Synthesis, Characterization and Physico-chemical Properties of New 2-(4- Arylpiperazine-1-yl)-1-(3-methylbenzofuran-2-yl)ethanoles as Potential Antihypertensive Agents

Six new arylpiperazinylbenzofurane derivatives as potential hybrid antihypertensive agents were designed and synthesized. The discussed compounds were prepared as free bases and subsequently they were transformed into hydrochloride salts. The position of preferential protonation of nitrogen in piperazine ring in hydrochloride salts was determined by means of IR spectra, 13C CP/MAS NMR spectra and 15N CP/MAS NMR spectra. These results were supported by ab initio/DFT calculations of partial charges and proton affinities. Physico-chemical properties of free bases and hydrochloride salts are discussed; especially partition and distributive coefficients log P and log D7.4, dissociation constants pKa, molecular surfaces and volumes. The experimental results were also subsequently correlated with ab initio/DFT calculations.