Pyrolysis and photolysis processes of pyran and thiopyran derivatives

Summary Pyrolysis and photolysis of 2-amino-3,5-dicyano-6-phenyl-4H-pyran (1) afford HNCO, acrylonitrile, cinnamonitrile, and 2-hydroxy-3,5-dicyano-6-phenylpyridine. Pyrolysis of 2-carboxyimino-3,5-dicyano-6-phenyl-4H-pyran (2) gives HCN, acrylonitrile, cinnamonitrile and 2-hydroxy-3,5-dicyano-6-phenylpyridine. Furthermore, both pyrolysis and photolysis of 2,6-diamino-3,5-dicyanothiopyran (3a) gives rise to HNCS, acrylonitrile and 6-amino-3,5-dicyano-6-mercaptopyridin. Moreover, comparative studies of pyrolysis and photolysis of 2,6-dicyano-4-arylthiopyran derivatives3b–d revealed similar results. The similarity of products obtained from pyrolysis and photolysis and the mechanistic implications of these data are discussed.

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Pyrolyse- und Photolyseprozesse von Pyran- und Thiopyranderivaten

Zusammenfassung Pyrolyse und Photolyse von 2-Amino-3,5-dicyano-6-phenyl-4H-pyran (1) ergeben HNCO, Acrylnitril, Zimtsäurenitril und 2-Hydroxy-3,5-dicyano-6-phenyl pyridin. Durch Pyrolyse von 2-Carboximino-3,5-dicyano-6-phenyl-4H-pyran (2) entstehen HCN, Acrylnitril, Zimtsäurenitril und 2-Hydroxy-3,5-dicyano-6-phenylpyridin. Weiters resultieren sowohl Photolyse als auch Pyrolyse von 2,6-Diamino-3,5-dicyanithiopyran (3a) in der Bildung von HNCS, Acrylnitril und 6-Amino-3,5-dicyano-6-mercaptopyridin. Vergleichende Untersuchungen zur Pyrolyse und Photolyse von 2,6-Dicyano-4-arylthiopyranderivaten (3b–d) lieferten vergleichbare Ergebnisse. Die Ähnlichkeit der Resultate von Pyrolyse und Photolyse sowie die sich daraus ergebenden mechanistischen Implikationen werden diskutiert.

     

Ring transformations of 4H-pyrans. Pyridines from 2-amino-4H-pyrans

Ring transformations of 4H-pyrans into pyridines are reported. Treatment of 2-amino-4,6-diaryl-3,5-dicyano-4H-pyrans (I) with nitrosylsulfuric acid brings about their transformation into 3,5-dicyano-4,6-diaryl-2-pyridones (VI) which can also be obtained from α-benzoylcinnamonitriles (IX) and cyanoacetamide. Similarly, 2-amino-4,6-diaryl-5-carbethoxy-3-cyano-4H-pyrans (II) lead to 4,6-diaryl-5-carbethoxy-3-cyano-2-pyridones (VII). Treatment of both series of pyrans with sulfuric acid results in the formation of the corresponding 3,4-dihydro-2-pyridones (IV and V). Reaction of pyrans II with ammonium acetate in acetic acid yields 2-amino-4,6-diaryl-5-carbethoxy-3-cyanopyridines (XII). Pyrans I undergo an entirely different type of reaction upon treatment with this reagent leading to 2,4,6-triaryl-3,5-dicyano-1,4-dihydropyridines (XV).     

Reaction of 2,6-dibutylaminohepta-2,5-dien-4-one with malononitrile

Malononitrile reacted with the title compound to give 6-amino-5-cyano-2-(3,3-dicyano-2-methylallylidene-4-methyl-2H-pyran (3). Treatment of 3 with hot 80% sulfuric acid yielded 4,7-dimethyl-56-hydroxy-2(1H)quinolone. With concentrated aqueous sodium hydroxide, 3 gave 5-amino-3,6-dicyano-4,7-dimethyl-2(1H)quinolone and 5-amino-6-carbamoyl-3-cyano-4,7-dimethyl-2(1H)quinolone. The reaction of 3 with hydrochloric in acetic acid gave a mixture of 6-amino-3,7-dicyano-2,8-dimethyl-4-quinolizone and 3-cyano-4-methyl-6-(3,3-dicyano-2-methylallyl)-2-pyrone. Compound 3 also reacted with methylamine, butylamine and piperidine to give 8-amino-5-cyano-4-methyl-2-pyridone, 6-bulylamino-5-cyano-4-methyl-2-pyridone and 5-eyano-4-methyl-6-piperidino-2-pyridone respectively.     

The mannich reaction in the synthesis of N,S-containing heterocycles 4. Aminomethylation of 6-amino-3,5-dicyano-1,4-dihydropyridine-2-thiolates: A convenient regioselective route to 3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene derivatives

Treatment of N-methylmorpholinium 4-R-6-amino-3,5-dicyano-1,4-dihydropyridine-2-thiolates (R = 2-ClC₆H₄ and 2-MeOC₆H₄) with primary amines in the presence of an excess of formaldehyde gave 13-R-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-1,9-dicarbonitrile derivatives in high yields (66–95%). In a similar way, aminomethylation of 3-R-10-amino-7,11-dicyano-9-aza-3-azoniaspiro[5.5]undeca-7,10-diene-8-thiolates (R = Me and Et) afforded 1′-alkyl-8-thioxospiro[3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-13,4′-piperidine]-1,9-dicarbonitriles in 43–91% yields. Alternatively, these compounds were obtained by multicomponent cyclocondensation of N-alkylpiperidin-4-ones, cyanothioacetamide, primary amines, and aqueous formaldehyde. The starting 3-R-10-amino-7,11-dicyano-9-aza-3-azoniaspiro[5.5]undeca-7,10-diene-8-thiolates were prepared by a new method from N-alkylpiperidin-4-ones and cyanothioacetamide. The structure of 5,11-bis(4-ethoxyphenyl)-13-(2-methoxyphenyl)-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-1,9-dicarbonitrile was examined by X-ray diffraction analysis. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1014–1022, May, 2007.     

Synthesis and structure of 6-amino-3,5-dicyano-4-heptylpyridine-2(1H)-thione

Condensation of caprylic aldehyde with cyanothioacetamide taken in a ratio of 1:2 affords 6-amino-3,5-dicyano-4-heptylpyridine-2(1H)-thione. The structure of the thione was studied by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–198, January, 1997.     

Recyclization of 2,6-Diamino-4-aryl(cyclohexyl)-3,5-dicyano-4<Emphasis Type="Italic">H</Emphasis>-thio(seleno)pyrans

Recyclization of 2,6-diamino-4-aryl(cyclohexyl)-3,5-dicyano-4H-thio(seleno)pyrans in the presence of an equimolar amount of an α-bromo carbonyl compound, ethyl iodide, 1,2-dibromoethane, or 3-chlorophenyl isocyanate yields, respectively, 3-aryl(cyclohexyl)-2-[thiazol(selenazol)-2-yl]acrylonitriles, 6-amino-4-phenyl-2-ethylsulfanyl-1,4-dihydropyridine-3,5-dicarbonitrile, 5-amino-7-phenyl-2,3,4,7-tetrahydrothiazolo[3,2-a]pyridine-6,8-dicarbonitrile, or N,N′-bis(3-chlorophenyl)urea.     

Synthesis of N-methylmorpholinium 6-oxo-3,5-dicyano-1,4,5,6-tetrahydro-4-(spirocyclopentane)pyridine-2-thiolate with the Michael reaction

N-Methylmorpholinium 6-oxo-3,5-dicyano-1,4,5,6-tetrahydro-4-(spirocyclopentane)pyridine-2-thiolate was obtained by reaction of cyclopentylidenecyanoacetic ester with cyanothioacetamide or cyclopentylidenecyanothioacetamide with cyanoacetic ester in the presence of N-methylmorpholine; it is used in synthesis of substituted 2-alkylthiotetrahydropyridines, 5-oxo-6,8-dicyano-2,3,6,7-tetrahydro-(5H)-7-(spirocyclopentane)-thiazolo[3,2-a]pyridine, 5-allyl-2-methylthio-3,5-dicyano-4,5-dihydro-4-(spirocyclo-pentane)pyridin-6(1H)-one, and 3-amino-6-oxo-5-cyano-4,5-dihydro-4-(spirocyclopentane)-2H-pyrazolo[5,4-b]pyridin-6(7H)-one. T. G. Shevchenko Lugansk State Pedagogical Institute, Lugansk 348011, Ukraine, N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 208–212, February, 1998.     

1,2,4-Triazines, 9. The synthesis of novel 4-amino-1,6-dihydro-1,2,4-triazinones

3-Alkylthio-4-amino-1,6-dihydro-1,2,4-triazin-5(4H)-ones were synthesized by the reduction of 3-thio-4-amino-1,2,4-triazine-3,5(2.H,4H)-diones and successive S-alkylation. The regiospecific alkylation on the N-1 position or the exo amino group leads to a variety of 1,6-dihydro-1,2,4-triazin-5(4H)-one derivatives. An alternative synthesis of 3-thio-4-amino-1,6-dihydro-1,2,4-triazine-3,5(2H,4H)-diones was accomplished through the cyclization of 1-thiocarbohydrazidoacetamide derivatives.     

Synthesis of 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones and their conversion into 2-aryl-1,2,4-triazine-3,5-(2H,4H)odiones. A new synthesis of 1-aryl-6-azauracils

Treatment of 6-amino-5-arylazo-1,3-dimethyluracils with urea or N,N′-carbonyldiimidazole gave the respective 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones, which were hydrolyzed with alkali to afford 2-aryl-2,3,4,5-tetrahydro-3,5-dioxo-1,2,4-triazine-6-carboxylic acids (1-aryl-6-azauracil-5-carboxylic acids). Thermal decomposition of these carboxylic acids gave the corresponding 2-aryl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-6-azauracils). Methylation of the latter with methyl iodide gave the corresponding 2-aryl-4-methyl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-3-methyl-6-azauracils).     

The Mannich reaction in the synthesis of N,S-containing heterocycles 8. Aminomethylation of 3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates as a method for the synthesis of new functionally substituted 3,7-diazabicyclo[3.3.1]nonane derivatives

Aminomethylation of 3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates upon treatment with primary amines and excess formaldehyde leads to 3,7-diazabicyclo[3.3.1]nonane derivatives. N-Methylmorpholinium 4-(2-chlorophenyl)-3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolate was obtained by the reaction of (E)-3-(2-chlorophenyl)-2-cyanoprop-2-enethioamide with 1-cyanoacetyl-3,5-dimethylpyrazole and N-methylmorpholine in acetone in quantitative yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2397–2400, December, 2007.     

Synthesis of 2,4-diamino-9H-indeno[2,1-d]pyrimidines

As part of a search for new antifolic, antimalarial, and antitumor agents, a series of 2,4-diamino-9H-indeno[2,1-d]pyrimidines was prepared by condensation of guanidine with substituted 2-alkoxy-3-cyano-1H-indenes. Base-catalyzed cyclization of 1,2-bis(cyanomethyl)benzenes afforded 2-amino-3-cyano-1H-indenes, which were converted into 3-cyano-2-methoxy-1H-indenes by acid hydrolysis and treatment of the resultant 1-cyano-2-indanones with diazomethane. Alternatively, 2-amino-3-cyano-1H-indenes could be transformed directly into 2-ethoxy-3-eyano-1H-indenes by reaction with ethanol and sulfuric acid. The 2,4-diamino-9H-indeno[2,1-d]-pyrimidines represent a new type of planar, tricyclic pyrimethamine analog, in which free rotation of the phenyl and pyrimidine rings is prevented by means of a methylene bridge.     

Synthesis and alkylation ofN-methylmorpholinium 6-amino-3,5-dicyano-4-methylpyridine-2-thiolate

The condensation of acetaldehyde with a twofold excess of cyanothioacetamide andN-methylmorpholine givesN-methylmorpholinium 6-amino-3,5-dicyano-4-methylpyridine-2-thiolate. This compound is also formed by recyclization of 2,6-diamino-3,5-dicyano-4-methyl-4H-thiopyran. From this pyridinethiolate, several substituted 2-alkylthiopyridines and 3,6-diamino-5-cyano-4-methyl-2-methoxycarbonylthieno[2,3-b]pyridine were obtained.     

Structural reassignment of the alleged 6-hydroxy-1,2,4-triazine-3,5-(2H,4H)dione

The reaction of 6-amino-1,2,4-triazine-3,5-(2H,4H)clione with sodium hydroxide or nitrous acid has been shown to give 5-hydroxy-1,2,4-triazole-3-carboxylic acid instead of 6-hydroxy-1,2,4-triazine-3,5-(2H,4H)dione as reported in the literature. The triazolecarboxylic acid was also obtained from the aminotriazine and hydrochloric acid.     

An Efficient Mannich-Type One-Pot Synthesis of 3,5,7,11-Tetraazatricyclo [7.3.1.02,7]tridec-2-ene Derivatives Starting from Functionalized 1,4-Dihydropyridines

3,5,7,11-Tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene derivatives were prepared in one-pot manner from N-methylmorpholinium 6-amino-3,5-dicyano-4-spiro(1′-cycloalkane)-1,4-dihydropyridine-2-thiolates, primary amines, and formaldehyde in 70–88% yields. The structure of 5,11-dibenzyl-13-spiro(1′-cyclopentane)-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-1,9-dicarbonitrile was determined by X-ray diffraction analysis.     

An Efficient <Emphasis Type="Italic">Mannich</Emphasis>-Type One-Pot Synthesis of 3,5,7,11-Tetraazatricyclo [7.3.1.0<Superscript>2,7</Superscript>]tridec-2-ene Derivatives Starting from Functionalized 1,4-Dihydropyridines

Summary. 3,5,7,11-Tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene derivatives were prepared in one-pot manner from N-methylmorpholinium 6-amino-3,5-dicyano-4-spiro(1′-cycloalkane)-1,4-dihydropyridine-2-thiolates, primary amines, and formaldehyde in 70–88% yields. The structure of 5,11-dibenzyl-13-spiro(1′-cyclopentane)-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-1,9-dicarbonitrile was determined by X-ray diffraction analysis.     

Pseudo four-component and regioselective synthesis of 4-amino-3,5-dicyano-6-arylphthalates using triethylamine catalyst

An efficient triethylamine-catalyzed synthesis of 4-amino-3,5-dicyano-6-arylphthalates is described.A one-pot,simple pseudo four-component reaction between arylaldehydes,dialkyl acetylenedicarboxylates, and twice as much malononitrile gave 4-amino-3,5-dicyano-6-arylphthalates in good to excellent yields.     

Synthesis of 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one. Derivatives and their ring transformation into 5-benzamido-1,2,4-triazolidine-3,5-dione derivatives

Some 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one derivatives 6 and 9 have been synthesized in two ways. The expected thermal ring transformation into 2,5-disubstituted 1,3,4-oxadiazoles did not occur but, by acid hydrolysis of 5-aryl-3-[3-benzylidene-2-methyl(or phenyl)carbazoyl]-1,3,4-oxadiazol-2(3H)-ones 6 , a new ring transformation took place and the corresponding 4-benzamido-1-methyl(or phenyl)-1,2,4-triazolidine-3,5-dione derivatives 11 were formed. The 4-amino-1-phenyl-1,2,4-triazolidine-3,5-dione ( 19 ) has been prepared and its structure was confirmed by some reactions.     

Multicomponent synthesis of 2-alkylthio-6-amino-3,5-dicyano-1,4-dihydropyridine-4-spirocycloalkanes. Molecular and crystal structure of 6-amino-2-(2-methylbenzylthio)-3,5-dicyano-1,4-dihydropyridine-4-spirocyclopentane

2-Alkylthio-6-amino-3,5-dicyano-1,4-dihydropyridine-4-spirocycloalkanes were synthesized via the reaction of cycloalkylidene malononitriles with cyanothioacetamide and alkyl halides. The structure of 6-amino-2-(2-methylbenzylthio)-3,5-dicyano-1,4-dihydropyridine-4-spirocyclopentane was determined by the X-ray diffraction analysis.     

Combining Performance with Thermal Stability: Synthesis and Characterization of 5-(3,5-Dinitro-1H-pyrazol-4-yl)-1H-tetrazole and its Energetic Derivatives

In this study, we present the synthesis of 5-(3,5-dinitro-1H-pyrazol-4-yl)-1H-tetrazole and its energetic derivatives starting from 4-amino-3,5-dinitropyrazole, which was diazotized and cyanide substituted. A subsequent cycloaddition reaction with sodium azide led to 5-(3,5-dinitro-1H-pyrazol-4-yl)-1H-tetrazole ( 3 ). Several alkaline metal and nitrogen-rich salts were prepared and characterized by low-temperature X-ray diffraction. Additionally, all compounds were analyzed by vibrational spectroscopy (IR), ¹H, ¹³C and ¹⁴N NMR spectroscopy, elemental analysis and differential thermal analysis (DTA). Additionally, the heats of formation for selected compounds were calculated using the atomization method based on CBS-4M enthalpies as well as important detonation parameters by using the EXPLO5 code (V6.05). Furthermore, the sensitivities of 3 and all synthesized salts toward friction, impact and electrostatic discharge according to BAM (Bundesamt für Materialforschung) were determined and compared to RDX.     

Syntheses with nitriles. 60. Preparation of 4-amino-5-cyano-6-phenylpyrimidines from 2-amino-1,1-dicyano-2-phenylethene

The reaction of 2-amino-1,1-dicyanobut-1-ene and 2-amino-1,1-dicyano-2-phenylethene, respectively, with N,N-dimethylformamide dimethylacetal provided the corresponding (N,N-dimethylaminomethylene)amino derivatives. 2-[(N,N-Dimethylaminomethylene)amino]-1,1-dicyano-2-phenylethene was converted into 4-amino-5-cyano-6-phenylpyrimidines by treatment with primary aliphatic and aromatic amines. The structure of the reaction products was confirmed by ¹³C nmr spectroscopy.