| abstract |
A process for resolving a racemic modification of beta -adrenergic aryl- or hetaryl-oxypropanolamines such as (+/-)-2-[2-hydroxy-3-[[2-(1_H-indol-3-yl)-1,1-dimethylethyl]amino]prop oxy]benzonitrile into its individual enantiomers is described. The process comprises converting the racemic modification into a pair of diastereomeric urea derivatives by reaction with a chiral aralkylisocyanate; separation into the individual diastereomers; and facile regeneration of the starting amine by cleavage of the intermediate urea compound using hydrazine. This final step is improved by the addition of an alpha -keto carboxylic acid, such as pyruvic acid, which functions as a scavenger of nucleophilic by-products. |