Syntheses of a series of linear pentaamines with three and four methylene chain intervals.

Abstract

The kinds of linear pentaamines with various combinations of 3 or 4 methylene chain intervals were synthesized. The methods were tentatively classified into two, leading to symmetrical and unsymmetrical pentaamines, all of which were prepared by successive alkylation of secondary amino derivatives of benzylamine with N-(3-bromopropyl or 4-bromobutyl)phthalimide in the presence of KF-Celite, coupled with the purification of the phthaloyl compounds by silica gel column chromatography. Protecting benzyl and phthaloyl groups were removed by usual methods. The carbon-13 unclear magnetic resonance (13C-NMR) spectra of the ten pentaamines were recorded in D2O as fully protonated forms, and a comparative analysis of their spectra allowed the complete assignment of all 13C chemical shifts.