24703-43-3 Dispiro(furan-3(2H),2'(5'H)-furan-5',6''-(6H)naphtho(1,8-bc)furan)-2''(2''aH)-one, 3',3'',4',4'',5'',5''a,7'',8'',8''a,8''b-decahydro-2''a,5''a,7''-trimethyl-, (2''aS-(2''aalpha,5''abeta,6''alpha(S*),7''alpha,8''aalpha,8''balpha))- Premarrubiin