Orthoamide und Iminiumsalze, CVIII. Umsetzungen von Orthoamiden der Alkincarbonsäuren mit CH/NH-aciden, tautomeriefähigen Verbindungen

Abstract

Abstract The reaction of keten-O,N-acetals, which can exist in tautomeric forms, with orthoamides of alkine carboxylic acids 4 affords pyridine carboxylic acid esters or -nitriles. Analogous reactions of the orthoamides 4 with imidazole-2-yliden-acetic acid ester or -acetonitrile deliver imidazo[1,2-a]pyridines. From N-alkyl-3,3-diamino-acrylic acid derivatives and orthoamides of propiolic acid 4-aza-heptatriencarbonitriles can be prepared, whereas orthoamides of phenylpropiolic acid deliver directly 2H-pyrimidine-2-ylidene-cyanacetic acid derivatives. 4-Amino-cumarine reacts with orthoamides 4 to give isomeric 5-oxo-[1]-benzopyrano[4,3-b]pyridines. The orthoamides 4 transform 1,3-diimino-isoindolin into 2-cyanphenylpyrimidines. 2-(Pyrazol-1-yl)-benzamides can be prepared from 3-indazolinon and orthoamides 4. The reaction of orthoamides 4 with 6-amino-1,3-dimethyl-uracil proceeds in a complex manner and gives primary products which are very likely imidazo-diazepines. By thermolysis of one of these products a fluorescent pyrolo-imidazolidindione is obtained, which was alkylated with triethyloxonium tetrafluoroborate to give a quaternary ammonium tetrafluoroborate.