744-25-2Relevant academic research and scientific papers
α-dicarbonylmonophenylhydrazones as nucleophiles and neighbouring groups
Mo?hrle, Hans,Keller, Georg
, p. 533 - 546 (2007/10/03)
The α-dicarbonylmonophenylhydrazones 1 and 8 do not react as simple "CH-acidic compounds" in the Mannich condensation reaction. In a concerted reaction with aminals in absolute dioxane they give rise to the products 5a-e and 10a-e with better practicability and much higher yields compared with the conventional method. The formal Mannich bases 5a/ 5b/5d and 10a/10b/10d with a cyclic amine part show in the dehydrogenation, using mercury-EDTA, a neighbouring group participation of the phenylhydrazono moiety yielding the corresponding lactams. With 5c only cyclization occurs leading to 1,2,4-triazine 19 in low yield, while 10c shows no dehydrogenation but an amine elimination to the vinyl-azo compound 21 with consecutive cycloaddition leading to the 1,2-diazine 23.
