 Three years after the synthesis of zidovudine, Jerome Horwitz and his colleagues in Chicago prepared another dideoxynucleoside now known as zalcitabine (ddC).Zalcitabine is a synthetic pyrimidine nucleoside analogue, structurally related to deoxycytidine, in which the 3´-hydroxyl group of the ribose sugar moiety is substituted with hydrogen.Zalcitabine was approved by the FDA for the treatment
of HIV-1 in June 1992.