摘要:
Disclosed are methods for the synthesis of chiral alcohols by Sortase A-mediated oxidoreductase oligomers, which relates to the field of biocatalysis. In the present disclosure, oxidoreductase oligomers were used as biocatalysts for chiral alcohol preparation. Compared to wild-type enzymes, the oxidoreductase oligomers significantly improved catalytic activity and thermal stability. The sortase A-mediated oxidoreductase oligomers had 6-8 folds improvement in specific activity over that of the wild-type enzymes. The oligomers displayed a Tm value 6-12° C. higher than that of the wild-type, suggesting the sortase A-mediated oxidoreductase oligomers significantly improved thermostability of the enzymes. The oxidoreductase oligomers catalyzed asymmetric transformation to produce (S)-1-phenyl-1,2-ethanediol or (R)-1-phenethyl alcohol within 3-6 hr, with an optical purity of 98%-100% and a yield of 98%-99%.
摘要:
The present invention relates to kinetic resolution of racemic δ-hydroxyl ester via asymmetric catalytic hydrogenation and an application thereof. In the presence of chiral spiro pyridyl phosphine ligand Iridium catalyst and base, racemic δ-hydroxyl esters were subjected to asymmetric catalytic hydrogenation to obtain extent optical purity chiral δ-hydroxyl esters and corresponding 1,5-diols. The method is a new, efficient, highly selective, economical, desirably operable and environmentally friendly method suitable for industrial production. An optically active chiral δ-hydroxyl ester and 1,5-diols can be obtained at very high enantioselectivity and yield with relatively low usage of catalyst. The chiral δ-hydroxyl ester and 1,5-diols obtained by using the method can be used as a critical raw material for asymmetric synthesis of chiral drugs (R)-lisofylline and natural drugs (+)-civet, (−)-indolizidine 167B and (−)-coniine.
摘要:
This invention relates to the production of terephthalic acid by 1) cycloaddition of 2,5 substituted furan (such as 2,5-bis hydroxymethylfuran or 5-hydroxymethylfurfural) and ethylene, and 2) the subsequent oxidation of the dehydrated cycloaddition product to terephthalic acid. The invention relates more particularly to overall biobased pathways for making terephthalic acid from carbohydrates such as hexoses (e.g., glucose or fructose).
摘要:
The present disclosure is related to silica-based Lewis acid catalysts, being essentially devoid of strong Brønsted acid character, and their ability to effect the [4+2] cycloaddition and dehydrative aromatization of dienes and dienophiles containing oxygenated substituents to form substituted benzene products. In some embodiments, the processes comprise contacting biomass-derived substrates with ethylene to form terephthalic acid and its derivatives.
摘要:
The present invention relates to the field of perfumery. More particularly, it concerns a process for the preparation of 2-methyl-4-phenyl-2-butanol, or even 4-cyclohexyl-2-methyl-2-butanol from 4,4-dimethyl-2,6-diphenyl-1,3-dioxane.
摘要:
A phenyl carbamate compound; a composition for treating and/or preventing stroke containing the phenyl carbamate compound or a pharmaceutically acceptable salt thereof as an active ingredient; a method of treating and/or preventing stroke comprising administering the phenyl carbamate compound or a pharmaceutically acceptable salt thereof to a patient in need of stroke treatment; and a use of the phenyl carbamate compound or a pharmaceutically acceptable salt thereof in treating and/or preventing stroke, are provided.
摘要:
The present invention relates to organic electroluminescent devices, in particular blue-emitting devices, in which compounds of the formulae (1) to (4) are used as host material or dopant in the emitting layer and/or as hole-transport material and/or as electron-transport material.
摘要:
A method for the synthesis of 1,3-di(chloropropyl)-5-tert-butyl benzene includes the steps of conducting Friedl-Crafts alkylation of 1,3-diisopropyl benzene by tert-butyl chloride in the presence of an alkylation catalyst to obtain 1-tert-butyl-3,5-diisopropylbenzene; peroxidizing the 1-tert-butyl-3,5-diisopropyl benzene by gaseous oxygen in the presence of a peroxidation catalyst in a basic solution to obtain 1,3-di(peroxypropyl)-5-tert-butylbenzene; reducing the 1,3-di(peroxypropyl)-5-tert-butylbenzene with a reducing agent to 1,3-di(hydroxylpropyl)-5-tert-butylbenzene; and chlorinating the 1,3-di(hydroxypropyl)-5-tert-butylbenzene to obtain 1,3-di(chloropropyl)-5-tert-butyl benzene.
摘要:
The present invention discloses a process for isolating enantiomer components from a mixture of enantiomers through particle-size-controlled crystallization, comprising the steps of: (a) forming a solution of a mixture of enantiomers (R) and (S) in a solvent in the absence of any further additives or agents; (b) seeding the solution of step (a) simultaneously or consecutively with seed crystals of enantiomer (R) and with seed crystals of enantiomer (S), wherein the seed crystals of enantiomer (R) differ in size and/or in quantity from the seed crystals of enantiomer (S) to allow separation of the crystals composed of a mixture enriched with enantiomer (R) from the crystals composed of a mixture enriched with enantiomer (S); (c) inducing simultaneous crystallization of enantiomer (R) and enantiomer (S); and (d) isolating crystals composed of a mixture enriched with enantiomer (R) from crystals composed of a mixture enriched with enantiomer (S) through size separation of the crystals, preferably through sieving, melting or sedimentation, in particular through sieving.