1-Substituted 5, 6-dihydrouracils show certain biological activity which includes antitumor [1] and antiretroviral [2, 3] properties. 5, 6-Dihydrouracil derivatives have also been used as adrenoblocking agents [4]. It is known that 1-aryl-5, 6-dihydrouracils and their 2-thio analogs
