Molecular structure, spectral and thermal properties and in silico biological activity of new bis-phthalimidopropylalkylammonium conjugates of bile acids

Abstract

• Nine novel quaternary bis-phthalimidopropylalkylammonium conjugates of bile acids were synthesized. • 1 H NMR, 13 C NMR, FT-IR and ESI-MS were performed for the characterization. • Computational study was done at PM5 method level for comparative analysis. • In silico study was done to facilitate the search for pharmacological activity. New quaternary bis-phthalimidopropylalkylammonium conjugates of lithocholic, deoxycholic and cholic acids were obtained by reaction of bile acids with bromoacetic acid bromide to give bile acid 3α-bromoacetates. These intermediates were subjected to nuclephilic substitution with N,N -bis-(phthalimidopropyl)- N -ethylamine, N,N -bis-(phthalimidopropyl)- N -decylamine and N,N -bis-(phthalimidopropyl)- N -hexadecylamine to give the final quaternary ammonium salts. The structures of products were confirmed by spectral ( 1 H NMR, 13 C NMR, 2D NMR and FT-IR) analysis, mass spectrometry (ESI-MS) as well as PM5 semiempirical methods and B3LYP ab initio methods. In addition, differential scanning calorimetric (DSC) studies were performed for compounds of different hydrocarbon chain length. Estimation of the pharmacotherapeutic potential has been accomplished for synthesized compounds on the basis of Prediction of Activity Spectra for Substances (PASS).