Showing structure for (3s,4ar,5s,6r,6ar,10r,10as,10br)-5-(acetyloxy)-4a,6a,7,10b-tetramethyl-5'-oxo-10-(pyridine-3-carbonyloxy)-2,5,6,9,10,10a-hexahydro-1h-spiro[naphtho[2,1-b]pyran-3,3'-oxolan]-6-yl pyridine-3-carboxylate