Synthetic approach to exo-endo cross-conjugated cyclohexadienones and its application to the syntheses of dehydrobrachylaenolide, isodehydrochamaecynone, and trans-isodehydrochamaecynone.
Methodology for synthesis of exo-endo cross-conjugated dienones with trans- and cis-decalin systems has been reported. Bromination of the silyl enol ether of alpha'-methyl alpha,beta-unsaturated ketones with PTAB and successive dehydrobromination of the resulting alpha'-bromo-alpha'-methyl alpha,beta-unsaturated ketones under three conditions (DBU/PhH; TBAF/THF; Li(2)CO(3), LiBr/DMF) gave the desired exo-endo cross-conjugated dienones in good yield. This method was applied to the syntheses of dehydrobrachylaenolide (1), isodehydrochamaecynone (5c), and trans-isodehydrochamaecynone (11) starting from tuberiferine (7), chamaecynone (5a), and trans-chamaecynone (9). Eudesmanolides possessing an alpha-methylene gamma-lactone moiety, i.e., 1, 7, and 13, exhibited significant inhibitory activity toward the induction of the intercellular adhesion molecule-1 (ICAM-1). Compound 1 showed greater activity than 7 and 13. All compounds possessing an ethynyl group, 5d, 9, 11, and 14, showed the same degree of termiticidal activity, and the exo-endo cross-conjugated dienone structure in 11 had no influence on the activity.
Higuchi
Yohsuke
Y
Graduate School of Science and Technology, and Department of Chemistry and Chemical Engineering, Faculty of Engineering, Niigata University, 2-8050 Ikarashi, Japan.
Shimoma
Fumito
F
Koyanagi
Rei
R
Suda
Kouji
K
Mitsui
Tomokazu
T
Kataoka
Takao
T
Nagai
Kazuo
K
Ando
Masayoshi
M
D000818:Animals; D003510:Cyclohexanes; D007306:Insecticides / Q000138:chemical synthesis* / Q000494:pharmacology; D018799:Intercellular Adhesion Molecule-1 / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D020049:Isoptera / Q000187:drug effects; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000494:pharmacology; D013237:Stereoisomerism
D003510:Cyclohexanes; D007306:Insecticides; D007375:Interleukin-1; D009281:Naphthalenes; D012717:Sesquiterpenes; C477989:dehydrobrachylaenolide; C477990:isodehydrochamaecynone; D018799:Intercellular Adhesion Molecule-1; C007229:decalin