Synthesis and crystal structure of (Z)-4-(p-bromo phenylthio)-3-(p-nitrobenzoyloxy)-3-buten-2-one

A new enone (CH3CO-C (pNO(2)C(6)H(4)COO) = CH-S-C6H4 (p-Br) 5, C(17)H(12)NR rO(5)S, M-r = 422. 25) was synthesized and its crystal structure was determ ined by X-ray diffraction method. The crystal belongs to the monoclinic sys tem, space group P2(1)/c with a = 6. 4121 (9), b = 12. 804 (1), c = 20. 998 (2) Angstrom, beta = 94. 884 (9)degrees, V = 1717. 1 (3) Angstrom(3), Z = 4, D-c = 1. 633 g/cm(3), mu(MoK alpha) = 2. 542 mm(-1), F (000) = 848. Fina l R = 0. 0428 and wR = 0. 0916 for 3335 reflections with I > 2 sigma (I). T he title compound exists as Z isomer with p-bromothiophenolate and o-nitrob enzoate groups cis-arranged around asymmetrical centre. This observation su ggests that the substitution of thiophenolate for bromine is a stereoselect ive step.