“…Dibenzyl ketone has also been used to a larger extent as the ketone component in the Mannich reaction. In this way l,5-diaryl- In the reaction of dibenzyl ketone, paraformaldehyde, and ammonium acetate l,5-diphenyl-3-hydroxymethyl-9-ethoxy-9-hydroxy-3,7-DABN acetate (77) is Dibenzyl ketone after nitration also undergoes Mannich reaction to give the corresponding 3,7-DABNs.110 On introduction of methyl substituents in the ortho positions of the phenyl groups of dibenzyl ketone the ease of formation of 3,7-DABN decreases. Bispidines are formed from l-phenyl-3-(o-tolyl)-propan-2-one almost as easily as from l,3-diphenylpropan-2-one.…”