Design and synthesis of tricyclic derivatives as high density lipoprotein cholesterol enhancers

A pharmacophore for increasing HDLC was proposed based on common structural features of non-thio-containing compounds with HDLC enhancing properties. A search of the compound database identified various series of these non-thio-containing compounds, including a novel tricyclic imidazoisoquinolone. Preparation of l-aryl-3-oxo-1,3-dihydro-2-benzofuran-1-carboxamides using a novel and widely applicable one-step process from 2-acyl benzoic acids is reported. Reaction of diamines with 1-aryl-3-oxo-1,3-dihydro-2-benzofuran-1-carboxamides and related aza-analogues proceeded with regio-control to furnish imidazoisoquinolones, pyrimidoisoquinolones, and imidazonaphthyridines. NMR studies and X-ray crystallography confirmed the regiochemistry of the products. Compounds of these series increased concentrations of HDLC in test animals following oral administration.