Tadalafil EP Impurity I (Mixture of Diastereomers)

(6’R,8a’R)-6′-(benzo[d][1,3]dioxol-5-yl)-2′-methyl-2′,3′,8′,8a’-tetrahydro-1’H-spiro[indoline-3,7′-pyrrolo[1,2-a]pyrazine]-1′,2,4′(6’H)-trione