Naphthalene-2-carboxylic acid (3R,5R,7R,8R,9S,10S,12S,13R,14S,17R)-3-acetoxy-7-hydroxy-17-((R)-3-methoxycarbonyl-1-methyl-propyl)-10,13-dimethyl-hexadecahydro-cyclopenta[a]phenanthren-12-yl ester