aryl-N′-benzoylethylenediamines in a type of Bischler-Napieralski reaction afforded 1,2-diaryl-2-imidazolines in good yields, rather than the 2,3-dihydro-1H-[1,4]-benzodiazepines. Blocking of the amino nitrogen by a methyl or ethyl group, to avoid imidazoline formation, gave starting material rather than the expected dihydrobenzodiazepine. When p-tosyl was the blocking group, imidazoline was again the only product isolated. Analytical and spectroscopic data of several unreported 1,2-diaryl-2-imidazolines are presented.     

1,3-Dipolare Cycloaddition aromatischer Nitril-ylide und Nitril-oxide an Dicyan und Diazocyanide

1,3 Dipolar Cycloaddition of Aromatic Nitrile Ylides and Nitrile Oxides with Cyanogen and Diazocyanides Nitril ylides 2 generated from the imidoyl chlorides 1 react with cyanogen and aryldiazocyanides to 2,5(4)-dia-ryl-1H-imidazole-4(5)-carbonitriles 3a , b or 5(4)-(arylazo)-2,4(5)-diaryl-1H-imidazoles 4a and 2,3,5-triaryl-2,3-dihydro-1H-1,2,4-triazole-1-carbonitriles 5a – f , respectively (Scheme 1). Reactions of benzonitrile oxides 7 with these dipolarophiles lead to 3,3′-diaryl-5,5′-bi[1,2,4]oxadiazoles 8a – c or 3-aryl-5-(arylazo)-1,2,4-oxadiazoles 9a – j (Scheme 2).     

Substituted pyrimidines. II. 1,3-Dimethylisocytosine and related compounds

1,3-Dimethyl-1,2-dihydro-2-imino-4(3H)pyrimidinone (1,3-dimethylisocytosine) was prepared by methylation of 2-amino-3-methyl-4(3H)pyrimidinone and was degraded in alkaline solution to a mixture of 3-methyl-2-methylamino-4(3H)pyrimidinone, 1,3-dimethyl-2,4-(1H,3H)pyrimid-indione, 2-methylamino-l-methyl-4(1H)pyrimidinone, 1-methyl-2,4-(1H,3H)pyrimidindione and 3-methyl-2,4-(1H,3H)pyrimidindione. Thiation of the title compound gave both 1,2-dihydro-1,3-dimethyl-2-thio-4(3H)pyrimidinone and 1,3-dimethyl-2,4-(1H,3H)pyrimidinedithione. The title compound is a tautomerically fixed pyrimidine and its uv spectra were compared with related compounds, notably 3-methyl-2-dimethylarnino-4(3H)pyrimidinone which is also tautomerically fixed.     

Reactions of 1,2,4-triazole derivatives with a “model” thiirane

Reactions of 3-mono- and 3,5-disubstituted 1,2,4-triazoles with a “model” thiirane, 8-bromo-1,3-dimethyl-7-(thiiran-2-ylmethyl)-3,7-dihydro-1H-purine-2,6-diones proceed at the positions N¹ and N² of the triazole ring and yield 7-(5-R-3-R′-1,2,4-triazol-1-yl)methyl- and/or 7-(5-R′-3-R-1,2,4-triazol-1-yl)methyl-1,3-dimethyl-6,7-dihydro[1,3]thiazolo[2,3-f]-purine-2,4-(1H,3H)-diones. 3-Methylsulfonyl-1,2,4-triazole reacted regiospecifically at the position N¹ forming 1,3-dimethyl-7-[(3-methyl-sulfonyl-1,2,4-triazole-1-yl)-methyl]-6,7-dihydro[1,3]thiazolo-[2,3-f]purine-2,4(1H,3H)-dione.     

Synthesis of Substituted 5,6-Dihydro-4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepines

A one-pot synthetic approach to the novel 5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepines by thermal cyclization of 4-acylhydrazino-2,3-dihydro-1H-1,5-benzodiazepines is described.     

Direct introduction of heterocyclic residues into 1,2,4-triazin-5(2H)ones

3-Aryl-1,2,4-triazin-5(2H)-ones 1a-c react with indoles 2a-c in trifluoroacetic acid/chloroform or in boiling butanol or acetic acid to give 3-aryl-6-(indolyl-3)-1,6-dihydro-1,2,4-triazin-5(2H)-ones 3a-g . Oxidation of the dihydro-1,2,4-triazin-5(2H)-ones 3a-e afforded 6-(indolyl-3)-1,2,4-triazin-5(2H)-ones 4a-e , products of nucleophilic substitution of hydrogen in 1a-c . Refluxing 1b with N-methylpyrrote 5b in butanol for an extended time resulted in the formation of 3-(4-chlorophenyl)-6-(1-meuiylpyrrolyl-2)-1,2,4-triazin-5(2H)-one 4h. The reaction of 1a-c with indoles 2a-c , pyrroles 5a,b , 1,3-dimethyl-2-phenylpyrazol-4-one (8) and aminothiazoles 9a,b in acetic anhydride affords the 1-acetyl-3-aryl-6-hetaryl-1,6-dihydro-1,2,4-triazin-5(2H)-ones 6a-s . Reaction of 1a-c with N-methyl-pyrrole 5b in acetic anhydride gives beside the 1:1 addition products 6h-k also the 2:1 addition products 7a-c .     

New aspects of the chemistry of 2,3-dihydro-1H-1,5-benzodiazepine

Under basic catalysis conditions the reaction of 4- and 4'-substituted chalcones with o-phenylenediamine leads to 2,3-dihydro-2,4-diaryl-1H-1,5-benzodiazepines; -amino adducts, the ability of which to undergo intramolecular condensation increases as the basicity of the catalyst is increased, are formed as intermediates. A different pathway for the process (the formation of an azomethine) is observed in the reaction with cinnamaldehyde. It is concluded that conformational factors play a primary role in the direction of the reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–700, May, 1980.     

Synthesis and spectral properties of 2,3-dihydro-2-[(o- and p-substituted)anilinylidene]-1H-4-(p-methylphenyl)-7-[(o- and p-methyl)phenoxy]-1,5-benzodiazepines

A series of twelve new 2,3-dihydro-2-[(o- and p-substituted)anilinylidene]-1H-4-(p-methylphenyl)-7-[(o- and p-methyl)phenoxy]-1,5-benzodiazepines, which have potentially useful pharmacological properties, has been synthesized by condensing the 3,3-dimercapto-1-(p-methylphenyl)-2-propen-1-one with 3,4-diaminophenyl-R-phenyl ethers. Subsequently the 1H-1,5-benzodiazepine-2-thiones obtained were treated with the (o- and p-substituted)aniline. The structure of all products was corroborated by ir, ¹H nmr, ¹³C nmr and ms.     

Five-membered 2,3-dioxo heterocycles: LIV. Double spiro heterocyclization of methyl 1-aryl-3-benzoyl-4,5-dioxo-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrrole-2-carboxylates with 3-arylamino-5,5-dimethylcyclohex-2-en-1-ones

Methyl 1-aryl-3-benzoyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with 3-arylamino-5,5-dimethylcyclohex-2-en-1-ones in boiling benzene to give the corresponding 1,1′-diaryl-3′-benzoyl-4′-hydroxy-6,6-dimethyl-1,1′,2,4,5,5′,6,7-octahydrospiro[indole-3,2′-pyrrole]-2,4,5′-triones and 1′-aryl-4-arylamino-3-benzoyl-6′,6′-dimethyl-1′,2′,4′,5′,6′,7′-hexahydro-5H-spiro[furan-2,3′-indole]-2′,4′,5-triones whose structure was proved by X-ray analysis.     

5,6,7,8-Tetrafluoro-4-hydroxycoumarin derivatives in reactions with o-phenylenediamine

The reactions of 5,6,7,8-tetrafluoro-4-hydroxycoumarin derivatives with o-phenylenediamine occur with pyrone heterocycle cleavage and formation of substituted benzodiazepin-2-ones. 5,6,7,8-Tetrafluoro-4-hydroxycoumarin affords 4-(3,4,5,6-tetrafluoro-2-hydroxyphenyl)-2,3-dihydro-1H-1,5-benzodiazepin-2-one, 3-acetimidoyl-5,6,7,8-tetrafluoro-4-hydroxycoumarin produces 3-(3,4,5,6-tetrafluoro-2-hydroxybenzoyl)-4-methyl-1,2-dihydro-1H-1,5-benzodiazepin-2-one, and 3-acetyl-5,6,7,8-tetrafluoro-4-hydroxycoumarin yields both these heterocycles.     

Application of N,3-diaryl-3-oxo-propanethioamide in synthesis: an efficient and mild domino approach to highly substituted fused chromenones

A convenient and rapid synthesis of hitherto unknown 3-aroyl-4-aryl-2-phenylamino-4H-benzo[g]chromene-5,10-diones in high yield from β-aroyl-thioacetanilide, aromatic aldehyde, and 2-hydroxy-1,4-naphthoquinone via InCl₃ catalyzed one-pot three-component tandem Knoevenagel condensation–Michael addition–intramolecular cyclization–elimination reaction sequence is disclosed for the first time. This domino protocol has been used to obtain highly substituted pyrano[3,2-c]chromen-5(4H)-ones and 7,7-dimethyl-7,8-dihydro-4H-chromen-5(6H)-ones from N,3-diaryl-3-oxo-propanethioamide, aromatic aldehyde, and 4-hydroxycoumarine or dimedone under mild reaction conditions. A plausible reaction mechanism is proposed. The 4H-pyrano[3,2-c]chromen-5-one and 7,7-dimethyl-7,8-dihydro-4H-chromen-5(6H)-one derivatives possessing 3-(2-chlorobenzoyl)-2-phenylamino-substituents further cyclized under basic conditions to yield penta-cyclic 7,13-diaryl-5,14-dioxa-13-aza-benzo[a]naphthacen-6,8(7H,13H)-dione and tetra-cyclic 6,12-diaryl-3,3-dimethyl-3,4-dihydro-2H-chromeno[2,3-b]quinolin-1,11(6H,12H)-dione, respectively.     

Features of the reaction of 3,4-dihydroxy-6-oxo-2,4-alkadienoic acid esters with acetone and <Emphasis Type="Italic">p</Emphasis>-toluidine

Three-component reactions of 3,4-dihydroxy-6-oxo-2,4-alkadienoic acids with acetone and p-toluidine were studied; their specific feature was the formation of the regioisomeric esters of 4-hydroxy-2,2-dimethyl-1-(4-methylphenyl)-5-(2-oxoalkyliden)-2,5-dihydro-1H-pyrrole-3-carboxylic acids and [4-alkanoyl-3-hydroxy-5,5-dimethyl-1-(4-methylphenyl)-1,5-dihydro-2H-pyrrol-2-ylidene]acetic acid. Structure of the synthesized compounds was discussed based on the data of IR and ¹H NMR spectroscopy and X-ray diffraction analysis.     

1,3,4,6-tetracarbonyl compounds. 3. synthesis, structural features, and antimicrobial activity of 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-1,6-diones

The Wittig reaction of 5-aryl-2,3-dihydro-2,3-furandiones with aroylmethylenetriphenylphosphoranes is regioselective and leads to the formation of 5-aryl-2-aroylmethylene-2,3-dihydro-3-furanones. In the presence of acid the products react with water, giving satisfactory yeilds of 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-1,6-diones. The latter were also obtained by the reaction of 2,3-furandiones with alkylnitroamines. The base-catalyzed condensation of 2,3-furandiones with acetophenones led to 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-1,6-diones, which exist in DMSO solution in equilibrium with the cyclic oxo tautomers —substituted 2-hydroxy-2,3-dihydro-3-furanones. Some of the synthesized compounds exhibit antimicrobial activity toward standard strains ofStaphylococcus aureus andEscherichia coli.For Communication 2, see [1].Perm Pharmaceutical Academy, Perm, Russia; e-mail: kvo@pi.ccl.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1466–1475, November, 1999.     

Synthesis and properties of 2,2,4-trisubstituted 2,3-dihydro-1H-1,5-benzodiazepines

General conditions for the condensation of acetylarenes with o-phenylenediamine hydrochloride, leading to the formation of 2,4-diaryl-2-methyl-2,3-dihydro-1H-1,5-benzodiazepines, have been worked out. It has been shown that this reaction is an equilibrium one, that the equilibrium is extremely sensitive to the amount of water in the reaction medium, and that the process takes place with the formation of bisazomethines as intermediates. The UV, IR, and PMR spectra and the dipole moments of the heterocyclic compounds obtained are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 126–131, January, 1984.