Intramolecular photoreaction of thio-barbiturates with an alkenyl or a benzyl group in their N-alkyl side chain. Regioselective synthesis of ring-fused pyrimidine derivatives through photocyclization of mono- and di-thiobarbiturates

摘要

Upon irradiation, thiobarbiturates with an alkenyl (4,5) or a benzyl (14, 15, 21) group in their N-alkyl side chain give bi- and tri-cyclic fused pyrimidine derivatives through regioselective [2+2] photocycloaddition or Norrish type II reaction, respectively.