Über Dihydro-3-thioxo-3H-1,2-dithiolo[4,3-d]pyrimidin-5(4H)-one und Dihydro-3H-1,2-dithiolo[4,3-d]pyrimidin-3,5(4H)-dithione Über Heterocyclen, 34. Mitt.

Zusammenfassung Dihydro-3-thioxo-3H-1,2-dithiolo[4,3-d]pyrimidin-5(4H)-one (2) geben bei Methylierung 4-Methylderivate (2) bzw. Tetrahydro-3-methylthio-5-oxodithiolopyrimidiniumsalze (6); aus den Dithionen (3) entstehen 5-Methylthio-bzw.5-Methylthio-4-methylderivate (4) bzw. Tetrahydro-3-methylthio-5-thioxodithiolopyrimidiniumsalze (6). Peressigsäure führt2 in das Tetrahydrodithiolopyrimidiniumhydrogensulfat (10) über.2 bzw.3 geben mit Phenylhydrazin 3-Phenylhydrazone; Tetrahydro-3-methylthiodithiolopyrimidiniumjodide (6) reagieren mit Aminen bei Anwesenheit vonHMPT zu den 3-Iminoverbindungen.10 gibt mit Methylketonen und Wasserstoffakzeptoren 3-Acylmethylendihydrodithiolopyrimidin-5(4H)-one.

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Dihydro-3-thioxo-3H-1.2-dithiolo[4.3-d]pyrimidin-5(4H)-ones and dihydro-3H-1.2-dithiolo[4.3-d]pyrimidin-3,5(4H)-dithiones

Dihydro-3-thioxo-3H-1.2-dithiolo[4.3-d]pyrimidine-5(4H)-ones (2) give on methylation 4-methylderivatives (2) and tetrahydro-3-methylthio-5-oxodithiolopyrimidinium salts (6) resp.; from dithiones (3) arise 5-methylthio-resp. 5-methylthio-4-methylderivatives (4) resp. tetrahydro-3-methylthio-5-thioxo-dithiolopyrimidinium salts (6). Peracetic acid converts2 to tetrahydrodithiolopyrimidinium hydrogensulphate10. 2 and3, resp. give with phenylhydrazine 3-phenylhydrazones. Tetrahydro-3-methylthiodithiolopyrimidiniumiodides (6) react with amines in presence ofHMPT to 3-iminocompounds.10 gives with methyl ketones and hydrogen acceptors 3-acylmethylendihydro-dithiolopyrimidine-5(4H)-ones.

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Herrn Prof. Dr.E. Ziegler zum 60. Geburtstag gewidment.     

Synthesis of Indolo phenothiazin-6-one derivatives

Summary 5H-Indolo[3,2-a]-6H-phenothiazin-6-one and its regioisomer 1H-Indolo[2,3-a]-6H-phenothiazin-6-one were prepared by the condensation of 2-aminobenzenethiol with carbazole-1, 4-dione or with isomeric mixture of bromo-carbazole-1,4-diones.

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Synthese von Indolo-Phenothiazin-6-on-Derivaten (Kurze Mitteilung)

Zusammenfassung 5H-Indolo[3,2-a]-6H-phenothiazin-6-on und sein Regioisomer 1H-Indolo[2,3-a]-6H-phenothiazin-6-on wurden mittels Kondensation von 2-Aminobenzolthiol mit Carbazol-1,4-dion oder mit einer isomeren Mischung von Bromcarbazol-1,4-dionen hergestellt.

     

Benzimidazole condensed ring systems,III . Synthesis of some substituted 2,3-dihydrocyclopenta-1H-[4′,5′: 2,3]pyrido[1,2-a]benzimidazole-11-carbonitriles

Summary The synthesis of compound3 by condensing 1H-benzimidazole-2-acetonitrile (1) with ethyl cyclopentanone-2-carboxylate (2) in the presence of ammonium acetate is described. Methylation of3 with trimethyl phosphate yielded the N-methyl derivative4. Methods for converting3 to some of its related derivatives in which the carbonyl function was replaced by Cl, N₃ and amines are also reported.

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Kondensierte Ringsysteme des Benzimidazols, 3. Mitt.. Synthese von substituierten 2,3-Dihydrocyclopenta[4,5:2,3]pyrido[1,2-a]benzimidazol-11-carbonitrilen

Zusammenfassung Die Synthese der tetracyclischen Verbindung3 durch Kondensation von 1H-Benzimidazol-2-acetonitril (1) mit Cyclopentanon-2-carbonsäureester (2) in Gegenwart von Ammonacetat wird beschrieben. Die Methylierung von3 mit Trimethylphosphat liefert das N-Methylderivat4. Die Sauerstoffunktion in3 kann durch Chlor, Azid und Aminogruppen ersetzt werden.

     

Simple synthesis of 6-alkyl-5H-benzo[a]phenoxazin-5-ones

6-Alkyl-5H-benzo[a]phenoxazin-5-ones were prepared by the reaction of 5H-benzo[a]phenoxazin-5-one with carboxylic acid in the presence of silver ion and peroxydisulfate.

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Eine einfache Synthese von 6-Alkyl-5H-benzo[a]phenoxazin-5-onen (Kurze Mitteilung)

Zusammenfassung 6-Alkyl-5H-benzo[a]phenoxazin-5-one wurden mittels Reaktion von 5H-Benzo[a]phenoxazin-5-onen mit Carbonsäuren in Gegenwart von Silberionen und Peroxydisulfat dargestellt.

     

Synthesis and antimicrobial activity of some 2-alkyl-2H-1,4-benzothiazin-3(4H)-ones and 2-alkylbenzo[d]imidazolo[2,1-b]-thiazolidin-3-ones

Summary Sodium 2-aminothiophenoxide (1) reacts with ethyl 2-bromoalkanoates (2) under direct cyclization to form 2-alkyl-2H-1,4-benzothiazin-3(4H)-ones (3). Reaction of the sodium salt of 2-mercaptobenzimidazole (4) with2 or 2-bromoalkanoic acids (5) affords only S-alkylated products (6 or7, respectively). The cyclization products — 2-alkylbenzo[d]imidazolo[2,1-b]thiazolidin-3-ones (8) — can be obtained only from the corresponding 2-(2-benzimidazolylthio)alkanoic acids (7) by the action of acetic anhydride. Both compounds3 and8 exhibit only moderate antimicrobial activity against some gram-positive bacteria.

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Synthese und antimikrobielle Wirkung von einigen 2-Alkyl-2H-1,4-benzothiazin-3(4H)-onen und 2-Alkylbenzo[d]imidazolo[2,1-b]thiazolidin-3-onen

Zusammenfassung Bei der Reaktion von Natrium-2-aminothiophenolat mit 2-Bromoalkansäure-ethylestern (2) entstehen als Cyclisierungsprodukte 2-Alkyl-2H-1,4-benzothiazin-3(4H)-one (3). Die Umsetzung von Natriumbenzimidazol-2-thiolat mit2 oder mit 2-Bromoalkansäuren (5) liefert nur S-Alkylierungsprodukte (6 oder7). Die Cyclisierungsprodukte — 2-Alkylbenzo[d]imidazolo[2,1-b]thiazolidin-3-one (8) — sind nur durch Umsetzung von entsprechenden 2-(2-Benzimidazolylthio)-alkansäuren (7) mit Acetanhydrid erhältlich. Die Verbindungen3 und8 weisen nur mäßige antimikrobielle Wirkung gegen einige gram-positive Bakterien aus.

     

Synthesis of some substituted triazolo[4,3-b][1,2,4]triazines as potential anticancer agents

The synthesis of some 3-substituted amino-6,7-diphenyl-1,2,4-triazolo[4,3-b][1,2,4]triazines (15) by cyclodesulfurisation of the corresponding N-(5,6-diphenyl-1,2,4-triazin-3-yl)-N-[substituted thio (carbamoyl)]hydrazines (3) using dicyclohexylcarbodiimid (DCC) and mercuric chloride is described. Moreover, trials to prepare 3-substituted amino-7-hydroxy-6-methyl-1,2,4-triazolo[4,3-b][1,2,4]triazines were not successful.

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Synthese einiger substituierter Triazolo[4,3-b][1,2,4]-triazine als potentielle Antikrebswirkstoffe

Zusammenfassung Es wird die Synthese einiger 3-substituierter Amino-6,7-diphenyl-1,2,4-triazolo[4,3-b][1,2,4]-triazine (15) mittels Cyclodesulfurisierung der entsprechenden N-(5,6-Diphenyl-1,2,4-triazin-3-yl)-N-[subst.thio(carbamoyl)]-hydrazine (3) unter Verwendung von Dicyclohexylcarbodiimid (DDQ) beschrieben. Versuche zur Herstellung von 3-substituierten Amino-7-hydroxy-6-methyl-triazolo[4,3-b][1,2,4]-triazinen schlugen fehl.

     

Nitropyrazoles

A method of synthesizing nitro derivatives of lH,4H-pyrazolo[4,3-c]pyrazole is developed, and some of its transformations are studied. 3-Methyl-6-nitro-, 3-carboxy(methoxy-carbonyl, carbamoyl)-6-nitro-, 3-amino-6-nitro-, 3-nitro-, 3,6-dinitro-, 1,4-diacetonyl-3,6-dinitro-, and lH,4H-3-aminopyrazolo[4,3-c]pyrazoles were obtained from 1H,4H-3 -methylpyrazolo[4,3-c]pyrazole. Unsubstituted 1H,4H-pyrazolo[4,3-c]pyrazole, the first member of this series, was obtained for the first time. The compounds prepared were characterized by¹H,¹³C,¹⁴N, and¹⁵N NMR spectroscopy. NH-Acidity and basicity of the series of pyrazolo[4,3-c]pyrazoles synthesized is studied and the effect of the fused pyrazole ring on these properties is examined.Deceased March 18, 1989.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1108–1113, June, 1993.     

Transformations of 1-azinyl-4-ethoxycarbonyl thiosemicarbazides. The synthesis of 3-ethoxycarbonylamino-s-triazolo[4,3-x]azines

1-Azinyl-4-ethoxycarbonyl thiosemicarbazides4,5, and12 and 1-azinyl-4-ethoxycarbonylmethyl thiosemicarbazide17, prepared from the corresponding heterocyclic hydrazino compounds and ethoxycarbonyl isothiocyanate or ethoxycarbonylmethyl isothiocyanate, were converted by oxidation with bromine in acetic acid into derivatives of fused 3-ethoxycarbonylamino-s-triazolo[4,3-a]pyridine6, -pyridazine7, and -pyrazine13,18 and20. The thiosemicarbazide derivative8 was transformed at 0 °C into bis-s-triazolo[4,3-b:34-f]pyridazine derivative9, while at room temperature 6-bromo-s-triazolo[4,3-b]pyridazine (10) was obtained. Further transformations of 8-substituted 3-ethoxycarbonylamino-s-triazolo[4,3-a]pyrazines13 and14 afforded derivatives of bis-s-triazolo[4,3-a:3,4-c]pyrazine15 and s-triazolo[4,3-a]tetrazolo[1,5-c]pyrazine16.

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Transformation von 1-Azinyl-4-ethoxycarbonylthiosemicarbaziden. Die Synthese von 3-Ethoxycarbonylamino-s-triazolo[4,3-x]azinen

Zusammenfassung Die aus den entsprechenden heterocyclischen Hydrazinverbindungen und Ethoxycarbonylmethylisothiocyanaten hergestellten 1-Azinyl-4-ethoxycarbonylthiosemicarbazide4,5 und12 und 1-Azinyl-4-ethoxycarbonyl-methylthiosemicarbazid17 wurden mittels Oxidation mit Brom in Essigsäure in die kondensierten Produkte 3-Ethoxycarbonylamino-s-triazolo[4,3-a]pyridin6, -pyridazin7 und -pyrazine13,18 und20 übergeführt. Das Thiosemicarbazidderivat8 wurde bei 0 °C in das Bis-s-trazolo[4,3-b:3,4-f]pyridazin-Derivat9 transformiert, währenddessen bei Raumtemperatur 6-Brom-s-triazolo[4,3-b]pyridazin (10) erhalten wurde. Weitere Transformationen der 8-substituierten 3-Ethoxycarbonylamino-s-triazolo[4,3-a]pyrazine13 und14 ergaben Derivate von Bis-s-triazolo[4,3-a:3,4-c]pyrazin15 und s-Triazolo[4,3-a]tetrazolo[1,5-c]pyrazin (16).

     

On the reaction between 3H-1,2-dithiolo[3,4-b]pyridine-3-thione and primary alkyl and arylalkylamines

3H-1,2-Dithiolo[3,4-b]pyridine-3-thione ( 10 ) reacts with primary alkylamines to give 1,2-dihydro-2-thioxo-3-pyridinecarbothioamides 11a-g and two minor products. Isothiazolo[5,4-b]pyridine-3(2H)-thiones 12a-g and 3-imino-3H-1,2-dithiolo[3,4-b]pyridines 13a-g were isolated and characterized. Further investigations allowed the synthesis of 12 and 13 in good yield.     

Pyrano[4,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidinium salts

Reactions of 5-aryl- and 5,7-diaryl-1,3-dimethyl-2,4-dioxopyrano[4,3-d]pyrimidinium salts with hydrazine were studied. In the former case, the reaction products were the 6-amino-1,3-dimethyl-2,4-dioxopyrido[4,3-d]pyrimidinium salts. 5,7-Diarylpyrano[4,3-d]pyrimidinium salts were transformed into either the corresponding pyridinium salts or 1H-pyrimido-[5,4-d][1,2]diazepine-2,4(3H,9H)-diones, depending on the hydrazine concentration and the reaction time. For Part 1, see Ref. 1. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1720–1725, May, 2008.     

Amidinoyl isothiocyanates in the synthesis of condensed heterocycles: Preparation of quinazolino[3,4-c][1,3,5]-benzotriazepines and quinazolino[3,4-c][1,2,3,5]-benzotetraazepines

Summary When heated, amidinoyl isothiocyanates (I) with 2-nitrophenyl isothiocyanate cyclize to 4-(2-nitroanilino)quinazolines (II) and after reduction to 2-amino derivatives (III). The latter serve as precursors to derivatives of the title compounds.

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Amidinoylisothiocyanate als Bausteine in der Synthese von kondensierten Heterozyklen. Darstellung von Chinazolino[3,4-c][1,3,5]-benzotriazepinen und Chinazolino[3,4-c][1,2,3,5]-benzotetraazepinen

Zusammenfassung Beim Erhitzen cyclisieren Amidinoyl-isothiocyanate (I) mit 2-Nitrophenyliso-thiocyanaten zu 4-(2-Nitroanilino)chinazolinen (II) und nach Reduktion zu 2-Aminoderivaten (III). Die letztgenannten dienen als Ausgangssubstanzen für Derivate der Titelverbindungen.

     

Reactions of cyclic 1,3-dicarbonyl compounds with 1,2(1,4)-dihydro-1-methyl-2(4)-methylene-N-heterocycles. A new access to 6,12-methano-dibenz[d,g]-[1,3]oxazocinones

Summary The enamine-type methylene-N-heterocycles1–5 react with cyclic 2-ethoxymethylene-1,3-dicarbonyl compounds6 to give 2-[2-(hetarylidene)ethylidene]-1,3-dicarbonyl compounds7–14. The result of the reactions between 1,2-dihydro-1-methyl-2-methylene-quinoline (1a) and cyclic 1,3-dicarbonyl compounds depends on the nature of the dihydro intermediatesA/B. Dehydrogenation of keton intermediatesA results in 2-(1,2-dimethyl-4(1H)-quinolylidene)-1,3-dicarbonyl compounds17–21. Enol intermediatesB with 6-membered dicarbonyl ring form 6,12-methano-dibenz-[d,g][1,3]oxazocinones22–25.¹H NMR spectra and X-ray structure analysis prove the structure of23.

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Reaktionen cyclischer 1,3-Dicarbonylverbindungen mit 1,2(1,4)-Dihydro-1-methyl-2(4)-methylen-N-heterocyclen. Ein neuer Zugang zu 6,12-Methano- dibenz[d,g][1,3]oxazocinonen

Zusammenfassung Aufgrund ihres Enamincharakters reagieren die Methylen-N-heterocyclen1–5 mit cyclischen 2-Ethoxymethylen-1,3-dicarbonylverbindungen6 zu den 2-[2-(Hetaryliden)ethyliden]-1,3-dicarbonylverbindungen7–14. Das Ergebnis der Reaktionen zwischen 1,2-Dihydro-1-methyl-2-methylen-chinolin (1a) und cyclischen 1,3-Dicarbonylverbindungen hängt von der Natur der zwischenzeitlich entstehenden DihydroverbindungenA/B ab. Die Intermediat-KetoneA gehen durch Dehydrierung während der Reaktion in die 2-(1,2-Dimethyl-4(1H)chinolyliden)-1,3-dicarbonylverbindungen17–21 über. Die Intermediat-EnoleB mit sechsgliedrigem Dicarbonylring bilden in intramolekularer Reaktion die 6,12-Methano-dibenz[d,g][1,3]oxazocinone22–25, deren Struktur am Beispiel der Verbindung23 durch¹H-NMR sowie durch Röntgenkristallstrukturanalyse bewiesen wird.

     

Novel heterocyclic systems based on 8-R-4,5-dihydro-4,4-dimethyl-[1,2]dithiolo[3,4-c]quinoline-1-thiones

Based on the reaction of 8-R-4,5-dihydro-4,4-dimethyl[1,2]dithiolo[3,4-c]quinoline-1-thiones with oxalyl chloride followed by the reactions of 1,3-dipolar cycloaddition and diene synthesis with participation of acetylenedicarboxylic acid dimethyl ester, we have developed approaches to synthesis of novel polycondensed heterocyclic systems: [1,2]dithiolo[3,4-c]pyrrolo[3,2,1-ij]quinoline-4,5-dione, 6-(1,3-dithiol-2-ylidene)-1,2-dioxo-5-thioxo-7H-pyrrolo[3,2,1-ij]quinoline and 4,5-dioxospiro(pyrrolo)-[3,2,1-ij]thiopyrano[2,3-c]quinoline-11,2′-[1,3]dithiole. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 610–615, April, 2006.     

Oxadiazole condensed ring systems,II: Synthesis of new 2-aryl-1,3,4-oxadiazolo[3,2-a]-s-triazine-5,7(6H)-diones

Summary The syntheses of 1,3,4-oxadiazolo[3,2-a]-s-triazine-5,7(6H)-diones4 through the condensation of 2-amino-5-aryl-1,3,4-oxadiazoles1 with ethoxycarbonyl isocyanate2 is described. Methylation of4b with trimethyl phosphate yielded the N-methyl derivative5.

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Kondensierte Ringsysteme des Oxadiazols, 2. Mitt. [1]: Synthese von neuen 2-Aryl-1,3,4-oxadiazolo[3,2-a]-s-triazin-5,7(6H)-dionen

Zusammenfassung Die Synthese von 1,3,4-Oxadiazolo[3,2-a]-s-triazin-5,7(6H)-dionen4 durch Kondensation von 2-Amino-5-aryl-1,3,4-oxadiazolen1 mit Ethoxycarbonylisocyanat2 wird beschrieben. Die Methylierung von4b mit Trimethylphosphat gibt das N-Methyl-Derivat5.

     

Synthesis,Antibacterial, and Antifungal Activities of Imidazo[2,1-c][1,2,4]triazoles and 1,2,4-Triazolo[4,3-a]pyrimidinones

A straightforward method has been developed for the synthesis of 1-phenyl-imidazo [2,1-c][1,2,4]triazole derivatives 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones derivatives 6a–g starting from 5-amino-1-phenyl[1,2,4]triazole and p-toluenesulfonic acid (PTSA). This methodology affords a number of 1-phenyl-imidazo [2,1-c][1,2,4]triazoles 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones 6a–g in reasonable yields and short reaction times. The structures of all new compounds were elucidated using infrared, ¹H and ¹³C NMR, and high-resolution mass spectrometry. Some of the newly synthesized compounds were screened for their antimicrobial activity.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications ^® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of substituted 2,3,5,6,7,8-hexahydropyrazolo[4,3-d][1,2]diazepine-8-carboxylates

Substituted 2,3,5,6,7,8-hexahydropyrazolo[4,3-d][1,2]diazepine-8-carboxylates were prepared in good to excellent yields from ethyl (2E)-3-(dimethylamino)-2-{(4Z)-4-[(dimethylamino)methylidene]-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl}propenoate with 1,2-disubstituted hydrazines by heating in an alcohol.     

Transformations of 1-(2-chloropyridyl-3)-4-ethoxycarbonyl-and 1-(2-chloropyridyl-3)-4-ethoxycarbonylmethyl thiosemicarbazides. Attempts to prepare pyrido[3,2-e]-1,2,4-thiadiazine

2-Chloro-3-hydrazinopyridine (2) was converted with ethoxycarbonyl and ethoxycarbonylmethyl isothiocyanates into 1,4-disubstituted thiosemicarbazides3 and4, while with phenyl isothiocyanate directly 1H-pyrido[3,2-e]-1,3,4-thiadiazine7 was formed. Attempts to cyclize the thiosemicarbazides3 and4 into pyridothiadiazine derivatives5 and6 failed. In the reaction of3 with hydrazine 2-aminothiazolo[5,4-b]pyridine (9) was formed, while4 gave only the corresponding hydrazide10. The cyclization of the side chain occurred in compound4 by heating in aqueous hydrochloric acid to give11, which was further transformed with N,N-dimethylformamide dimethyl acetal (DMFDMA) into12, while with diethyl acetylene dicarboxylate the thiazolidone derivative13 was produced.

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Transformationen von 1-(2-Chlorpyridyl-3)-4-ethoxycarbonyl- und 1-(2-Chlorpyridyl-3)-4-ethoxycarbonylmethylthiosemicarbaziden. Versuche zur Synthese von Pyrido[3,2-e]-1,2,4-thiadiazinen

Zusammenfassung 2-Chlor-3-hydrazinopyridin (2) wurde mit Ethoxycarbonyl- und Ethoxycarbonylmethylisothiocyanaten zu 1,4-disubstituierten Thiosemicarbaziden3 und4 umgesetzt, mit Phenylisothiocyanaten wurden direkt die 1H-Pyrido[3,2-e]-1,3,4-thiadiazine7 erhalten. Versuche zur Cyclisierung der Thiosemicarbazide3 und4 zu den Pyridothiadiazinderivaten5 und6 gelangen nicht. Bei der Reaktion von3 mit Hydrazin entstand 2-Aminothiazolo[5,4-b]pyridin (9),4 gab nur das entsprechende Hydrazid10. Die Cyclisierung der Seitenkette von4 gelang durch Erhitzen in wäßriger HCl unter Bildung von11, das seinerseits mit N,N-Dimethylformamiddimethylacetal (DMFDMA) weiter zu12 umgesetzt wurde, währenddessen mit Diethylacetylendicarboxylat die Thiazolidonderivate13 entstanden.

     

Ein Beitrag zur Chemie des 2,3-Dihydro-3-oxo-benzo[b]thiophen-1,1-dioxids Synthesen mit Nitrilen, 86. Mitt.

Summary 2,3-Dihydro-3-oxo-benzo[b]thiophen-1,1-dioxide (1) reacts as CH-acidic component with amidines of orthoesters and anilines resp. to give the anilinomethylene derivates3, 4, and5. With triethyl orthoformiate the hydroxymethylene-compound7 is obtained. Anilino- and phenylhydrazino derivates8 and9 prove the carbonyl activity of1, azo-coupling leads to10, whereas treatment of1 with sulfur and malononitrile yields the benzo[b]thieno[2,3-d]thiophenes11. Introduction of substituents with active NH-functions in position 2 of the dicyanomethylene-product2, such as azocoupling, reaction with phenyl isocyanate and formation of enamines, leads to ring closure reactions between a nitrile and the NH-group. Thereby the phenyl-benzo[4,5]thieno[2,3-c]pyridazines12, the phenyl-1H-benzo[4,5]thieno[2,3-c]pyridines13 and the phenylamino-benzo[4,5]thieno[2,3-c]pyridines14 are obtained.¹³C and¹⁵N-NMR spectroscopy was used as proof of the ring closure reactions.

     

Synthesis of Some Pyrazolo[3, 4]pyrimidine Derivatives for Biological Evaluation

Abstract

A novel β -enaminonitrile of 1-(6-p-tolyl-pyridazin-3-yl)-pyrazole derivative 2 was formed using (6-p-tolyl-pyridazin-3-yl)-hydrazine ( 1 ) and 2-ethoxymethylenemalononitrile. The β-enaminonitrile derivative 2 was in turn used as a precursor for the preparation of pyrazoles ( 4 , 6 ), pyrazolo[3, 4-d]-pyrimidines ( 3 , 7–12 ) and pyrazolo[4, 3-e][1,2,4]triazolo[4,3-c]pyrimidine ( 13 ). Also, N- and S-acyclic nucleosides 14 and 15 were prepared. Some of the prepared products showed potent antimicrobial activity.     

Synthesis of 2-acetyl-3-methyl-4H-1,4-benzothiazine and its derivatives

Summary 2-Aminothiophenol (1) reacts with 3-chloro-2,4-pentanedione (2) in the presence of pyridine to form 2-acetyl-3-methyl-4H-1,4-benzothiazine (3) in high yields. Reaction of3 with hydrazine gives 4-(2-aminophenylthio)-3,5-dimethylpyrazole (5). Condensation of3 with 4-nitrobenzaldehyde yields the corresponding Schiff base7. Hydroxylamine with benzothiazine3 affords 3,9a-dimethyl-3a, 9a-dihydro-9H-isoxazolo[4,5-b][1,4]benzothiazine (8).

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Synthese von 2-Acetyl-3-methyl-4H-1, 4-benzothiazin und seinen Derivaten

Zusammenfassung 2-Aminothiophenol (1) reagiert mit 3-Chlor-2,4-pentandion (2) in Anwesenheit von Pyridin unter Bildung von 2-Acetyl-3-methyl-4H-1,4-benzothiazin (3) in sehr hoher Ausbeute. Benzothiazin3 kondensiert mit Hydrazin zu 4-(2-Aminophenylthio)-3,5-dimethylpyrazol (5), dessen Aminogruppe reagiert mit 4-Nitrobenzaldehyd zu einer Schiffschen Base (7), die spektroskopisch charakterisiert wurde. Benzothiazin3 mit Hydroxylamin ergibt 3,9a-Dimethyl-3a,9a-dihydro-9H-isoxazolo[4,5-b][1,4]benzothiazin (8). Die Stereochemie der letztgenannten Verbindung wurde ermittelt.