CHEMICAL STRUCTURE AND ANTIMICROBIAl. ACTIVITY OF BIS-PHENOLS 725 SUMMARY The broad spectrum antimicrobial activity of five isomeric 2,2'-methyl- enebis (dichlorophenols) and of the asymmetrical 3,4,4',5'-tetrachloro-2,2'- methylenediphenol was investigated. Greater over-all activity was shown by the three compounds in which the hydrogens adjacent to the hydroxyl groups are not substituted by chlorines, the most potent bis-phenol being the 3,5-dichloro isomer. On the other hand, less active was 2,2'-methyl- enebis (4,6-dichlorophenol), also referred to in the literature as G-5 ©. Against S. aureus, C. vulgaris and the dermatophytes, the activity of all isomers was found to be of the same magnitude. At a concentration of 20 ug./ml., no activity against gram-negative bacteria was observed in pres- ence of soap. (Received July 2, 1964) REFERENCES (1) Gump, W. S., and Walter, G. R., y. Soc. Cosmetic Chemists, 14, 269 (1963). (2) Gump, W. S. and Walter, G. R., Ibid., 11, 307 (1960). (3) Weiler, M., Wenk, B., and St6tter, H., U.S. Patent #1,707,181, March 26, 1929. Zinke, A. and Ziegler, E., Bet., 74, 1729 (1941). Ziegler, E. and Simmler, I., Ibid., 74, 1871 (1941). (4) J.R. Geigy, A. G., British Patent 3772,590, January 26,1955. Schetty, G., Stammbach, W., and Model, E., U.S. Patent 32,730,554, January 10, 1956. (5) Walter, G. R. and Gump, W. S., y. Soc. Cosmetic Chemists, 13, 477 (1962). (6) Tiessens, G.J., Rec. Tray. Chim., 50, 112 (1931). (7) Hurtley, W. H., y. Chem. Soc., 79, 1303 (1901). (8) Fox, D. L. and Turner, E. E., Ibid., 1853 (1930). Van Loon, A., Verkade, P. E., and Wepster, B. M., Rec. Tray. Chim., 79, 993 (1960). (9) Sloane, H. J., •tnal. Chem., 33, 691 (1961). (10) Kohn, M. and Fink, S., Monatsh. Chem., 56, 407 (1930). (11) Imperial Chemical Industries l,td., British Patent 3760,341, October 31, 1956. (12) Imperial Chemical Industries Ltd., British Patent 3760,342, October 31, 1956.

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