ABSTRACT
[reaction: see text]We describe here an inherent problem in direct epoxidation of the endocyclic olefin in 2H-pyrans fused to 2-pyrones. Such difficulties led to the development of highly stereoselective trans- and cis-dihydroxylations of these olefinic systems in both 2H-pyrans and dihydropyridines fused to a 2-pyrones or a 2-cyclohexenone. Protocols for the removal of the activated allylic hydroxyl group are also reported.
Subject(s)
Alkenes/chemistry , Alkenes/chemical synthesis , Heterocyclic Compounds, 2-Ring/chemistry , Heterocyclic Compounds, 2-Ring/chemical synthesis , Pyrones/chemistry , Quinolines , Alkaloids/chemistry , Catalysis , Cyclohexanones/chemistry , Hydroxylation , Imines/chemistry , Molecular Structure , Pyrans/chemistry , Pyridines/chemistry , Stereoisomerism , Structure-Activity RelationshipABSTRACT
A general approach to synthesis of dihydroxanthone derivatives is described here. In vitro evaluation of these dihydroxanthones demonstrated that some derivatives possess moderate anti-cholinesterase activities and better selectivities than tacrine for acetylcholinesterase over butyrylcholinesterase. Structural effects on anti-cholinesterase activities were also examined, and docking experiments were carried out to provide preliminary understandings of these experimental observations.
