4,5,6-Tri-O-benzoyl-2,3-di-S-ethyl-2,3-dithio-D-allose diethyl dithioacetal

Abstract

Abstract. C35H4206S4, monoclinic, P2, a = 9.185 (1), b = 10.0160 (8), c = 20.448 (2) /k, fl = 99.29 (1) °, D x = 1.23 g cm -3 for Z = 2, F(000) = 728. Direct methods were used to determine the structure from four-circle diffractometer intensity measurements. Least-squares refinements using large blocks converged with R = 0.091. The absolute configuration was determined from the anomalous dispersion of the S atoms and confirmed that assigned by chemical and NMR methods. The molecule has a bent-chain conformation similar to that found in solution. Introduction. Systematic absences noted on allWeissenberg and precession photographs (0k0, k odd) and the compound's optical activity suggested the space group to be P2~. This assignment has been confirmed by the successful refinement.A colourless crystal of dimensions 0.05 × 0.30 × 0.45 mm was used for X-ray intensity measurements. 2042 independent reflexions [maximum 0 = 50 °, 2(Cu K~t) = 1.5418 A] were measured on a Hilger & Watts diffractometer employing the o.r--20 scan technique. The intensities were corrected for Lorentz and polarization