Photo-stability and Photo-reactivity of halogenated 8-methoxypsoralen, the basis for designing of new drugs

Abstract

8-methoxypsoralen is an efficient photosensitizer agent, used widely in PUVA therapy in treatment of different skin disorders like psoriasis, and other inflammatory skin disorders or recently in treatment of cancer diseases such as cutaneous T-cell lymphoma. Teen different substitutions of this compound have been made in this work, through fluorine and bromine atoms substitutions in order to increase its photosensitizer efficiency. In each system, we replace only one hydrogen atom of 8-methoxypsoralen by fluorine atom in the first five system, whereas, in the other five system substituted made by bromine atoms. These teen systems are studied by means of computational quantum method-DFT at MPWB95/6-311+G(d,p) level of theory. The results show that the 3-bromo-8-methoxypsoralen (X₅ system; of bromine substituted case) has the smallest transition state energy among all suggested teen compounds with a barrier accounted only 2.92 kcal/mol. Optimization of the neutral, radical anion and radcial cation, triplet state, electron affinity, ionization potential, transition state energy, defluorination or debromination process of each system is obtained and discussed in detail.