DIFFERENTIAL SUSCEPTIBILITY OF SCLEROTIUM-CEPIVORUM BERK TO SOME SYNTHESIZED VISNAGIN SULFONAMIDE DERIVATIVES

Twenty-five visnagin sulfonamide derivatives were tested in vitro agai nst sclerotial germination, growth and cellulolytic activity of Sclero tium cepivorum Berk. The effectiveness of the derivatives depends on t he concentration and the substituent introduced to the title compound. The introduction Of SO2Cl2 to C-9 of visnagin induced high toxicity t han introducing SO2NH2. Compounds with sulfonyl piperidine or sulfonyl morpholine gave small toxicity only at 30 and 75 mug cm-3. Addition o f N-aryl ring to visnagin-9-sulfonamide rendered the title compound to be more toxic. The substitution of the N-aryl ring by m-CH3, m-Cl or p-Cl enhanced the toxicity, while its substitution with o-CH3, p-CH3, p-Br, o-OCH3 or m-OCH3 caused a drop in the toxicity as compared to co mpounds with unsubstituted aryl ring. Visnagin sulfonamide derivatives having azole rings were strongly inhibitory for sclerotial germinatio n, growth, sclerotial formation and cellulolytic activity, even when a pplied at 4 mug cm-3. The most toxic one was that having dimethyl isox azole. The cleavage of gamma-pyrone ring led to a decline in the toxic ity as compared with the other sulfonamide derivatives.