Asymmetric synthesis of (2S)‐and (2R)‐4‐(3‐t‐butylamino‐2‐hydroxypropoxy)‐benzimidazol‐2‐[¹¹C]‐one ((S)‐and (R)‐[¹¹C]‐CGP 12177) from optically active precursors

Abstract

Abstract Enantiomers of CGP 12177 ((2S)‐and (2R)‐4‐(3‐t‐butylamino‐2‐hydroxypropoxy)‐benzimidazol‐2‐one), a potent adrenergic β‐receptor antagonist were synthesized and labelled with 11 C for Positron Emission Tomography studies of β‐receptors in heart. The synthesis was accomplished from (2S)‐and (2R)‐3‐tosyloxy‐1,2‐propanediol acetonide. Enantiomeric excess was greather than 95% for each of the prepared enantiomers. (S)‐ and (R)‐[ 11 C]‐CGP 12177 were obtained with a specific radioactivity of 29.6‐44.4 GBq/μmol.