Simvastatin EP Impurity F

: Simvastatin USP Related Compound F; epi-Lovastatin; Lovastatin epimer; (1S,3R,7S,8S,8aR)-8-[2-[(2R,4R)-4-Hydroxy-6-oxotetrahydro-2H-pyran-2-yl]ethyl]-3,7-dimethyl-1,2,3,7,8,8a-hexahydronaphthalen-1-yl (2R)-2-methylbutanoate;