Synthese von 2,2a,3,4-Tetrahydro-azeto[1,2-d]benz[b]-1,4-oxazin-2,4-dionen

Synthesis of 2,2a,3,4-Tetrahydroazeto[1,2-d]benzo[b]-1,4-oxazine-2,4-diones The 1-(2-hydroxyaryl)-4-oxoazetidine-2-carboxylic acids 7c, 7d and 10 react with dicyclohexylcarbodiimide to give the title compounds 11, 12 and 13 . Compound 13 can also be obtained by nitration of 12 . The starting materials 7c , 7d and 10 are synthesized from the l-aryl-4-oxoazetidine-2,2-dicarboxylates 4a and 4b , which are available from 1 by a method analogous to that described by Sheehan²⁾ or via 8 and 9 .     

Heterocyclen, 57. Mitt. Synthese von Thiazolo[4,5-d]pyridazinen

Heterocycles LVII: Syntheses of Thiazolo[4,5-d]pyridazines The syntheses of some 4-substituted 5-ethoxycarbonyl-2-phenylthiazoles and of some 7-substituted thiazolo[4,5-d]pyridazines are described.     

Heterocyclen, 46. Mitt. Synthese von Thiazolo[4,5-d]pyridazinen

On Heterocycles, XLVI: Syntheses of Thiazolo[4,5-d]pyridazines The syntheses of some 5-acetyl-2-aryl-4-formyl thiazoles and of some thiazolo[4,5-d]pyridazines are described.     

Synthese und Eigenschaften von 3-Alkoxy-3,4-dihydro-2H-1,3-benzothiazin-2,4-dionen

Synthesis and Properties of 3-Alkoxy-3,4-dihydro-2H-1,3-benzothiazine-2,4-diones The reaction of 2-mercaptobenzoic acid, 1,1′-carbonyldiimidazole and O-alkylhydroxylamine affords 3-alkoxy-3,4-dihydro-2H-1,3-benzothiazine-2,4-diones 3 . Acid catalyzed methanolysis of the tetrahydropyranyloxy group in 3d gives the cyclic N-hydroxy imide 3e , which can be easily acylated with benzoyl chloride or 4-tolylisocyanate giving rise to the benzothiazine derivatives 3f and 3g .     

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.     

Bicyclische α-Aminosäuren, 3. Mitt. Zur Synthese von 2-(1-Tetralyl)- und 2-[5-(5,6,7,8-Tetrahydro)-chinolyl]-glycin

Bicyclic α-Amino Acids, III: On the Preparation of 2-(1,2,3,4-Tetrahydronaphthalen-1-yl)- and 2-(5,6,7,8-Tetrahydroquinoline-5yl-)glycine Attempted halogenation of 2 does not yield the expected bromo(1,2,3,4-tetrahydronaphthalen-1-yl)acetic acid 4 but the cyclic ketone 3 . The α-ketoesters 5 can be decarbonylated to yield the substituted malonic esters 6 . Compounds 6a and 7a react with isopropyl nitrite to yield the oximinocarboxylic acid 8a which can be hydrogenated at room temperature to yield the title compound 9a . Hydrogenation at 80° C leads to the decalylamino acid 10a . The analogous sequence of reactions ( 6b and 7b→8b→9b ) fails to yield tetrahydroquinolinylglycine 9b .     

Synthese von 5-Aryl-5,8-dihydropyrido[2,3-d]pyrimidin-2,4-diaminen

Syntheses of 5-Aryl-5,8-dihydropyrido[2,3-d]pyrimidine-2,4-diamines 2,4,6-Triaminopyrimidine (2) is reacted with 3,4,5-trimethoxybenzylidene-1,3-dicarbonyl compounds of type 1 to yield the Michael adducts 3 which are cyclised in acidic medium to the 5,8-dihydropyrido[2,3-d]diamines 5 . The title compounds possess a rigid trimethoprim structure and are of interest as potential inhibitors of dihydrofolate reductase (DHFR).     

Bicyclische α-Aminosäuren, 2. Mitt. Zur Synthese von 3-(1-Tetralyl)- und 3-[5-(5,6,7,8-Tetrahydro)-chinolyl]-alanin

Bicyclic α-Amino Acids, II. On the Preparation of 3-(1-Tetralyl)-and 3-[5-(5,6,7,8-Tetrahydro)quinolyl]alanine Carbonyl olefination of the tetralones 4 does not yield the expected compounds 6 but the isomeric acetic acid derivatives 7 with endocyclic double bond, from which the ketoesters 10 can be prepared via intermediates 8 and 9 . Saponification of 9 and 10 fails to yield the α-ketoacids 11 and 12 .     

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 .     

Dihydroisochinolinumlagerung, 36. Mitt. Synthese von 9,10-Dimethoxy-1-(3,4-dimethoxyphenyl)-1,2,3,4-tetrahydro-11bH-benzo[a]chinolizin

Dihydroisoquinoline Rearrangement, XXXVI: Synthesis of 9,10-Dimethoxy-1-(3,4-dimethoxy-phenyl)-1,2,3,4-tetrahydro-11bH-benzo[a]e Starting from papaverine the title compound 1 was obtained in a three-step synthesis.     

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 ).     

Synthese und Eigenschaften von 1- und 10-Amino-11H-5,6-dihydrodibenz[b,e]azepin-6,11-dionen

Syntheses and Properties of 1-and 10-Amino-11 H-5,6-dihydrodibenz[b,e]azepine-6,1l-diones A method is described for the separation of the mixture of the dihydrodibenz[b,e]azepinediones 1 and 3 resulting from a Schmidt reaction of 1-amino-anthraquinones. Compounds 1 und 3 , as well as the derived enamines 14a , 14b and 19 can be reduced to the alcohols 7b , 11 , 17a and 17b which in turn can be converted to the lactones 9a , 9c , 12 and 16a and to the oxazine derivative 18 .     

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 .     

Azepino-indole, 1. Mitt. Versuche zur Synthese von Azepino[3,4-b]indolen über Skatylidenketone

Azepinoindoles, I: Attemps to the Synthesis of Azepino[3,4-b]indoles via Scatylideneketones The reaction between scatylideneketones and hydroxylamine leads to 3,5-disubstituted 2-isoxazolines. The corresponding oximes are not available. A more convenient method for the synthesis of ethyl-scatylidenacetoacetate is described.     

Antimykotische Wirkstoffe, 11. Mitt. 4-Amino-3-methylpyrazolo[3,4-d]pyrimidine

Antimycotic Drugs, XI: 4-Amino-3-methylpyrazolo[3,4-d]pyrimidines The ring closure of the 5-amino-4-cyano-3-methylpyrazoles 4a-e leading to the 4-amino-3-methyl-pyrazolo[3,4-d]pyrimidines 6a-e has been effected with formamide (5) . Structures of type 4 (4a-h) arise from the interaction of (ethoxyethylidene)malononitrile (1) with the hydrazine derivatives 2a-h via the (hydrazinoethylidene)malononitriles 3 .     

Bicyclische α-Aminosäuren, 4. Mitt.1) Synthese von 3-(1-Tetralyl)- und 3-[5-(5,6,7,8-Tetrahydro)-chinolyl]-alanin

Bicyclic α-Amino Acids, IV: Synthesis of 3-(L1,2,3,4-Tetrahydro-l-naphthalenyl)- and 3-(5,6,7,8-Tetrahydro-5-quinolinyl)alanine The title compounds 1a , b are prepared by Strecker synthesis with the aldehydes 7a , b which are available from 2a , b . The structures of 1a , b and the configurations of the isomeric nitriles 3a , b / 4a , b were elucidated by ¹H- and ¹³C-NMR spectroscopy.     

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.