Aldol a-naphthylamine

Miuoinapninyiamme conuensanvn iOuvci (no formula is given). A solid which can be prepd from a soln of a mixt of 1.5 mol of aldol-a-naphthylamine and 0.5 mol of aldol-f - naphthyl amine in 1.5 mols of dil HCi with 1.5 mols of acetaldehyde. This was followed by neutralization, filtering, purification and drying... 

Phenyl -6 -naphthylamine Parahydroxyphenyl -0 -naphthylamine Dinaphthyl -p -phenylenediamine Aldol-a-naphthylamine... 

The reaction step of heterocyclization of iminocarbonyl compounds 136 is probably the rate-limiting stage, as for monocyclic pyrylium salts [82AHC(Suppl)]. Its rate is determined by the electrophilicity of the carbonyl group and by steric factors. In the case of a bulky 3-aryl group, especially with donor substituents, the rate of heterocyclization should be retarded, and because of this influence, the behavior of 136 becomes dependent on the nature of R3. Thus, if R3 = Me or Et, the possibility of intramolecular aldol-type condensation is real, and a-naphthylamines 140 are formed (82KGS552). 

To explain all the results it was necessary to assume that the aromaticity of the arylamine had to be broken by adding an ammonia molecule to the arylamine (Scheme 6). This explains why a high NH3 pressure is required and why the reaction runs better with naphthylamine than with aniline. Then ring opening occurs through a reverse aldol-type reaction (Scheme 7) and ring closure might occur... 

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