[Coumarin-containing chiral discriminating agents. VII. New crystalline 1H-NMR enantiomeric excess determination reagent for alcohols and amines, (R)-(-)- and (S)-(+)-O-coumarinylmandelic acids].
The Mitsunobu reaction of commercial 4-hydroxycoumarin with both (R)-(-)- and (S)-(+)-tert-butyl mandelates derived from commercial enantiopure mandelic acids furnished (S)-(+)- and (R)-(-)-tert-butyl O-coumarinylmandelates which were, then, treated with trifluoroacetic acid to give novel crystalline optically pure (S)-(+)- and (R)-(-)-O-coumarinylmandelic acids [SCMOH and RCMOH], respectively in good overall yields. Diastereotopic nonequivalence 1H-NMR examination of the resultant esters and amides without any racemization or kinetic resolution by way of a Steglich's procedure (a DCC-DMAP method) has proved each acid to be a useful, efficient and reliable chiral derivatizing agent for the enantiomeric excess determination of chiral alcohols and amines.
Nagasawa
K
K
Hokkaido College of Pharmacy, Otaru, Japan.
Seto
N
N
Hara
C
C
Ito
K
K
D000438:Alcohols / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D003374:Coumarins / Q000737:chemistry*; D003460:Crystallization; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008333:Mandelic Acids / Q000737:chemistry*; D013237:Stereoisomerism
D000438:Alcohols; D000588:Amines; D003374:Coumarins; D007202:Indicators and Reagents; D008333:Mandelic Acids