Convenient Synthesis of 6H-[1,2,4,5]Tetrazino[3,2-b]quinazolin-6-ones

Summary.  The reaction of 3-amino-2-thioxo-4(1H)-quinazolinone or its 2-methylthio derivative with hydrazonoyl halides in the presence of ethanol and triethylamine affords 6H-[1,2,4,5]tetrazino[3, 2-b]quinazolin-6-ones. Received January 2, 2001. Accepted (revised) April 11, 2001     

Synthesis of 5H-benzothiazolo[3,2-a]quinazolin-5-ones

5H-Benzothiazolo[3,2-a]quinazolin-5-ones (Va-d) were synthesized by thermal cyclization of N-(2-benzothiazolyl)-2-fluorobenzamides (IVa-d) which were obtained by allowing 2-fluorobenzoyl chloride to react with 2-aminobenzothiazoles.     

Synthesis of 5H-benzoxazolo[3,2-a]quinazolin-5-ones

5H-Benzoxazolo[3,2-a]quinazolin-5-ones (Xa-d) were synthesized in excellent yields from N-(2-hydroxyphenyl)anthranilic acids (Ia-d) and cyanogen bromide. The synthesis was based on the mechanistic consideration of the reactions of salicylic acid with cyanogen bromide previously reported in the literature. A versatile alternative route to these novel heterocyclic compounds was through thermal cyclization of N-(2-benzoxazolyl)-2-fluorobenzamides (XIII) obtained by reacting 2-fluorobenzoyl chloride with 2-aminobenzoxazoles. The reaction of Xb with ethanol in the presence of potassium hydroxide gave an ethoxyquinazolinone (XVII). Similarly, the alkaline hydrolysis of Xb afforded an quinazolindione (XVIII).     

3-Methyl[1,3,4]thiadiazino[2,3-b]quinazolin-6-ones

4H,6H-[1,3,4]Thiadiazino[2,3-b]quinazolin-6-one with a methyl group in position 3 (6a) has been synthesised by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (1) with allyl bromide (2) followed by treatment with bromine and subsequent dehydrohalogenation of the brominated product (4) with ethanolic sodium hydroxide. Its isomeric 3-methyl-2H,6H-[1,3,4]thiadiazino[2,3-b]quinazolin-6-one (6b) has also been obtained by condensation of1 and bromoacetone (7) followed by cyclisation of the intermediates (8 or9) with hydrobromic acid or with concentrated sulphuric acid. The structures have been established on the basis of IR and PMR data.

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3-Methyl[1,3,4]thiadiazino[2,3-b]chinazolin-6-one

Zusammenfassung Zur Synthese von 4H,6H-[1,3,4]thiadiazino[2,3-b]chinazolin-6-on (6a) wurde die Kondensation von 3-Amino-2-mercapto-3H-chinazolin-4-on (1) mit Allylbromid mit nachfolgender Behandlung mit Brom und Dehydrohalogenierung des bromierten Produktes4 mit ethanolischer Natronlauge herangezogen. Das zu6a isomere 2H,6H-Produkt6b wurde ebenfalls durch Kondensation von1 mit Bromaceton und nachfolgender Cyclisierung der Zwischenprodukte8 bzw.9 mit HBr oder H₂SO₄ erhalten. Die Strukturen wurden mittels IR und NMR abgesichert.

     

Investigation of 1,2,4-triazino [6,5-b]indole-derivatives

A method was worked out for the preparation of isatin -semicarbazone, the starting material for the synthesis of 3-hydroxy-l,2,4-triazacarbazoles, and the structure of the latter was refined. Nucleophilic exchange of 3-chloro-l,2,4-triazacarbazole (which was obtained for the first time) with amines, hydrazines, and arylhydrazines was studied.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 855–857, June, 1972.     

Synthesis of 1,2,4-triazolo[3,2-b]-1,3-thiazines

1,2,4-Triazolo[3,2-b]-1,3-thiazines were obtained by the reaction of 1,2,4,-triazole-3-thiones with an equimolar amount of 1-phenyl-2-cyanoacetylene in the presence of triethylamine or potassium hydroxide. It is shown that triazolethiones form N,S diadducts upon reaction with a twofold excess of cyanoacetylene. The nature of the heteroatom in the exo position of the heteroring affects the direction of addition to phenylcyanoacetylene. 2,4-Bis(1-phenyl-2-cyanovinylene)-1,2,4-triazol-3-one was synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1051–1053, August, 1982.     

Synthesis of 4-Amino-6-R-4,5-dihydro-3-phenacylthio-1,2,4-triazin-5-ones and 8H-3-R-7-Aryl-1,2,4-triazino[3,4-b][1,3,4]thiadiazin-4-ones

A study was carried out on the reaction of 4-amino-6-R-2,3,4,5-tetrahydro-3-thioxo-1,2,4-triazin-5-ones with halo ketones in alkaline media to yield 4-amino-6-R-4,5-dihydro-3-phenacylthio-1,2,4-triazin-5-ones, which then convert to 8H-3-R-7-aryl-1,2,4-triazino[3,4-b][1,3,4]thiadiazin-4-ones.     

Synthesis of 6-phenyl and 6-styrylthiazolo[3,2-b] [1,2,4]triazoles

Thiazole rings have been often encountered in the structure of antibiotic or antitumor drugs. An easy synthesis of them has revealed itself necessary in order to elucidate the mechanism of action of these naturally occurring substances. A method of preparation of conjugated b-ethylenic thiazole[3,2-b] [1,2,4]triazoles by heating a 3-thio substituted [1,2,4]triazole in the presence of polyphosphoric acid is reported here, giving the expected product in a 60% yield.     

新型1,2,4-三唑并[3,2-d][1,5]苯并氧氮杂(艹卓)-2-酮的合成

取代苯并二氢吡喃-4-酮(1)的芳腙在冰醋酸中与KNCO发生[3 2]环加成反应,加成产物经KMnO4氧化开环得偕偶氮异氰酸酯(3).3在HBF4的催化下发生环化-重排反应,合成得到一系列新型6-7-5三环系1,2,4-三唑并[3,2-d][1,5]苯并氧氮杂(艹卓)2-酮(5a～5g).由X单晶衍射测定了化合物5a的晶体结构.     

Synthesis of 2-aryl-5H-[1,3,4]-thiadiazolo[2,3-b]quinazolin-5-ones

3-Amino-2-thioxo-1,2,3,4-tetrahydroquinazolin-4-ones were converted into 2-aryl-5H-[1,3,4]thiadiazolo[2,3-b]quinazolin-5-ones on treatment with carboxylic acids and POCl₃. 3-Arylmethylidenamino-2-thioxo-1,2,3,4-tetrahydroquinazolin-4-ones also cyclized to 2-aryl-5H-[1,3,4]thiadiazolo[2,3-b]quinazolin-5-ones when oxidized with potassium chlorate in acetic acid, but on heating they were deaminated to give 2-thioxo-1,2,3,4-tetrahydroquinazolin-4-one and aryl nitriles. __________ Translated from Khimiya Geteotsiklicheskikh Soedinenii, No. 5, 787–791, May, 2006.     

Convenient Synthesis of Fluorine-Containing 2-Aryl-5H-[1,3,4]thiadiazolo[3,2-a]quinazolin-5-ones

Russian Journal of Organic Chemistry - An efficient synthetic approach to new fluorine-containing [1,3,4]thiadiazolo[3,2-a]quinazolin-5-ones has been developed on the basis of intramolecular...     

Synthesis and Tuberculostatic Activity of 1,3-Thiazacycloalkyl[3,2-b]-1,2,4-triazoles

The 4-hydroxyalkyl-1,2,4-triazole-3-thiones cyclization allowed us to work out the effective method of 1,3-thiazacycloalkyl[3,2-b]-1,2,4-triazoles synthesis. Some of the compounds that were obtained were tested for their tuberculostatic activity.     

Some reactions of 2H-[1]benzothieno[3,2-b]pyran-2-ones and related compounds

The conversion of 2H-[1]benzothieno[3,2-b]pyran-2-ones into mono- and dithio-derivatives and the preparation of some dibenzothiophenes, sulphines and pyridones are described.

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Einige Reaktionen von 2H-[1]Benzothieno[3,2-b]pyran-2-onen und verwandten Verbindungen

Zusammenfassung Es wird die Umsetzung von 2H-[1]benzothieno[3,2-b]pyran-2-onen zu Monound Dithio-Derivaten und die Darstellung einiger Dibenzothiophene, Sulfine, und Pyridone beschrieben.

     

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.     

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.     

Thiochromenone-Annelated Heterocycles: Regioselective Synthesis of Furo[3,2-b]-thiochromen-9-ones

Summary.  A number of hitherto unreported furo[3,2-b]thiochromenone derivatives were regioselectively synthesized in good yields starting from 3-allyloxy-thiochromenones. Received September 18, 2000. Accepted (revised) November 15, 2000     

新型1,2,4-三唑并[3,2-d][1,5]苯并氧氮杂-2-酮的合成

取代苯并二氢吡喃 4 酮 ( 1)的芳腙在冰醋酸中与KNCO发生 [3 2 ]环加成反应 ,加成产物经KMnO4氧化开环得偕偶氮异氰酸酯 ( 3 ) .3在HBF4的催化下发生环化 -重排反应 ,合成得到一系列新型 6 7 5三环系 1,2 ,4 三唑并 [3 ,2 d] [1,5 ]苯并氧氮杂 2 酮 ( 5a～ 5g) .由X单晶衍射测定了化合物 5a的晶体结构