Showing papers on "Selenourea published in 1986"

Preparation of sydnone compounds substituted by thio and seleno functional groups at the 4-positions.

Abstract: The introduction of thio and seleno functional groups to the 4-position of a sydnone ring was successfully attempted using 4-lithiosydnones (2) and 4-bromosydnones (3) as starting compounds. The reaction of 2 with tetraalkylthiuram disulfides, bis[alkoxy(thiocarbonyl)] disulfides, and bis[alkylthio(thiocarbonyl)] disulfides provided 4-sydnonyl dithiocarbamates, O-alkyl S-(4-sydnonyl) dithiocarbonates, and dialkyl 4-sydnonyl trithiocarbonates, respectively in good yields. In addition, treatment of 2 with thiocyanogen and selenocyanogen gave rise to bis(4-sydnonyl) sulfides (11) and bis(4-sydnonyl) selenides (12), respectively. These products, 11 and 12 were also formed by the reaction of 3 with potassium thiocyanate and selenocyanate, respectively. Furthermore, it was found that 3 reacted with selenourea and potassium O-ethyl dithiocarbonate under heating to provide 12 and 11, respectively. It was also found that the reactivity of these sydnone compounds 2 and 3 was quite different in many cases from that ...

Production of selenourea

Abstract: PURPOSE:To obtain a compound useful as semiconductor-related materials, medicines, etc, relatively readily in good yield at a low cost without a danger of explosion and fire, by reacting an aqueous solution of cyanamide with hydrogen selenide CONSTITUTION:An aqueous solution of cyanamide expressed by the formula R1N=C=NR2 [R1 and R2 are H or CnH2n+1 (n is 1-6)] is reacted with hydrogen selenide at 10-50 degC to afford the aimed selenourea expressed by the formula The hydrogen selenide is fed by reacting successively selenium vapor with hydrogen and the amount of the hydrogen selenide is 20-50g/hr, preferably 30-40g/hr based on 1l solution The concentration of the aqueous solution is 2-50%, preferably 5-30%, and pH is 3-11 The aqueous solution of the cyanamide is directly used for the reaction