20548-02-1Relevant academic research and scientific papers
Synthesis of (R)- and (S)-4-hydroxyisophorone by ruthenium-catalyzed asymmetric transfer hydrogenation of ketoisophorone
Hennig, Michael,Puentener, Kurt,Scalone, Michelangelo
, p. 1849 - 1858 (2000)
The first synthesis of (R)- and (S)-4-hydroxyisophorone by catalytic transfer hydrogenation of ketoisophorone is reported. Ruthenium catalysts containing commercially available chiral amino alcohols afforded 4-hydroxyisophorone in up to 97% selectivity an
Cloning, sequence analysis, and expression in Escherichia coli of the gene encoding monovalent cation-activated levodione reductase from Corynebacterium aquaticum M-13.
Yoshisumi,Wada,Takagi,Shimizu,Nakamori
, p. 830 - 836 (2001)
The gene encoding (6R)-2,2,6-trimethyl-1,4-cyclohexanedione (levodione) reductase was cloned from the genomic DNA of the soil isolate bacterium Corynebacterium aquaticum M-13. The gene contained an open reading frame consisting of 801 nucleotides correspo
Synthesis method of 4-hydroxy-2, 2, 6-trimethyl cyclohexanone
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Paragraph 0031; 0033-0035; 0037-0039; 0041-0045, (2022/03/01)
The invention provides a synthesis method of 4-hydroxy-2, 2, 6-trimethyl cyclohexanone, which comprises the following steps: (1) carrying out selective hydrogenation on tea flavor ketone under the action of a Lindlar catalyst to obtain 2, 2, 6-trimethyl-1, 4-cyclohexanedione, and (2) carrying out selective hydrogenation on 2, 2, 6-trimethyl-1, 4-cyclohexanedione to obtain 4-hydroxy-2, 2, 6-trimethyl cyclohexanone, wherein chiral rhodium is used as a hydrogenation catalyst in the step (2). The invention provides a new method for synthesizing the damascenone intermediate 4-hydroxy-2, 2, 6-trimethyl cyclohexanone, the operation is simple, the initial raw material tea flavor ketone is easy to obtain, and the 4-hydroxy-2, 2, 6-trimethyl cyclohexanone is high in yield and high in selectivity.
On the bi-enzymatic behaviour of Saccharomyces cerevisiae-mediated stereoselective biotransformation of 2,6,6-trimethylcyclohex-2-ene-1,4-dione
Uzir, Mohamad Hekarl,Najimudin, Nazalan
, p. 56 - 64 (2018/02/13)
Baker's yeast has been well-known to have the ability to reduce a variety of substrates into many optically active compounds. One of the important chemicals is (4R,6R)-4-hydroxy-2,2,6-trimethylcyclohexanone or in short, (4R,6R)-actinol, a product formed f
An engineered old yellow enzyme that enables efficient synthesis of (4R,6R)-actinol in a one-pot reduction system
Horita, Shoichiro,Kataoka, Michihiko,Kitamura, Nahoko,Nakagawa, Takuya,Miyakawa, Takuya,Ohtsuka, Jun,Nagata, Koji,Shimizu, Sakayu,Tanokura, Masaru
, p. 440 - 445 (2015/03/05)
(4R,6R)-Actinol can be stereo-selectively synthesized from ketoisophorone by a two-step conversion using a mixture of two enzymes: Candida macedoniensis old yellow enzyme (CmOYE) and Corynebacterium aquaticum (6R)-levodione reductase. However, (4S)-phorenol, an intermediate, accumulates because of the limited substrate range of CmOYE. To address this issue, we solved crystal structures of CmOYE in the presence and absence of a substrate analogue p-HBA, and introduced point mutations into the substrate-recognition loop. The most effective mutant (P295G) showed two- and 12-fold higher catalytic activities toward ketoisophorone and (4S)-phorenol, respectively, than the wild-type, and improved the yield of the two-step conversion from 67.2 to 90.1%. Our results demonstrate that the substrate range of an enzyme can be changed by introducing mutation(s) into a substrate-recognition loop. This method can be applied to the development of other favorable OYEs with different substrate preferences.
OPSIN-BINDING LIGANDS, COMPOSITIONS AND METHODS OF USE
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Page/Page column 157, (2010/12/31)
Compounds and compositions of said compounds along with methods of use of compounds are disclosed for treating ophthalmic conditions related to mislocalization of opsin proteins, the misfolding of mutant opsin proteins and the production of toxic visual cycle products that accumulate in the eye. Compounds and compositions useful in the these methods, either alone or in combination with other therapeutic agents, are also described.
Synthesis of biotinylated retinoids for cross-linking and isolation of retinol binding proteins
Nesnas, Nasri,Rando, Robert R,Nakanishi, Koji
, p. 6577 - 6584 (2007/10/03)
The synthesis of (3R)-3-[Boc-Lys(biotinyl)-O]-11-cis-retinol bromoacetate and 3-[Boc-Lys(biotinyl)-O]-all trans-retinol chloroacetate is described. These biotinylated retinoids are instrumental in labeling the retinol binding proteins (RBPs) via a nucleophilic displacement of the haloacetate by a residue in the binding site of the protein. The covalently linked biotin will allow for a facile isolation and purification of the protein on a streptavidin column thus rendering the protein ready for a tryptic digest followed by mass spectrometric analysis. The 11-cis retinoid was synthesized via metal reduction of an alkyne intermediate generated from a Horner-Wadsworth-Emmons (HWE) reaction whereas the all-trans was synthesized via two consecutive HWE couplings.
Reduction of aliphatic and aromatic cyclic ketones to sec-alcohols by aqueous titanium trichloride/ammonia system. Steric course and mechanistic implications
Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
, p. 2235 - 2243 (2007/10/03)
In contrast to the dissolved metal and metal hydride reductions, the reduction of cyclic ketones by the aqueous TiCl3/NH3 system favours the formation of the less thermodynamically stable axial alcohol. The ammonium ion formed in situ is essential for the reduction to proceed because it behaves as a mild Br?nsted acid in basic medium and favours the protonation of the intermediate ketyl. The corresponding α-hydroxy radical is then rapidly reduced under conditions where the first electron transfer to the substrate takes place. We suggest that the stereoselectivity is determined by the second reduction step, which occurs through the less hindered transition state, regardless of whether the radical to be reduced is thermodynamically favoured or not.
Acceleration of the reduction of aldehydes and ketones using Mn(dpm)3 catalyst and phenylsilane in the presence of dioxygen
Magnus, Philip,Fielding, Mark R
, p. 6633 - 6636 (2007/10/03)
Saturated ketones and aldehydes are reduced to alcohols by phenylsilane and Mn(dpm)3(cat) in the presence of dioxygen.
Total synthesis and biological activities of (+)- and (-)-boscialin and their 1'-epimers
Busch, Joachim,Grether, Yvonne,Ochs, Dietmar,Sequin, Urs
, p. 591 - 597 (2007/10/03)
Natural (-)-boscialin [(-)-1] has recently been described as one of the constituents of various medicinal plants. To obtain more material for investigations of its biological activities, we carried out the synthesis of (-)-1 and its isomers. Starting from the chiral building block 2, the key steps of the synthesis involved a regioselective reduction and a nucleophilic addition. The enantiomer of the natural product, (+)-boscialin [(+)-1], could be obtained via acid-catalyzed epimerization of hydroxyketone 4 to (+)-3. Starting the synthesis with (-)-3 led to (-)-boscialin [(-)-1] with the natural absolute configuration. In addition to (+)- and (-)-boscialin, the corresponding 1'-epimers (+)- and (-)-epiboscialin were also obtained. In vitro assays with (-)-boscialin [(-)-1] and its three stereoisomers were carried out to test for activity against microbes, parasites, and human fibroblasts. The investigations revealed activity against various microbes and against Trypanosoma brucei rhodesiense and also revealed cytotoxicity against human cancer cells.
