5-Oxo Atorvastatin tert-Butyl Ester is the Boc-protected form of 5-Oxo Atorvastatin (O847155); a derivative of Atorvastatin (A791750, Ca Salt) which is a selective, competitive HMG-CoA reductase inhibitor and can lower both elevated LDL-cholesterol and triglyceinhibitorrides in patients with hypercholesterolemia.