cyanide gave a mixture of cyclopropanecarboxylic acid 6a and 6b. This unique ring-contracting cyclopropane formation is pictured as a sequential Favorskii type reaction. alpha-Cyclodextrin improved the selectivity and yields of the reactions conducted in an aqueous medium.
Zerumbone 1, having powerful latent reactivity and containing two conjugated double bonds and a double conjugated carbonyl group is the major component of the essential oil of wild ginger, Zingiber zerumbet Smith. The conjugation system plays an important role in the expression of biological activity. N-Bromosuccinimide (NBS) reaction of 1 gave high reactive intermediate 2 with an exo-methylene group, which was obtained from 1 quantitatively. Treatment of 2 with nucleophiles gave various zerumbonependant derivatives, including C-H, C-O, C-N, and C-C bond formation, maintaining the conjugation system through S(N)2'-type reaction. Almost all zerumbone-pendant derivatives showed a good value of IC50 against the suppressive effect of NO generation. Among them, amine derivative 5, binding with 2 mol of zerumbone, showed the strongest activity (IC50: 0.24 mu M). (C) 2013 Elsevier Ltd. All rights reserved.
Chemistry of Zerumbone. 2. Regulation of Ring Bond Cleavage and Unique Antibacterial Activities of Zerumbone Derivatives
作者:Takashi KITAYAMA、Kaneyoshi YAMAMOTO、Ryutaro UTSUMI、Masahiro TAKATANI、Richard K. HILL、Yasushi KAWAI、Seiji SAWADA、Tadashi OKAMOTO
DOI:10.1271/bbb.65.2193
日期:2001.1
Further investigation of the chemistry of the elevenmembered cyclic sesquiterpene, zerumbone, the major component of the wild ginger, Zingiber zerumbet Smith, has revealed a new selective epoxidation process, a further example of a novel Favorskii-initiated double ring contraction, and a regiospecific fragmentation of zerumbone dibromide derivatives. Several zerumbone derivatives were found to be selective inhibitors of the growth of Gram-positive bacteria.