(4R,4aS,7aR,12bS)-3-(cyclopropylmethyl)-9-((ethoxycarbonyl)oxy)-4a-hydroxy-3-methyl-7-oxo-2,3,4,4a,5,6,7,7a-octahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium methyl sulfate