Expedient synthesis of (S)- and (R)-norcoclaurine from (S)- and (R)-norarmepavine [corrected] prepared by the 1-phenylethylurea method.
(+/-)-Norarmepavine [3] [corrected] prepared by Bischler-Napieralski synthesis afforded, on reaction with (S)-(-)-1-phenylethylisocyanate, ureas 4 and 5 which were separated and purified by crystallization from EtOH and 70% HOAc. Alcoholysis of 4 and 5 with sodium butoxide in n-BuOH afforded (S)-norarmepavine [3a] and (R)-norarmepavine [3b] [corrected], respectively. Hplc analysis of ureas prepared from 3a and 3b with (S)-(-)-1-phenylethylisocyanate showed them to be optically pure alkaloids. Refluxing 3a and 3b with 48% HBr afforded the hydrobromide salts of (S)-norcoclaurine [1a] and its (R)-isomer 1b, respectively.
Sekine
Y
Y
Laboratory of Analytical Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
Brossi
A
A
D000470:Alkaloids / Q000138:chemical synthesis*; D044182:Benzylisoquinolines; D055598:Chemical Phenomena; D002621:Chemistry; D013237:Stereoisomerism; D044005:Tetrahydroisoquinolines
D000470:Alkaloids; D044182:Benzylisoquinolines; D044005:Tetrahydroisoquinolines; C064689:armepavine; C012348:higenamine