Synthesis of 1-hydrazinopyridazino[4,5-b]quinoxaline and related compounds

This paper describes the synthesis of 1-hydrazinopyridazino[4,5-b]quinoxaline ( 10 ), tetrazolo[4,3-b]pyridazino[4,5-b]quinoxaline ( 11 ) and some 1,2,4-triazolo[4,3-b]pyridazino[4,5-b]quinoxalines 13 . Starting with 2-ethoxycarbonyl-3-methylquinoxaline 1,4-dioxide ( 1 ), 1,2-dihydro-1-oxopyridazino[4,5-b]quinoxaline ( 5 ) was prepared by three different ways: (a) chlorination of 1 in acetic acid gave 2-ethoxycarbonyl-3-dichloromethylquinoxaline 1,4-dioxide, which reacts with an excess of hydrazine to give about 60% of 5 ; (b) oxidation of 1 with selenium dioxide gave 90% of 2-ethoxycarbonyl-3-formylquinoxaline 1,4-dioxide ( 3 ), which reacts with hydrazine to give 5 (63%); (c) compound 3 was treated with hydrazine to give 1,2-dihydro-1-oxopyridazino-[4,5-b]quinoxaline 1,4-dioxide ( 4 ) (70%), which by reduction with sodium dithionite gave 5 (80%). Compound 5 reacts with phosphorus pentasulfide or the Lawesson reagent to give 1,2-dihydro-1-thiocarbonylpyridazino[4,5-b]quinoxaline ( 9 ), which treated with hydrazine gave 5 (80%). This last compound reacts with nitrous acid to give 11 . Some hydrazones 12 from 10 are described. Heating the aldehyde hydrazones 12a,c,d with dimethylsulfoxide some 1,2,4-triazolo[4,3-b]pyridazino[4,5-b]quinoxalines 13 were obtained. Compound 13a was also obtained in the reaction of 10 with benzoyl chloride. Reaction of 3 with phenylhydrazine gave 1,2-dihydro-1-oxo-2-phenylpyridazino[4,5-b]quinoxaline ( 6 ). Reactions of 5 with acetic anhydride and dimethylsulfate gave, respectively, 1-acetoxypyridazino[4,5-b]quinoxaline ( 8 ) and 1,2-dihydro-1-oxo-2-methylpyridazino-[4,5-b]quinoxaline ( 7 ). All the compounds were characterized by elemental analysis and ¹H-nmr spectra. Compounds 5 and 10 showed antihypertensive activity in rats.     

An anomalous reaction of 7-chloro-2-hydrazono-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepine with sodium acetate and 1,1′-carbonyldiimidazole

The addition of 7-chloro-2-hydrazono-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepine 3 to a mixture of sodium acetate and 1,1′-carbonyldiimidazole 1 at room temperature gave, in moderate yields, carbonyl-1,1′-bis[7-chloro-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepin-2-ylidene hydrazone] 7 instead of the expected 2-acetylhydrazono-7-chloro-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepine 4 .     

Reactions of 2-(4,5-dihydro-3-furyl)-1,3-diphenyl-1,3-diaza-2λ<Superscript>3</Superscript>-phospholidine and 4,5-dihydro-3-furylphosphonous diamides with nitrile imines

Reactions of 2-(4,5-dihydro-3-furyl)-1,3-diphenyl-1,3-diaza-2λ³-phospholidine (1) with nitrile imines are multistep processes involving cleavage of one P-N bond of the diazaphospholidine ring to form substituted 5-(2-chloroethyl)-4-(N,N′-diphenylethylenediamino)-1,4-dihydro-1,2,4λ⁵-diazaphosphorines 4 as final products. Analogs of phospholidine 1, namely, 4,5-dihydro-3-furylphosphonous dipiperidide and dimorpholide, react with C,N-diphenylnitrile imine with retention of both P-N bonds to give 5-(2-hydroxyethyl)-1,2,4-diazaphosphorinium chlorides. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1590–1593, July, 2005.     

4-(10-Methyl-10H-phenothiazin-3-yl)-1,4-dihydropyridines, 4,5-dihydroindeno[1,2-<Emphasis Type="Italic">b</Emphasis>]-and 5,5-dioxo-4,5-dihydrobenzo-thieno[3,2-<Emphasis Type="Italic">b</Emphasis>]pyridines

Different modifications of the Hantzsch synthesis using 10-methyl-10H-phenothiazine-3-carbaldehyde gave 4-(10-methyl-10H-phenothiazin-3-yl)-substituted 1,4-dihydropyridine-3,5-di-, 5-oxo-4,5-dihydro-1H-indeno[1,2-b]pyridine-, and 5,5-dioxo-4,5-dihydro-1H-5λ⁶-benzo[4,5]thieno[3,2-b]pyridine-3-carboxylic esters. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 280–288, February, 2007.     

Some novel heterocyclic systems derived from 7-amino-2,3-dihydro-8-nitro-1H-pyrrolo[1,2-α]benzimidazole and the corresponding diamine

The preparation of 7-amino-2,3-dihydro-8-nitro-1H-pyrrolo[1,2-a]benzimidazole from 1,4-diacetamido-2,3-dinitrobenzene is described. Reaction of this compound with 2,5-dimethoxytetrahydrofuran produces 2,3-dihydro-8-nitro-7-N-pyrrolo-1H-pyrrolo[1,2-a]benzimidazole, which can be cyclised to produce two new heterocyclic ring systems, 9,10-dihydro-8H-pyrrolo[1,2-a]pyrrolo(1′,2′:1,2]imidazo[5,4-f]quinoxaline and 9,10-dihydro-8H-pyrrolo[2,1-c]pyrrolo[1′,2′:1,2]imidazo[4,5-h][1,2,4]benzotriazine. The corresponding diamine, 7,8-diamino-2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole undergoes a variety of condensation reactions to produce several new heterocyclic systems, for example, with formic acid, 1,7,8,9-tetrahydroimidazo-[4,5-e]pyrrolo[2,1-6]benzimidazole is formed and with diacetyl, 9,10-dihydro-2,3-dimethyl-8H-pyrrolo-[1′,2′:1,2]imidazo[5,4-y]quinoxaline is obtained.     

Interaction of 3-p-toluoyl-1,2-dihydro-4H-pyrrolo-[2,1-c][1,4]benzoxazine-1,2,4-trione with benzylamine. Synthesis and crystal and molecular structure ofZ-3-(1-benzyl-2-hydroxy-4,5-dioxo-2-p-tolyltetrahydropyrrol-3-idene)-3,4-dihydro-2H-1,4-benzoxazin-2-one

3-p-Toluoyl-1,2-dihydro-4H-pyrrolo-[2,1-c][1,4]benzoxazine-1,2,4-trione reacts with benzylamine to yieldZ-3-(1-benzyl-2-hydroxy-4,5-dioxo-2-p-tolyltetrahydropyrrol-3-idene)-3,4-dihydro-2H-1,4-benzoxazin-2-one. The crystal and molecular structure of the latter compound was studied by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 566–569, March, 1997.     

Quinazolines and 1,4-benzodiazepines. XLVI. Photochemistry of nitrones and oxaziridines

The cyclic nitrones 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one 4-oxide ( 5a ) and 1,3-dihydro-7-methylthio-5-phenyl-2H-1,4-benzodiazepin-2-one 4-oxide ( 5b ) are photoisomerized to readily isolable oxaziridines, 7-chloro-4,5-epoxy-5-phenyl-1,3,4–5-tetrahydro-2H-1,4-benzodiazepin-2-one ( 6a ) and 4,5-epoxy-5-phenyl-1,3,4,5-tetrahydro-7-methylthio-2H-1,4-benzo-diazepin-2-one ( 6b ). Oxaziridine 6b upon further irradiation gave ring expansion and ring contraction products, 4,6-dihydro-2-phenyl-9-methylthio-5H-1,3,6-benzoxadiazocin-5-one ( 7b ) and 4-benzoyl-3,4-dihydro-6-methylthioquinoxalin-2(1H)-one ( 8b ) respectively. The ring contraction product, 4-benzoyl-6-chloro-3,4-dihydroquinoxalin-2(1H)-one ( 8a ), was obtained from irradiation of oxaziridine 6a .     

The synthesis of 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles,11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles and 1,2,4-triazolo[3,4-f]-1,2,4-triazino[4,5-a]indoles

This paper describes the synthesis of the previously unknown 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles (2) and 11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles (3) from 4-hydrazino-5H-pyridazino[4,5-b]indoles (1) , as well as the synthesis of 1,2,4-triazolo[3,4-f]-1,2,4-triazino-[4,5-a]indoles (10) from 2-indolecarbohydrazide (4) . Compounds 2 were obtained by acylation of compounds 1 , followed of thermal cyclization and compounds 3 by treating compounds 1 with nitrous acid. The reactions of compound 4 with formic acid or ethyl orthoformiate gave 1,2-dihydro-1-oxo-1,2,4-triazino[4,5-a]indole (6) . Treating this last compound with phosphorus oxychloride or phosphorus pentasulfide, followed by hydrazine, gave 1-hydrazino-1,2,4-triazino-[4,5-a]indole (9) . Acylation of this last compound, followed of cyclization gave compounds 10 . All the compounds were characterized by elemental analysis and ir and ¹H-nmr spectra.     

Cyclisierungsreaktionen von Hydrazonen, 2. Mitt.: Eine neue Methode bei der Herstellung von 1-Oxo-2-aryl-1,2-dihydro-(as-triazino) [4,5-a]benzimidazol-4-carbonsäurenitrilen

Zusammenfassung Durch Kupplung von Diazoniumsalzen mit 2-Cyanmethylbenzimidazol wurden einige 2-Arylhydrazonocyanmethylbenzimidazole (1) hergestellt, durch deren Cyclisierung (Einwirkung von Chlorameisensäureäthylester in trockenem Pyridin) Nitrile der 1-Oxo-2-aryl-1,2-dihydro-(as-triazino) [4,5-a] benzimidazol-4-carbonsäuren (2) gewonnen wurden. Dieselben Verbindungen wurden auch aus 1-Carbäthoxy-2-cyanmethylbenzimidazol nach einer kürzlich¹ beschriebenen Methode gewonnen.

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Cyclization reactions of hydrazones, II: New synthesis of 1-oxo-2-aryl-1,2-dihydro (as-triazino) [4,5-a]benzimidazole-4-carbonitriles

2-Arylhydrazonocyanomethylbenzimidazoles (1), obtained from diazonium salts and 2-cyanomethylbenzimidazole, cyclize by treatment with ethyl chloroformate in dry pyridine solution to give the corresponding 1-oxo-2-aryl-1,2-dihydro-(as-triazino)-[4,5-a]benzimidazole-4-carbonitriles (2). The same compounds were prepared from 1-carbethoxy-2-cyanomethylbenzimidazole according to the method recently described¹ too.

     

The Preparation of 4,5-Dihydro-5-Phenyl-5-(2-Phenylethenyl)Isoxazoles, 4,5-Dihydro-5-Methyl-5-(2-Phenylethenyl)Isoxazoles,or 4,5-Dihydro-5,5-DI-(2-Phenylethenyl)Isoxazoles from Dilithiated C(α),O-Oximes and Select α,β–-Unsaturated Ketones

C(α),O-oximes were dilithiated with lithium diisopropylamide and condensed with three α,β-unsaturated ketones: (2E)-1,3-diphenyl-2-propen-1-one, or (1E, 4E)-1,5-diphenyl-1,4-pentadien-3-one, or (3E)-4-phenyl-3-buten-2-one, followed by immediate acid cyclization to variously substituted 4,5-dihydroisoxazoles: 4,5-dihydro-5-phenyl-5-(2-phenylethenyl)isoxazoles, 4,5-dihydro-5-methyl-5-(2-phenylethenyl)isoxazoles, or 4,5-dihydro-5,5-di-(2-phenylethenyl)-isoxazoles.     

Derivatives of benzo[4,5]cyclohepta[1,2-b]thiophene. 4. Synthesis of 1-(9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-4-yl)-3-alkylaminoazetidines

Thirteen 1-(9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-4-yl)-3-alkylaminoazetidines 11 have been synthesized in three steps from 4-amino-9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophene ( 6 ), which was obtained from the reduction of either 4-azido 4 or 4-hydroxyimino 5 derivatives. All the compounds have been evaluated as potential antidepressive agents.     

Unambiguously confirmed structure of 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one

To determine the structures of two isomeric products, 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (2) and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (3) obtained by condensation of 2,3-diaminopyridine (1) with ethyl benzoylpyruvate [1–3], these compounds were hydrolyzed to give 2-methyl-4H-pyrido[2,3-b]pyrazin-3-one (4) and 3-methyl-1H-pyrido[2,3-b]pyrazin-2-one (5) , respectively [4,5]. Both hydrolysates 4 and 5 were hydrogenated to afford 2-methyl-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (6) and 3-methyl-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (7) . The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds.     

Polycondensed nitrogen heterocycles. VII. 5,6-Dihydro-7-h-pyrrolo[1,2-D]-[1,4] benzodiazepin-6-ones. A novel series of annelatcd 1,4-benzodiazepines

The synthesis of a novel class of annelated 1,4-benzodiazepinen, the 2-R-3 methyl-5,6-dihydro-7H-pyrrolo[1,2-d][1,4]benzodiazepin-6-ones (Ve-e), is described. The reaction of 2-(o-aminophenyl)-3-R-5-methylpyrroles(IIIa,b) with bromoacetyl bromide in the presence of triethylamine produced the title compounds. An alternative synthetic route was achieved by means of the reactions of 1a,b with the appropriated α-aminoacids. The catalytic reduction of IVe-e over 10% palladium on charcoal led in good to excellent yields directly to the formation of pyrrolo[1,2-d]-[1,4]benzodiazepines (Ve-e).     

Ab initio molecular orbital study of energies and conformers of 3,4-dihydro-1,2-dithiin, 3,6-dihydro-1,2-dithiin, 4H-1,3-dithiin,and 2,3-dihydro-1,4-dithiin

Optimized geometries and energies for 3,4-dihydro-1,2-dithiin ( 1 ), 3,6-dihydro-1,2-dithiin ( 2 ), 4H-1,3-dithiin ( 3 ), and 2,3-dihydro-1,4-dithiin ( 4 ) were calculated using ab initio 6-31G* and MP2/6-31G*//6-31G* methods. At the MP2/6-31G*//6-31G* level, the half-chair conformer of 4 is more stable than those of 1 , 2 , and 3 by 2.5, 3.5, and 3.6 kcal/mol, respectively. The half-chair conformers of 1 , 2 , 3 , and 4 are 2.9, 7.1, 2.0, and 5.6 kcal/mol, respectively, more stable than their boat conformers. The calculated half-chair structures of 1 – 4 are compared with the calculated chair conformer of cyclohexane and the half-chair structures for cyclohexene, 3,4-dihydro-1,2-dioxin ( 5 ), 3,6-dihydro-1,2-dioxin ( 6 ), 4H-1,3-dioxin ( 7 ), and 2,3-dihydro-1,4-dioxin ( 8 ). © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 1064–1071, 1998     

A new method of preparation of 1H-1,2-benzodiazepines by the rearrangement of 2,4,6-trichlorophenylhydrazones

A new method for preparing 1H-1,2-benzodiazepines is described. Hydrazones of generalised structure 1 undergo base catalysed cyclisation to form 4-imidazolyl-4,5-dihydro-1H-1,2-benzodiazepines of general structure 2 . These compounds readily eliminate imidazole to form 1H-1,2-benzodiazepines of general structure 3 .     

Reactions of regioisomeric 3,3-dimethyl- and 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyrones with N-nucleophiles

Reactions of 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyrone with ethylenediamine, hydrazine, or hydroxylamine yield 5-methyl-7-trifluoromethyl-2,3-dihydro-1H-1,4-diazepine, 3(5)-(2-hydroxy-2-methylpropyl)-5(3)-trifluoromethylpyrazole, and 5-hydroxy-3-(2-hydroxy-2-methylpropyl)-5-triflouromethyl-Δ², respectively. The same compounds were obtained from 2-amino-1,1,1-trifluoro-6-hydroxy-6-methylhept-2(Z)-en-4-one and 2-hydroxy-6, 6-dimethyl-2-trifluoromethyltetrahydro-4-pyrone.     

Charge-Transfer Salts of Ferrocene Derivatives with Bis(maleonitriledithiolato)metallate(III) Complexes ([M(mnt)2]−, M=Ni,Pt): A Ground-State High-Spin [(Ni(mnt)2)2]2− Dimer

New hexamethylated ferrocene derivatives containing thioether moieties (1,1′-bis[(tert-butyl)thio]-2,2′,3,3′,4,4′-hexamethylferrocene ( 3a , b )) or fused S-heteropolycyclic substituents (rac-1-[(1,3-benzodithiol- 2-yliden)methyl]-2,2′,3,3′,4,4′-hexamethylferrocene ( 5 ) and rac-1-[1,2-bis(1,3-benzodithiol-2-yliden)ethyl]-2,2′,3,3′,4,4′-hexamethylferrocene ( 14 )), as well as a series of ferrocene-substituted vinylogous tetrathiafulvalenes (1,1′-bis[1,2-bis(1,3-benzodithiol-2-yliden)ethyl]ferrocene ( 6a ), 1,1′-bis[1-(1,3-benzodithiol-2-yliden)-2-(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)ethyl]ferrocene ( 6b ), [1,2-bis(1,3-benzodithiol-2-yliden)ethyl]ferrocene ( 21a ), [1-(1,3-benzodithiol-2-yliden)-2-(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)ethyl]ferrocene ( 21b ), [1,2-bis(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)ethyl]ferrocene ( 21c ), [1-(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)-2-(1,3-benzodithiol-2-yliden)ethyl]ferrocene ( 21d )) were prepared and fully characterized. Their redox properties show that some of them are easily oxidized and undergo transformation to paramagnetic salts containing bis(maleonitriledithiolato)-metallate(III) anions [M(mnt)₂]⁻ (M=Ni, Pt; bis[2,3-dimercapto-κS)but-2-enedinitrilato(2⁻)]nickelate (1⁻) or -platinate (1⁻). The derivatives [ 3a ] [Ni(mnt)₂] ( 26 ), [ 3a ] [Pt(mnt)₂] ( 27 ), [Fe{(η⁵-C₅Me₄S)₂S}] [Ni(Mnt)₂] ( 28 ), [Fe{(η⁵-C₅Me₄S)₂S}] [Pt(mnt)₂] ( 29 ), [ 5 ] [Ni(mnt)₂]⋅ClCH₂CH₂Cl ( 30 ), [ 6a ] [Ni(mnt)₂] ( 31 ), [ 6a ] [Ni(mnt)₂]⋅ClCH₂CH₂Cl ( 31a ), [ 6a ] [Pt(mnt)₂] [ 32 ), and [ 6b ] [Ni(mnt)₂] ( 33 ) were prepared and fully characterized, including by SQUID (superconducting quantum interference device) susceptibility measurements. X-Ray crystal-structural studies of the neutral ferrocene derivatives 6a , b , 21c , d , and 1,1′-bis[1-(1,3-benzodithiol-2-yliden)-2-oxoethyl]ferrocene ( 23 ), as well as of the charge-transfer salts 26 – 28 , 30 , and 31a , are reported. The salts 28 and 30 display both a D⁺A⁻A⁻D⁺ structural motif, however, with a different relative arrangement of the [{Ni(mnt)₂}₂]²⁻ dimers, thus giving rise to different but strong antiferromagnetic couplings. Salt 26 exhibits isolated ferromagnetically coupled [{Ni(mnt)₂}₂]²⁻ dimers. Salt 27 displays a D⁺A⁻D⁺A⁻ structural motif in all three space dimensions, and a week ferromagnetic ordering at low temperature. Salt 31a , on the contrary, shows segregated stacks of cations and anions. The cations are connected with each other in two dimensions, and the anions are separated by a 1,2-dichloroethane molecule.     

Composés sulfurés hétérocycliques. CII. Action de l'hydroxylamine sur les dihydro-1,2 benzothiazine-3,1 thiones-4

Hydroxylamine reacts with 1-alkyl-1,2-dihydro-3,1-benzothiazine-4thiones ( 1 ), giving 1-alky1-3-hydroxy-2,3-dihydro-1H-quinazoline-4-thiones ( 2 ). The same reagent, in neutral medium, converts 1-aryl-1,2-dihydro-3,1-benzothiazine-4-thiones ( 3 ) into 1-aryl-4-hydroxyimino-1,4-dihydro-2H-3,1-benzothiazines ( 4 ). In acidic medium, the same starting materials lead to 1-aryl-3-hydroxy-2-3-dihydro-1H-quinazoline-4-thiones ( 5 ). genrally with some quantity of the isomer 4 . Thiones 2 and 5 , as well as oximes 4 , heated at 200°, decomopose, yielding, in varying proportions, 1H-quinazoline-4-thiones ( 6 or 7 ), 1H-quinazoline-4-ones ( 9 ) and 2,3-dihydro-1H-quinazoline-4-thiones ( 11 ). Reacting with methyliodide, 1H-quinazoline-4-thiones ( 7 ) give 4-methylthioquinazolin-1-ium iodidies ( 12 ) which can be hydrolysed into 1H-quinazolin-4-ones ( 9 ). The latter are also obtained by reacting benzonitrile N-oxide with the corresponding thiones. 1-Aryl-1 H-quinazoline-4-thiones ( 7 ) react readily with nitrogen nucleophiles XNH₂ to give 1-aryl-4-imino-1,4-dihydro-quinazolines diversely substituted on the imino group. While thiones 7 are S- methylated by methyl iodide, the corresponding 1-aryl-1H-quinazolin-4-ones (9), with the same reagent, ungergo a N-methylation, yielding 1-aryl-3-methyl-4-oxo-3,4-dihydroquinazolin-l-ium iodides ( 18 ). Structure have been confirmed by uv, ir and nmr spectra.     

Reactions of fused dihydro-1,2,4-thiadiazoles with isoselenocyanates giving 6aλ4-thia-1,3,4,6-tetraazapentalene derivatives and 5,10-dihydro-1,2,4-thiaselenazolo[4,5-b][2,4]benzodiazepines

3-Methyl-6,7-dihydro-5H-1,2,4-thiadiazolo[4,5-a]pyrimidine (1) reacted with isoselenocyanates with elimination of acetonitrile and concomitant addition of two molecules of the isoselenocyanate to give 2,3-di-substituted-6,7-dihydro-5H-2aλ⁴-thia-2,3,4a,7a-tetraazacyclopent[cd]indene-1(2H),4(3H)-diselones (6a)–(6j). 3-Methyl-5,10-dihydrobenzo[e]-1,2,4-thiadiazolo[4,5-a][1,3]diazepine (3) likewise reacted with alkyl isoselenocyanates to give the 2,3-dialkyl-5-10-dihydro-2aλ⁴-thia-2,3,4a,10a-tetraazapentaleno[3,3a,4-gh]benzocycloheptene-1,4-diselones (9a)–(9h), but reaction of (3) with aryl isoselenocyanates took place with elimination of acetonitrile and incorporation of one molecule of the aryl isoselenocyanate in the product to give 3-arylimino-5,10-dihydro-1,2,4-thiaselenazolo[4,5-b][2,4]benzodiazepines (10a)–(10h). Structure (10) is a new heterocyclic system. The pyrimidine (1) and the diazepine (3) reacted with aryl isoselenocyanates at room temperature in solvents of low polarity to give zwitterion 1:1 addition compounds (7) and (12), respectively. NMR studies reveal that the thiaselenazoles (10) react in solution with aryl isoselenocyanates to give diaryl diselones (11) in a reversible process involving a Dimroth rearrangement. © 1996 John Wiley & Sons, Inc.     

Synthesis of 3-alkoxycarbonylaminomethylcarbonylamino-4-benzoyl-1,2-dihydropyridines and their cyclization to 5-phenyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones

The regiospecific reaction of 3-benzyloxycarbonylaminomethylcarbonylamino-4-benzoylpyridine (6a) , or 3-t-butoxycarbonylaminomethylcarbonylamino-4-benzoylpyridine (6b) , with either acetyl chloride or ethyl chloroformate, and either n-butylmagnesium chloride or phenylmagnesium bromide afforded the respective 1-acetyl (or ethoxycarbonyl)-2-n-butyl (or phenyl)-3-benzyloxy (or t-butoxy) carbonylaminomethylcarbonylami-no-4-benzoyl-1,2-dihydropyridines 7 in 60-75% yield. Reaction of 1-acetyl (or ethoxycarbonyl)-2-n-butyl (or phenyl)-3-t-butoxycarbonylaminomethylcarbonyl-4-benzoyl-1,2-dihydropyridines 7b, 7f, 7d, 7h with trifluoroacetic acid gave the corresponding 5-phenyl-8-acetyl (or ethoxycarbonyl)-9-n-butyl (or phenyl)-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones 8a, 8b, 8c, 8d respectively in 45–63% yield. N¹-Methylation of 5-phenyl-8-acetyl-9-n-butyl (or phenyl)-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones 8a, 8b using sodium hydride and iodomethane yielded the corresponding N¹-methyl derivatives 9a (48%) and 9b (54%). Oxidation of 5,9-diphenyl-8-ethoxycarbonyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-one (8d) using p-chloranil afforded 1,3-dihydro-5,9-diphenyl-2H-pyrido[3,4-e]-1,4-diazepin-2-one (10) . 5-Phenyl-8-acetyl-9-n-butyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-one (8a) and the corresponding 8-ethoxycarbonyl analog 8c exhibited weak anticonvulsant activity indicating that 8a and 8c may be acting at the same site as the 7-halo-1,4-benzodiazepin-2-one class of compounds.