- Enantioselective binding of an 11-cis-locked cyclopropyl retinal. The conformation of retinal in bovine rhodopsin
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(equation presented) Binds to Opsin Does Not Bind to Opsin The conformation of the retinal chromophore in rhodopsin is central for understanding the visual transduction process. The absolute twist around the 12-s bond of the chromophore in rhodopsin has b
- Lou, Jihong,Hashimoto, Masaru,Berova, Nina,Nakanishi, Koji
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- A straightforward stereoselective synthesis of meso-, (S,S)- and (R,R)-2,6-diaminopimelic acids from cis-1,4-diacetoxycyclohept-2-ene
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A straightforward synthesis of meso-2,6-diaminopimelic acid (DAP) meso-1 was developed from 1,4-diacetoxycyclohept-2-ene (2) via an oxidative ring cleavage. Subsequently, an enantio-divergent synthesis of (S,S)- and (R,R)-1 was performed using a homochiral monoacetate 7 available from2 by enzymatic desymmetrization.
- Saito, Yukako,Shinkai, Takumi,Yoshimura, Yuichi,Takahata, Hiroki
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p. 5894 - 5896
(2008/09/20)
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- PALLADIUM(0) CATALYZED REACTIONS OF 1,4-EPIPEROXIDES
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The Pd(PPh3)4 catalyzed reaction of 2,3-saturated and 2,3-unsaturated 1,4-epiperoxides proceeds by courses markedly different from those of the previously reported transition metal catalyses.The Pd(0)-promoted reaction of 2,3-saturated epiperoxides gives the corresponding 4-hydroxy ketones and 1,4-diols as the major products.From 2,3-dedihydroepiperoxides are formed the corresponding 4-hydroxy enones, syn-1,2;3,4-diepoxides, and 1,4-diols.The results are interpreted in terms of competing Pd(0)/Pd(II) exchange mechanisms.Exposure of prostaglandin (PG) H2 methyl esterto Pd(PPh3)4 produces a mixture of methyl esters of PGD2, PGE2, PGF2α, and (5Z,8E,10E,12S)-12-hydroxy-5,8,10-heptadecatrienoic acid.
- Suzuki, Masaaki,Oda, Yoshihisa,Hamanaka, Nobuyuki,Noyori, Ryoji
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p. 517 - 535
(2007/10/02)
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- Enzymatic Hydrolysis of 3,7-Diacetoxycycloheptene Derivatives
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Hydrolysis of 3,7-diacetoxycycloheptene using electric eel acetylcholinesterase gives optically pure (3R,7S)-3-hydroxy-7-acetoxycycloheptene, and hydrolysis using lipase enzyme from Candida cyclindracea gives which same hydroxy acetate, but in only 44percent enantiomeric excess, in contrast to the normal behaviour of lipase which gives (S) alcohols for related hydrolyses; 3,7-diacetoxy-4,6-dimethylcycloheptene (10) is not hydrolysed by acetylcholinesterase, but is readily hydrolysed by lipase to give (3S,4R,6S,7R)-3-hydroxy-7-acetoxy-4,6-dimethylcycloheptene.
- Pearson, Anthony J.,Bansal, Harjinder S.,Lai, Yen-Shi
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p. 519 - 520
(2007/10/02)
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- PALLADIUM(O) CATALYZED REACTION OF 1,3-DIENE 1,4-EPIPEROXIDES
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Reaction of 1,3-diene 1,4-epiperoxides with Pd(PPh3)4 catalyst forms the corresponding 4-hydroxy enones, syn diepoxides, and 1,4-diols as the major products.The results are interpreted as being due to competing Pd(O)/ Pd(II) and Pd(O)/ Pd(I) exchange mechanisms.
- Suzuki, M.,Oda, Y.,Noyori, R.
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p. 4413 - 4416
(2007/10/02)
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