95457-15-1Relevant academic research and scientific papers
Biotransformation of 4β-hydroxyeudesmane-1,6-dione by Gliocladium roseum and Exserohilum halodes
García-Granados, Andrés,Gutiérrez, María C.,Rivas, Francisco,Arias, José M.
, p. 891 - 895 (2001)
Biotransformation of sesquiterpene 4β-hydroxyeudesmane-1,6-dione by the filamentous fungi Gliocladium roseum and Exserohilum halodes was achieved. With Exserohilum halodes, only one metabolite was obtained, as a result of the regio- and stereo-selective reduction of the keto group at C-1, which is difficult to achieve by chemical means. Five metabolites were produced with Gliocladium roseum, three of which, the 7α-hydroxylated, the 7α, 11- and the 1α,8α-dihydroxylated derivatives, have not previously been reported. The hydroxylation at C-11 is the main action of this microorganism. These 11-hydroxylated compounds can be chemically transformed into 6β.12-eudesmanolides.
Improved microbiological hydroxylation of sesquiterpenoids: semisynthesis, structural determination and biotransformation studies of cyclic sulfite eudesmane derivatives.
Garcia-Granados, Andres,Gutierrez, Maria C,Rivas, Francisco
, p. 2314 - 2320 (2007/10/03)
Two new cyclic sulfite eudesmane derivatives have been investigated. Their (R) and (S) sulfur configuration and the structural arrangement of their "A" rings have been assigned by means of their 13C and 1H NMR chemical shifts and have been confirmed by single-crystal X-ray analyses. Microbial-transformation of these epimer cyclic sulfites and their dihydroxyeudesmane precursor have been studied using the hydroxylating fungus Rhizopus nigricans. Increased biocatalysis rates and considerable differences in the biotransformation of both cyclic sulfite eudesmanes have been found. Promising 8alpha,11-dihydroxy derivatives have been isolated from the (S)-diastereomer bioconversion.
Chemical-Microbiological Synthesis of 6β-Eudesmanolides from 11-Hydroxyl Derivatives obtained by Rhizopus nigricans cultures: Synthesis of 6β-Dendroserins.
Garcia-Granados, Andres,Martinez, Antonio,Parra, Andres,Rivas, Francisco,Onorato, M. Esther,Arias, Jose M.
, p. 1091 - 1102 (2007/10/02)
The relationship between the structure of the substrates and the action of the fungus Rhizopus nigricans has been studied in order to obtain, in the highest possible yield, 11-hydroxyl derivatives which were dehydrates to the "exo" position, hydroborated with 9-BBN and oxidized with RuH2(PPh3)4 to give 11-R and 11-S-6-epi-dendroserin.In course of the biotransformation processes, 8α-hydroxyl and 7α-hydroxyl derivatives were also obtained, as well as the oxidation of the hydroxyl groups at C-1, an unusual process with Rhizopus nigricans.We have proved that the eudesmanones are more easily hydroxylated at C-11 than the hydroxyeudesmane compounds.Key Words: Biotransformation; 6β-eudesmanolides; 11-hydroxyeudesmanes; Rhizopus nigricans
SESQUITERPENES FROM TWO SUBSPECIES OF SIDERITIS VAROI
Garcia-Granados, Andres,Molina, Antonio,Buruaga, Antonio Saenz de,Buruaga, Juan Manuel Saenz de
, p. 97 - 102 (2007/10/02)
Key Word Index - Sideritis varoi; Labiatae; sesquiterpenes; eudesmenes; 13C NMR.Two subspecies of Sideritis varoi afforded, in addition to previously reported diterpenes, the following series of new eudesmane and eudesmene acetates: 1β-hydroxy-6β-acetoxy-eudesm-4(15)-ene; 1β,4β-dihydroxy-6β-acetoxy-eudesmane; 1β-hydroxy-6β-acetoxy-eudesm-3-ene; 1β-hydroxy-6β-acetoxy-eudesm-4-ene.The structures of these compounds were elucidated by chemical and spectroscopic means.
