Reactions of 2-acyl-1,3-indandiones with monosubstituted hydrazines and hydrazides

Methyl- and phenylhydrazines react with 2-(diphenylacetyl)-1,3-indandione ( 1 ) to yield respectively the 1-(methylhydrazone) and the 1-(phenylhydrazone) of 2-(diphenylacetyl)-1,3-indandione ( 2a and 2b ). In comparison, acetic and benzoic acid hydrazides react with 1 to give respectively the α-(acetylhydrazone) and the α-(benzoylhydrazone) of 2-(diphenylacetyl)-1,3-indandione ( 3a and 3b ). Cyclization of 2a and 2b gives 2,3-disubstituted indeno[1,2-c]pyrazol-4(2H)-ones ( 7a and 7b ). Cyclization of 3a and 3b , followed by methylation, gives 1-methyl- and 2-methyl-3-(diphenylmethyl)indeno[1,2-c]pyrazol-4(1 and 2H)-ones ( 9a and 9b ). 2-Isovaleryl-1,3-indandione reacts with phenylhydrazine to give directly 3-isobutyl-1-phenylindeno[1,2-c]-pyrazol-4(1H)-one ( 10 ).     

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.     

Synthesis of quinazolino-1,3-benzothiazine derivatives

The ring-closure reactions of N-(3,4-dimethoxyphenylthiomethyl)-2-nitrobenzamide derivatives 5a,b with phosphoryl chloride gave 4-(2-nitrophenyl)-2H1,3-benzothiazine derivatives 7a,b , which on reduction yielded 4-(2′-aminophenyl)-3,4-dihydro-2H-1,3-benzothiazines 8a,b. Reaction of these compounds with phosgene led to a new heterocyclic ring system, 6H,8H-quinazolino[3,4-c][1,3]benzothiazine derivatives 9a,b. The structures of the title compounds were proved via their ir and nmr (¹H, ¹³C) spectra.     

Synthesis of 3H-thieno[3,2-c]-1,2-dithiole-3-thione and its reaction with n-butylamine

A convenient synthesis of 3H-thieno[3,2-c]-1,2-dithiole-3-thione (7) is proposed. The reaction of 7 with n-butylamine afforded the N-butylthieno[3,2-c]isothiazole-3(2H)-thione (7a) in dynamically equilibrium [1] with its 3H-thieno[3,2-c]-1,2-dithiole-N-butyl-3-imino isomer 7b. Characterizations and antimicrobial activities of the synthesized products are reported.     

Synthesis and selected properties of N-substituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]pyrazinones

The reactions of methyl α-(2-formyl-1H-pyrrol-1-yl)carboxylates with N-substituted aliphatic 1,2-, 1,3-, and 1,4-diamines afford new pyrrole-containing heterocyclic systems: 1,2,3,10b-tetrahydroimidazo[1,2-a]pyrrolo[2,1-c]pyrazin-5(6H)-ones, 1,3,4,11b-tetrahydro-2H-pyrrolo[2′,1′:3,4]pyrazino[1,2-a]pyrimidin-6(7H)-ones, and 1,2,3,4,5,12b-hexahydro-pyrrolo[2′,1′:3,4]pyrazino[1,2-a][1,3]diazepin-7(8H)-ones. The reduction of these compounds with different reagents was studied.     

[1,3]Dioxolo[5,6][1]benzothieno[2,3-c]-quinolin-6(5H)-ones

Summary The reaction of 3,4-methylenedioxycinnamic acid (1) with thionyl chloride resulted in the formation of 7-chlorothieno[2,3-f]-1,3-benzodioxole-6-carbonyl chloride (2) and cinnamoyl chloride (3). Subsequent reaction of the former withp-substituted anilines led to the formation of 7-chloro-N-(p-substituted phenyl)-thieno[2,3-f]-1,3-benzodioxole-6-carboxamides (4a–c) which on photocyclization afforded 2-substituted [1,3]dioxolo[5,6][1]benzothieno[2,3-c]quinolin-6(5H)-ones (5a–c) in fairly good yields and high purity. The structures have been confirmed by IR,¹H NMR, and analytical methods.Accepted for presentation at the Hong Kong International Symposium on Heterocyclic Chemistry (August 13–16, 1995)     

Synthesis and structure elucidation of the condensation products between thiophene dicarbaldehydes and aromatic amines. Potential analgesic and anti-inflammatory agents

Thiophene-3,4-dicarbaldehyde 1 reacts in the presence of 2-mercaptoethanol to yield N-aryl-5,6-dihydro-4-oxo-4H-thieno[3,4-c]pyrroles 2 and N-aryl-4-arylimino-5,6-dihydro-4H-thieno[3,4-c]pyrroles 3 , while thiophene 2,3-dicarbaldehyde 4 reacts with aromatic amines to give N-aryl-5,6-dihydro-6-oxo-4H-thieno[2,3-c]pyrroles 5 in good yields. Labeling experiments and nmr spectral analysis give evidences for the possible reaction mechanism.     

Synthesis of 1H,3H-imidazo[1,5-c]thiazole-5,7-[6H,7aH]-dione and 7,8-dihydro-5-H-imidazo[1,5-c][1,3]thiazine-1,3-[2H,8aH]-dione and derivatives

1H,3H-Imidazo[1,5-c]thiazole-5,7-[6H,7aH]-dione and the corresponding 7-thione derivatives as well as 7,8-dihydro-5H-imidazo[1,5-c][1,3]thiazine-1,3-[2H,8aH]-dione and the corresponding 3-thione derivatives were synthesized starting from L -cysteine and DL -homocysteine thiolactone, respectively. The second group of bicyclic compounds represents a new heterocyclic ring system. The structures of the compounds were confirmed by spectroscopic studies and elemental analyses.     

The reactions of some pyraiiylideneiminium salts with amines. II

The iminium salt, N,N-dimethyl-N-[2-(2-phenyl-4H-l-benzopyran-4-ylidene)ethylidene] imin-ium perchlorate ( 3 ), reacts with secondary amines by exchanging the dimethylimino group for the added amine. Primary amines also reacted with 3 in the same manner. The bis iminium salts, N,N,N',N'-tetramethyl-N,N'-[2-(2-phenyl-4H-l-benzopyran-4-ylidene)-1,3-propanediylidene]-bis(immium perclilorate) ( 4 ) and the corresponding thiapyran derivative ( 5 ), react with ammonia to give 5-dimethylamino-2-phenyl-5H-1-benzopyrano[3,4-c]pyridine ( 10 ) and the thia analog 11 . The reactions of 4 and 5 with primary amines give 3-alkyl-5-dimethylamino-2-phenyl-5H-l-beiizopyrano[3,4-c]pyridinium perclilorate salts or the corresponding thiapyrano compounds. Compounds 4 and 5 react with secondary amines by exchanging the dimethylimino groups with the secondary amine and addition of the amine at the 2-position of the pyran or thiapyran ring.     

Die Struktur des Adduktes aus 3-Dimethylamino-2,2-dimethyl-2H-azirin und 3-Methyl-2,4-diphenyl-1,3-oxazolium-5-olat. Vorläufige Mitteilung

Structure of the adduct from 3-dimethylamino-2,2-dimethyl-2H-azirine and 3-methyl-2,4-diphenyl-1,3-oxazolium-5-olate 3-Dimethylamino-2,2-dimethyl-2H-azirine ( 1 ) reacts with 3-methyl-2,4-diphenyl-1,3-oxazolium-5-olate ( 5a ) to give a 1:1 adduct ( 7 ) in a 88% yield. Its crystal structure has been determined by X-ray analysis (direct methods) and refined with 1056 structure amplitudes to R = 0,032. The crystal system is monoclinic, space group P2₁/c, with unit cell dimensions a = 10.663, b = 9,828, c = 18,592 Å, and β = 90,63°. It is obvious that 4-dimethylamino-5,5-dimethyl-2-[α-(N-methyl-benzamido)benzyliden]-Δ³-1,3-oxazoline ( 7 ) arises from an addition of 1 to the valence-polaromeric ketene form 5b of the mesoionic oxazolone 5a (Scheme 3).     

Pyrimidines. 20. Novel reactions of 5-cyano-1,3-dimethyluracil. A simple synthesis of pyrido[2,3-d]pyrimidines

A reaction of 5-cyano-1,3-dimethyluracil (1, R = CN) with acetone in base afforded 1,3,7-trimethylpyrido-[2,3-d]pyrimidine-2,4(1H,3H)dione ( 9a ) in a moderate yield. From a reaction mixture of 1 (R = CN) with butanone, 1,3,6,7-tetramethyl- and 7-ethyl-1,3-dimethylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione ( 9b and 9c , respectively) were isolated in low yields. When ethyl cyanoacetate or malononitrile was used in place of the ketone in the above reaction, 7-amino-6-ethoxycarbonyl- and 7-amino-6-cyano-1,3-dimethylpyrido[2,3-d]-pyrimidine-2,4(1H,3H)-dione ( 14a and 14b , respectively) were obtained in quantitative yields. A plausible mechanism for the formation of bicyclic compounds is discussed.     

Synthesis of polycyclic pyridazinediones as chemiluminescent compounds

Reactions of 1,3-disubstituted 5-aminopyrazole-4-carbonitrile derivatives 3a-o with dimethyl acetylenedicarboxylate in the presence of potassium carbonate in dimethyl sulfoxide gave the corresponding dimethyl 1,3-disubstituted pyrazolo[3,4-b]pyridine-5,6-dicarboxylates 4a-o which were allowed to react with excess hydrazine hydrate under ethanol refluxing conditions followed by heating at 250-300° to give 1,3-disubstituted 4-amino-1H-pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyridazine-5,8(6H,7H)-diones 7a-s in good yields. Similarly, 1,3-disubstituted 4-hydroxy-1H-pyrazolo[4′3′:5,6]pyrido[2,3-d]pyridazine-5,8(6H,7H)-diones 10a-c were obtained from alkyl 1,3-disubstituted 5-aminopyrazole-4-carboxylates 8a-c . These tricyclic pyridazine derivatives were alternatively synthesized from 4-hydroxypyrrolo[3,4-e]pyrazolo[3,4-b]pyridine-5,7-diones 13a-c prepared by reactions of 5-aminopyrazoles (8e-g) with methyl 1-methyl-4-methylthio-2,5-dioxo-1H-pyrrole-3-carboxylate (11a) followed by the Gould/Jacobs reaction. 1-Methyl-4-methylthio-2,5-dioxo-1H-pyrrole-3-carbonitrile smoothly reacted with 2-aminobenzimidazoles to give the corresponding 5-amino-3-methyl-1H-pyrrolo[3′4′:4,5]pyrimido[1,2-a]benzimidazole-1,3(2H)-diones 16a-e , which were readily converted to the desired 12-aminopyridazino[4′,5′:4,5]pyrimido-[1,2-a]benzimidazole-1,4(2H,3H)-diones 17a-e in good yields. Other pyridazinopyrimidine derivatives were also obtained by the reaction of the corresponding 2-aminoheterocycles with the maleimide in good yields. Substituted anilines reacted 11b in refluxing methanol to give the corresponding methyl 4-phenylamino-1-methyl-2,5-dioxo-1H-pyrrole-3-carboxylates 25a-e which were converted in good yields to 2-methylpyrrolo[3,4-b]quinoline derivatives 26a-e by heating in diphenyl ether. Reaction of 26a-c with hydrazine hydrate gave 10-hydroxypyridazino[4,5-b]quinoline-1,4(2H,3H)-diones 27a-e in good yields. The desired 10-aminopyridazino[4,5-b]pyridazine-1,4(2H,3H)-diones 30a-e were obtained in good yields by the chlorination of 4a-e with phosphorus oxychloride followed by aminolysis with 28% ammonium hydroxide. Some pyridazino[4,5-a][2.2.3]cyclazine-1,4(2H,3H)-diones 37a,b as luminescent compounds were synthesized via several steps from indolizine derivatives. The key intermediates, dimethyl 6-dimethylamino[2.2.3]cyclazine-1,2-dicarboxylates 34, 36 , were synthesized by the [8 + 2] cycloaddition reaction of the corresponding 7-dimethylaminoindolizines 33, 35 with dimethyl acetylenedicarboxylate in the presence of Pd-C in refluxing toluene. Some were found to be more efficient than luminol in light production. 4-Amino-3-methylsufonyl-1-phenyl-1H-pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyridazine-5,8(6H,7H)-dione (7r) , 10-hydroxypyridazino[4,5-b]-quinoline-1,4(2H,3H)-diones 27a-e , and 10-aminopyridazino[4,5-b]quinoline-1,4(2H,3H)-diones 30a-e showed the greatest chemiluminescence intensity in the presence of hydrogen peroxide peroxidase in a solution of phosphate buffer at pH 8.0.     

Synthesen von Heterocyclen, 101. Mitt.: Zur Chemie des 6-Chlor-4-hydroxy-2-oxopyran-3-carbonsäurechlorids

Zusammenfassung 6-Chlor-4-hydroxy-2-oxopyran-3-carbonsäurechlorid (1) reagiert mit N,N'-Di-p-tolyl-carbodiimid zum 7-Chlor-4,5-dioxo-3-p-tolyl-2-p-tolylimino-3,4-dihydro-2H,5H-pyrano[3,4-e][1,3]oxazin (3). Benzoxazol gibt mit1 in analoger Reaktion über6 die Verbindung7.

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6-Chloro-4-hydroxy-2-oxo-pyran-3-carboxylic acid chloride (1) reacts with N,N'-di-p-tolyl-carbodiimide yielding 7-chloro-4,5-dioxo-3-p-tolyl-2-p-tolylimino-3,4-dihydro-2H,5H-pyrano-[3,4-e] [1,3]oxazin (3). In an analogous reaction1 interacts with benzoxazol via6 to yield compound7.

     

Reaction of cyclic imidates with α,β‐unsaturated esters: Synthesis of new pyrrolo[2,1‐b]‐1,3‐oxazine and pyrido[2,1‐b]‐1,3‐oxazine derivatives

The cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a , 1b , 1c , 1d , 1e , 1f , with dimethyl acetylenedicarboxylate 2 , trimethyl ethylenetricarboxylate 4 , or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a , 3b , 3c , 3d , 3e , 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b , 5c , 5d , 5e , 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a , 7b , 7c , 7d , 7e , 7f (32–59%), respectively. In these reactions, 1a , 1b , 1c , 1d , 1e , 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2 , 4, and 6 to give annulation products 3 , 5 , and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011).     

Synthesis of 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide

The reaction of methyl 2-bromo-6-(trifluoromethyl)-3-pyridinecarboxylate ( 1 ) with methanesulfonamide gave methyl 2-[(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridine-carboxylate ( 2 ). Alkylation of compound 2 with methyl iodide followed by cyclization of the resulting methyl 2-[methyl(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridinecarboxylate ( 3 ) yielded 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 4 ). The reaction of compound 4 with α,2,4-trichlorotoluene, methyl bromopropionate, methyl iodide, 3-trifluoromethylphenyl isocyanate, phenyl isocyanate and 2,4-dichloro-5-(2-propynyloxy)phenyl isothiocyanate gave, respectively, 4-[(2,4-dichlorophenyl)methoxy]-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazine 2,2-dioxide ( 5 ), methyl 2-[[1-methyl-2,2-dioxido-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4-yl]oxy]propanoate ( 6 ), 1,3,3-trimethyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 7 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-[3-(trifluoromethyl)phenyl]-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 8 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-phenyl-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 9 ) and N-[2,4-dichloro-5-(2-propynyloxy)phenyl]-4-hydroxy-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2] thiazine-3-carboxamide 2,2-dioxide ( 10 ).     

Spirocyclohexadienones: XIII. Reactions of schiff bases with enamines derived from 3,4-dihydroisoquinoline and with spiro[naphthalene-1,3′-pyrrol]-4-one

Addition of 1,3,3-trimethyl-3,4-dihydroisoquinolines to N-benzylideneanilines gives substituted N-[2-(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)-1-phenylethyl]anilines, whereas 2′,5′,5′-trimethyl-4′,5′-dihydro-4H-spiro[naphthalene-1,3′-pyrrol]-4-one reacts with N-benzylideneanilines along two pathways involving cyclization to substituted 2,3,3a,4,10,11-hexahydrobenzo[f]pyrrolo[2,3-d]quinolin-5(1H)-ones or elimination of the aniline residue with formation of substituted 5′,5′-trimethyl-2-styryl-4′,5′-dihydro-4H-spiro[naphthalene-1,3′-pyrrol]-4-ones.     

Synthesis of some 3-substituted quino[3,2-c][1,8]naphtyridines. A new heterocyclic ring system

Isatoic acid reacts with 7-mcthyl-2,3-dihydro-1,8-naphthyridin-4(1H) one ( 8 ) to give 3-methyl-5,6-dihvdroquino[3,2-c][1,8]naphthyriclin-7-carboxylic acid ( 9a ), which was transformed into the 3-methylquino[3,2-c][1,8]naphthyridine ( 7a ) by refluxing with copper chromite in quinoline. The same product ( 7a ) was also obtained by aromatization of the 3-methyl-5,6-dihydroquino-[3,2-c][1.8]naphthvridine ( 10a ), prepared by condensation of the ketone ( 8 ) and o-aminobenzaldehyde. Other 3-substituted quino[3,2-c][1,8]naphthyridines ( 7b,c,d,e ), which contain a new heterocyclic, ring structure, have been prepared using o-aminobenzaldehyde and 7-sub-stituted-2,3-dihv dro-1,8-naphthyridin-4(1H) ones ( 12 and 13 ) as starting materials. Also, the preparation of the parent nucleus ( 7f ) is described.     

New heterocyclic structures. [1,2,5]Thiadiazolo[3′,4′:4,5]pyrimido-[2,1-b][1,3]thiazine and thiazolo[3,2a][1,2,5]thiadiazolo[3,4-d]pyrimidine

Derivatives of two new molecular structures, namely, 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazin-10-one and 6,7-dihydro-9H-thiazolo[3,2-a][1,2,5]thiadiazolo[3,4-d][pyrimidin-9-one, and derivatives of N-substituted sulfamic acid, namely, (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-on-7-yl)sulfamic acid and (7-amino-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-5-on-6-yl)sulfamic acid, were separated out as by-products in the reduction reaction of 8-amino-3,4-dihydro-7-nitroso-2H,6H-pyrimido[2,1- b][1,3]thiazin-6-one and 7-amino-2,3-dihydro-6-nitroso-5H-thiazolo[3,2-a]pyrimidin-5-one derivatives, respectively, with sodium hydrosulfite. A mechanism of reaction, which hypothesizes the action of sodium hydrosulfite in an asymmetic form, is proposed. The results of single-crystal X-ray investigation on 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazin-10-one (R = 0.032 for 863 reflections) and (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b]- [1,3]thiazin-6-on-7-yl)sulfamic acid, sodium salt (R = 0.028 for 3507 reflections) are reported.     

The synthesis of methyl 2-(benzyloxycarbonyl)amino-3-dimethylaminopropenoate. The synthesis of trisubstituted pyrroles, 3-amino-2H-pyran-2-ones,fused 2H-pyran-2-ones and 4H-pyridin-4-ones

Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate ( 2 ) was prepared from methyl N-(benzyloxycarbonyl)glycinate ( 1 ) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-(benzyloxycarbonyl)amino-4H-quinolizin-4-ones 5 and 6 , ?2H-pyran-2-ones 17–19 , ?2H-1-benzopyran-2-ones 28–31 , and -naphthopyrans 32–35 , ?2H-pyrano[3,2-c]pyridine-2,5-dione 46 , -pyrano-[4,3-b]pyran-2,5-dione 47 , -pyrano[3,2-c]benzopyran-2,5-dione 48 , -pyrano[2,3-c]pyrazol-6-ones 49 and 50 , -pyrano[2,3-d]pyrirnidin-7-ones 51 and 52 derivatives. In the reaction of 2 with 1,3-diketones trisubsti tuted pyrroles 14–16 were formed. Selective removal of benzyloxycarbonyl group was achieved by cat alytic transfer hydrogenation with Pd/C in the presence of cyclohexene to afford free 3-amino compounds 7 , 8 , 20 , 36–38 and 53–57 in yields better than 80%.     

Studies on the synthesis of heterocyclic compounds. III. Preparation of some pyrazolo[3,4-C] [1,5]benzodiazocin-10(11H)one derivatives

Starting from the readly available N-melhyl-N-(1-phenyl-3-R-pyrazol-5-yl)-2-nitrobenzamides (1a,b), the pyrazoles, 4-aeetyl substituted 2a,b, were prepared in high yield. Reduction of 2a gave the amino derivative 4a, which was eyclized to the desired pyrazolo[3,4-c][1,5]benzodiazo-cin-10(11H)one (5a). Compound 2b afforded 5b directly. Compound 5b was also prepared by the action of phosphorus oxychloride on N-methyl-N-(1,3-diphenylpyrazol-5-yl)-2-acetamido-benzamide (6b).