Kostraby, Margaret Mary (1999) The yeast mediated synthesis of the l-ephedrine precursor, l-phenylacetylcarbinol, in an organic solvent. PhD thesis, Victoria University of Technology.

Abstract

l-Ephedrine and d-pseudoephedrine are important pharmaceutical products commonly found in anti-asthmatic formulations, nasal decongestant mixtures and sinus preparations. d-Pseudoephedrine is the active ingredient in "Sudafed". l-Ephedrine is currently synthesised in a three step process. The first step utilises fermenting yeast in water to catalyse the acyloin condensation of benzaldehyde and acetaldehyde to form the l-ephedrine precursor, l-phenylacetylcarbinol (l-PAC). The second step involves the reaction of l-PAC with methylamine to form the corresponding N-methyl imine; the final step employs a metal catalyst to facilitate the reduction of the imine with hydrogen. This study is focused on the first step of the synthesis, which suffers from the drawback that two by-products, benzyl alcohol and l-phenylpropan-l,2-diol are always formed. The study aims to improve the efficiency of the l-PAC formation by performing the reaction with dried yeast in an organic solvent.

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