Tautomers The enol (left) and keto (right) tautomers of<unk> .<unk>  exhibits pH dependent keto-enol tautomerization.<unk>  exists in the tricycic (-ol) form in neutral media and undergoes protonation to the benzophenone tautomer in acidic media. QSAR studies have indicated that the ability of<unk>  to inhibit NE and DA reuptake may be mediated by the protonated (benzophenone) tautomer. Synthesis<unk>  synthesis: The synthesis of<unk>  starts by reaction of a substituted benzoylbenzoic acid (1) with ethylenediamine. The product 3 can be rationalized as being an aminal from the initially formed monoamide 2. This is then subjected to reduction with LiAlH4 and-without isolation-air oxidation. Reduction probably proceeds to the mixed aminal/carbinolamine 4; such a product would be expected to be in equilibrium with the alternate aminal 5. The latter would be expected to predominate because of the greater stability of aldehyde aminals over the corresponding ketone derivatives. Air oxidation of the tetrahydroimidazole to the imidazoline will then remove 5 from the equilibrium. There is thus obtained the anorectic agent<unk>  (6). The synthesis of homomazindol (the six-member ring A homologue) is accomplished by substitution of 1,2-diaminoethane with 1,3-diaminopropane.
Mazindol
Cloroqualone
Eclabium
Meptazinol
Triethylenetetramine
Nalmefene
Pipofezine
Michellamine