10.1007/BF00479363
The research focuses on the reaction of N-methyl-2-pyrrolidone and N-methyl-2-piperidone acetals with enamino diketones, aiming to synthesize cyclic dienediamines. The study found that these reactions yield dienediamines, which can be further converted to 3-(8-methylamino)ethyl-6,6-dimethyl-5,6,7,8-tetrahydro-5-coumarinone hydrochloride when heated in dilute hydrochloric acid. Key chemicals used in the process include N,N-dimethylacetamide diethylacetal, aminomethylene- and N,N-dimethylaminomethylenedimedones, and various lactam acetals. The research concluded that the structure of the products depends on the ratio of reagents used, and the synthesized compounds contain a substituted dienediamine fragment, which may have significant effects on the degree of conjugation due to the presence of bulky rings. The study also noted that dienediamine IX and dieneamidino enamine VI are converted to coumarin derivative VIII upon heating in dilute hydrochloric acid.