pronethalol pronethalol pronethalol (also known as nethalide or compound 38,174; trade name alderlin) was an early non-selective beta blocker clinical candidate. it was the first beta blocker to be developed by james black and associates at imperial chemical industries, and the first to enter clinical use, in november 1963. pronethalolclinical dataroutes ofadministrationoralatc codenonelegal statuslegal status withdrawn identifiers iupac name 1-(naphthalen-2-yl)-2-(propan-2-ylamino)ethanol cas number54-80-8 ypubchem cid4930chemspider4761uniixbp4rt1imqchemblchembl16476comptox dashboard (epa)dtxsid8021193 chemical and physical dataformulac15h19nomolar mass229.323 g·mol−13d model (jsmol)interactive imagechiralityracemic mixture smiles cc(c)ncc(c1=cc2=cc=cc=c2c=c1)o however, it was never used widely due to carcinogenicity in mice, which was thought to result from formation of a carcinogenic naphthalene epoxide metabolite, and was superseded by propranolol from 1965 onward.