A T-T dimer characterized by an amide linkage to replace the phosphodiester
backbone has been synthesized using a modified radical strategy. The new s
ynthetic approach makes use of a thymidin-3'-yl phosphorodithioate derivati
ve as a precursor of 3'-allyl-3'-deoxythymidine. Standard chemical transfor
mations of this derivative led to the desired T-T dimer incorporating an am
ide bond. The latter was irradiated with 254 nm wavelength light to yield m
ainly cyclobutane and [6-4] photoadducts.