Nitroketenaminale, 7. Mitt.: Synthese von substituierten 2-Amino-3-nitropyridinen aus 1,3-Biselektrophilen und 2-Nitroethen-1,1-diamin

Nitroketenaminals, VII: Synthesis of Substituted 2-Amino-3-nitropyridines from 1,3-Biselectrophiles and 2-Nitroethen-1,1-diamine The reaction of the enones 1a-f with the nitroketenaminal 2 leads to the 4,6-disubstituted 2-amino-1,4-dihydro-3-nitropyridines 3a-f . Compounds 3a-c,f are oxidized in low yields by air to the pyridines 4a-c,f . 5- and 6- substituted 2-amino-3-nitropyridines ( 9a,b and 11 ) can be prepared from 2, 8a,b , and 10 , respectively.     

Synthese und pharmakologische Prüfung von 2- und 3-substituierten Pyrano[2,3-b]indolonen

Synthesis and Pharmacological Test of 2- and 3-Substituted Pyrano[2,3-b]indolones . The condensation of oxindole (3a) with ethyl 2-methylacetoacetate (6b) leads to the propionyloxindole 4 . With the acetal esters 6f, 6g and 6h and the cyclic β-ketoesters 12, 13 and 14 the reaction results in the 3-acyloxindoles 7f, 7c , and 7d or 7h and 15a, 15b, 15c . These can be cyclised to the 2- and 3-substituted pyrano[2,3-b]indolones 16a–16c and 17a–17c .     

Thiophen als Strukturelement physiologisch aktiver Substanzen, 2. Mitt. Die Synthese von basisch substituierten 3H-Thieno[2,3-d]-imidazolen

Thiophene as a Structural Element of Physiologically Active Compounds, II: Synthesis of Base-Substituted 3H-Thieno[2,3-d]imidazoles The synthesis of the substituted 3H-thieno[2,3-d]imidazoles 14 and 15 is described. It proceeds by Curtius rearrangement of (acylalkylamino)thiophenecarbonylazides 11 .     

Chinazolinone, 1. Mitt. Synthese von Indolo[2,1-b]chinazolinonen

Quinazolinones, I: Synthesis of Indolo[2,1-b]quinazolinones Three routes are described for the synthesis of the new indolo[2,1-b]quinazolinones 2a–2d . Reaction mechanisms are discussed.     

Anellierte Thiopyrone, 1. Mitt. Thiopyrano[3,2-b]indol-4(5H)-one,Thiopyrano[2,3-b]indol-4(9H)-one als Nebenprodukte

Fused Thiopyrones, I: Thiopyrano[3,2-b]-indol-4(5H)-ones, Thiopyrano[2,3-b]indol-4(9H)-ones as Byproducts The 3-(3-indolylthio)acrylic acids 3 cyclize with polyphosphoric acid (PPA) to yield the isomeric title compounds 4 and 5 , which are characterized by their sulfones, thiones and oxonol dyes.     

Synthese von Carbazolderivaten, 2. Mitt.: 2-Substituierte Indole als Zwischenprodukte von Pyrrolino[3,4-c]carbazolen

Synthesis of Carbazole Derivatives, II: C-2-substituted Indoles as Intermediates of Pyrrolino[3,4-c]carbazoles Starting from the indole derivatives 4, 7 and 15 Grignard reaction, nucleophilic substitution at the pertinent dithian, and Wittig reaction afford preparatively useful side chains. By intramolecular Michael reaction the pertinent compounds lead to the pyrrolidino- and pyrrolino[3,4-c]carbazoles 32 and 33 , respectively.     

Einfache Synthese von Isochino[2,3-c][2,3]benzoxazepinon und -[2,3]benzodiazepinonen sowie ihrer Vorstufen

Facile Synthesis of Isoquino[2,3-c][2,3]benzoxazepinone and -[2,3]benzodiazepinones and Their Precursors The isoquinolones 8a , 11a and 17 can be prepared easily from 6 , ammonia and hydroxylamine or hydrazine ( 14a ). By dehydration the isoquino-fused isoquinolone 9 , 2,3-benzoxazepinone 13 and 2,3-benzodiazepinone 16a are obtained. Reactions of the dicarboxylic acid 4 with the hydrazines 14a - c afford the 2,3-benzodiazepines 15a , b and 21 . The oxime 10 rearranges thermally, probably via 13 , to form the phthalide 12 .     

Heterocyclen via Mannich-Kondensation, 6. Mitt. Synthese von 2-Amino-3-pyridyl-phenylketonen

Heterocycles via Mannich Condensation, VI: Syntheses of 2-Amino-3-pyridylphenyl Ketones The ethyl 2-benzoylacetimidates 1a-c and 2-benzoylacetamidine (2a) exist in solution as enols. Ketonic Mannich bases condense with 1a-c and 2a to yield 2-amino-3-pyridylphenyl ketones.     

Thiophen als Strukturelement physiologisch aktiver Substanzen, 6. Mitt. Die Synthese von cis- und trans-Octahydro-thieno[2,3-c] chinolinen

Thiophene as a Structural Element of Physiologically Active Compounds, VI: The Synthesis of cis- and trans-Octahydrothieno[2,3-c]quinolines . Two methods are described for the preparation of 3 , which is the key starting material for the synthesis of the title compounds 15 and 16 . Compound 12 is reduced to the diastereomeric amines 13 and 14 , which are subjected to the Pictet-Spengler reaction to yield compounds 15a and 16a . Both enantiomers of 15a were isolated.     

Synthese von 5H-Pyrido[2,3-c]-2-benzazepinen

Synthesis of 5H-Pyrido[2,3-c]-2-benzazepines The title compounds can be obtained by two differend ways: Ring closure of 2-benzazepine enaminonitrile 1 and the C₂-building blocks 2, 7 and 8 gives rise to the title compounds 6, 9 and 10 . - The second way starts with Wolff-Kishner-reduction of the 2-amino-3-benzoylpyridines 16a,b to the 2-amino-3-benzylpyridines 18a,b . Benzoylation of 18a,b leads to the dibenzoylated compounds 20 and 21 , respectively, which can be transformed to the monobenzoylated pyridines 22 resp. 23 . Applying the Bischler-Napieralski-reaction on 22a,b and 23a,b leads to the 5H-pyrido[2,3-c]-2-benzazepines 24a,b and 25a,b . By means of ¹H-, ¹³C- and ¹⁵N-NMR-data it is demonstrated that ethyl benzoylcyanacetimidate ( 12a ) exists as benzoylketene-O,N-acetal 12a AE .     

Verbesserte Synthese von methyl- und phenylsubstituierten Pyrido[2,3-d]pyrimidin-2,4-diaminen

Improved Synthesis of Methyl- and Phenyl-substituted Pyrido-[2,3-d]pyrimidine-2,4-diamines The title compounds 4b-g, 10a,b and 13 can be prepared in improved yields by “cyclocondensation” of the 1,3-biselectrophiles la-e, 5b,f,g, 7b,d, 8a,b , and 12 with 2,4,6-triaminopyrimidine ( 2 ).     

Reaktionen an Heterocyclen mit 2-Acyl-2-propenon-Teilstruktur, 3. Mitt. Pyrido[3,2-c]cumarine aus 3-substituierten 1-Benzopyranen und Enaminen

Reactions with Heterocycles Containing a 2-Acyl-2-propenone Structure, III: Pyrido[3,2-c] coumarins from 3-Substituted 1-Benzopyrans and Enamines 4-Oxo-4H-chromene-3-carbaldehydes 1 react with enamines 2 and 3 to form 5-hydroxy-5H-[1]benzopyrano[4,3-b] pyridines 4 and 5 . Oxidation of the products leads to pyrido[3,2-c]coumarines 6 and 7 which are also obtained directly from the 4-oxo-4H-chromene-3-carboxylic acid 8 and from the carboxylic acid ester 9 . From the chromanone Mannich base 14 the pyridocoumarine 6a can be obtained by C-alkylation of the enamine 2 , cyclisation, and oxidation with chromium(VI) oxide.     

Anellierte Thiopyrone, 5. Mitt.1): Darstellung und Reaktionen von 3-Formyl-indeno[1,2-b]-, -[1]benzofuro[3,2-b]-, -[1]-benzothieno[3,2-b]thiopyronen und 3-Formyl-thiopyrono[3,2-b]indolen

Fused Thiopyrones, V: Syntheses and Reactions of 3-Formyl-indeno[1,2-b]-, -[1]benzofuro[3,2-b]-, -[2]benzothieno[3,2-b]thiopyrones, and 3-Formyl-thiopyrono[3,2-b]indoles Alternative syntheses of the title compounds are described. The configuration of the oximes, obtained from the aldehydes, is proved. Furthermore the syntheses of the nitriles and the carboxylic acids is presented.     

Anellierte Thiopyrone, 2. Mitt. Thiopyrano[3,2-b]indol-4(5H)-on- und Thiopyrano[2,3-b]indol-4(9H)-on-2-carbonsäuren

Fused Thiopyrones, II; 2-Carboxylic Acids of Thiopyrano [3,2-b]indol-4(5H)-one and Thiopyrano[2,3-b]indol-4(9H)-one 3-Indolylthiofumaric acids 2 are cyclized by polyphosphoric acid (PPA) to yield the isomeric title compounds 6 and 8 .     

1,2-Cyclisierungsreaktionen an Indolderivaten, 5. Mitt. Synthese von 3H-Pyrrolo[1,2,-a] indol-3-onen

Synthesis of 3H-Pyrrolo[1,2-a]indole-3-ones The reaction of some 3-substituted indoles with diketene leads to the 1-acetoacetyl-indoles 1b – f . These and 1-acetoacetyl-indole ( 1a ) cyclize with polyphosphoric acid (PPA), forming the 3H-pyrrolo-[1,2-a]indole-3-ones 2a – f .     

Regiospezifische Synthese von 2-Phenyl-pyrano[3,4-b]pyranonen (Oxaflavon-Derivaten) mit Tetrahydro-3-pyranon

Regiospecific Synthesis of 2-Phenylpyrano[3,4-b]pyranones (Oxaflavone Derivatives) with Tetrahydro-3-pyranone Under controlled conditions tetrahydro-3-pyranone ( 5 ) reacts with trimethylchlorosilane regiospecifically to yield the enolether 6 . Cleveage with methyllithium and reaction with cinnamoyl chloride furnishes the 4-cinnamoylpyranone 8 . Proton catalysed cyclisation and dehydrogenation with DDQ afford the pyrano[3,4-b]pyranones 9 and 10 .     

Nitroketenaminale, 8. Mitt.: Synthese von 4-Aryl-2,6-diamino-3,4-dihydro-3,5-dinitropyridinen

Nitroketenaminals, VIII: Synthesis of 4-Aryl-2,6-diamino-3,4-dihydro-3,5-dinitropyridines The synthesis of the title compounds 5 resp. 7 from aldehydes 2 resp. 6a , b and primary/tertiary nitroketenaminals 1c,d,e is described. The reaction of 1b and 2 leads to a 1,4-dihydropyridine 5bA .     

Anellierte Thiopyrone, 3. Mitt. Sulfone aus Thiopyrano[3,2-b]indol-4(5H)-on- und Thiopyrano[2,3-b]indol-4(9H)-on-2-carbonsäuremethylestern

Fused Thiopyrones, III: Sulfones from Methyl 4,5-Dihydro-4-oxothiopyrano[3,2-b]indole-2-carboxylate and Methyl 4,9-Dihydro-4-oxothiopyrano[2,3-b]indole-2-carboxylate On treatment with m-chloroperbenzoic acid (mCPBA) the thiopyrones 1 and 4 are oxidized to the sulfones 2 and 5 , which add ethanol to yield the thiopyranosulfones 3 and 6 as mixtures of diastereomers. In one case a 3-hydroxy compound ( 7 ) could be isolated.     

Heterocyclen via Mannichbasen, 7. Mitt. Synthese von Pyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-9(4H)-onen

Heterocycles via Mannich Bases, VII: Synthesis of Pyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-9(4H)-ones The title compounds 4 are synthesised from 5-amino-3-methylpyrazolo[1,5-a]pyrimidin-7(4H)-one (2) and ketone Mannich bases or dehydro Mannich bases.