Text this: Crystal structures of (S)-3-{1-[(4-chlorophenyl)-sulfonyl]piperidin-2-yl}pyridine, (S)-3-[1-(4-methylphenyl)piperidin-2-yl]pyridine, (S)-3-{1-[(4-methoxyphenyl)sulfonyl]piperidin-2-yl}pyridine and (S)-3-{1-[(3,4-dimethylphenyl)sulfonyl]piperidin-2-yl}pyridine