Ethyl vinyl ether was used to protect –OH on glycidol based on a literature reported protocal.59 In a typical procedure, 0.675 mol glycidol and 200 mL ethyl vinyl ether were loaded in a round-bottom flask, to which 1.25 g TsOH was then added. The reaction was allowed to proceed at room temperature (RT) for 3h. The resulting mixture was then purified by washing with 100 ml saturated aqueous solution of NaHCO3 for 3 times. The organic layer obtained was dried by MgSO4. After filtration of MgSO4, the excess ethyl vinyl ether was removed by rotary evaporation.…
Sterols in plants are almost completely derived from acetyl-coenzyme A (acetyl-CoA). Acetyl-CoA is dimerized to acetoacetyl-CoA that then forms 3- hydroxy-3-methylglutaryl-CoA (HMG-CoA) by a condensation reaction. HMG-CoA is reduced to mevalonic acid by 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), a rate-limiting step in human isoprenoid biosynthesis. HMGR over-expression in transgenic tobacco plants resulted in increased levels of total sterols, indicating that HMGR is a limiting enzyme also in plant sterol biosynthesis (Schaller et al., 1995). The next step in sterol synthesis is to form squalene from mevalonic acid, and this is performend by a series of reactions where the final step is catalysed by the squalene synthase enzyme (SQS).…
Identifying Unknown Esters Produced by Fischer Esterification Introduction This procedure was performed in order to prepare an ester using an unknown alcohol and unknown acid via Fischer Esterification. Then to identify this unknown ester using gas chromatography. Esters are a derivative of carboxylic acids.…