Spectroscopic analyses,intra-molecular interaction,chemical reactivity and molecular docking of imerubrine into bradykinin receptor

Imerubrine, a biologically active natural product, is one of the initial members of tropoloisoquinolines and biosynthetically related to the more common azafluoranthene alkaloids. We perform a comprehensive quantum chemical analysis on imerubrine using density functional theory at B3PW91/6-311?+?G(d,p) level. The equilibrium molecular structure of imerubrine has been obtained. The weak intra-molecular C–H?O interactions are recognized, characterized and quantified by quantum theory of atoms in molecule and relaxed force constants. The chemical reactivity of imerubrine is explained and discussed with the help of highest occupied molecular orbital, lowest unoccupied molecular orbital and molecular electro static potential surfaces as well as a number of reactivity descriptors. The infrared spectrum of imerubrine has been calculated and the vibrational modes have been assigned on the basis of the potential energy distribution with the highest possible accuracy. The nuclear magnetic resonance spectra of imerubrine have been calculated, analyzed and compared with available experimental data. A good agreement between experimental and calculated values has been observed. The molecular docking of imerubrine into B1 bradykinin receptor (PDB ID: 1HZ6) shows that it is capable to bind with the receptor and hence, it can act as an effective bradykinin receptor agonist.