The 1,1-bis(dimethylamino)-1,3-butadienes (keten aminals) 11a–l are prepared from orthoamide derivatives of alkyne carbonxylic acids 9b , d , e , i and CH 2 -acidic compounds 10a–c , f–h , k , o . The C-silylated orthoamide derivative 9c shows an ambivalent behaviour towards CH-acidic compounds. Reactions of 9c with strong CH 2 -acidic compounds like the nitro alkanes 10m , n and strongly enolized carbonyl compounds as methyl acetoacetate, cyanoacetamide, dibenzoylmethane, 1,3-dimethylbarbituric acid proceed under desilylation to give the ketene aminals 11u–z . In contrast to these reactions, the C-silylated ketene aminals 11o–t are obtained from 9c and weaker CH 2 -acidic compounds as dimethyl malonate, cyanoacetic acid derivatives and benzylcyanides. CH 2 /NH 2 -acidic compounds [cyanoacetamide ( 10d ) and N -ethyl-cyanoacetamide ( 10f )] react with the orthoamide derivatives 9b , e–g at the acidic carbon-hydrogen bond to give the ketene aminals 11ac , ad , af , ag , ai , which cyclize to the pyridones 14a–d , d–g on heating. From the reaction of the orthoamide 9d with cyanoacetamide the pyridone 14c results directly. The persubstituted pyridone derivative 19 is formed by the reaction of cyanoacetamide with a mixture of the isomeric orthoamides 15 and 16 . The 5,5-diamino-2,4-pentadienamide 11v attacks the orthoamide 9a at C3/C1. In the product 20 a cross conjugated multiple bond system is formed which contains an 1-aza-2,3-diamino function and a further ketene aminal function.