As opposed to popular myth, Merck’s development of MDMA was intended to provide a new way to induce blood clotting, not to ‘suppress appetite’ as commonly believed:

The company [Merck] did develop the drug in 1912, but the appetite suppressant story is an urban myth, passed on from source to source through "uncritical copy-paste procedures". Instead, documents from the time show that ecstasy emerged during the company’s efforts to develop a potentially life-saving medicine that would help blood to clot.

The best available blood clot medicine at the time, hydrastinin, was patented by Merck’s local rival Bayer. Merck chemists believed that a similar compound called methylhydrastinin would be equally effective and set about trying to make it from scratch in a way not covered by the Bayer patent. Ecstasy, also known as MDMA, was first produced during these experiments, but attracted little attention. Merck’s recent search found just a passing reference to the drug: in a patent the company filed in 1912 to protect its new blood clot agent, which had been tested on patients in a Berlin hospital. Patent 274350 did not refer to MDMA by name, but described its properties among a list of other new intermediates: "colourless oil, boiling point 155C at 20mm pressure, its salt forms white crystals".

You live and learn.