Elisabeth Egholm Jacobsen

Enantioselective enzymatic preparation of chiral glutaric monocarboxylic acids and amides

Enantioselective hydrolyses and ammonolyses of diethyl-3-hydroxyglutarate (1) and dimethyl-3-hydroxyglutarate (2) gave a maximum of 91 and 98% enantiomeric excess (ee), respectively, using immobilized lipase B from Candida antarctica. The ees were determined using chiral GLC of the monoamides and achiral GLC of diasteromeric derivatives of the monocarboxylic acids. The catalyst was re-used more than 10 times with retention of high activity and selectivity.

Enantiopure derivatives of 1,2-alkanediols: substrate requirements of lipase B from Candida antarctica.

Efficient methods for kinetic resolution of 1-phenoxy-2-butanol, 1-phenylmethoxy-2-butanol, and 1-phenoxy-2-pentanol were developed using lipase B from Candida antarctica as catalyst. Resolutions were performed in order to investigate the substrate requirements needed to obtain a high E-value. The effect of the substrate structure on E is different for transesterifications in organic media as compared to hydrolysis. The influence of different acyl donors on the E-value was also investigated.

Chemoenzymatic synthesis of enantiopure 1-phenyl-2-haloethanols and their esters

Abstract Several secondary haloalcohols have been resolved by esterification catalyzed by lipases A and B from Candida antarctica (CALA and CALB, respectively). Immobilized CALB (Novozym 435) gave better selectivities and faster reaction rates than CALA (Novozyme 735) with all of the substrates. Vinyl butanoate was the favoured acyl donor compared to vinyl acetate due to remarkably faster reactions. The alcohols (R)-2a, (R)-2c and the butanoates (S)-3a-c have been isolated with 98–99% enantiomeric excess (ee) in good yields.

2-C-Methyl-d-erythritol. Produced in plants, forms aerosols in the atmosphere. An alternative pathway in isoprenoid biosynthesis

Abstract 2-C-Methyltetritols, or 2-methyl-1,2,3,4-butanetetraols, which exist as four stereoisomers, are found to be present in the atmosphere above the Amazonian rainforest. 2-C-methyl-d-erythritol was originally isolated from Convolvulus glomeratus and later synthesized enantiomerically pure. It has been claimed that these compounds are produced from isoprene by radical oxidation in the atmosphere. More recently, detailed analysis has shown that the mixture of stereoisomers from forests in both Brazil and Sweden contains unequal amounts of enantiomers. This shows that the oxidation must be due to enzymatic activity in plants. A review of the history of these compounds, synthesis and the significance of stereochemistry is given. Moreover, the significance of 2-C-methyl-d-erythritol for the non-mevalonate route to isoprenoids is briefly discussed.

Investigating learners' viewing behaviour in watching a designed instructional video

The production and use of video in education has increased during the last years. However, most videos are not designed in a proper way to enhance attention and learning. In this article we report on the design of an instructional video based on existing multimedia learning principle as well as film and video theory and the result of an eye tracker study of students watching it. The eye tracker technology enables us to study the effects of the design elements in an objective way. We show that the design principles used in the production help viewers to focus on important aspects in the video.