Study On Synthesis Of Selenourea And Selenoureas

Selenourea is not only an important intermediate for organic synthesis but an important starting material of selenium-containing heterocyclic compounds, which have a very high biological activity; selenourea is also the raw material for synthesis of efficient solar cells ZnSe and CdSe films; the lattice of selenourea can be used for the main project, which has a wide range of application.In the experiment, selenourea was successfully synthesized by using cyanamid, selenium power and sodium borohydride. Moreover, some selenourea derivatives were synthesized by using selenourea as starting material, such as 2-amido-4-phenyl- selenazole, 2-amido-2- selenazolin-4-one, 2-amido-4,5,6,7-tetrahydrobenzo-1,3- selenazole. Each of products were identified by measuring melting points, element analysis and IR, and every step was optimized.In the synthesis of selenourea step, sodium hydrogen selenide was used as raw material instead of hydrogen selenide , which is virulent, effluvial. The effects of reaction temperature, the mole ratio of cyanamid and selenium power, reaction time, light, different solvents and its dosage were preliminarily researched. A lot of single factor experiments obtained the synthesis optimum condition was: ethanol as solvent, the mole ratio of Cyanamid and seneium power was 1.2, reaction temperature was 80℃, reaction time was 1h, avoiding light. With these conditions, the product was obtained with a yield of 78.4%.2-amido-4-phenylselenazole was synthesized by using selenourea andω-bromobenzophenone at room temperature for its simple process and high yield. The factors that influenced the reaction, such as the ratio ofω-bromobenzophenone and selenourea, heating were investigated. The single factor experiments obtained the synthesis more suitable condition was: acetone as solvent, the ratio ofω-bromobenzophenone and selenourea was 0.9, reaction time was 4h at room temperature, the product was obtained with a yield of 82.9%.2-amido-2- selenazolin-4-one was synthesized by using selenourea and ethyl chloroacetate for anhydrous ethanol as the solvent. The factors that influenced the reaction, such as reaction temperature, the ratio of ethyl chloroacetate and selenourea, reaction time were investigated. The single factor experiments obtained the synthesis more suitable condition was: the ratio of ethyl chloroacetate and selenourea was 1.3, reaction temperature was 80℃, reaction time was 2 h . With these conditions, the product was obtained with a yield of 81.6%.