Chemical transformations on 6-aryl-3-cyano-4-methylthio-pyran-2(<i>H</i>)-ones: Synthetic and structural studies on novel N-phenylpyrazoles and <i>N-</i>phenylpyrazolylcoumarins

Abstract

Seven 6-aryl-3-cyano-4-methylthiopyran-2(<i>H</i>)-ones <b>1-7</b> have been prepared and used for the efficient synthesis of twelve 1,3-diaryl-5-cyanomethylpyrazoles <b>8-19</b>, one 3-cyanomethyl-5-(3,4-methylenedioxyphenyl)pyrazole <b>22</b> and one 5-cyanomethyl-3-phenylisoxazole <b>23</b>. Further, two 1,3-diaryl -5-cyanomethylpyrazoles <b>10</b> and <b>11</b> have been used for the preparation of three novel <i>N</i>-phenylpyrazolylcoumarins <b>24-26</b>. Structures of 3-cyano-6-(3,4-methylenedioxyphenyl)-4-methylthiopyran-2(<i>H</i>)-one <b>7</b>, 3-cyanomethyl-5-(3,4-methylenedioxyphenyl)pyrazole <b>22</b> and 5-cyanomethyl-3-phenylisoxazole <b>23</b> have been confirmed by their X-ray crystallographic studies.