The synthesis of [ 14 C]BRL 26830a, a novel β‐adrenoceptor agonist

Abstract BRL 26850A has been extensively reported 1 as a novel β‐adrenoceptor agonist. In order to perform metabolism studies, carbon‐14 radiolabelled BRL 26830A was synthesised from potassium [ 14 C]cyanide. As BRL 26830A contains two asymmetric centres, the initial product required resolution of the two enantiomeric pairs. This was achieved by sequential fractional crystallisation of the free base and then the hydrobromide salt to obtain the required (R * , R * )‐( + ) enantiomeric pair before final conversion to the hemifumarate salt ([ 14 C]BRL 26830A).