Synthesis of enantiomers of 2′‐aminomethyl‐5‐benzylacyclouridine (AM‐BAU) and 2′‐aminomethyl‐5‐benzyloxybenzylacyclouridine (AM‐BBAU). Potent inhibitors of uridine phosphorylase

Racemic 2′‐aminomethyl‐5‐benzyl‐acyclouridine (AM‐BAU, 5 ) and 2′‐aminomethyl‐5‐benzyloxybenzyla‐cyclouridine (AM‐BBAU, 6 ) have been found to be very active inhibitors of uridine phosphorylase [1]. Their enantiomers were synthesized from chiral 2,2‐dimethyl‐1,3‐dioxolane‐4‐methanol ( 7a,b ). S ‐(—)‐AM‐BAU ( 5a ) and S ‐(—)‐AM‐BBAU ( 6a ) were prepared from the R ‐(—) isomer 7a , and R (+)‐AM‐BAU ( 5b ) and R ‐(+)‐AM‐BBAU ( 6b ) from the S ‐(+) isomer 7b . A different route from the S ‐(+) isomer 7b to S ‐(—)‐AM‐BBAU ( 6a ) was also determined to be feasible.