13C Nmr study of 1,2,4-triazino[4,5-b]indazole derivatives

The main nmr parameters of 1,2,4-triazino[4,5-b]indazole derivatives were measured on the basis of their ¹³C nmr spectral analysis compared to indazole models. ¹J C-H coupling constants were studied and the correct structure of 1,2,4-triazino[4,5-b]indazoles was elucidated.     

Condensed imidazo-1,2,4-azines. 15. Reaction of 1,2-diaminobenzimidazole with 5-phenyl-2,3-dihydrofuran-2,3-dione

The reaction of 1,2-diaminobenzimidazole with 5-phenyl-2,3-dihydrofuran-2,3-dione in acetic acid gave a mixture of 2-benzoylmethyl-1,2,4-triazino [2,3-a]-benzimidazol-4H-3-one and 3-benzoylmethyl-1,2,4-triazino[2,3-a]benzimidazol-1H-2-one, the intramolecular cyclization of which gave isomeric 2-phenylfuro-[5,4-e]- and 2-phenylfuro[4,5-e]-1,2,4-triazino[2,3-a]benzimidazoles. Only the corresponding furo[4,5-e]-1,2,4-triazino[2,3-a]benzimidazole was isolated when the reaction was carried out in sulfuric acid.See [1] for Communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 533–535, April, 1987.     

as-Triazino[4,5-a]indoles. II. Etude des as-triazinoindolones

The synthesis of 1,2-dihydro-1-oxo-as-triazino[4,5-a]indoles was achieved by rearrangement of 2-oxadiazolyl-indoles under alkaline conditions or by cyclisation of indole-N-ethoxymethylid-ene hydrazides. The cyclisation of the N-carbethoxyhydrazone of the indole-2-carboxaldehyde gave the 1,2-dihydro-1-oxo-as-triazino[4,5-a]indole. The study of the lactim-lactam tautomerism was accomplished using the ir and nmr spectra.     

Condensed imidazo-1,2,4-azines. 21. Synthesis of 2-arylfuro(pyrrolo-, thieno-)[2,3-e]-1,2,4-triazino[2,3-a]benzimidazoles by cyclization of 2-aroyl-1,2,4-triazino[2,3-a]benzimidazol-4H-3-ones

2-[(-Ethyl-, arylimino)phenethyl]-1,2,4-triazino[2,3-a]benzimidazoles were obtained by reaction of 2-aroylmethyl-1,2,4-triazino[2,3-a]benzimidazol-4H-3-ones with ethyl(aryl)amines or urea. By the action of phosphorus oxychloride, these benzimidazoles cyclize into substituted pyrrolo[2,3-e]-1,2,4-triazino[2,3-a]benzimidazoles, heating of which in polyphosphoric acid leads to the formation of furo[2,3-e]-1,2,4-triazino[2,3-a]benzimidazoles, while by the action of P₄S₁₀, they are transformed into thieno[2,3-e]-1,2,4-triazino[2,3-a]benzimidazoles.For Communication 20, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1109–1113, August, 1989.     

1,2,4-Triazino[4,3-c]- and [2,3-c]quinazolines

This paper describes the reactions of 2-o-aminophenyl-1,4,5,6-tetrahydro-1-methyl-1,2,4-triazine with a variety of reagents to give substituted 1,2,4-triazino[4,3-c]quinazolines or 1,2,4-triazino[2,3-c]quinazolines. Certain representative compounds of these two new heterocyclic systems were characterized by the tlc, ir, nmr, mass spectra, and identified by unequivacol synthesis.     

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.     

Etude des conditions d'accès au triazino-1,2,4-[4,5-b] indazole

1,2,4-Triazino[4,5-b]indazol-1(2H)one and its derivatives were prepared by transposition of 3-[2-(-1,3,4-oxadiazolyl)]indazole or by ring closure of indazole ethoxymethylidenehydrazides. The synthesis of 1,2,3,4-tetrahydro-l,2,4-triazino[4,5-b]indazole-1,4-dione was achieved by cyclising the N-carbethoxyhydrazide of indazole-3-carboxylic acid and the synthesis of 1,2,4-triazino-[4,5-b]indazol-4(3H)one was made by cyclising the N-carbethoxy-hydrazone of indazole-3-carboxaldehyde. The Oxydation of 1,2,4-triazino[4,5-b]indazole-l(2H)thione gave 1,2,4-triazino-[4,5-b]indazoles. Nmr spectral data are reported.     

Parallel solid-phase synthesis of 2-imino-4-oxo-1,3,5-triazino[1,2-a]benzimidazoles via tandem aza-Wittig/heterocumulene-mediated annulation reaction

The parallel synthesis of a large number of 2-imino-4-oxo-1,3,5-triazino[1,2-a]benzimidazole derivatives via a solid-phase 1,3,5-triazino-annulation reaction is described. The solid-phase approach involves the in situ generation of iminophosphorane derivatives derived from resin-bound 2-aminobenzimidazoles employing Mitsunobu conditions. The subsequent Aza-Wittig reaction of the iminophosphoranes with isocyanates leads to highly reactive carbodiimides, which undergo an intramolecular heterocyclization reaction to form tetrasubstituted 2-imino-4-oxo-1,3,5-triazino[1,2-a]benzimidazoles in high yields (74-94%) and good purity (>80%).     

Synthèses de 1,2,4-triazolo[4,3-d][1,4]diazépines et de 1,2,4-oxadiazolo[4,5-d][1,4]diazépines par cycloaddition dipolaire-1,3

We report here a one-step synthesis of the 4,5,6,7-tetrahydro-1H- 1,2,4,-triazolo[4,3-d][1,4]diazepine, 4-6, and 1,2,4-oxadiazolo[4,5-d][1,4]-diazepine, 7-10, by 1,3-dipolar cycloaddition of nitrile imines and nitrile oxides with 2,3-dihydro-H-1,4-diazepine, 1. In all cases these cycloaddition are peri- and regioselectives (the C ? N bond is sole affected) and occures with high yields. Structure and conformations of cycloadducts have been assigned by means of nmr analysis     

Synthesis,molecular structure,and applications of 2-hydroxylamino-4,5-dihydroimidazolium-O-sulfonate to the synthesis of novel heterocyclic ring systems

2-hydroxylamino-4,5-dihydroimidazolium-O-sulfonate (1) has been prepared by reacting 2-chloro-4,5-dihydroimidazole with hydroxylamine-O-sulfonic acid. Deprotonated compound 1a containing both the nucleophilic endocyclic nitrogen atoms and electrophilic exocyclic nitrogen was used for the syntheses of 3-substituted 6,7-dihydro-5H-imidazo[2,1-c][1,2,4]oxadiazoles 2-9 and 6,7-dihydro-5H-imidazo[2,1-c][1,2,4]thiadiazole-3-thione (10) by tandem nucleophilic addition-electrophilic amination reaction. The method promises utility in the synthesis of a variety of other heterocycles. On the other hand, the convenient routes to 7,8-dihydroimidazo[1,2-c][1,3,5]thiadiazine-2,4(6H)-dithione (16) and 2,6,7,8-tetrahydroimidazo[1,2-a][1,3,5]triazine-4(3H)-thione derivative (17) are reported starting from compound 1. The structures of the compounds prepared were established by elemental analyses, IR, NMR, and MS spectra, and in some instances X-ray analyses.     

1,2,4-Triazines VIII. The synthesis of 1,2,4-triazino[2,3-e]pyrazolo[1,5-a]-1,3,5-triazines and 1,2,4-triazino[4,3-e]pyrazolo[],5-a] -1,3,5-triaziness

Substituted 2,5-dihydro-3[3-methyI(or phenyl)-5-aminopyrazolyl]-1,2,4-triazin-5-ones reacted with orthoesters to yield exclusively 1,2,4-triazino[2,3-e]pyrazolo[1,5-a]-1,3,5-triazin-5-ones. The structure elucidation was supported by independent synthesis of the isomeric 1,2,3-triazino-[4,3-e]pyrazolo[1,5-α]-1,3,5-triazin-7-one as well as by spectroscopical methods.     

Synthesis of heterocyclic compounds possessing the 4H-thieno[3,2-b]pyrrole moiety

A series of novel heterocyclic combinatorial libraries containing 4H-thieno[3,2-b]pyrrole, thieno[2',3':4,5]-pyrrol[1,2-d][1,2,4]triazine and thieno[2',3':4,5]pyrrolo[1,2-a]pyrazine heterocyclic moieties were obtained by parallel solution-phase synthesis. Key steps include different reactions of initial alkyl 4H-thieno[3,2-b]-pyrrole-5-carboxylates, such as alkylation with alkylating agents; transformation of the carboxylate group into different reactive functionalities, followed by reactions with electrophilic species; intramolecular cyclizations; and amide bond formation. Simple manual techniques for parallel reactions were coupled with easy purification procedures to give high-purity final products.     

The synthesis of novel polycyclic heterocyclic ring system via photocyclization. 18. Benzo[h]naphtho-[1′,2′:4,5]thieno[2,3-c]quinoline and benzo[h]naphtho-[1′,2′:4,5]thieno[2,3-c] [1,2,4]triazolo[4,3-a]quinoline

The synthesis of two previously unknown polycyclic ring systems, benzo[h]naphtho[1′2′:4,5]-thieno[2,3-c]quinoline ( 1 ) and benzo[h]naphtho[1′,2′:4,5]thieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline ( 2 ), was achieved via oxidative photocyclization of 1-chloro-N-(1-naphthyl)naphtho[2,1-b]thiophene-2-carboxamide ( 5 ). The total assignment of their ¹H and ¹³C nmr spectra was determined by the concerted use of two-dimensional nmr methods.     

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.

     

Synthesis of 4-and 5-substituted 2-methyl-and 2-(2-carboxyethyl)-1,2,4-triazino-[2,3-a]benzimidazol-4(5)H-3-ones

Condensation of 2-alkylamino-1-aminobenzimidazoles and quaternary 1,2-diamino-3R-benzimidazolium salts with pyruvate and α-ketoglutaric acid has given 4-and 5-substituted 2-methyl-and 2-(2-carboxyethyl)-1,2,4-triazino[2,3-a]benzimidazol-4(5)H-3-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 738–747, May, 2006.     

New method for the annelation of a pyridine ring on derivatives of imidazole and benzimidazole

The interaction of (Z)-1,3-diaryl-4-bromo-2-buten-1-ones with 1-substituted (benz)imidazoles in benzene gave (Z)-1-R-3-(2,4-diaryl-4-oxo-2-butenyl)-1H-imidazolium bromides and (Z)-1-R-3-(2,4-diaryl-4-oxo-2-butenyl)-1H-benzimidazolium bromides which readily cyclize in the presence of base to form derivatives of 7,9-diarylpyrido[1,2-a]benzimidazole and 6,8-diarylpyrimidazo[1,2-a]pyridine. The effects of the nature of substituents in the benzene ring of the diarylbutenones and the substituent at N(1) in the (benz)imidazoles on the alkylation and cyclization reactions has been studied. The optimum conditions for the synthesis of the 5-R-4-hydroxy-2,4-diphenyl-4,5-dihydro-1H-pyrido[1,2-a]benz-imidazol-10-ium, 5-R-2,4-diaryl-4-hydroxy-4,5-dihydro-3H-pyrido[1,2-a]benzimidazol-10-ium, and 5-R-2,4-diaryl-5H-pyrido[1,2-a]benzimidazol-10-ium have been found.     

Synthesis of 1,2,4-triazolo[4,3-c]-, tetrazolo[1,5-c]-, and 1,2,4-triazino[5,6-c]pyrano[4'3':4,5]pyrrolo-[3,2-e]pyrimidine derivatives

4-Hydrazinopyrano[4',3':4,5]pyrrolo[2,3-d]pyrimidines served as precursors in the synthesis of new heterocyclic systems, namely, 1,2,4-triazolo[4,3-c]-, tetrazolo[1,5-c]-, and 1,2,4-triazino[5,6-c] pyrano[4',3':4,5]-pyrrolo[3,2-e]pyrimidines.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, 375014 Yerevan. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 700-703, May, 1995. Original article submitted January 10, 1995; revision submitted April 20, 1995.     

Recherches en série triazépine-1,2,4: II — Etude de la réaction de l'acétylacétate d'éthyle avec les diamino-3,4 oxo-5 dihydro-4,5 triazines-1,2,4

The reaction of 3,4-diamino-5-oxo-4,5-dihydro-l,2,4-triazine or its 6-methyl or 6-phenyl substituted derivatives and ethyl acetoacetate gave three compounds: 4,7-dioxo-9-methyl-1,4,6,7-tetrahydro-as-triazino[4,3-b]-1,2,4-triazepine in poor yield, isomeric 4,9-dioxo-7-methyl-1,4,8,9-tetrahydro-as -triazino[4,3-b]-1,2,4-triazepine and by competitive cyclisation, 2-methyl-7-oxo-3,7-dihydro-s-triazolo[3,2-c]-1,2,4-triazine. By condensation of 3-methylamino-4-amino-5-oxo-4,5-dihydro-1,2,4-triazine with ethyl acetoacetate, the formation of 4,9-dioxo-7,10-dimethyl-4,8,9,10-tetrahydro-as-triazino[4,3-b]-1,2,4-triazepine was strongly favored.     

Heterocyclic analogs of pleiadiene. 59. Reaction of 1-acetonyl- and 1-phenacylperimidinium salts with hydrazine and ammonium acetate

1-Acetonyl-3-methyl- and 1-methyl-3-phenacylperimidinium salts react with hydrazine hydrate to give tetrahydro-derivatives of the hitherto unknown heterocyclic system 1,2,4-triazino[4,3-a]perimidine. On boiling in acetic acid with ammonium acetate, 3-phenacyl- and 3-(2,4-dimethyl)phenacyl-1-methylperidinium salts are converted into 1-methylamino-8-(4-phenylimidazol-1-y1)naphthalenes, with small amounts of 11-methylimidazo[1,2-a]perimidines also being formed.For No. 58, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1389–1395, October, 1986.The author thank V. A. Anisimova for discussions, and N. A. Klyuev and A. I. Chernyshev for obtaining the PMR and mass spectra.     

Cyclocondensation of 5-benzoyl-3-ethoxycarbonyl-6-methylthio-1-R-1,2-dihydropyrid-2-ones with heterocyclic N,N-and N,C-1,3-dinucleophiles

[3+3] Cyclocondensation of 5-benzoyl-3-ethoxycarbonyl-6-methylthio-1-R-1,2-dihydropyrid-2-ones with heterocyclic N,N-and N,C-1,3-dinucleophiles proceeds regioselectively to give a series of new tri-and tetracyclic heterosystems, viz. derivatives of 5,6-dihydropyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-6-one, 1,2-dihydropyrido[2,3-d]pyrido[2′,3′: 3,4]pyrazolo[1,5-a]pyrimidin-2-one, 8,9-dihydro-5H-pyrido-[2,3-d]thiazolo[3,2-a]pyrimidin-8-one, 1,2-dihydrobenzo[4,5]imidazo[1,2-a]pyrido[2,3-d]pyrimidin-2-one, and 1,2-dihydrobenzo[4,5]imidazo[1,2-g][1,6]naphthyridin-2-one.