ISSN:
0899-0042
Keywords:
chiral cyclic hemiketal derivatives NMR data
;
crystal structure elucidation
;
high-performance liquid chromatography (HPLC)
;
quinine salt resolution of rac-endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2-carboxylic acid
;
preparative resolution of rac-warfarin and rac-p-chlorowarfarin
;
reaction mechanism
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reaction of rac-warfarin, (-)-(1S,2R,4R)-endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2- carboxylic acid [(-)-HCA] and carbodiimide reagents gave two noncyclic ketonic diastereoisomeric derivatives whereas rac-warfarin and (-)-HCA acid chloride with 4-(dimethylamino)pyridine gave four cyclic hemiketal diastereoisomeric ester derivatives. The structure and stereochemistry of diastereoisomeric esters prepared from warfarin and p-chlorowarfarin were determined from 1H- and 13C-NMR spectra, mass spectra, and hydrolysis to warfarin and p-chlorowarfarin enantiomers. The structure and stereochemistry of one of the cyclic hemiketal diastereoisomeric derivatives of warfarin are supported by an X-ray crystallographic determination. Mechanisms for the formation of all products are proposed. © 1994 Wiley-Liss, Inc.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chir.530060812
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