Nalmefene Impurity G Catalogue N211337 CAS 144265-45-2 M.W 353.46 M.F C22H27NO3 Specifications FAQs (4R,4aS,7aS,12bS)-3-(Cyclopropylmethyl)-9-methoxy-7-methylene-1,2,3,4,5,6,7,7a-octahydro-4aH-4,12-methanobenzofuro[3,2-e]isoquinolin-4a-ol