The highly α,α′ selective and stereocontrolled homocoupling reaction of allylic halides was achieved using barium reagent. The double-bond geometry of the starting allylic chloride was completely retained. The α,α′ cross-coupling products were also prepared stereospecifically and regioselectively by this method.
Pharmaceutical compositions including carotenoid analogs or derivatives for the inhabition and amelioration of disease
申请人:Lockwood Fournier Samuel
公开号:US20050075337A1
公开(公告)日:2005-04-07
A method for inhibiting and/or ameliorating the occurrence of diseases associated with reactive oxygen species, reactive nitrogen species, radicals and/or non-radicals in a subject whereby a subject is administered a carotenoid analog or derivative, either alone or in combination with another carotenoid analog or derivative, or co-antioxidant formulation. The analog or derivative is administered such that the subject's risk of experiencing diseases associated with reactive oxygen species, reactive nitrogen species, radicals and/or non-radicals may be thereby reduced. The analog or analog combination may be administered to a subject for the inhibition and/or amelioration of any disease that involves production of reactive oxygen species, reactive nitrogen species, radicals and/or non-radicals. In some embodiments, the invention may include a pharmaceutical composition including an analog or derivative of a carotenoid. The carotenoid analog or derivative may be synthetic. The carotenoid analog may include a conjugated polyene with between 7 to 14 double bonds. The conjugated polyene may include an acyclic alkene including at least one substituent and/or a cyclic ring including at least one substituent. In some embodiments, a carotenoid analog or derivative may include at least one substituent. The substituent may enhance the solubility of the carotenoid analog or derivative such that the carotenoid analog or derivative at least partially dissolves in water. In some embodiments, a pharmaceutical composition may include a biologically inactive carrier. The pharmaceutical composition may be adapted to be administered to a human subject.
A squalene synthase-like enzyme initiates production of tetraterpenoid hydrocarbons in Botryococcus braunii Race L
作者:Hem R. Thapa、Mandar T. Naik、Shigeru Okada、Kentaro Takada、István Molnár、Yuquan Xu、Timothy P. Devarenne
DOI:10.1038/ncomms11198
日期:——
analogous to that of C30 squalene. Confirming this hypothesis, the current study identifies C20 geranylgeranyl diphosphate (GGPP) as a precursor for lycopaoctaene biosynthesis, the first committed intermediate in the production of lycopadiene. Two squalene synthase (SS)-like complementary DNAs are identified in race L with one encoding a true SS and the other encoding an enzyme with lycopaoctaene synthase
Tetraterpene Synthase Substrate and Product Specificity in the Green Microalga <i>Botryococcus braunii</i> Race L
作者:Hem R. Thapa、Su Tang、James C. Sacchettini、Timothy P. Devarenne
DOI:10.1021/acschembio.7b00457
日期:2017.9.15
proteins as well as a structural comparison with the human SS (HSS) crystal structure. Characterization of the LOS mutants in vitro identified Ser276 and Ala288 in the LOS activesite as key aminoacids responsible for controlling substrate binding, and thus the promiscuity of this enzyme. Mutating these residues to those found in HSS largely converted LOS from lycopaoctaene production to C30 squalene production
The highly alpha,alpha' selective and stereocontrolled homocoupling reaction of allylic halides was achieved using barium reagent. The double-bond geometry of the starting allylic chloride was completely retained. alpha,alpha' Cross-coupling products were also prepared stereospecifically and regioselectively by this method.