Dutasteride Impurity: 4aR,4bS,6aS,7S,9aS,9bS,11aR)-N-[2,5-Bis(trifluoromethyl)phenyl]hexadecahydro-4a,6a-dimethyl-2-oxo-1H-Indeno[5,4-f]quinoline-7-carboxamide(Dihydro Dutasteride).