H. Schäfer

Synthese und Reaktionen von 2-Amino-1-aryl-5-oxo-Δ2-pyrrolin-3-carbonitrilen

SummaryThe reaction of malononitrile with α-chloro acetanilides1 in presence of potassium carbonate yields the 1-aryl-5-oxo-Δ2-pyrrolin-3-carbonitriles2, in presence of triethylamine the 4,6-diamino-1-aryl-2-oxo-2,3-dihydropyrrolo[2,3-b]pyridin-5-carbonitriles3 are formed. From 2-chloroacetylamino-benzencarbonitrile and malononitrile the 5-amino-1-oxo-1,2-dihydropyrrolo[1,2-a]chinazolin-3-carbonitrile (4) arise. Analogously from the 2-chloroacetylamino-thiophen-3-carbonitries5 the 7,8-dihydro-thieno[3,2-e]pyrrolo[1,2-a]pyrimidine derivatives6 are obtainable. Hydrolysis of2 a by treatment with hydroxide or acid, respectively, yields the 1,1,2-ethanetricarboxylic acid and derivatives9 a,b. Phenyldiazonium salt reacts with2 to form the triazene 7 only.

Synthese und Reaktionen von 2-Arylhydrazono-2-cyan-N,N-dialkyl-acetamidinen

SummaryThe title compounds3 were synthesized by reaction of arlyhydrazono-malononitriles1 with secondary amines and used for subsequent cyclization reactions. Thus,3 undergoes cyclooxidation by treatment with CuSO4/pyridine to form the 5-dialkylamino-2-aryl-1,2,3-triazolo-4-carbonitriles4. From4 a and hydrazine hydrate/DMF the 4-(1,3,4-triazolyl-5)-1,2,3-triazole5 c is obtainable. The chloroacetylation of3 is accompanied by hydrolysis of the amino group to yield the arylhydrazono-N-chloracetyl cyanoacetamides6. The quaternisation of6 with pyridins is followed by the Thorpe cyclization to form the 4-amino-5-arylazo-6-hydroxy-3-pyridinio-pyrid-2-on-chlorides8, useful as cationic dyes. The reaction of3 with trichloroacetonitriles yields the 5-arylazo-4-imino-2-trichlormethyl-1,4-dihydropyrimidines10 a–c which can be converted into the 5-arylazo-2-hydrazino-pyrimidine derivatives10 d–f.From10 d the 6-phenylazo-triazolo[4,3-a]pyrimidine derivative11 is obtainable. From3 and phenylisothiocyanate the 5-arylazo-4-imino-1,4-dihydropyrimidin-2-thiones12 arise. The structures were investigated by13C-NMR-spectroscopy.

Zur Synthese von 4-Aminochinolinen durch intramolekulareFriedel—Crafts-Reaktion

Treatment of arylaminomethylene-malononitriles,-cyanoacetamides and-ω-cyanoacetophenones with AlCl3 yields substituted 4-aminoquinolines2, while quinolin-4-ones3 are obtained from ethyl arylaminomethylene cyanoacetates. N-β-naphthylcyanoacetamide reacts in the presence of AlCl3 to form 1-amino-3-benzo[f]quinolinone (6). Isothiazolo[4,3−c]quinolines (10) and pyrimido[5,4−c]quinolines (11, 12) can be obtained from2. 4-Aminoquinoline-3-carboxylic acids derived from2, can be decarboxylated.3 are cyclized to form oxazino[5,6−c]-quinolinones (4).

Synthese neuartig substituierter Pyridazin-6(1H)-one

SummaryArylhydrazono acetamides1 react with chloroacetic acid chloride to give N-chloroacetyl derivatives2. Subsequent reaction with pyridines followed by ring closure yield 1-(4-amino-6-oxo-pyridazin-5-yl)-pyridinium chlorides3. Analogously, 1-(6-oxo-pyridazin-5-yl)-pyridinium chloride (5) and 6-oxo-5-pyridinio-pyridazin-4-olate (4) are formed from phenylhydrazono derivatives and pyridine. Treatment of3 and4 with hydrazinium hydrate gives 4,5-diamino-6-oxo-pyridazin-3-carbohydrazides6 and 5-amino-4-hydroxy-pyridazin-6(1H)-one (8). An analogous ring cleavage of3e and5 gives rise to 4,5-diamino- and 5-amino-pyridazin-6(1H)-ones7. On treatment of the pyridinium salts3 with caustic soda in water, nucleophilic addition of the amino group to the pyridinium ring takes place and stable dehydrated products9 are isolated.

Zur Synthese und Struktur von 8-Nitro-imidazo [1,2-a]pyridinen

SummaryThe title compounds were synthesized by reaction of nitroketene aminals with β-chlorovinylcarbonyl compounds. The chloromethylene malononitriles1 react with nitromethylenimidazolin (2 a) and -benzimidazoles2 b to yield the 8-nitro-2,3-dihydroimidazo[1,2-a]pyridines3 and the 4-nitropyrido[1,2-a]-benzimidazoles6, both containing an amino group. Analogously, from the special 3-chloro-2-propeniminium salt7 and2 a the imidazopyridine derivative9 was formed. The 3-aryl-3-chloro-2-propeniminium salts10 were converted into the nitro-dihydroimidazo[1,2-a]pyridines11 and the pyrido[1,2-a]benzimidazole12 containing the aryl group by reaction with2 a and2 b, respectively. The structures were investigated by 2-dimensional1H/13C-NMR-spectroscopy.

New syntheses of 2,4-diaminopyrroles and aminopyrrolinones

SummaryOxazolin-2-ylidene-malononitriles3a–d, obtainable from thioketenaminals and α-halogen-ketones, react with primary and secondary amines to afford 2,4-diamino-pyrroles5a–h. Mercaptobenzen as nucleophilic agent gives the 4-amino-2-phenylthio-pyrrole5j. Analogously, cyano-(3,5-diphenyl-3H-oxazol-2-ylidene)-acetic acid methyl esters were prepared as intermediates for the synthesis of 2-amino-4-oxo-pyrrolines10a–d. The isomeric 4-amino-2-oxo-pyrrolines13a–d can be obtained from 4-amino-2-methoxy-pyrroles, which serves as proof for the position of substituents. The structures were investigated by1H and13C NMR spectroscopy.ZusammenfassungDie Oxazolin-2-yliden-malononitrile3a–d. die aus Thioketenaminalen und α-Halogenketonen erhalten wurden, reagieren mit primären und sekundären Aminen zu den 2,4-Diaminopyrrolen5a–h. Mercaptobenzol als nukleophiles Reagens liefert 4-Amino-2-phenylthiopyrrol (5j). Analog wurden Cyan-(3,5-diphenyl-3H-oxazol-2-yliden)-essigsäuremethylester als Zwischenprodukte für die Synthese der 2-Amino-4-oxo-pyrroline10a–d hergestellt. Die isomeren 4-Amino-2-oxo-pyrroline13a–d können aus den 4-Amino-2-methoxy-pyrrolen11a,b erhalten werden, was als Nachweis für die Position der Substituenten dient. Die Verbindungen wurden1H- und13C NMR-spektroskopisch untersucht.

Syntheses with pyridinium and sulfonium salts of acylated β-enaminonitriles

SummaryPyridinium and sulfonium salts2a–e which can be prepared from 3-amino-2-(α-haloacetyl)-crotonitriles and 3-amino-2-(α-halo-acetyl)-3-phenyl-acrylonitriles react with malononitrile in the presence of a base to 3-amino-2-pyridinio-phenolates3a,b and 3-amino-2-sulfonio-phenolates3c–e. In an analogous way, 3-amino-2-(diethyloxyphosphoryl)-phenol5a and 3-amino-2-(p-tolyl-sulfonyl)-phenol5b have been prepared. 2,3-Diamino-phenoles6a,b are formed from the pyridinium salts3a,b. The behaviour of the pyridinium salts2a,b towards heterocumulenes has been investigated. Cyanamide leads to the (2-amino-4-hydroxy-pyrid-3-yl)-pyridinium salt8c. Phenylisothiocyanate gives the 3-pyridinio-2-thioxo-pyridin-4-olates9a,b. Carbon disulfide gives rise to 3-pyridinio-2-thioxo-pyridin-4-olate10 or 3-pyridinio-2-thioxo-thiopyran-4-olate11, depending on the substituent at the 6-position. Phenylisocyanate reacts to the pyrimidin-2,4-dione12 with loss of N-methyl-pyridinium chloride. S-methylation of9a and cleavage of the pyridine moiety yields the 3-amino-2-methylthio-pyrid-4-one14. The structures were investigated by1H and13C NMR spectroscopy.ZusammenfassungPyridinium- und Sulfoniumsalze2a–e, die aus 3-Amino-2-(α-halo-acetyl)-crotonsäurenitril und 3-Amino-2-(α-halo-acetyl)-zimtsäurenitril hergestellt werden können, reagieren mit Malonsäuredinitril in Gegenwart einer Base zu 3-Amino-2-pyridinio-phenolaten3a,b und 3-Amino-2-sulfonio-phenolaten3c–e. In Analogie wurden 3-Amino-2-(diethyloxyphosphoryl)-phenol5a und 3-Amino-2-(p-tolyl-sulfonyl)-phenol5b erhalten. 2,3-Diamino-phenole6a,b werden aus den Pyridiniumsalzen3a,b gebildet. Das Verhalten der Pyridiniumsalze2a,b gegenüber Heterokumulenen ist untersucht worden. Cyanamid führt zum (2-Amino-4-hydroxy-pyrid-3-yl)-pyridiniumsalz8c. Phenylisothiocyanat liefert die 3-Pyridinio-2-thioxo-pyridin-4-olate9a,b. In Abhängigkeit vom Substituenten in der Position 6 entsteht bei der Reaktion mit Schwefelkohlenstoff ein 3-Pyridinio-2-thioxo-pyridin-4-olat10 oder ein 3-Pyridinio-2-thioxo-thiopyran-4-olat11. Phenylisocyanat reagiert zum Pyrimidin-2,4-dion12 unter Verlust von N-Methyl-pyridiniumchlorid. S-Methylierung von9a und Spaltung des Pyridiniumringes ergibt das 3-Amino-2-methylthio-pyrid-4-on14. Die Verbindungen wurden1H- und13C-NMR-spektroskopisch untersucht.