Complex sentence: Bisacodyl is a diphenylmethane (in fact, a modified triphenylmethane) derivative and was first used as a laxative in 1953 due to its similarity to phenolphthalein.
Split into simpler sentences: Bisacodyl is a derivative of diphenylmethane (in fact, a modified triphenylmethane) derivative. It was first used as a laxative in 1953 due to its structural similarity to phenolphthalein.