Oxidation of 3-hydroxykynurenine. A reexamination

The oxidation mixture of 3-hydroxykynurenine ( 1 ), treated with aqueous acetic anhydride and, subsequently, with acidic methanol, yields the 1-hydroxy-3-carbomethoxy-5-methoxy-11-(β-aspartoyl-N-acetyl-methyl ester)pyrido[3,2-a]phenoxazine ( 5 ), the 1-hydroxy-11-(β-aspartoyl-N-acetyl-methyl ester)-5.H-pyrido[3,2-a]-phenoxazin-5-one ( 6 ), the 1-methoxy-11-(β-aspartoyl-N-acetyl-methyl ester)-5H-pyrido[3,2-a]phenoxazin-5-one ( 6a ), the l,5-dimethoxy-11-(β-aspartoyl-N-acetyl-methyl ester)pyrido[3,2-a]phenoxazine ( 7 ) and the 1-methyl-1(1′-[11-(β-aspartoyl-methyl esterimino)]ethenyl)ketal-1H,5H-pyrido[3,2-a]phenoxazin-5-one ( 8 ). A probable scheme, for the compound formation, is reported.     

The photochemical reactions of 5H-benzo[a]phenoxazin-5-one with alkylthiols and thiophenol

6-Alkylthio- and 6-phenylthio-5H-benzo[a]phenoxazin-5-ones have been synthesized by the photochemical reaction of 5H-benzo[a]phenoxazin-5-one with alkylthiols and thiophenol.     

Photochemistry of ommochromes and related compounds

The photochemistry of some synthetic ommochromes, the 1-methoxy-11-(β-aspartoyl-acetyl-methyl ester)-5H-pyrido[3,2-a]phenoxazin-5-one ( 2 ), the 1-methyl-1-(1′-[1′[11-(β-aspartoyl-methyl ester-imino)]ethenyl)-ketal-1 H,5H-pyrido[3,2-a]phenoxazin-5-one ( 3 ) and the 1,5-dimethoxy-11-(β-aspartoyl-N-acetyl-methyl ester)-pyrido[3,2-a]phenoxazine ( 4 ), obtained from the oxidation of the 3-hydroxykynurenine ( 1 ), has been examined. In an acidic methanol solution of 2 , a reversible solvent photoaddition was observed, associated with a yellow-red bathochromic shift. The mixture, stored in the dark, quantitatively records the starting absorption spectrum. In an acidic enviroment, 3 and 4 , affording 2 , show the same photochemical behaviour. A plausible mechanism, for explanation of the process is suggested.     

Studies on reactive intermediates. Part I. An approach to the synthesis of 2-phenyl-7-carbethoxy-5H-1,3,4-thiadiazolo[2,3-a]pyrimidin-5-one

2-Phenyltetrazolo[4,5-a]-1,3,4-thiadiazole ( 4 ), in its azido form, reacted with diethyl fumarate and diethyl maleate to give 2-phenyl-7-carbethoxy-5H-1,3,4-thiadiazolo[2,3-a]pyrimidin-5-one ( 5 ). To assign the structure of compound 5 , 2-phenyl-5-carbethoxy-7H-1,3,4-thiadiazolo[2,3-a]pyrimidin-7-one ( 6 ) was prepared from the reaction of 2-amino-5-phenyl-1,3,4-thiadiazole ( 7 ) with diethylacetylene dicarboxylate. Physical properties and spectral data of compound 6 were different from compound 5 . Theoretical and experimental aspects are discussed.     

Synthesis of 11-aza-5H-benzophenoxazin-5-one and 11-Aza-5H-pyridophenoxazin-5-one derivatives

The 1,6-disubstituted- and 4,6-disubstituted-11-aza-5H-benzo[a]phenoxazin-5-one as well as 6-substituted-11-aza-5H-pyrido[a]phenoxazin-5-one derivatives were prepared by the condensation of 2-amino-3-hydroxypyridine with 5-substituted-2,3-dihalogeno-1,4-naphthoquinones and 6,7-dibromo-5,8-quinolinequinone respectively. The resulting compounds were subjected to reduction, acetylation, dehalogenation and reaction with aniline.     

New polyheterocyclic series based on 4,5,6,7-tetrahydrothieno[2,3-c]pyridine

4,8-Dimethyl-6,7,8,9-tetrahydropyrido[4′,3′:4,5]thieno[2,3-e][1,2,4]triazolo[3,4-a]-4H-pyrimidin-5-ones, 7-methyl-2,3,6,7,8,9-hexahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrrolo[1,2-a]-1H, 10H-pyrimidin-10-one, 8-methyl-1,2,3,4,7,8,9,10-octahydropyrido[4′,3′:4,5]thieno[2,3-d]-11H-pyrimidin-11-one, and 9-methyl-2,3,4,5,8,9,10,11-octahydro[4′,3′:4,5]thieno[2,3-d]azepino-[1,2-a]-1H, 12H-pyrimidin-12-one which consist four new heterocyclic ring systems were synthesized from 2-amino-3-carbethoxy-5-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine.     

New long alkyl side-chain benzo[a]phenoxazines as micellisation probes

Several novel fluorescent benzo[a]phenoxazinium chlorides possessing a long aliphatic chain substituent at the 5-amino function of the heterocycle were efficiently synthesised. All compounds obtained absorbed and emitted at longer wavelengths with moderate to good fluorescent quantum yields. The photophysics of N-[10-methyl-5-(octylamino)-9H-benzo[a]phenoxazin-9-ylidene]ethanaminium chloride and N-[10-methyl-5-(dodecylamino)-9H-benzo[a]phenoxazin-9-ylidene]ethanaminium chloride was studied in Triton^® X-100 and in cetyltrimethylammonium bromide micellar media, demonstrating the capability of these fluorophores in detecting the micellisation process.     

Simple synthesis of 6-alkyl-5H-benzo[a]phenoxazin-5-ones

6-Alkyl-5H-benzo[a]phenoxazin-5-ones were prepared by the reaction of 5H-benzo[a]phenoxazin-5-one with carboxylic acid in the presence of silver ion and peroxydisulfate.

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Eine einfache Synthese von 6-Alkyl-5H-benzo[a]phenoxazin-5-onen (Kurze Mitteilung)

Zusammenfassung 6-Alkyl-5H-benzo[a]phenoxazin-5-one wurden mittels Reaktion von 5H-Benzo[a]phenoxazin-5-onen mit Carbonsäuren in Gegenwart von Silberionen und Peroxydisulfat dargestellt.

     

Synthesis of some 5H-benzo[a]phenoxazin-5-one derivatives

The substituted 6-bromo and 6-chloro-5H-benzo[a]phenoxazin-5-ones, prepared by condensation of substituted 2-aminophenols with 2,3-dibromo or 2,3-dichloro-1,4-naphthoquinone in methanolic potassium hydroxide solution, have been dehalogenated to substituted 5H-benzo[a]phenoxazin-5-ones in the presence of sodium hydrosulfite dissolved in aqueous pyridine under nitrogen atmosphere.     

Synthesis of 5H-pyrido[2,3-a]phenoxazin-5-one and 5H-pyrido[3,2-a]phenoxazin-5-one derivatives

The 5H-pyrido[2,3-a]phenoxazin-5-one derivatives and 5H-pyrido[3,2-a]phenoxazin-5-one derivatives were prepared by the condensation of substituted 2-aminophenols with 6,7-dibromo-5,8-quinolinequinone followed by dehalogenation in the presence of sodium hydrosulfite dissolved in aqueous pyridine under a nitrogen atmosphere.     

Synthesis of benzophenothiazinone derivatives from 2,3,5-trisubstituted-1,4-naphthoquinones with 2-aminothiophenol

The 1-substituted-5H-benzo[2,3-a]phenothiazin-5-one, 4-substituted-5H-benzo[6,5-a]phenothiazin-5-one and 6-substitutedbenzo[a][1,4] benzothiazino[3,2-c]phenothiazine derivatives were prepared by the condensation of 5-substituted-2,3-dichloro-1,4-naphthoquinones with 2-aminothiophenol. Reduction, acetylation and dehalogenation of the resulting compounds were carried out and the structures of the products were inferred from comparison with the authentic compound.     

A facile one-pot synthesis of 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones

Abstract  

The reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one or its 2-methylthio derivative with hydrazonoyl halides, in the presence of triethylamine, yielded 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The structure of the latter compounds was further confirmed by reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one with the appropriate active chloromethylenes followed by coupling of the products with benzenediazonium chloride to afford the non-isolable azo-coupling products which converted, in situ, to 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The reaction mechanism was proposed and the products were screened for their biological activity. Some of the newly synthesized compounds had a moderate effect against some bacterial and fungal species.     

Photocyclization of 2-[1]benzothien-3-yl)-3-phenylpropenoic acids

Photocyclization of the substituted 2-([1]benzothien-3-yl)-3-phenylpropenoic acids 3a-c in the presence of iodine and air in a benzene-cyclohexane mixture afforded a separable mixture of three compounds, benzo[b]naphtho[2,1-d]thiophene-6-carboxylic acids 4a-c , 6H-benzo[b]naphtho[2,3-d]thiopyran-6-ones 5a-c , and 10-methoxy-2-methyl-6H-benzo[b]naphtho[2,3-d]pyran-6-one ( 6 ).     

The photochemical synthesis of 6-acyl-5H-benzo[a]phenoxazin-5-ones

6-Acyl-5H-benzo[a]phenoxazin-5-ones were prepared by the photochemical reaction of 5H-benzo[a]phenoxazin-5-one with aldehydes.

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Die photochemische Synthese von 6-Acyl-5H-benzo[a]phenoxazin-5-one (Kurze Mitteilung)

Zusammenfassung Die Titelverbindungen wurden mittels photochemischer Reaktion von 5H-Benzo[a]phenoxazin-5-onen mit Aldehyden hergestellt.

     

Photochemical reactions of 6-alkylamino- and 6-alkylanilino-5H-benzo[a]phenothiazin-5-ones

Photochemical reactions of 6-alkylamino- and 6-alkylanilino-5H-benzo[a]phenothiazin-5-ones have been investigated. 6-Ethylamino- and 6-isopropylamino-5H-benzo[a]phenothiazin-5-ones and 6-methylanilino- and 6-ethylanilino-5H-benzo[a]phenothiazin-5-ones gave 6-amino-5H-benzo[a]phenothiazin-5-one and 6-anilino-5H-benzo[a]phenothiazin-5-one, respectively, on irradiation.     

Studies on the synthesis of heterocyclic compounds. Part IV. Further investigation of the pschorr reaction with some pyrazole derivatives

Thermal decomposition of the diazonium sulfate derived from N-methyl-(1-phenyl-3-methylpyrazol-5-yl)-2-aminobenzamide afforded products formulated as 1-phenyl-3-methyl[2]benzopyrano[4,3-c]pyrazol-5-one (yield 10%), 1,4-dimethyl-3-phenylpyrazolo[3,4-c]isoquinolin-5-one (yield 10%), N-methyl-(1-phenyl-3-methylpyrazol-5-yl)-2-hydroxybenzamide (yield 8%) and 4′-hydroxy-2,3′-dimethyl-1′-phenylspiro[isoindoline-1,5′-[2]-pyrazolin]-3-one (yield 20%). Decomposition of the diazonium sulfate derived from N-methyl-(1,3-diphenylpyrazol-5-yl)-2-aminobenzamide gave products formulated as 7,9-dimethyldibenzo[e,g]pyrazolo[1,5-a][1,3]-diazocin-10-(9H)one (yield 8%), 4-methyl-1,3-diphenylpyrazolo[3,4-c]isoquinolin-5-one (yield 7%) and 4′-hydroxy-2-methyl-1′,3′-diphenylspiro[isoindoline-1,5′-[2]pyrazolin]3-one (yield 10%). The spiro compounds 6a,b underwent thermal and acid-catalysed conversion into the hitherto unknown 2-benzopyrano[4,3-c]pyrazole ring system 7a,b in good yield. Analytical and spectral data are presented which supported the structures proposed.     

Reaction of dichloroketene and sulfene with N,N-disubstituted 6-amino-methylene-b,7,8,9 -tetrahydro-5H-benzocyclohepten-5-ones. Synthesis of 6-(2,2-Dichloroethylidene)-b,7,8,9-tetrahydro-5H-benzocyclohepten-5-one and of 5H-benzo[3,4]cyclohepta[2,l-b]pyran and 5H-Benzo[3,4]cyclo-hepta[1,2-e]-1,2-oxathiin derivatives

The 1,4-cycloaddition of dichloroketene to N,N-disubstituted 6-aminomethylene-b,7,8,9-tetra-hydro-5H-benzocyclohepten-5-ones afforded N,N-disubstituted 4-amino-3,3-dichloro-3,4,6,7-tetrahydro-5H-benzo[3,4]cyclohepta[2,l-b]pyran-2-ones only in the case of aromatic or strong hindering aliphatic N-substitution. The adducts gave N,N-disubstituted 4-amino-3-chloro-b,7-dihydro-5H-benzo[3,4]cyclohepta[2,l-b]pyran-2-ones by dehydrochlorination with collidine. Upon chromatography on neutral alumina, two products were instead isolated in the case of usual aliphatic N-substitution (diethylamine, piperidine), namely 6-(2,2-dichloroethylidene)-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-one and the dehydrochlorinated 2-pyrone; this latter was the sole product in the case of pyrrolidine substitution. The 1,4-cycloaddition of sulfene occurred readily to give N,N-disubstituted 4-amino-3,4,6,7-tetrahydro-5H-benzo[3,4]cyclohepta-[1,2-e]-1,2-oxathiin 2,2-dioxidesin the case of both aliphatic and partially aromatic N-substitution.     

Methyl and Phenylmethyl 2-Acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate in the Synthesis of heterocyclic systems: Preparation of 3-amino-4H-pyrido-[1,2-a]pyrimidin-4-ones

Methyl 2-acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate ( 4 ) and phenyl-methyl 2-acetyl-3-{[2-(dimethylamino)-1(methoxycarbonyl)ethenyl]amino}prop-2-enoate ( 5 ) were prepared in three steps from the corresponding acetoacetic esters, and used as reagents for the preparation of N³-protected 3-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 10 – 12 , 5H-thiazolo[3,2-a]pyrimidin-5-one 13 , 4H-pyrido[1,2-a]-pyridin-4-one 19 and 2H-1-benzopyran-2-ones 20 – 23 . Free 3-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 24 – 26 were prepared from 10 – 12 by removal of the 2-(methoxycarbonyl)-3-oxobut-1-enyl or 3-oxo-2-[(phenyl-methoxy)carbonyl]but-1-envl as N-protecting group by various methods.     

Furopyridines. XVIII. Photocycloaddition of furo[2,3-c]pyridin-7(6H)-one with acrylonitrile

The photocycloaddition of furo[2,3-c]pyridin-7(6H)-one ( 1 ) and its N-mefhyl derivative ( 1-Me ) to acrylonitrile has been studied. The structures of the photoadducts isolated by colum chromatography were determined by the nuclear magnetic resonance spectroscopy and single crystal X-ray analysis. The cyclo-addition of 1 afforded an adduct 2 at the carbonyl oxygen and 8-cyano-8,9-dihydrofuro[d]azocin-7(6H)-one ( 3 ), and the addition of 1-Me the N-methyl derivative 3-Me of 3 , (9S*)-9-cyano-6-methyl-3a,7a-dihydro-3a,7a-ethanofuro[2,3-c]pyridin-7(6H)-one ( 4 ), (2S*, 2aR*, 7bR*)- ( 5 ) and (1R*, 2aS*, 7bS*)-2-cyano-3-methyl-4-oxo-1,2,2a,3,4,7b-hexahydrocyclobuta[e]furo[2,3-c]pyridine ( 6 ).     

Selenium heterocycles. XV. Reaction of 2-aminoselenazoles and 2-amino-1,3,4-selenadiazoles with acetylenic compounds

2-Aminoselenazoles with ethyl propiolate or dimethyl acetylenedicarboxylate gave 7H-selenazolo[3,2-a]pyrimidin-7-ones. 2-Amino-1,3,4-selenadiazoles with dimethyl acetylenedicarboxylate gave 7H-1,3,4-selenadiazolo[3,2-a]pyrimidin-7-ones; with ethyl propiolate the reaction took an unusual path and 2-carbethoxy-5H-selenazolo[3,2-a]pyrimidin-5-one was isolated. The assignment of the structures were supported by spectra analysis.