Halostachine

Halostachine, CgH jON. This base was isolated from Halostachis caspica, also given as Halostaehys caspia (Chenopodiaceae), where it is... 

As a result of their potent pharmacological activity, 4-aryl-1,2,3,4- tetrahydroisoquinolines have attracted numerous synthetic efforts. Treatment of ( S)-1 with acetone under acid catalysis generates ( S)-( + )-2,2-dimethyl-5-phenyl-l,3-dioxolan-4-one (55) in 80% yield. Reaction of 55 with methylamine followed by lithium aluminum hydride reduction of the resultant amide provides ( S)-(+ )-A-methylamino-l-phenylethanol [(5)-( + )-halostachine] (56). N-... 

Boc protection of the amine, complexation with hexacarbonylchromium, and then amine deprotection with neat formic acid provides (R)-( + )-halostachine(tricarbonyl)chromium(0) (57). Treatment of 57 with 3,4-dimethoxybenzyl bromide in dichloromethane affords in 36% yield (i )-( + )-tricarbonyl f -2-[3,4-dimethoxybenzyl(methyl)amino]-l-phenylethanol -chromium(O) (58), which undergoes a highly selective acid-promoted cyclization that proceeds with retention of configuration to yield, after decomplexation, optically pure (R)-(-h)-6,7-dimethoxy-2-methyl-4-phenyl-l,2,3,4-tetrahydroisoquinoline (59) in moderate yield (Scheme 11) [13]. 

It would appear as though the natural phenethylamines were connected with some general biochemical mechanism, which is not even limited to plants alone. Even adrenaline, this typical animal hormone may be expected to occur in plants its chemical skeleton is already represented in halostachine (side chain) and in oxytyramine and coryneine (3 4 position of the hydroxyls). The occurrence of adrenaline (6%) in... 

Halostachine was discovered by Yu. I. Syrneva (18) in the Chenopodiaceae Halostachys caspica C. A. Mey. The erroneously assigned molecular structure, C6H6 CH(NH-CH3)CH20H, was later corrected by G. P. Menshikov and M. N. Rubinstein (19) to C8H6-CH(OH)CH2NH-CHa. 

Halostachine is oxidized to benzoic acid by permanganate. It reacts with thionylchloride giving CeHiaNCl-HCl, m.p. 168-169 (from alcohol) JV-methylhalostachine yields with thionylchloride CioHhNCI--HCl, m.p. 202-203 . This compound is reduced by sodium amalgam to the base CioHuN (identical with AT-dimethyl-/3-phenethylamine), b.p. 

Phenethanolmethylamine (racemic halostachine) Tyramine N-Methyltyramine Hydroxytyramine... 

The pharmacological action of the natural alkaloid is similar to that of ephedrine (18). The racemic synthetic compound had already been examined by Barger and Dale. Hyde, Browning, and Adams prepared a series of homologues of d,2-ephedrine, in which the alkyl group on the jS-carbon was replaced by H, ethyl, and n-propyl. The only homologue that gave a dependable increase in blood pressure was the a-phenyl-/3-methylaminoethanol, i.e., racemic halostachine (20). 

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