Azulene derivatives as TXA2/PGH2 receptor antagonists—II. Synthesis and biological activity of 6-mono- and 6-dihydroxylated-isopropylazulenes
作者:Masayuki Yokota、Satoko Uchibori、Hiromi Hayashi、Rei Koyama、Kazuhiro Kosakai、Shuichi Wakabayashi、Tsuyoshi Tomiyama
DOI:10.1016/0968-0896(96)00038-7
日期:1996.4
In order to examine the correlation between activity and hydrophilicity of the side chain of sodium 3-[4-(4-chlorobenzenesulfonylamino)butyl]-6-isopropylazulene-1-sulfonate (KT2-962), a non-prostanoid TXA(2)/PGH(2) receptor antagonist, one or two hydroxyl groups were introduced into the isopropyl moiety. A series of 6-hydroxylated-isopropylazulenes were synthesized by regioselective oxidation of 6-isopropylazulenes and their in vitro and in vivo antagonistic activities were studied. Both the primary and tertiary alcohols, monohydroxylated derivatives, exhibited potent biological activities comparable to unmodified 6-isopropylazulenes both in vitro and in vivo. In contrast, the activities of 1,2- and 1,3-diols of 6-substituted derivatives, markedly decreased, but recovered by O-isopropylidenation of the dihydroxyl moiety. These findings indicate that the moderate hydrophobicity of substituent at the 6-position of the azulene ring might be required for the activity and the size of the substituent at this position, not so rigid for keeping potent biological activity. Copyright (C) 1996 Elsevier Science Ltd