Ritonavir Impurity 1

1,3-Thiazol-5-ylmethyl N-[(1S,2S,4S)-4-(acetylamino)-1-benzyl-2-hydroxy-5-phenylpentyl]carbamate (Ritonavir EP Impurity C) is an impurity of the selective HIV protease inhibitor Ritonavir (R535000).