A novel activity of halohydrin dehalogenases towards spiroepoxides has been found. The enzyme from Arthrobacter sp. (HheA) catalysed highly regioselective azidolysis of spiroepoxides containing 5, 6 and 7-membered cycloalkane rings, while the enzyme from Agrobacterium radiobacter (HheC), besides high regioselectivity, also displayed moderate to high enantioselectivity (E up to >200) that can be applied for the kinetic resolution of chiral spiroepoxides. The orientations of spiroepoxides in the active site of halohydrin dehalogenases were studied by quantum-chemical calculations and docking simulations. Analyses of the complexes obtained revealed the origins of diastereoselectivity and enantioselectivity of the investigated biotransformations.
Process for making neo-enriched p-menthane compounds
申请人:Renessenz LLC
公开号:EP2450337A2
公开(公告)日:2012-05-09
A process for making neo-enriched p-menthane intermediates is disclosed. Lewis acid-catalyzed rearrangement of an oxaspiro compound provides an aldehyde mixture comprising normal (II) and neo (III) p-menthane-3-aldehydes:
with the neo aldehyde (III) as the major product. The aldehyde mixture is readily oxidized to provide the corresponding carboxylic acids, and the acids are easily converted to a host of neo-enriched p-menthane esters or amides. The esters and amides are valuable as physiological coolants.
本发明公开了一种制造新富集对孟烷中间体的工艺。路易斯酸催化的氧杂螺化合物重排提供了一种醛混合物,其中包括正常 (II) 和新 (III) 对孟烷-3-醛:
新醛 (III) 为主要产物。醛混合物很容易被氧化,生成相应的羧酸,而羧酸又很容易转化为大量新富集的对门烷酯或酰胺。这些酯类和酰胺类化合物是很有价值的生理冷却剂。
Stereoselectivity and Substrate Specificity in the Kinetic Resolution of Methyl-Substituted 1-Oxaspiro[2.5]octanes by <i>Rhodotorula </i><i>g</i><i>lutinis</i> Epoxide Hydrolase
作者:Carel A. G. M. Weijers、Petra Meeuwse、Robert L. J. M. Herpers、Maurice C. R. Franssen、Ernst J. R. Sudhölter
DOI:10.1021/jo050533w
日期:2005.8.1
[GRAPHICS]The kinetic resolution of a range of methyl-substituted 1-oxaspiro[2.5]octanes by yeast epoxide hydrolase (YEH) from Rhodotorula glutinis has been investigated. The structural determinants of substrate specificity and stereoselectivity of YEH toward these substrates appeared to be the configuration of the epoxide ring and the substitution pattern of the cyclohexane ring. For all compounds tested, O-axial epoxides were hydrolyzed faster than the corresponding O-equatorial compounds. In concern of the ring substituents,.YEH preferred methyl groups on the Re side of the ring. Placement of substituents close to the spiroepoxide carbon decreased the reaction rate but increased enantioselectivity. YEH-catalyzed kinetic resolutions of 4-methyl 1-oxaspiro [2.5] octane epimers were most enantioselective,(E > 100).
Facial Stereoselectivity of Two-Step Additions Initiated by Electrophilic Halogens to Methylenecyclohexanes. A Comparison with Epoxidation
作者:Giuseppe Bellucci、Cinzia Chiappe、Giacomo Lo Moro、Giovanni Ingrosso
DOI:10.1021/jo00124a047
日期:1995.9
Kinetic resolution by epoxide hydrolase catalyzed hydrolysis of racemic methyl substituted methylenecyclohexene oxides
A complete kinetic resolution of 2,2-dimethylmethylenecyclobexene oxide and a partial resolution of the cis and trans-2-methylmethylenecyclohexene oxides, but not of their 3-methyl substituted isomers, have been achieved by partial hydrolysis to the corresponding diols using the microsomal epoxide hydrolase. No substrate enantioselectivity was in found for the hydrolysis of all these substrates by the cytosolic epoxide hydrolase.