6-Bromo-1-isoquinolinecarboxylic Acid acts as a reagent in the preparation of (S)-6-(3-hydroxy-2-methylpropylamino) isoquinoline-1-carbonitrile via palladium-catalyzed Buchwald-Hartwig amination reaction of 6-bromoisoquinoline-1-carbonitrile with (S)-3-amino-2-methylpropan-1-ol.