L-Norephedrine

C[5H240 104-40-5) see Nonoxinol 9 iiurbornane-2fj Oj3ejro-dicarboxylic acid anhydride (CyH,(,0 14166-28-0) see Tandospirone norborn-5-cne 2 ji o 3e.ro>dicarboxylic acid anhydride (CyH 0 2746-19-2) see Tandospirone L-norephedrine... 

The vicinal aminoalcohol D,L-norephedrine (47) is cleaved to benzoic acid (67 %) and benzaldehyde (25%) in 0.1 M potassium hydroxide (10 °C). Under less alkaline conditions (pH 7.5) the cleavage reaction is suppressed, but now a greater number of products with an azomethine, probably 48, as major component (37 %) is obtained. 

The synthesis of Oxyfedrine is based on the Mannich Reaction (see under Organic Name Reactions part J ) wherein one mole each of a ketone i.e., m-methoxy acetophenone reacts with a primary amine i.e., L-norephedrine in the presence of paraformaldehyde to give rise to a product with an additional —CH2— moiety derived from formaldehyde (or paraformaldehyde) i.e., oxyfedrine with the elimination of a mole of water. 

D)-Amino acids are also prepared through crystallisation of their corresponding diastereomeric salts. An important application of this truly competitive method was developed by Friedrich Asinger (1907 -1999, Austrian chemist) and the product successfully commercialised by Degussa Separation of the (D,L)-penicillamine-acetone adduct with (L)-norephedrine was conducted at a ten-tonne scale. The unwanted (L)-penicillamine-acetone adduct is racemised and recycled. 

From the results of Suedee et al. [11] listed in Table 11.2, it is clear that the geometry around the chiral carbon (fi-C) in the print molecules of (-l-)-ephedrine, (-l-)-pseudoephedrine, and (-l-)-norephedrine was essential for enantiomeric recognition and separation of /3-blocker racemates. Since (-l-)-antipodes of print molecules possess the same spatial arrangements as (-)-antipodes of jS-blockers, this could explain a higher affinity and lower Rf values of the later. The substituents... 

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