Reaktionen vinyloger Hydrazide mit Carbiminium-Verbindungen / Reactions of Vinylogous Hydrazides with Carbiminium Compounds

Vinylogous hydrazides of type 1 react with methyleniminium salts only in 2-position to form aminomethylated compounds 2·HX. The oxidation of 1 with Hg(II)-EDTA results in a twofold dehydrogenation to the lactams 3, which may be aminomethylated in 2-position. The methylpiperidine derivatives 4 and 5 with Hg(II)-EDTA yield in a monodehydrogenation cyclic iminium compounds. These are isolated as 6 · ClO and 7 · ClO respectively, and show an enolimine structure, which is not accessible to intramolecular aminoalkylation. With the 2-methylsubstituted enhydrazinones 11 methyleniminium salts cause an attack at 4-position, vinylogous to the carbonyl function, and produce the aminomethylated derivatives 13. Oxidation of 11 gives rise to the lactams 12, which are inert to Mannich reagents. The Mannich bases 2 undergo an amine elimination to form the pyrazolinium betaines 15. The aminomethylated lactams 20 show, in addition to amine eliminations, retro Mannich reactions and from the cleavage products methylenebis(lactam-enhydrazinones) 21 result. Formaldehyde and primary amines generate with 1 and 3 the tetrahydropyrimidine derivatives 24/25 and 22/23, respectively. Hexahydroacridinediones 27 are obtained from the reaction of 21 with formaldehyde and acetic acid.