Two-photon chemistry from upper triplet states of thymine

Photolysis of the benzophenone chromophore by means of high energy laser pulses has been used as a tool to populate upper thymine-like triplet states via intramolecular sensitization. These species undergo characteristic n pi* photoreactivity, as revealed by the Norrish-Yang photocyclization of 5-tert-butyluracil.
Financial support by the Spanish government (CTQ2009-13699, CTQ2012-32621, RyC-2007-00476 to V.L.-V. and JAE-Predoc 2011-00740 contract to V.V.-C.) and the Generalitat Valenciana (Prometeo program) is gratefully acknowledged. M.Y, is thankful for Grants-in-Aid for Scientific Research (KAKENHI) from JSPS (No. 23350059) and the "Element Innovation" Project by the Ministry of Education, Culture, Sports, Science, and Technology, Japan.