Conformational preferences for some 3-(4 '-substituted phenylsulfonyl)-1-methyl-2-piperidones through spectroscopic and theoretical studies - Olivato, Paulo Roberto; Santos, Jean Miguel Mansera; Cerqueira Júnior, Carlos Rogério; Vinhato, Elisângela; Zukerman-Schpector, Júlio; Ng, Seik Weng; Tiekink, Edward R. T; Dal Colle, Maurizio (Journal of Molecular Structure, 2012)