Dulcin

Dulcin is an artificial sweetener about 250 times sweeter than sugar, discovered in 1883 by the Polish chemist Józef (Joseph) Berlinerblau (27 August 1859 – 1935). It was first mass-produced about seven years later. Although it was discovered only five years after saccharin, it never enjoyed the latter compound's market success. Nevertheless, it was an important sweetener of the early 20th century and had an advantage over saccharin in that it did not possess a bitter aftertaste.
Early medical tests marked the substance as safe for human consumption, and it was considered ideal for diabetics. However, an FDA study in 1951 raised many questions about its safety, resulting in its removal from the market in 1954 after animal testing revealed harmful chronic-toxicitic properties. . Food and drug Safety association has also said that "Consequently, the Federal Security Administrator regards these chemicals as poisonous substances which have no place in any food". In Japan, poisoning accidents by dulcin occurred frequently, and use of dulcin was forbidden in 1969.
Dulcin is also known by the names sucrol and valzin.
Preparation.
Dulcin can be produced by the addition of potassium cyanate to "p"-phenetidine hydrochloride in an aqueous solution at room temperature.
An alternate way to make dulcin is by mixing urea and "p"-phenetidine hydrochloride to a mixture of hydrochloric acid and glacial acetic acid.