90-81-3Relevant articles and documents
BIOCATALYTICAL PROCESS FOR RACEMIZATION OF D-EPHEDRINE
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Page/Page column 9-12, (2020/05/28)
This invention relates to methods for racemization of dextro-rotatory ephedrine via enzymatic kinetic conversion, and is particularly useful for conversion of dextro- rotatory ephedrine (d- ephedrine) to racemic mixture of dextro-rotatory ephedrine (d-ephedrine) and levo-rotatory ephedrine (l-ephedrine) to recover the levo-rotatory ephedrine that exhibit potential bronchodilatory and anti-hypotensive activities. The process provides a suspension of Rhizopus Oryzae fungi pellets in diammonium phosphate buffer having pH in the range of pH 5 to 9 and effective sonication to extract specific enzymes for inversion of functional groups present on the chiral carbon atom of d-ephedrine molecule at low temperature which has advantages of working at lower temperature range (20 to 50 °C), lower energy consumption, lesser formation of by-products.
Diastereoselective reduction of α-aminoketones: Synthesis of anti- and syn-β-aminoalcohols
Fraser, David S.,Park, Sheldon B.,Chong, J. Michael
, p. 87 - 101 (2007/10/03)
Reduction of N-t-BOC-protected-N-alkyl α-aminoketones with LiEt 3BH or Li(S-Bu)3BH furnishes protected syn-β-aminoalcohols with high selectivities. In contrast, removal of the BOC group followed by reduction of the aminoketone gives anti-β- aminoalcohols with variable selectivities. With aromatic ketones, selectivities are typically high while aliphatic ketones show mediocre to high selectivities depending on steric considerations.
Synthesis of syn- and anti-1,2-amino alcohols by regioselective ring opening reactions of cis-3-aminooxetanes
Bach, Thorsten,Schroeder, Juergen
, p. 3707 - 3710 (2007/10/03)
N-t-Butyloxycarbonyl (Boc) substituted cis-2-phenyl-3-aminooxetanes 3 undergo a ring expansion to oxazolidinones 5 upon treatment with trifluoroacetic acid. The reaction occurs at the C(2) position under inversion of configuration. Alternatively, 3-aminooxetanes can be ring-opened at the less substituted C(4) position with retention of the relative configuration between C(2) and C(3) as exemplified by the synthesis of (+)-pseudoephedrine (2). The cis3-aminooxetanes serve as precursors for either syn- or anti-1,2-amino alcohols.