Ephedrine, structure

Enzyme-substrate complex, 1041 Ephedrine, structure of, 65 Epibatidine, molecular model of. 332 Epichlorohydrin, epoxy resins from, 673-674 Epimer, 303... 

Therapeutic Function Sympathomimetic Bronchodilator Chemical Name Benzenemethanol, a-(l-(methylamino)ethyl)-, (R-(R, S ))-Common Name Efedrin Ephedrine Structural Formula ... 

All four chiral auxiliaries are available derivatives of ephedrine. Structurally, they are vicinal amino-alcohols, which are able to act as l,4-N,0-bidentate ligands for many metal cations. The stability of such complexes generally enhances with the hardness of the central metal ion [17]. 

These results indicate that in these new ester mydriatics, the structural factors, which influence the development of this type of pharmacological action are similar to those made evident by the chemical investigations of Jowett and Pyman and the pharmacological work of Marshall, Dale, Laidlaw and Cushny on the tropeines. The nature of the basic component is obviously important since mydriasis is produced by simple bases such as ephedrine. As regards the nature of the esterifying acid, Jowett and Pyman drew the following conclusions — ... 

Chemical Structures. Figure 1 shows the chemical structures for 14 phenylethylamine compounds. Nine of these compounds are used clinically as anorectics (ii-amphetamine, phentermine, diethylpropion, phenmetrazine, phendimetrazine, clotermine, chlorphentermine, benzphetamine, and fenfluramine). Four of these compounds are not approved for clinical use and are reported to have hallucinogenic properties (MDA, PMA, DOM, and DOET). The final compound ( /-ephedrine) is used clinically for bronchial muscle relaxation, cardiovascular, and mydriatic effects. Figure 2 shows the chemical structure for MDMA, the methyl analog of MDA. MDMA is not approved for clinical use and has been reported to produce both LSD-like and cocaine-like effects. 

From calculations of the preferred conformation of the ephedrine and pseudo ephedrine molecules the topography of the adrenergic receptor as a flat surface has been deduced (26). This view, however, does not explain the decisive effect of the additional methyl group its relative position should not influence the interaction with the proposed receptor to a large extent (Fig. 7a). However, as the differences in activities are especially high for the ephedrine and pseudo ephedrine isomers, we believe that the receptor must have an intercalated structure similar as projected for the "binding sites" of the silicones (Fig. 7b). ... 

A limited study has been made of the role of the structure of the catalyst in the phase-transfer epoxidation reaction (77). The catalysts tried were mainly salts of quinine (3a-g), cinchonidine (4), ephedrine (5), and a camphor derivative (6) (Figure 14). The conclusions were as follows ... 

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. 

In contrast to the highly specific structural requirement for ligands at the various adrenoceptor subtypes the re-uptake mechanism (into the axon and into the vesicle) are less discriminative. Compounds without hydroxyl moieties at the phenyl ring have no affinity towards the adrenoceptors but serve as a substrate for the re-uptake mechanisms, thereby competing with noradrenaline and as a consequence increasing its concentration in the synaptic cleft. Drugs enhancing the sympathetic tone by this mechanism are called indirect sympathomimetics, for example tyramine, ephedrine, amphetamine. 

Figure 4.8 shows the UV absorption spectrum of a 100 mg/100 ml solution of ephedrine. Ephedrine has the simplest type of benzene ring chromophore, which has a spectrum similar to that of benzene with a weak symmetry forbidden band ca 260 nm with anA (1%, 1 cm) value of 12. Like benzene its most intense absorption maximum is below 200 nm. There are no polar groups attached to or involved in the chromophore so that its vibrational fine structure is preserved because the chromophore does not interact strongly with the solvent. 

It is a synthetic compound with structural similarity to ephedrine and is available in racemic and dextro isomers. It increases the systolic and diastolic blood pressure. Amphetamine is a potent CNS stimulant and causes alertness, insomnia, increased concentration, euphoria or dysphoria and increased work capacity. Amphetamine produces wakefulness and improved physical performance. It contracts the sphincter of the bladder and relaxes the bronchial smooth muscle in large doses. Amphetamines are drugs of abuse and can produce behavioural abnormalities and can precipitate psychosis. It can produce psychological but no physical dependence. 

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