Cryst. Res. Technol. 38, No. 2, 182 – 192 (2003) / DOI 10.1002/crat.200310021 2003 © 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 0232-1300/03/0202-0182 $ 17.50+.50/0 Crystal structure of 3-hydroxy methyl 4,6-dimethoxy-9- phenylsulfonyl-carbazole L. Govindasamy 1 , V. Rajakannan 1 , D. Velmurugan*, 1 A. K. Mohanakrishnan 2 , and P. C. Srinivasan 2 1 Department of Crystallography and Biophysics University of Madras, Guindy Campus, Chennai-600 025, India. 2 Department of Orgsnic Chemistry, University of Madras, Guindy Campus, Chennai-600 025, India. Received 2 February 2000, revised 16 December 2002, accepted 7 January 2003 Published online 15 February 2003 Key words phenylsulfonyl, tetrahedral configuration, carbazole alkaloids, sulfonamides, DNA intercalation, N-phenylsulfonamide. PACS 87.64.Bx The crystal structure of 3-Hydroxy methyl 4,6-dimethoxy-9-phenylsulfonyl-carbazole. (C 21 H 19 NO 5 S) has been determined [CCDC 194425]. The compound crystallizes from methanol in the monoclinic system, space group I2/c, with unit cell parameters: a = 20.498(2), b = 9.258(2), c = 21.866(3)Å, beta = 116.450(10)º, Z = 8, V = 3715.2(10)Å 3 . The crystal structure was solved by direct methods and refined by full-matrix least squares to a final R-value of 0.050 with 3508 unique reflections. The planar carbazole ring fragment is inclined at an angle of 79.9(1)º to the phenylsulfonyl group. The sum of the angle about N is 351.6(2)º. The atoms linked to the central hexavalent S atom are arranged in a tetrahedral configuration with the larger deviations in the O-S- O angles [O1-S-O2 = 119.7(2)º] and the O1-S-N and O2-S-N angles [106.1(2) and 106.9(1)º, respectively]. 1 Introduction Indole and its various substituted products have long been known for their interesting chemical and biological activities [1]. The indole ring system is present in a number of natural products, many of which are found to possess pharmacological properties like anti-microbial, anti-inflammatory and anti-implantation activities [2]. Carbazoles formed by the fusion of indole ring with aromatic six-membered ring, are also widely used in many areas in biological sciences. In recent times 2,3-disubstituted indoles have been used as bidentate synthons for the synthesis of various medicinally important carbazole alkaloids. In carbazole derivatives, the preliminary study showed that the presence of oxygenated substituents on the carbazole ring increases their biological activity [3]. The structures of these derivatives are analogous to that of ellipticine, a plant alkaloid having pronounced anti-tumour activity [4] and are found to have DNA intercalating properties [5-7]. Derivatives of the pyrido[4,3-b]carbazole alkaloid ellipticine (which intercalates with DNA and inhibits topoisomerase II) are being used clinically to inhibit the growth of several human tumors. The pyrido[4,3-b]carbazole alkaloid ellipticine and some of its derivatives exhibit pronounced anti-cancer activity in animals and human systems [8]. Synthetic approaches to substituted carbazoles are of special interest and contemporary importance since the growing variety of carbazole alkaloids isolated show anti-microbial, anti-viral (Tubingensin A) and cytotoxic properties (Tubingensin B: a cytotoxic Carbazole alkaloid) against consumption of the sclerotia by insects [9,10]. Benzo- and pyrido-annellated carbazoles are pharmacologically interesting since such compounds have potential for the development of compounds with anti-tumor activity. The principle of the action is intercalation in human B-DNA or an alternative interaction, e.g. groove binding with this biopolymer [11]. Quino[3,4-b]carbazole analogues may act as potential DNA binders [12]. Intercalation between the base ____________________ * Corresponding author: e-mail: d_velu@vsnl.net, d_velu@yahoo.com, velmurugan@hotmail.com