Condensed Tetrazolo-1,3,5-triazines. 1. Synthesis of 5-Polynitromethyltetrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]-1,3,5-triazin-7-one Salts

The aziridation of 2-R-4,6-bis(trinitromethyl)-1,3,5-triazines containing electron-donor substituents has been studied. It was found that the corresponding 4-azido-2-dialkylamino-6-trinitromethyl-1,3,5-triazines are formed when R = NMe₂, NEt₂. When R = O^–NMe₄ ⁺ a novel reaction route was discovered leading to the tetramethylammonium salt of 5-polynitromethyltetrazolo[1,5-a]-1,3,5-triazin-7-one which is formed as a result of azido-tetrazole and lactim-lactam tautomeric conversion. Denitration of this salt at the trinitromethyl group occurs with retention of the tetrazolo-1,3,5-triazine structure. An X-ray analysis was carried out for the denitration product which was the dipotassium salt of 5-dinitromethyltetrazolo[1,5-a]-1,3,5-triazin-7-one.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 259–266, February, 2005.     

Condensed tetrazolo-1,3,5-triazines. 4. Synthesis of salts of 5-aminotetrazolo[1,5-a]-1,3,5-triazin-7-one

2-Amino-4-azido-1,3,5-triazin-6(1H)-ones were synthesized by successive substitution of the trinitromethyl groups in 2-amino-4,6-bis(trinitromethyl)-1,3,5-triazines under the influence of azide and nitrite ions. Interaction of 2-amino-4-azido-1,3,5-triazin-6(1H)-ones with bases led to the azido-tetrazole tautomeric conversion give salts of 5-aminotetrazolo[1,5-a]-1,3,5-triazin-7-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1211–1219, August, 2006.     

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.     

Recyclization of Condensed Carbethoxypyrimidines Accompanied by Substitution of a Carbon Atom into the Heterocycle

Condensation in ethanol of ethyl ethoxymethyleneacetoacetate with systems containing an amidine fragment (substituted 3-aminopyrazoles and 3-amino-1,2,4-triazole) gave 6-carbethoxy-7-methylpyrazolo[1,5-a]pyrimidines. Addition of base to solutions of the obtained bicyclic carbethoxy derivatives in the course of several minutes caused rearrangement to 6-acetyl-7-hydroxypyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-1,2,4-triazolo[1,5-a]pyrimidine respectively. A more prolonged refluxing in 15% aqueous alcohol solution of base caused 6-carbethoxy-7-methyl-2-phenylpyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-2-phenylpyrazolo[1,5-a]pyrimidine to recyclize to 7-methylpyrazolo[1,5-a]pyrimidine.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 569–576, April, 2005.     

A general approach toward the synthesis of 8-acylamidopyrazolo[1,5-a]-1,3,5-triazines

An expedient synthesis of 8-acylamidopyrazolo[1,5-a]-1,3,5-triazines was developed by treating 8-amino-4-[N-(4-aminophenyl)-N-(methyl)amino]pyrazolo[1,5-a]-1,3,5-triazine with various acyl chlorides following by the displacement of the so-formed N-(methyl)-N-[4-(acylamido)phenyl]amino leaving group with various amines. Applications to high-throughput synthesis are suggested.     

Interaction of aminoazoles with Meldrum’s acid and dialkyl ketones or cyclohexanone

Interaction of 3-amino-5-methylpyrazole, 3-amino-5-methylthio-, and 3,5-diamino-1,2,4-triazole with Meldrum’s acid, acetone, ethyl methyl ketone, and cyclohexanone leads to alkyl-substituted pyrazolo[3,4-b]pyridin-6-ones and 1,2,4-triazolo[1,5-a]pyrimidin-7-ones respectively. The structure of 5,5-dimethyl-2-methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidin-7-one was demonstrated by an X-ray structural investigation. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 595–601, April, 2007.     

Cyclizations of N-(1-Chloro-2,2,2-trihaloethylidene)-O-methylurethanes with 5-Amino-3-methylisoxazole and 3-Amino-5-methylisoxazole

N-(1-Chloro-2,2,2-trihaloethylidene)-O-methylurethanes undergo cyclization with 5-amino-3-methylisoxazole and 3-amino-5-methylisoxazole to give respectively 6-trihalomethylisoxazolo[5,4-d]pyrimidin-4(5H)-ones and 2-trihalomethyl-4H-isoxazolo[2,3-a]-1,3,5-triazin-4-ones.     

Synthesis and reactions of 2-[3-(trifluoromethyl)phenyl]furo[3,2-<Emphasis Type="Italic">c</Emphasis>]pyridine

(E)-3-{5-[3-(Trifluoromethyl)phenyl]furan-2-yl}propenoic acid (I) was prepared from 5-[3-(tri-fluoromethyl)phenyl]furan-2-carbaldehyde under the Doebner’s conditions. The obtained acid was converted to the corresponding azide II, which was cyclized by heating in diphenyl ether to 2-[3-(trifluoromethyl)phenyl]-4,5-dihydrofuro[3,2-c]pyridin-4-one (III). This compound was aromatized with phosphorus oxychloride to chloroderivative IV which was reduced with H₂NNH₂-Pd/C to the title compound V. 2-[3-(Trifluoromethyl)phenyl]furo[3,2-c]pyridin-5-oxide (VI) was synthesized by reaction of V with 3-chloroperoxybenzoic acid in dichloromethane. On treatment of VI with benzoyl chloride and potassium cyanide (Reissert-Henze reaction), corresponding 2-[3-(trifluoromethyl)phenyl]furo[3,2-c]pyridine-1-carbonitrile (VII) resulted. 5-Amino-2-[3-(trifluoromethyl)phenyl]furo[3,2-c]pyridin-5-ium-4-methylbenzene sulfonate (VIII) was prepared by direct N-amination of the title compound V with 1-[(aminooxy)sulfonyl]-4-methylbenzene in dichloromethane. Then, VIII was transformed to a non-isolated zwitterionic N-imid IX which afforded the corresponding furo[3,2-c]pyrazolo[1,5-a]pyridine carboxylic acid esters X, XI by 1,3-dipolar cycloaddition reactions with dimethyl but-2-ynedionate (DBD) or ethyl propiolate. The structures of all compounds were confirmed by their IR and NMR spectra. Presented at the 1st International Conference “Applied Natural Sciences” on the occasion of 10th anniversary of the University of St. Cyril and Methodius, Trnava, 7–9 November 2007.     

Imidazo[1,5-a]- and Thiazolo[3,4-a]quinoxalines Based on 3-(a-Thiocyanobenzyl)quinoxalin-2(1H)-one

When 3-(a-thiocyanobenzyl-2(1H)-one is heated, competing processes of [a]-annelation of the imidazole or thiazole rings occurs with formation of imidazo[1,5-a]- and thiazolo[3,4-a]quinoxalin-4(5H)-ones.     

Polyfunctional nitriles in the synthesis of derivatives of 1,3,4-thiadiazolo-[3,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidines

A one-pot method has been developed for the synthesis of 2-R-7-methyl-5-oxo-5H-1,3,4-thia-diazolo[3,2-a]pyrimidine by condensation of β-alkylthio(alkoxy)propionitrile, thiosemicarbazide, and ethyl acetoacetate in PPA, and also (7-methyl-5-oxo-5H-1,3,4-thidiazolo[3,2-a]pyrimidin-2-yl)-acetamide from cyanoacetamide, thiosemicarbazide, and ethyl acetoacetate. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, 1096–1100, July, 2008.     

新型2-甲基-5-羟基-7-氨基-吡唑[1,5-a]并嘧啶衍生物的合成

以3-甲基-5-氨基-吡唑和氰乙酸乙酯为原料,合成了2-甲基-5-羟基-7-氨基-吡唑[1,5-a]并嘧啶(2);2与芳胺的重氮盐溶液反应,合成了7个新型的2-甲基-5-羟基-6-芳基偶氮-7-亚氨基-吡唑[1,5-a]并嘧啶衍生物,收率87%~93%,其结构经~1H NMR,IR和ESI-MS表征。     

The Mannich reaction in the synthesis of N,S-containing heterocycles 3. Unexpected direction of the aminomethylation reaction of N-methylmorpholinium 1-amino-2,4-dicyano-4-ethoxycarbonyl-1,3-butadienethiolate. One stage cascade synthesis of new derivatives of pyrido[1,2-<Emphasis Type="Italic">a</Emphasis>][1,3,5]triazine

The interaction of N-methylmorpholinium 1-amino-2,4-dicyano-4-ethoxycarbonyl-1,3-butadienethiolate with primary amines and formaldehyde leads to the formation of ethyl esters of 7-cyano-6-thioxo-1,3,4,6-2H-pyrido[1,2-a][1,3,5]triazine-9-carboxylic acid in place of the expected derivatives of pyrido[2,1-b][1,3,5]thiadiazine. The structure of the ethyl ester of 7-cyano-3-phenyl-6-thioxo-1,3,4,6-2H-pyrido[1,2-a][1,3,5]triazine-9-carboxylic acid was demonstrated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1075–1081, July, 2007.     

Condensed isoquinolines. 21. Condensation of <Emphasis Type="Italic">o</Emphasis>-bromomethylphenylacetonitrile with substituted anthranilic acids

The reaction of substituted anthranilic acids and esters with o-bromomethylphenylacetonitrile give 2,3-R,R¹-7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one hydrobromides. It was found that 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones can exist in the two tautomeric imine and enamine forms. The tautomeric equilibrium position depends on the nature and position of the substituent in the quinazoline fragment. The borohydride reduction, oxidation, and reaction of 2,3-R,R¹-7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones with electrophilic reagents has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 562–573, April, 2007.     

Hydrolysis of 7,7-Substituted Derivatives of 3-tert-Butyl-3,4-dihydro-2H-thiazolo-[3,2-a][1,3,5]triazin-6(7H)-one

Alkaline hydrolysis of 3-tert-butyl-7,7-bis(hydroxymethyl)-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]-triazin-6(7H)-one can occur in three directions: with cleavage of the tetrahydrotriazine ring, with cleavage of the thiazolidine ring, and also with opening of both rings. Depending on the process conditions, either the hydrolysis product corresponding to the first direction or the hydrolytic decomposition products corresponding to the second and third directions can be obtained in preparative quantities. Hydrolysis of 3,3′-di-tert-butyl-3′,4′-dihydro-2′ H-spiro[(perhydro-1,3-oxazine)-5,7′-thiazolo[3,2-a][1,3,5]triazin]-6′-one in (NH₄)₂CO₃ solution occurs in two steps: in the first step, cleavage of the tetrahydrotriazine ring occurs; and in the second step, opening of the perhydrooxazine ring occurs. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1089–1097, July, 2005.     

Condensed isoquinolines 23. Reaction of <Emphasis Type="Italic">o</Emphasis>-bromomethylphenyl-acetonitrile with anthranilic acids: Synthesis of 6H, 12H,17H-dibenzo[3,4:6,7][1,8]-naphthyridino[1,8-<Emphasis Type="Italic">ab</Emphasis>]quinazoline-6,17-diones

The direction of the reaction of anthranilic acids with o-bromomethylphenylacetonitrile upon fusion depends on the temperature and nature of the substituent in the anthranilic acid. The reaction may lead to three types of products: Derivatives of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones below 150°C and to 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one or derivatives of 6H,12H,17H-dibenzo[3,4:6,7][1,8]naphthyridino[1,8-ab]quinazoline-6,17-diones above 150°C depending on the nature of the substituent in the anthranilic acid. A study was carried out on the mechanism for the formation of 6H,12H,17H-dibenzo[3,4:6,7][1,8]naphthyridino[1,8-ab]quinazoline-6,17-diones, which permitted the preparation of 6-(4-methylphenyl)-6,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1059–1067, July, 2007.     

Condensed isoquinolines 31. Reaction of 5-aryl-3-halo-12H-isoquino[2,3-a]quinazolines with electrophilic reagents

Treatment of 5-aryl-3-halo-12H-isoquino[2,3-a]quinazolines with electrophilic reagents readily forms their oxidation products. Acylation of the 3-chloro-5-phenyl-7,12-dihydroisoquino[2,3-a]quinazolinium perchlorate with Ac₂O in the presence of pyridine gave the product of electrophilic substitution at the C-7 atom 1-(3-chloro-5-phenyl-12H-isoquino[2,3-a]quinazolin-7-yl)-1-ethanone. By the same route phenacyl bromides react with the anhydro base 1 to give 5-aryl-7-(2-aryl-2-oxoethyl)-3-halo-isoquino[2,3-a]quinazolin-13-ium bromides. These salts readily react with nucleophilic reagents to form the products of addition at the C-12 atom. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1044–1052, July, 2008.     

Synthesis and reactions of 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones

Cycloacylation of N-R-3-oxo-3-phenylpropanethioamides by diethyl ethoxymethylenemalonate occurs selectively to form 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones which are convenient starting materials for the synthesis of bi-and tricyclic hetero systems including the previously unknown 9-R-7-ethoxycarbonyl-5-phenyl-8,9-dihydropyrido[2,3-d][1,2,4]triazolo[1,5-a]-pyrimidin-8-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1660–1669, November, 2007.     

Synthesis and tautomerism of 5,7-diaryl-3-cyano-and 5,7-diaryl-3-ethoxycarbonyl-4,7(6,7)-dihydropyrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines

The cyclocondensation of 3-amino-4-cyanopyrazole and 3-amino-4-ethoxycarbonylpyrazole with 1,3-diaryl-2,3-propen-1-ones gives the corresponding 3-substituted 5,7-diaryl-4,7(6,7)-dihydropyrazolo[1,5-a]pyrimidines. Their tautomeric composition in solution has been investigated by ¹H NMR. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1824–1832, December, 2007.     

Improved method for the preparation of 3-aryl- and 3-styrylimidazo[1,5-a]pyridines

A new convenient method is proposed for the preparation of 3-aryl- and 2-styrylimidazo[1,5-a]pyridines involving the cyclocondensation of 2-(acylaminobenzyl)pyridines in acetic anhydride with adding of p-toluenesulfonic acid.Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 252660 Kiev; e-mail: olga@elan-ua.net. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 640–642, May, 2000.