18 糸状菌Cladosporium cladosporioides の生産する植物生長調節物質Cladosporolの構造(口頭発表の部)

概要

論文の詳細を見る
Cladosporol(1) was isolated from the culture filtrate of a fungus, Cladosporium cladosporioides, which showed activity promoting root elongation of lettuce seedlings. The molecular formula C_<20>H_<16>O_9 was determined from the HR-EIMS of its triacetate. Cladosporol has two acetophenone-type chromophores indicated by UV spectrum and two of a conjugated and a hydogen bonded conjugated ketone from IR spectrum. The six partial structures A to F were deduced from the spectral analysis of ^1H-NMR, ^<13>C-NMR, DEPT, HSQC and ^1H-^1H COSY of cladosporol and triacetylcladosporol. These partial structures were unambiguously combined together to construct the plain structure of cladosporol based on the HMBC analysis of triacetylcladosporol. The absolute stereochemistry of an epoxyalcohol moiety(C_2,C_3,C_4) was determined from the J H-H values of hydrogens on these carbons and positive Cotton effect at 340nm comparing with those of the known compounds, (+)-epoxydon and (+)-isoepoxydon. The strong splitting Cotton effect centering at 216nm, observed in the CD of cladosporol, should be derived from the exciton chirality of two tetralone chromophore interaction reflecting the remaining C4'. The most stable conformations of two epimers at C4' were calculated by a computer with QUANTA and the sign of splitting Cotton effect was estimated for each epimer. The CD spplitting pattern of the S epimer agreed with the observed CD. Thus, the structure of cladosporol was elusidated as shown in Fig. 5 with absolute stereochemistry.
天然有機化合物討論会の論文
1992-09-10

18 糸状菌Cladosporium cladosporioides の生産する植物生長調節物質Cladosporolの構造(口頭発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク