Synthesis of (5‐methyl‐2‐oxo‐1,3‐dioxol‐4‐YL)methyl 7‐[D‐O‐(L‐alanyl)[β‐14C]mandelamido]‐3‐[[(5‐methyl‐1,3,4‐thiadiazol‐2‐YL)thio]methyl]‐3‐cephem‐4‐carboxylate and its active compound

(5-Methyl-2-oxo-1,3-dioxol-4-yl)methyl 7-[D-O-(L-alanyl)[β-14C]-mandelamido]-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-3-cephem-4-carboxylate (14C-KY-109) and its parent drug (14C-KY-087) were synthesized from D-(-)-mandelic-β-14C acid prepared by optical resolution of DL-(±)- mandelic-β-14C acid. The overall radiochemical yields were 16.2% for 14C-KY-087 and 49.6% for 14C-KY-109, based on D-(-)-mandelic-β-14C acid. Both the products had radiochemical purities greater than 97% as measured by TLC.