Some stereoisomers and tautomers of gemcitabine – A DFT treatment

Gemcitabine which is a cancer chemotherapy agent has a wide application against various types of tumors. In the present study, gemcitabine and its various stereoisomers and also its 1,3- and 1,5-type proton tautomers have been investigated within the constraints of density functional theory (DFT) at the level of B3LYP/6-311++G(d,p). All the isomers/tautomers presently considered (in vacuum conditions) have not only exothermic heat of formation values but also possess favorable Gibbs free energy of formation values and they are electronically stable. Various quantum chemical data have been collected and discussed including UV-VIS spectra.