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Sterically Hindered N-Aryl-2(1H)-Quinolones and N-Aryl-6(5H)Phenanthridinones: Separation of Enantiomers and Barriers to Racemization

The novel N-aryl-4-chloro-trimethyl-2(1H)-quinolones (1)-(4) have been synthesized by condensation of the appropriate diphenylamine with diethyl methymalonate and subsequent chlorination of the resulting N-aryl-4-hydroxy-trimethyl-2(1H)-quinolones (7)-(10). 5-(1-Naphthyl)-6-(5H)phenanthridinone (5) has been synthesized by the Chapman rearrangement of the 6-(1-naphthoxy)phenanthridine (11). Separation of the enantiomers (M) and (P) of the quinolones (1)-(4) and phenanthridinones (5), (6) was achieved by liquid chromatography on triacetylcellulose. The barriers to partial rotation about the C-N bond in (1)-(6) were determined by thermal racemization of enantiomers and are compared with those of structurally related molecules.

N-aryl-4-chloro-trimethyl-2(1H)-quinolones; 5-(1-Naphthyl)-6-(5H)phenanthridinone; Separation of the enantiomers (M) and (P); barriers to partial rotation about the C-N bond

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