2, 3-Dihydro-3, 8-diphenylbenzo [1, 4] oxazines were identified as a new class of potent cholesteryl ester transfer protein inhibitors. The most potent compound 6a (IC50= 26nM) possessed a favorable pharmacokinetic profile with good oral bioavailability in rat (F= 53%) and long human liver microsome stability (t1/2= 62min). It increased HDL-C in human CETP transgenic mice and high-fat fed hamsters. The structure and activity relationship of this ...