Crystal structure of propylthiouracil determined using high-resolution synchrotron X-ray powder diffraction

The crystal structure of propylthiouracil, a drug used in the treatment of hyperthyroidism, was determined by means of high-resolution synchrotron X-ray powder diffraction data. The Rietveld method was employed to refine the structure. This drug crystallizes in an orthorhombic (Pcab) space group, with unit cell parameters a = 28.67338(23) angstrom, b = 11.15287(6) angstrom, c = 10.66821(5) angstrom, V = 3411.59 (4) angstrom(3), Z = 16, Z' = 2, M = 170.23 g mol(-1), rho(calc) = 1.3258(1) g cm(-3). The goodness-of-fit and R-factors were, respectively: chi(2) = 1.599, R-Bragg = 1.57%, R-wp = 8.85% and R-exp = 5.53%. Four hydrogen bonds involving the atoms N(6)-H(12)center dot center dot center dot S(39), N(19)-H(21)center dot center dot center dot O(41), N(27)-H(33)center dot center dot center dot S(18) and N(40)-H (42)center dot center dot center dot O(20) form a network of molecular aggregates in propylthiouracil.