The chemistry of 2H-3,1-benzoxazine-2,4(1H)-dione (isatoic anhydride). 18. A short synthesis of swietenidin A

N-Methylisatoic anhydrides react with the lithium enolate of ethyl methoxyacetate at low temperatures to produce intermediates which, when cyclized, afford 4-hydroxy-3-methoxy-2(1H)-quinolinones. By this route, 3-methoxy-N-methylisatoic anhydride ( 8 ) can be converted to the alkaloid swietenidin A (2) in 71% yield.     

2H-3,1-benzoxazine-2,4-(1H)-dione (isatoic anhydride). 15. Reactions with lactone enolates

The reaction of N-methylisatoic anhydride, 1 , with the lithium enolates derived from various butyrolactones or δ-valerolactone produces stable anthranoyl lactone derivatives 4 . Heating these products in toluene results in a cyclization to afford 4-hydroxy-3-(2-hydroxyalkyl)-1-methyl-2(1H)-quinolinones, 8 and 14 , in good yields.     

Transformation of 4-(1-dimethylaminoethylidene)-2-phenyl-5(4H)-oxazolone into methyl 2-benzoylamino-3-oxobutanoate. The synthesis of 1-substituted 4-benzoylamino-3-methyl-5(2H)-pyrazolones

Methyl 2-benzoylamino-3-oxobutanoate ( 3 ) was prepared from hippuric acid (1) which was converted with N,N-dimethylacetamide and phosphorus oxychloride into 4-(1-dimethylaminoethylidene)-2-phenyl-5(4H)-oxazolone ( 2 ) followed by hydrolysis with hydrochloric acid in methanol. Compound 3 was treated with hydrazines 4 to give 4-benzoylamino-3-methyl-1H-pyrazol-5(2H)-one ( 6a ) and its 1-substituted derivatives 6b-j . The corresponding hydrazones 5f, i, j were isolated as intermediates.     

A facile and novel synthesis of 1,6-naphthyridin-2(1H)-ones

A new and convenient procedure for the synthesis of 1,6-naphthyridin-2(1H)-ones and their derivatives is described. In the first scheme 5-acetyl-6-[2-(dimethylamino)ethenyl]-1,2-dihydro-2-oxo-3-pyridinecarbonitrile ( 4 ) obtained by the reaction of N,N-dimethylformamide dimethyl acetal with 5-acetyl-1,2-dihydro-6-methyl-2-oxo-3-pyridinecarbonitrile ( 3 ) was cyclized to 1,2-dihydro-5-methyl-2-oxo-1,6-naphthyridine-3-carbonitrile ( 5 ) by the action of ammonium acetate. Thermal decarboxylation of acid 7 obtained from the hydrolysis of nitrile 5 led to a mixture of 5-methyl-1,6-naphthyridin-2(1H)-one ( 8 ) and its dimer 9 . Hydrazide 11 obtained from nitrile 5 in two steps was converted to 3-amino-5-methyl-1,6-naphthyridin-2(1H)-one ( 12 ) by the Curtius rearrangement. The amino group of 12 was readily replaced by treatment with aqueous sodium hydroxide to yield 3-hydroxy-5-methyl-1,6-naphthyridin-2(1H)-one ( 13 ). In the second scheme, Michael reaction of enamines of type 20 with methyl propiolate, followed by ring closure gave 5-acyl(aroyl)-6-methyl-2(1H)-pyridinones ( 21 ) which in turn were treated with Bredereck's reagent to produce 5-acyl(aroyl)-6-[2-(dimethylamino)ethenyl]-2(1H)-pyridinones ( 22 ). Treatment of 22 with ammonium acetate led to the formation of 1,6-naphthyridin-2(1H)-ones 23 .     

A new approach to the synthesis of substituted 2(1H)-quinolinones

A new synthetic approach for the preparation of substituted 2(1H)-quinolinones 5 from readily available anilines has been developed. The four step procedure resulted in the synthesis of a variety of substituted 2(1H)-quinolinones in good yields and under mild reaction conditions.     

The chemistry of 2H-3,1-benzoxazine-2,4(1H)-dione (isatoic anhydride). 9. Synthesis of 2-arylquinoline alkaloids

A one-step synthesis of N-methyl-2-aryl-4-quinolone alkaloids is described. These compounds are readily prepared from the reaction of an N-methylisatoic anhydride with the lithium enolate of an acetophenone. By this method, the reaction of N-methylisatoic anhydride ( 5 ) or 5-methoxy-N-methylisatoic anhydride ( 7 ) with acetophenone produces the alkaloids N-methyl-2-phenyl-4-quinolone ( 1 ) and eduline ( 2 ) in 81% and 70% yield, respectively. An analogous reaction of 5 with 3,4-methylenedioxyacetophenone gives graveoline ( 3 ) in 63% yield whereas 7 and α-methoxyacetophenone affords japonine ( 4 ) in 61% yield.     

Bildung von 5,6-Dihydro-1,3(4H)-thiazin-4-carbonsäure-estern aus 4-Allyl-1,3-thiazol-5(4H)-onen

Formation of Methyl 5,6-Dihydro-l, 3(4H)-thiazine-4-carboxyiates from 4-Allyl-l, 3-thiazol-5(4H)-ones . The reaction of N-[1-(N, N-dimethylthiocarbamoyl)-1-methyl-3-butenyl]benzamid ( 1 ) with HCl or TsOH in MeCN or toluene yields a mixture of 4-allyl-4-methyl-2-phenyl-1,3-thiazol-5(4H)-one ( 5a ) and allyl 4-methyl-2-phenyl-1,3-thiazol-2-yl sulfide ( 11 ; Scheme 3). Most probably, the corresponding 1,3-oxazol-5(4H)-thiones B are intermediates in this reaction. With HCl in MeOH, 1 is transformed into methyl 5,6-dihydro-4,6-dimethyl-2-phenyl-1,3(4H)-thiazine-4-carboxylate ( 12a ). The same product 12a is formed on treatment of the 1,3-thiazol-5(4H)-one 5a with HCl in MeOH (Scheme 4). It is shown that the latter reaction type is common for 4-allyl-substituted 1,3-thiazol-5(4H)-ones.     

Über 4-Alkylamino-bzw. 4-Arylamino-5,6-dihydro-2(1H)-pyridinthione

Heating 1-alkyl- or 1-aryldihydro-6-methyl-2(1H)-pyrimidinethiones5, 6 in an inert medium causes rearrangement to 4-alkylamino-(4-arylamino-)-5,6-dihydro-2(1H)-pyridinethiones11, 12, probably via the methylene form29, by thermal heterolysis of the N₁/C₂ bond and exchange of the alkylamino (arylamino) group 1 through the carbon atom of the methylene group 6. The aminodihydropyridinethiones11, which can be regarded as cyclic derivatives of 3-aminothiocrotonamide, react with bistrichlorophenylmalonate under diacylation, and with formaldehyde and primary amines to yield aminodialkylation products of the enamine system, tetrahydro-4-hydroxy-7,7-dimethyl-5-thioxopyrido[4,3-b]pyridine-2(1H)-ones13, 14 and hexahydro-7,7-dimethylpyrido[4,3-d]pyrimidine-5(6H)-thiones18, 19, 21 respectively. H₂O₂ converts11 to the corresponding 4-aminodihydro-2(1H)-pyridones22, which can be reconverted into11 with P₄S₁₀.11 reacts with alkyl halides to 2-alkylthiodihydropyridines23, 24, 25. The mechanism of the methylpyrimidine-pyridine rearrangement is discussed.     

Syntheses of substituted 1-methyl-2-(1,3,4-thiadiazol-2-yl)-4-nitropyrroles and 1-methyl-2-(1,3,4-oxadiazol-2-yl)-4-nitropyrroles

Starting from readily available ethyl-4-nitropyrrole-2-carboxylate ( 1 ), substituted 1-methyl-2-(1,3,4-thiadiazol-2-yl)-4-nitropyrroles and 1-methyl-2-(1,3,4-oxadiazol-2-yl)-4-nitropyrroles were prepared. The reaction of 1 with diazomethane gave ethyl 1-methyl-4-nitropyrrole-2-carboxylate ( 2 ). Reaction of compound 2 with hydrazine hydrate afforded the corresponding hydrazide 3 . The reaction of 3 with formic acid yielded 1-(1-methyl-4-nitropyrrole-2-carboxyl)-2-(formyl)hydrazine ( 7 ). Refluxing of the latter with phosphorus pentasulfide in xylene yielded compound 6 in 40% yield. Reaction of compound 7 with phosphorus pentoxide afforded compound 9 . Reaction of compound 3 with 1,1′-carboxyldiimidazole in the presence of triethylamine yielded 2-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-oxadiazoline-4(H)-5-one ( 11 ). Refluxing compound 3 with cyanogen bromide in methanol gave compound 12 . Compound 13 could be obtained through the reaction of compound 3 with carbon disulfide in basic medium. Alkylation of compound 13 afforded the correspanding alkylthio derivative 14 . Reaction of 1-methyl-4-nitropyrrole-2-carboxylic acid ( 15 ) with thiosemicarbazide and phosphorus oxychloride gave 2-amino-5-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazole ( 16 ). Sandmeyer reaction of compound 16 yielded 2-chloro-5-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazole ( 17 ). Refluxing of the latter with thiourea afforded 2-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazoline-4(H)-5-thione ( 18 ). Alkylation of compound 18 gave the corresponding alkylthio derivative 19 . Oxidation of the latter with hydrogen peroxide in acetic acid yielded 2-(1-methyl-4-nitro-2-pyrrolyl)-5-methylsulfonyl-1,3,4-thiadiazole ( 20 ).     

Heterocyclization reactions of azinoisocyanates. Synthesis of 2H-1,2,4-triazol-3(4H)-one derivatives

The reaction of 1-aminoethylidenehydrazones 9 with di-tert-butyl dicarbonate and 4 -dimethylaminopyridine led to the corresponding azinoisocyanates 10 , which underwent thermal rearrangement under the reaction conditions to give 4-(tert-butoxycarbonyl)-5-methyl-2H-1,2,4-triazol-3(4H)-ones 14 . However, amidrazone 17 gave 2-(2-tert-butoxycarbonyloxy-2-phenyl)ethyl-4-(tert-butoxycarbonyl)-5-methyl-2H-1,2,4-triazol-3(4H)-one 22 and N-aziridinyliminocarbamate 18 under the similar conditions.     

Regiospecific synthesis of 2-methyl-4-arylcarbonyl-2H-1, 2-benzothiazin-3(4H)-one 1, 1-dioxides

Acylation of 2-methyl-2H-1, 2-benzothiazin-3(4H)-one 1, 1-dioxide 3 with aryl anhydrides in the presence of dimethylaminopyridine occurs regiospecifically to afford 2-methyl-4-arylcarbonyl-2H1, 2-benzothiazin-3(4H)-one 1, 1-dioxides 2a-f .     

Chemistry of 5(2H)-isoxazolones: Novel conversion of positional isomers

Reactions of 4-arylidene-3-methyl-5(4H)-isoxazolones with nucleophiles lead to 4-substituted-benzyl-3-methyl-5(2H)-isoxazolones. Formation of 5(4H)- and 5(2H)-isoxazolone derivatives have been observed when 4-substituted-arylidene-3-rriethyl-5(4H)-isoxazolones are reacted with methyl magnesium iodide. Oxidation of 4-substituted-benzyl-3-methyl-5(2H)-isoxazolones with manganic acetate and pyridinium chlorochromate, gives 4,4′-bis[4-substituted-benzyl-3-methyl-5(4H)-isoxazolone]. Oxidation of 4-substituted-benzyl-3-methyl-5(2H)-isoxazolones with metachloroperbenzoic acid gives 4-hydroxy-4-substituted-benzyl-3-methyl-5(4H)-isoxazolones and reactions of the same substrates with N-bromosuccinimide furnish 4-bromo-4-substitutedbenzyl-3-methyl-5(4H)isoxazolones.     

Ringschlussreaktionen mit 2-(β-Styryl)benzylaminen 5-Phenyl-1H-2-benzazepine. 23. Mitteilung über siebengliedrige Heterocyclen

Cyclization reactions with 2-(β-styryl)benzylamines 5-Phenyl-1H-2-benzazepines Cyclization of the urea derivative 3 with POCl₃ to give 2-(4-methyl-1-piperazinyl)-4-phenylquinoline ( 4 ) was carried out in analogy to the quinoline synthesis of Foulds & Robinson. This reaction was used for the preparation of 2-benzazepines. The trisubstituted ureas 6 and 8 , derived from the 2-(β-styryl)-benzylamines 5 , were cyclized with POCl₃ to yield the 3-amino-5-phenyl-1H-2-benzazepines 7 and 9 , respectively. Similarly, cyclization of the corresponding acetyl-derivatives 10 gave the 3-methyl-5-phenyl-1H-2-benzazepines 12 . On the other hand, the disubstituted urea 15 , cyclized under the same conditions to the 1-methyl-1-phenylisoindoline derivative 16 , and 2-(β-styryl)benzylamine ( 5a ) on treatment with phosgene gave the isoindoline 17 in an analogous manner.     

Synthetic studies directed toward the pseurotins. Part II. Synthesis of related highly functionalized furan-3(2H)-ones

The synthesis of 2,2-bis(hydroxymethyl)-4-methyl-5-phenylfuran-3(2H)-one ( 9 ), 5-[(1S,2S,Z)-1,2-(ethylidenedioxy)hex-3-enyl]-2,2-bis(hydroxymethyl)-4-methylfuran-3(2H)-one ( 24 ), and 5-[(1S,2S,Z)-1,2-(ethylidenedioxy)hex-3-enyl]-2-(hydroxymethyl)-4-methylfuran-3(2H)-one ( 28 ), which represent more advanced, suitably functionalized intermediates for the synthesis of pseurotin A ( 1 ), a secondary metabolite of Pseudeurotium ovalis STOLK , is described.     

Zur Einwirkung von Schwefel und Aminen auf Dihydro-2(1H)-pyrimidinone bzw.-thione

Zusammenfassung Dihydro-4,4,6-trimethyl-2(1H)-pyrimidinone (1) bzw.-thione reagieren mit Schwefel und Morpholin zu Tetrahydro-2-oxobzw.-2-thiono-4,4-dimethylpyrimidin-6-thiocarbonsäuremorpholiden (3); mit Schwefel in Dimethylformamid bzw. Tetramethylharnstoff bilden sich Dihydro-3-thiono-3H-1,2-dithiolo-[4,3—d]pyrimidin-5(4H)-one (5) bzw.-3,5-dithione. Das Dihydro-6-methyl-4-phenyl-2(1H)-pyrimidinon2 bzw.-thion geben mit Schwefel und Tetramethylharnstoff das Dihydro-1-methyl-2-oxo-bzw.-2-thiono-4-phenylpyrimidin-6-trimethylcarboxamidin (7). Methylheterocyclen, wie Chinaldin, werden bei analoger Behandlung in Chinolin-2-thiocarbonsäuredimethylamid usw. übergeführt.

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Reaction of sulfur + amines with dihydro-2 (1H)pyrimidinones and-thiones

Dihydro-4,4,6-trimethyl-2(1H)-pyrimidinones (1) and-thiones react with sulfur and morpholine to tetrahydro-2-oxo- and-2-thiono-4,4-dimethylpyrimidine-6-thiocarboxylic acid morpholides (3); with sulfur inDMF or tetramethylurea (TMU) the formation of dihydro-3-thiono-3H-1,2-dithiolo[4,3—d]pyrimidin-5(4H)-ones (5) or-3,5-dithiones, resp. was observed. Dihydro-6-methyl-4-phenyl-2(1H)-pyrimidinone (2) (-thione) with sulfur andTMU yields dihydro-1-methyl-2-oxo- and-2-thiono-4-phenylpyrimidin-6-trimethyl-carboxamidine (7). Methyl substituted heterocycles e.g. quinaldine, are converted under analogous conditions to quinoline-2-thiocarboxylic acid dimethylamide and corresponding compounds. *** DIRECT SUPPORT *** A3615139 00018

     

Synthesis of 1-[3-methyl-2(3H)-benzazolon-5- or 6-yl]-4-{4-[cis-2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl-methyl)-1,3-dioxolan-4-yl]methyleneoxyphenyl}piperazines

Reactions of 3-methyl-6-[4-(4-hydroxyphenyl)-1-piperazinyl]-2(3H)-benzoxazolone, 3-methyl-6-[4-(4-hydroxy-phenyl)-1-piperazinyl]-2(3H)-benzothiazolone and 1,3-dimethyl-5-[4-(4-hydroxyphenyl)-1-piperazinyl]-2(3H)-benzimidazolone with cis-{[2-(2,4-dichlorophenyl) -2-(1H-imidazol-1-ylmethyl)]-1,3-dioxolan-4-yl}methyl meth-anesulfonate in the presence of sodium hydride furnish the title compounds.     

Synthesis and tuberculocidic activity of some 4-arylaminomethylene-3-methyl-1-(pyrimidin-2-yl)pyrazol-5(4H)-ones

4-Arylaminomethylene-3-methyl-1-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)pyrazol-5(4H)-ones were synthesized by a three-component reaction between the 6-methyl-2-(3-methyl-5-oxo-2,5-dihydropyrazol-1-yl)pyrimidin-4(1H)-one, triethoxymethane, and an aromatic amine. These compounds were found to exist as aminomethyleneketones regardless of the electronic effects of substituents in the aromatic fragments. The resulting compounds showed pronounced tuberculocidic activity.     

Synthesis of 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones and their conversion into 2-aryl-1,2,4-triazine-3,5-(2H,4H)odiones. A new synthesis of 1-aryl-6-azauracils

Treatment of 6-amino-5-arylazo-1,3-dimethyluracils with urea or N,N′-carbonyldiimidazole gave the respective 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones, which were hydrolyzed with alkali to afford 2-aryl-2,3,4,5-tetrahydro-3,5-dioxo-1,2,4-triazine-6-carboxylic acids (1-aryl-6-azauracil-5-carboxylic acids). Thermal decomposition of these carboxylic acids gave the corresponding 2-aryl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-6-azauracils). Methylation of the latter with methyl iodide gave the corresponding 2-aryl-4-methyl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-3-methyl-6-azauracils).     

A convenient preparation of 3-methyl-3,4-dihydro-2(1H)-quinazolinone

3-Methyl-3,4-dihydro-2(1H)-quinazolinone ( 5 ) can be prepared in good yield and quality from o-nitrobenzyl chloride ( 1 ). The three-step sequence requires no purification of intermediates or final product.     

Nitroimidazoles. V . Synthesis of 1-methyl-2-(2-methyl-4-thiazolyl)nitroimidazoles

Reaction of readily available 2-methyl-4-formylthiazole ( 1 ) with glyoxal and ammonia gave 2-(2-methyl-4-thiazolyl)imidazole ( 2 ). Nitration of 2 with a mixture of nitric acid-sulfuric acid at 100° yielded 2-(2-methyl-4-thiazolyl)-4,5-dinitroimidazole ( 3 ) as the sole reaction product, while nitration at 65° afforded 2-(2-methyl-4-thiazolyl)-4-(or 5)-nitroimidazole ( 4 ). N-Methylation of compound 4 in the presence of base gave 1-methyl-2-(2-methyl-4-thiazolyl)4-nitroimidazole ( 6 ), whereas N-methylation with diazomethane afforded 1-methyl-2-(2-methyl-4-thiazolyl)-5-nitroimidazole ( 5 ). N-Methylation of compound 3 yielded 1-methyl-2-(2-methyl-4-thiazolyl)-3,5-dinitroimidazole ( 7 ) in high yield.