Structural, Quantum Chemical, Spectroscopic (UV, FT-IR, FT-Raman and NMR) and Molecular Docking Studies of Diphenylpyraline Hydrochloride as Antihistaminic Drug

Diphenylpyraline hydrochloride, chemically known as 4-benzhydryloxy-1-methypiperidine hydrochloride is a first-generation antihistaminic drug that produces therapeutic antiallergic effects by binding to histamine H-1 -receptors. The molecular structural and electronic properties of title compound have been computed at DFT/TD-DFT method with B3LYP/6-311++G(d,p) level. The theoretical spectral data has been compared with experimental ones, showing good agreement. The atomic charges, molecular electrostaitc potential (MEP), the natural bond orbitals (NBOs), the natural hybrid orbital (NHOs), the non-lilear optical (NLO) properties, the vibrational (IR and Raman) frequencies, UV-vis absorption wavelenghts and nuclear magnetic resonance (NMR) chemical shifts of diphenylpyraline hydrochloride have been investigated. The potential energy distribution (PED) of title compound was performed using the VEDA program and these values were compared with the experimental FT-IR and FT-Raman vibrational frequencies. Moreover, molecular docking studies have been performed between the 3RZE and 7DFL target proteins and the title compound. Docking results revealed that the title compound can be designed as potential antihistaminic agent.