Although Aleye? claimed to have synthesized a phenyl derivative of 2-thiohydantoinJ it was later demonstrated that the compound is a phenylpseudothiohydantoiri7 (IV). The first preparation of the true 2-thiohydantoin (11) was that of Kla~ on,~ who obtained it by heating the hydrochloride of ethyl aminoacetate with potassium thiocyanate at 140-150. In 1911, Komats~,'~ Wheeler, Nicolet and Johnson, b and Johnson and Sicoletsh reported new ...