engleski

Structural Analysis of Thiazolidine-isothiazolidine Rearrangement

As a continuation of our research on the reactivity of the amide of penicillanic acid we report a new type of thiazolidine-isothiazolidine rearrangement. This involves a simple procedure for the preparation of novel N-substituted isothiazolidin-3-one derivatives of azetidin-2-one. [A. Danilovski, M. Vinković, J. J. Herak Fifth Slovenian-Croatian Crystallographic Meeting, Zreče, Slovenia, June 13-15, 1996 (Abstracts, p. 27) ; A. Danilovski, M. Vinković, J. J. Herak Sixth Croatian-Slovenian Crystallographic Meeting, Umag, Croatia, June 19-21, 1997 (Abstracts, p. 51) ; J. J. Herak, M. Vinković Croat. Chem. Acta 69 (1996) 1367-1376.]. Crystals of compound (3S, 4R)-1-[(4S)-2-Benzyl-5, 5-dimethyl-3-oxo-isothiazolidine-4-yl]-3-bromo-4-chloro-azetidin-2-one were obtained by slow evaporation of ether solution. Crystallographic data were collected using PHILIPS PW1100/Stoe&Cie diffractometer and corrected, in addition to standard Lp-correction, for absorption effects using semiempirical y-scan method. The crystal structure was solved using direct methods implemented in SHELXS-97 and refined on F2 by SHELXL-97 program. Crystal Data: C15H16BrClN2O2S, Mr = 403.72, orthorhombic, space group P 212121 (No.19), Z = 4, a = 6.3670(6), b = 8.653(3), c = 31.068(2) Ĺ, V = 1711.6(6) Ĺ3, Dx = 1.567 gcm-3, F(000) = 816, m(MoKa) = 2.687 mm-1. wRF2 = 0.0992 and S = 0.961 for 199 parameters and 2875 unique reflections, while RF = 0.0460 for 1394 observed reflections with I ł 2s(I) criterion. Estimated Flack parameter x = -0.003(15). The possible mechanism of thiazolidine-isothiazolidine rearrangement, as well as the conformation of molecule, will be discussed in details.

structural analysis; thiazolidine-isothiazolidine; rearrangement

nije evidentirano