Template-assisted photodimerization of N-unprotected uracil derivatives: selective formation of the cis–syn photodimer

Abstract

A UV light-induced photodimerization of 5-[(imidazol-1-yl)methyl]uracil using glutamate- and aspartate-derived cyclic dipeptides (2,5-diketopiperazines – DKPs) as templates was investigated. Dual salt bridge formation between imidazole side chains and carboxylic acids resulted in the preorganization of the uracil monomers and the preferential formation of the cis–syn photodimer.