Reactions of arylglyoxals with tetrasulfur tetranitrides (S4N4): Formation of 2-aroyl-5-arylimidazoles and 2-aroyl-5-aryloxazoles

Treatment of arylglyoxal monohydrates with tetrasulfur tetranitride in p-dioxane at reflux afforded 2-aroyl-5-arylimidizoles and 2-aroyl-5-aryloxazoles in 10 to 31% and 17 to 32% yields, respectively. With non-hydrate of arylglyoxals, yields of the latter increase somewhat, whereas essentially no changes in yields of the former were observed. A mechanism is proposed for the formation of the products.     

Reaction of methyl 3-aroyl-1-aryl-4,5-dioxo-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrrole-2-carboxylates with arylhydrazines. synthesis of isomeric 5-arylcarbamoyl-4-aroyl- and 5-aryl-4-aryloxamoyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazoles

Methyl 3-aroyl-1-aryl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with arylhydrazines to give methyl 3-aroyl-1-aryl-2-(2-arylhydrazinyl)-4-hydroxy-5-oxo-2,5-dihydro-1H-pyrrole-2-carboxylates which underwent thermal recyclization into isomeric methyl 1-aryl-5-(arylcarbamoyl)-4-aroyl-1H-pyrazole- 3-carboxylates and methyl 1,5-diaryl-4-[2-oxo-2-(arylamino)acetyl]-1H-pyrazole-3-carboxylates.     

Synthesis of 6-aryl- and 5-aroylcomanic acids from 5-aroyl-2-carbethoxy-4-pyrones via a deformylative rearrangement and ring-opening/ring-closure sequence

The reaction of 1-aryl-2-(dimethylaminomethylene)butane-1,3-diones with diethyl oxalate in the presence of sodium hydride in THF gave ethyl 5-aroyl-4-oxo-4H-pyran-2-carboxylates, from which 4-oxo-6-aryl-4H-pyran-2-carboxylic acids (6-arylcomanic acids) were obtained in high yields via acid-catalyzed deformylative rearrangement. 5-Aroyl-4-oxo-4H-pyran-2-carboxylic acids (5-aroylcomanic acids) were prepared via а ring-opening/ring-closure sequence by the reaction of 5-aroyl-2-carbethoxy-4-pyrones with piperidine and subsequent basic hydrolysis and acidification.     

Substituted γ-Lactones. 35 . Reduction of 4-aroyl-3-hydroxy-2(5H)-furanones

The reduction of 4-aroyl-3-hydroxy-2(5H)-furanons 1a-c was investigated using different reducing agents. Sodium borohydride reacts with type 1 compounds by loss of water to yield 4-(arylmethylene)-2,3(4H,5H)-furandiones 2a-c . Platinum or charcoal supported by pallodium chloride transforms 1a to 4-benzyl-3-hydroxy-2(5H)-furanone ( 3). Compounds 2a and 2b react with o-phenylenediamine to give 3-(E-(1′-hydroxymethyl-2′-aryl)ethenyl]-2-quinoxalinones 4a and 4b . The lactone 3 under the same conditions splits out formaldehyde and forms 3-(2′-phenylethyl)-2-quinoxalinone ( 6 ). The structure assignments of the novel compounds are based on elemental analysis and nmr as well as ir spectroscopic data.     

Reactions of 1-(4-aminosulfonylphenyl)-5-aryl-4-aroyl-3-hydroxy-3-pyrrolin-2-ones with arylamines and hydrazine hydrate

Depending on the reaction condition, 1-(4-aminosulfonylphenyl)-5-aryl-4-aroyl-3-hydroxy-3-pyrrolin-2-ones reacted with aromatic amines to yield 3-arylamino-3-pyrrolin-2-ones or 4-[aryl (arylamino) methylene]tetrahydropyrrole-2,3-diones. Reactions of 1-(4-aminosulfonylphenyl)-5-aryl-4-aroyl-3-hydroxy-3-pyrrolin-2-ones with hydrazine hydrate afforded pyrrolo[3,4-c]pyrazol-6-ones.     

Synthesis of substituted 2-aroyl-3-methylchromen-4-ones from isovanillin via 2-aroyl-3-methylchroman intermediates

The synthesis of substituted 2-aroyl-3-methylchromen-4-one from isovanillin is described. O-Allylphenol (2) prepared from isovanillin (1) was allowed to react with various α-bromoacetophenone (3) to produce 2-(2-allyl-3,4-dimethoxy)phenoxy-1-aroylethanones (4). The resultant 4 were treated with 2 equiv of potassium tert-butoxide to afford the substituted 2-aroyl-3-methylchromans (5) through an isomerization of an allylic double bond and a carbanion-olefin intramolecular 6-endo-trig cyclization reaction. Subsequently, resultant 5 were oxidized with DDQ to yield the title compound 6, in good over-all yields.     

Synthesis and interconversion of 6-aroyl-4-oxohexanoie acids and 5-aryl-2-furanpropionic acids. Antiinflammatory agents

A series of 6-aroyl-4-oxohexanoic acids ( 2 ) was prepared for intermediate use by acid-catalyzed solvolysis of substituted 3-(2-furyl)acrylophenones ( 1 ). This reaction occasionally gave 5-aryl-2-furanpropionic acids ( 3 ) instead of, or in addition to, the desired diketones ( 2 ). Equilibrium between 2 and 3 was observed in the case where Ar is m-nitrophenyl. A rationalization for the formation of 3 is offered, and published reports with which our results differ are discussed. Diketones ( 2 ) were cyclized to furans ( 3 ) and antiinflammatory screening data are reported for the latter.     

Five-membered dioxoheterocycles: XCIX. Reaction of 1-aryl-4-aroyl-5-methoxycarbonyl-1H-pyrrole-2,3-diones with indoles. Crystal and molecular structure of substituted 2-(indol-3-yl)pyrrole

1-Aryl-4-aroyl-5-methoxycarbonyl-1H-pyrrole-2,3-diones react with indole and 2-methylindole with the formation of methyl 1-aryl-3-aroyl-4-hydroxy-2-(1H-indol-3-yl)-5-oxo-2,5-dihydro-1H-pyrrole-2-carboxylates. Crystal and molecular structure of methyl 3-benzoyl-4-hydroxy-2-(2-methyl-1H-indol-3-yl)-5-oxo-1-phenyl-2,5-dihydro-1H-pyrrole-2-carboxylate was examined.     

Synthesis of methyl esters of 5-aroyl-6-aryl-2-oxo-1,2,3,6-tetra-hydropyrimidine-4-carboxylic acids

Methyl esters of 5-aroyl-6-aryl-2-oxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acids were synthesized from three component mixtures of methyl esters of aroylpyruvic acids, urea, and substituted benzaldehydes. 8-Hydroxy-4,5-diphenyl-3,4-dihydropyrimido[4,5-d]pyridazin-2(1H)-one was synthesized by the reaction of 5-benzoyl-2-oxo-6-phenyl-1,2,3,6-tetrahydropyrimidin-4-carboxylate with hydrazine hydrate.     

Formation of 5-aroyl-3-(2H)isothiazolones from the reaction of 3-aroylpropionamides with thionyl chloride

Reaction of N-substituted-3-aroylpropionamides with excess thionyl chloride was found to give sulfur-nitrogen heterocyclic compounds, which were characterized as 2-substituted-5-aroyl-3-(2H)isothiazolones.     

Ring transformation of 5-aroyl-3(2H)-isothiazolones to 1,2,5-oxathiazole and 1,2,3-thiadiazole derivatives

Reaction of 2-substituted-5-aroyl-3(2H)-isothiazolones 2 with hydroxylamine and phenylhydrazine was found to give (N-substituted-carboxamido)methylene derivatives of 1,2,5-oxathiazole and 1,2,3-thiadiazole, 5 and 7 , respectively. The formation of these heterocycles was ascribed to a mononuclear heterocyclic rear-rangement of the initially formed ketone derivatives, oximes and hydrazones, through a nucleophilic attack of the = N-OH and = N-NH- groups on the S N bond of the isothiazolone ring. In a similar manner, reaction of isothiazolones 2 with hydrazine was found to give 4-aryl-5-(N-substituted-carboxamido)methyl-1,2,3-thiadiazoles 17 .     

Synthesis of 5-(aroylamino)-2-methyl-2H,-1,2,4-thiadiazol-3-ones by oxidative cyclization of 1-aroyl-5-methyl-2-thiobiurets

5-Aroylamino-2-methyl-2H-1,2,4-thiadiazol-3-ones 3 have been synthesized by oxidative cyclization of 1-aroyl-5-methyl-2-thiobiurets 2 with hydrogen peroxide in an alkaline solution. The needed 1-aroyl-5-methyl-2-thiobiurets 2 have been obtained through the addition of methylurea to the corresponding aroyl isothiocyanates.     

Facile catalyst-free pseudo five-component domino reactions in the expedient synthesis of 5-aroyl-1,3-diarylhexahydropyrimidines

The pseudo five-component domino reactions of (E)-3-(dimethylamino)-1-arylprop-2-en-1-one, formaldehyde and aniline afford 5-aroyl-1,3-diarylhexahydropyrimidines in good yields under catalyst-free conditions. This transformation involving 4 C-N and 1 C-C bond formations in a one pot operation presumably proceeds via Michael addition-elimination-Mannich type reaction-condensative annulation-reduction sequence.     

Formation of 3-phenylhydrazono-3-aroylpropionamides from the reaction of 5-aroyl-3(2H)-isothiazolones with phenylhydrazine

Reaction of 2-substituted-5-aroyl-3(2H)-isothiazolones 1 with phenylhydrazine in refluxing ethanol was found to give sulfur-free products, which were characterized as 3-phenylhydrazono-3-aroyl-N-substituted-pro-pionamides 4. Acid hydrolysis of the 3-benzoyl compounds 4 was shown to yield 1-phenyl-3-benzoyl-2-pyrazolin-5-one ( 7 ), whose structure was confirmed by an independent synthesis starting with the chloride of 1-phenyl-5-methoxypyrazole-3-carboxylic acid ( 10 ).     

Facile synthesis of fluorine-containing [4-aryl-4,5-dihydro-5-imino-1,3,4-thiadiazol-2-ylaryl]methanone, 2-amino-4-aryl-5-arylazothiazoles and 3-aroyl-4-acetyl/benzoyl-5-methyl-1-phenylpyrazoles through N-aryl-α-oxo-α-arylethanehydrazonoyl bromide

N-Aryl-α-oxo-α-arylethanehydrazonoyl bromides 2 react with potassium thiocyanate in ethanol leading to the formation of [4-aryl-4,5-dihydro-5-imino-1,3,4-thiadiazol-2-ylaryl]methanone 5 in quantitative yield. Treatment of 2 with thiourea and β-diketones affords 2-amino-4-aryl-5-arylazothiazoles 4 and 3-aroyl-4-acetyl/benzoyl-5-methyl-1-phenylpyrazoles 6 in 65–70 and 60–70% yields respectively. Compound 5 has also been subjected to acetylation and chloroacetylation. All the compounds are characterized by their analytical and spectral (ir, ¹H-nmr and ms) data. Mass fragmentation patterns of these compounds are discussed.     

Steric effect of ortho-substituents of 1-phenyl-3-methyl-4-aroyl-5-pyrazolones on the synergic extraction of lutetium with trioctylphosphine oxide

The substituent effect of ortho-substituted 4-aroyl derivatives of 1-phenyl-3-methyl-5-pyrazolones (HA) on the adduct formation reaction between their lutetium chelates and a neutral ligand, trioctylphosphine oxide (TOPO, L), in benzene was studied using a liquid-liquid extraction system. The lutetium 4-aroyl-5-pyrazolonates react with TOPO to form LuA₃L and LuA₃L₂ types of adducts. An obvious steric hindrance of the terminal group on the adduct formation reaction was observed. Linear relationships between the acid dissociation constant of the ortho-substituted 4-aroyl-5-pyrazolone derivatives and those of the corresponding benzoic acids, between the extraction constants of lutetium and the acid dissociation constants of pyrazolones and between the adduct formation constants of TOPO and the acid dissociation constants of pyrazolones could be obtained.     

Synthesis of 1-Aminocarbonylmethyl-5-aryl-4-aroyl-3-hydroxy-3-pyrroline-2-ones

Russian Journal of General Chemistry - A series of new 1-aminocarbonylmethyl-5-aryl-4-aroyl-3-hydroxy-3-pyrrolin-2-ones has been synthesized through a three-component reaction of aroylpyruvic acid...     

Synthesis,stereochemistry, and isomeric transformations of 4-aryl-5-aroyl-2-methylthio-2-imidazolines

The corresponding 4-aryl-5-aroyl-2-methylthio-2-imidazolines were obtained by the reaction of complexes of cis- and trans-3-aroylaziridines and boron trifluoride with methyl thiocyanate. It is shown on the basis of spectral data that the aziridine ring is opened regiospecifically at the C(₂) atom and stereospecifically with inversion of the configuration.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1484–1488, November, 1988.     

Synthesis,stereochemistry, and isomeric transformations of cis- and trans-1,2-dimethyl-4-aryl-5-aroyl-2-imidazolines

The corresponding trans- and cis-1,2-dimethyl-4-aryl-5-aroyl-2-imidazolines were obtained from complexes of cis- and trans-1-methyl-2-aryl-3-aroylaziridines with BF₃ by heating with acetonitrile. The reaction proceeds with inversion of the configuration of the starting 3-aroylaziridines. In the presence of bases the complexes of cis-1,2-dimethyl-4-aryl-5-aroyl-2-imidazolines readily undergo isomerization to the corresponding trans analogs. The structures of the products were established on the basis of the IR, PMR, and mass spectra and the results of elementary analysis. The configurations of the compounds were determined by means of the Overhauser nuclear effect.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 952–957, July, 1981.     

Five-membered 2.3-dioxo heterocycles: LXVIII. Three pathways in the reaction of methyl 3-aroyl-1-aryl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates with 3-amino-5,5-dimethylcyclohex-2-en-1-one

Methyl 3-aroyl-1-aryl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with 3-amino-5,5-dimethylcyclohex-2-en-1-one having no substituent on the nitrogen atom to give 3-aroyl-4-arylamino-6′,6′-dimethyl-6′,7′-dihydro-5H-spiro[furan-2,3′-indole]-2′,4′,5′(1′H,5′H)-triones or methyl 12-aroyl-11-aryl-9-hydroxy-5,5-dimethyl-3,10-dioxo-8,11-diazatricyclo[7.2.1.0^2,7]dodec-2(7)-ene-1-carboxylates. The latter underwent thermal recyclization to 3′-aroyl-1′-aryl-4′-hydroxy-6,6-dimethyl-6,7-dihydrospiro[indole-3,2′-pyrrole]-2,4,5′(1H,1′H,5H)-triones.