Synthesis of Selenocyanates and Selenoethers of Amino Pyrazoles and Amino Uracils by In Situ Triselenium Dicyanide from Malononitrile and Selenium Dioxide

Herein, we report
an efficient method for synthesis of novel selenocyanates
of amino pyrazole, amino uracil, and amino isoxazole derivatives using
in situ triselenium dicyanide from the combination of malononitrile
and selenium dioxide in DMSO medium. Using the same combination but
changing the stoichiometry of reagents and sequence of addition and
temperature, symmetrical selenoethers of amino pyrazoles and amino
uracils were prepared in good yields. Furthermore, selenocyanates
of amino pyrazoles were utilized for the synthesis of corresponding
alkynyl selenides in the presence of CuI and Cs2CO3. The salient features of this methodology are inexpensive
starting materials, short reaction time, and good to very good yields.
This method is also applicable for the gram-scale synthesis of selenocyanates
of amino pyrazoles and amino uracils.