Simvastatin EP Impurity C

: Dehydro Simvastatin; Simvastatin USP Related Compound C; 2,3-Anhydro Simvastatin; (1S,3R,7S,8S,8aR)-3,7-Dimethyl-8-[2-[(2R)-6-oxo-3,6-dihydro-2H-pyran-2-yl]ethyl]-1,2,3,7,8,8a-hexahydronaphthalen-1-yl 2,2-dimethylbutanoate ;