Ethanolamine derivatives, aromatic

Aromatic ethanolamine derivatives, e.g. ephedrine, also yield blue-colored chelates with Cu + ions (Chen-Kao reaction [4, 27]). 

This method [Eq. (10)] was first used in 1930 by Kondo and Tanaka60 for the preparation of 4-hydroxy-5-methoxytetrahydroisoquinoline from j8-hydroxy-j8-(o-methoxyphenyl)ethylamine and methylal (mixed in aqueous HC1). Such ethanolamine derivatives are frequently used in the Bischler-Napieralski synthesis of isoquinolines61 as the Pictet-Gams modification. In this case, the reaction proceeds with dehydration to yield completely aromatic isoquinolines directly. Preparations of the ethanolamines have been reviewed.62... 

Replacement of the ethanolamine head group is also well tolerated. Substitution with a cyclopropyl (243) [37], allyl (244) or propargyl group (245) [164] all led to an increase in binding affinity compared to AEA. Replacement of the head group with aromatics is also allowed. The phenyl derivative (246) retains affinity at the CBi receptor [37], whereas the 2-substituted A-methyl pyrrole (247) has a 2-fold improved affinity compared to AEA [167]. Interestingly, the 3-substituted furan derivative (23) that has micromolar affinity for the AEA transporter (see above) does not bind to the CBi receptor, but has good affinity for the CB2 receptor [167]. These results are summarised in Table 6.20. 

KCAs) are among the numerous classes of drugs developed to control hypertension. See also Enzyme Inhibitors. /(-Adrenoceptor antagonists exemplified hy the phenoxypropanolamine derivatives propranolol and alprenolol and or the phenethanolamine drugs such as sotalol and require for activity both the ethanolamine portion and an aromatic ring. Furthermore, the correct spatial arrangement of the phenyl, ethylamine, and hydroxyl moieties is critical for /1-blockade. 

Pentryl, or 2,4,6-trinitrophenyInitraminoethyI nitrate, is another explosive which is derived from ethylene. It is a nitric ester, an aromatic nitro compound, and a nitroamine. The substance was described in 1925 by Moran54 who prepared it by the action of mixed acid on 2,4-dinitrophenylethanolamine (large orange-yellow crystals from alcohol, m.p. 92°) procured by the interaction of dinitrochlorobenzene with ethanolamine. von Herz later prepared pentryl by the nitration of 0-hydroxyethylaniline, a material which is more commonly called phenylethanolamine and is now available commercially in this country, and was granted... 

The rearrangement products derived from aromatic and non-aromatic heterocyclic amines crystallize readily from the lower alcohols. Unlike those of many of the A-substituted glycosylamines, the crystals are not solvated. On the other hand, the ketose derivatives of aralkyl- and alkyl-amines, such as 2-phenylethylamine, ethanolamine, diethanolamine, glycine ethyl ester, and phenylalanine (see Table II), are hydrated or alcoholated, or both, and are difficult to isolate in pure crystalline form. The crystals which have been isolated were hygroscopic. Alcohols, aqueous alcohols, and water are the most commonly used solvents for crystallization. Acetone, ether, or benzene have been added to the alcoholic media in order to increase the yield of crystalline compound. The use of solvents that contain peroxides promotes decomposition of the crystals during storage. ... 

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