Synthesis starting from 3-methyl-2-phenyl-5-(3-methyl-2-phenyl-3,4-dehydropiperidyl-6)pyridine. 2-phenyldinicotinic and 4-azafluorenone-2-carboxylic acids

N-Methyl (ethyl, benzoyl, trifluoroacetyl)-substituted 3-methyl-2-phenyl-5-(3′-methyl-2′-phenyl-3′,4′-dehydropiperidyl-6′) pyridines and di(N-oxide) of the correspondingly substituted α,ß-dipyridyl were prepared. A method for synthesizing 2-phenyldinicotinic acid was developed. Cyclodehydration of this acid gave 4-azafluorenone-2-carboxylic acid. Transformations of this acid were carried out with respect to two functional groups. © 1986 Plenum Publishing Corporation.