Syntheses of Ring-Hydroxylated Nipradilols and Their Denitro Derivatives

抄録

Nipradilol (NIP), 3, 4-dihydro-8-(2-hydroxy-3-isopropylamino)propoxy-3-nitroxy-2H-1-benzopyran, is extensively metabolized in man and dogs. In order to identify the ring-hydroxylated metabolites we have synthesized cis- and trans-4-hydroxy-, and 5-hydroxy-NIP, their denitro derivatives and 7-hydroxy-denitro-NIP. As judged from their spectra, trans-4-hydroxy- and 5-hydroxy-NIP and their denitro derivatives corresponded to the isolated ring-hydroxylated metabolites. Moreover, a pharmacological study in anesthetized spontaneously hypertensive rat showed that the nitroxy derivatives caused a transient hypotensive response, and both the nitroxy derivatives and the denitro derivatives caused long-lasting bradycardia.