Synthesis of high specific activity tritium labeled (E)‐6‐(bromomethylene)‐tetrahydro‐3‐(1‐naphthalenyl)‐2H‐pyran‐2‐one as a selective probe for calcium‐independent phospholipase a₂

The synthesis of ( E )‐6‐(bromomethylene)‐tetrahydro‐3‐([4‐ 3 H]‐1‐naphthalenyl)‐2 H ‐pyran‐2‐one at a specific activity of 24.0 Ci/mmol is described. This probe was synthesized to determine whether ( E )‐6‐(bromomethylene)‐tetrahydro‐3‐(1‐naphthalenyl)‐2 H ‐pyran‐2‐one inhibits calcium‐independent myocardial phospholipase A 2 irreversibly via covalent modification. The material was synthesized in four steps from 1‐naphthalene acetic acid via [4‐ 3 H]‐1‐naphthaleneacetic acid. The yield from [4‐ 3 H]‐1‐naphthaleneacetic acid was 29.7%. The radiochemical purity of the HPLC‐purified final product was 99.5%.