Gravar-mail: Crystal structure of (S)-2-[(3S,8S,9S,10R,13S,14S,17R)-3-hy­droxy-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetra­deca­hydro-1H-cyclo­penta[a]phenanthren-17-yl]-N-meth­oxy-N-methyl­pro­pan­amide (Fernholz Weinreb amide)