Chiral HPLC studies on chemical behavior of 6-methoxydihydrosanguinarine in alcoholic solvent system

All the enantiomers of methoxydihydrosanguinarine (MS), ethoxydihydrosanguinarine (ES) and iso-propoxydihydrosanguinarine (PS) were separated by chiral HPLC. They were further identified by comparing the retention times of authentic standards as well as LC–MS. Interestingly, the approximately same conversion rates for the formation MS from ES or PS and the slower conversion of MS in isopropanol compared to ethanol demonstrated two step mechanism in the reaction of alkoxysanguinarine in alcohols, which is composed of the initial formation of sanguinarine as a planar intermediate and the addition of alcohol to intermediate as possible rate limiting step. Thus, sanguinarine has a pivotal role in the chemical behavior of alkoxysanguinarine in alcoholic solvents. Such possible variation of the structure of sanguinarine may be the source of its diverse biological activities.