| Abstract: | The iminium salt, N,N-dimethyl-N-2-(2,6-diphenyl-4H-pyran-4-ylidene)ethylidene]iminium perolilorate ( 1 ), reacts with secondary amines, such as piperidine, by exchanging the dimethyl-amino function for a piperidine. Primary amines react with 1 to give 1-alkyl-2-phenyl-4-phenacylidene-1,4-dihydropyridines. The bisiminium salt, N,N,N',N' -tetramethyI-N,N'-2-(2,6-diphenyl-4H-pyran-4-ylidene)-1,3-propanediylidene]bis(iminium perchlorate) ( 2 ), reacts with ammonia to give 3,6-diphenylcopyrine and with primary amines to give the corresponding N,N' -dialkyl quaternary copyrines. The salt 2 reacts with secondary amines with exchange of the dimethylamino groups of 2 by the secondary arnine and addition of the amine at the 2-position of the pyran ring. |
