FORMATION AND REACTIONS OF DIANIONS DERIVED FROM 4-METHYLCARBOSTYRIL AND TRANS-BETA-METHYLCINNAMANILIDE

Treatment of 4-methylcarbostyril (1) with 2 mol equiv of n-butyllithium in tetrahydrofuran-hexane effected ionization of the NH proton and one of the methyl protons to form resonance-stabilized dianion 2. Reaction of dianion 2 with carbonyl compounds, alkyl halides, and carbon dioxide afforded products arising from condensation of the electrophilic reagent at the exocyclic carbanion site. These reactions represent the first examples of successful carbon-carbon condensations at the methyl group of 1, a position which has previously been considered to be unreactive. trans-β-Methylcinnamanilide (12) also underwent similar twofold ionization with n-butyllithium to afford dianion 13. Protonation and alkylations of dianion 13 took place predominately at the α-carbanion site, while condensations with benzophenone and 9-fluorenone occurred preferentially at the terminal carbanion position. © 1969, American Chemical Society. All rights reserved.