Brominated phenylethylamine

From the New Zealand ascidian Cnemidocarpa bicornuta, the brominated phenylethylamine 29 has been isolated. It exhibits mild cytotoxicity to P-388 cells (IC50 46 pM) [42]. 

D. (Alternative) To a stirred and cooled solution of 0.1 M NaOH in 100 ml water at -5° add 0.04 M bromine over five minutes and stir one-half hour at 0°. Add 0.02 M (III) and stir 1 Vi hours at 0-5°. Stir sixteen hours at room temperature and 70° for one hour. Cool and extract with ether, dry and evaporate in vacuum to get (IV). Phenylethylamines from Substituted Benzenes CA 57,6721(1963)... 

The Amathla genus has a wide geographical distribution and its members from different oceans have given a relatively large number of alkaloids which contain the p-phenylethylamine structural unit. The compounds are all bromine-containing amides. 

The preparation of optically active cyclopropanecarboxamides 64 has been achieved starting from an organometallic chiral auxiliary. The (R)- and (5)-crotonoyliron complexes show good diastereoselectivity for the Z conformer when treated with diethylzinc, zinc(II) chloride and diiodomethane. A 10 1 mixture of (i ,i ,5// ,5,/ )-diastereomers was obtained. Starting from the (/i)-isomer, (-)-(/ )-62, decomplexation of the cyclopropanated intermediates (R,R,S)- and (R,S,R)-63 with bromine in the presence of (4-)-(7 )-l-phenylethylamine gave the corresponding cw-substituted amides 64 in a ratio of 10 1. 

With the correct choice of reaction conditions, however, the asymmetric synthesis of cis-suh-stituted cyclopropanecarboxylic acid derivatives is achieved. Stereoselective methylene transfer to (Z)-a, -unsaturated acyl systems bonded to optically active carbonyl()j -cyclopen-tadienyl)triphenylphosphanyliron 2 and oxidative decomplexation of the products gave cis-substituted cyclopropanecarboxamides 3. High asymmetric induction (up to 92% de) was observed with bromine/l-phenylethylamine as decomplexation agent. When the decomplexation was carried out with A-bromosuccinimide/ethanol, racemic cw-substituted cyclopropanecarboxylic acid esters were obtained. 

A very different, but similarly effective, auxiliary is the chiral carbonyl(t/5-cyclopentadienyl)(tri-phenylphosphine)iron moiety. When the z./i-unsaturated acyl-iron complex ( -)-(/ )-11 is treated by a modified Simmons Smith reagent, a 91 9 mixture of cyclopropane diastereomers is isolated in good yield73. Precomplexation of the starting iron complex by the Lewis acid zinc(II) chloride seems to be necessary to obtain good selectivity. The chiral iron moiety can then be removed oxidatively by bromine treatment, and the intermediate acyl bromides converted into amides by reaction with (/ )- -phenylethylamine. 

Fuganti s synthesis of serine (Scheme 19) relied on the stereospecific conversion of [l,l- H2]-2-phenylethylamine 68 to (1S)-[1- H,3-2-phenyl-ethanol 69 by Willia anomala (88). Acetylation, benzylic bromination, and... 

The ready oxidation of (l-aminoalkyl)phosphonous acids (aminoalkylphosphinic acids) with aqueous bromine, to give (l-aminoalkyl)phosphonic acids, raises still further the potential usefulness of the former. In a useful modification to one synthesis, the reaction between an aldehyde and either (R)- or (5 )-l-phenylethylamine hypophosphite salt yields the A-substituted (l-aminoalkyl)phosphinic acid which is simultaneously oxidized and deprotected when treated with bromine water. ... 

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