A single crystal X-Ray diffraction analysis of 1,9-dihydro[1] benzothiopyrano[4,3-c] pyrazole 5,5-dioxide

The structure of 1,4-rlihydro1 ]benzothiopyrano4,3-c ]pyrazole 5,5-dioxide was determined by single crystal x-ray diffraction. The molecule crystallizes in space group P2₁/c with a = 13.4378(6), b = 5.5938(3), c = 12.9837(6)Å, and β = 103.831°. The final R value is 0.083. Surprisingly, the tautomer with N(2)-H exists in the crystal with the pyrazole ring being planar. The entire system is not planar as the benzene ring is rotated about C(9a) and C(9b) with respect to the pyrazole ring. In the crystal structure the pyrazole exists as hydrogen-bonded dimers with two molecules related by a center of symmetry.