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-3-methyl-2(1H)-quinolones (1)-(4) have been synthesized by condensation of the appropriate diphenylamine with diethyl methylmalonate and subsequent chlorination of the resulting N-aryl-4-hydroxy-3- methyl-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.