2-methylamino-l-phenylpropane

Starting with two chiral centres, there should, therefore, be four stereoisomers, and this is nicely exemplified by the natural alkaloid (-)-ephedrine, which is employed as a bronchodilator drug and decongestant. Ephedrine is (li ,25)-2-methylamino-l-phenylpropan-l-ol, so has the structure and stereochemistry shown. 

The bronchodilator ephedrine is eryt/ ro-2-(methylamino)-l-phenylpropan-l-ol. The decongestant pseudoephedrine is f/ reo-2-(methylamino)-l-phenylpropan-l-ol. 

SYNS BIOPHEDRIN ECIPHIN EFEDRIN EPHEDRAL EPHEDRATE EPHEDREMAL EPHEDRIN 1-EPHEDRINE l(-)-EPHEDRINE EPHEDRITAL EPHEDROL EPHEDROSAN EPHEDROTAL EPHEDSOL EPHENDRONAL EPHOXAMIN FEDRIN O-HYDROXY-p-METHYL AMINE PROPYLBENZENE l-HYDROXY-2-METHYLAMINO-l-PHENYLPROPANE I-SEDRIN ISOFEDROL KRATEDYN MANADRIN ... 

MANDRIN (-)-a-(l-METHYLAMINOETHYL)BENZYL ALCOHOL l-a-(l-METHYLAMINOETHYL)BENZYL ALCOHOL 1-2-METHYLAMINO-l-PHENYLPROPAN-OL N-METHYLNOREPHEDRINE KASOL 1-PHENYL-2-METHYLAMINOPROPANOL SANEDRINE VENCIPON ZEPHROL... 

Pseudoephedrine (2-methylamino-l-phenylpropan-l-ol) is a nasal decongestant. U.S. 4,277,420 (to Monsanto) describes the preparation of the API and several possible precursors. Estimate the cost of production of each route and determine which route is cheapest. 

Ephedrine and pseudoephedrine (2-methylamino-l-phenylpropan-l-ol) are natural epimeric amino alcohols extracted from various species of the family of plants Ephedra. These plants have been used for millennia in China as stimulants and nasal decongestants. The structures of natural (—)-ephedrine and (+)-pseudoephedrine are depicted in Figure 3.3. The figure also shows norephedrine, which is the nitrogen-unsubstituted counterpart of ephedrine. These compounds are nowadays commercially available as inexpensive crystalline white solids and have been extensively used in phosphorus chemistry, as detailed in the next sections. 

Ephedrine is an alkaloid, a sympathomimetic amine with molecular formula Cjo Hi5 NOi, a molecular mass of 165.2, and the stmctural name (IR, 25)-2-methylamino-l-phenylpropan-l-ol. This bitter colorless or white solid-crystal is completely soluble in water, alcohol, chloroform, ether, and glycerol. Ephedrine is also produced by chemical synthesis and there is significant documentation of commercial ephedrine production using microbial biotransformation techniques [42]. Ephedrine has a structure close to methamphetamines, and its stimulant actions are comparable to epinephrine (adrenaline), a hormone produces by the adrenal glands that enhances heart rate and constriction of blood vessels in high-stress situations. Medicinal use of ephedrine began around 3000 B.C with the Chinese from md hudng, but its isolation was first reported in 1855 and its pharmaceutical application started in 1930 [22]. Studies on ephedrine s molecular structure show that two asynunetric carbon atoms are involved in ephedrine s molecular skeleton therefore, four optically active stereoisomers forms naturally occur as follows (IR, 2S)-(—)-ephedrine, (IS, 2R)-(+)-ephedrine, (IR, 2R)-( )-pseudoephedrine, (IS, 2S)-(+)-pseudoephedrine (Fig. 27.2). 

Ephedrine (l/ -25-2-methylamino-l-phenylpropan-l-ol) is an adrenergic amine present in many kinds of pharmaceutical preparations, obtained by synthesis or from natural sources. Belonging to the genus Ephedra (Ephedraceae), the Chinese species Ephedra sinica and Ephedra equisetina, also known as ma huang, and the Indian and Pakistani species E. gerardiana, E. intermedia, and E. major are the... 

According to the lUPAC definition, any diastereo-mer that has the opposite configuration at only one or two tetrahedral stereogenic centers is called an epimer, and the process of epimer formation by changing one of the asymmetric centers in the molecule is known as epimerization. The positions in two diastereomers that have different configurations are called epimeric. For example, for 2-(methylamino)-l-phenylpropan-l-ol (ephedrine), the IR,2R- and 1/ ,25-stereoisomers have the same configuration at Cl, but they are epimeric at the C2 atom (Figure 1.20). 

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