Conformational preferences for some 3-(4′-substituted phenylsulfonyl)-1-methyl-2-piperidones through spectroscopic and theoretical studies

► Conformational analysis study of alpha-phenylsulfonyl-delta-valerolactams. ► Solvent effect on the conformational equilibrium through IR. ► Theoretical calculation in the gas-phase and with solvent effect (PCM). ► Single crystal X-ray diffraction analysis.