(+)-Calanolide A 142632-32-4 2H,6H,10H-Benzo(1,2-b:3,4-b':5,6-b'')tripyran-2-one, 11,12-dihydro-12-hydroxy-6,6,10,11-tetramethyl-4-propyl-, (10R,11S,12S)- 2H,6H,10H-Benzo(1,2-b:3,4-b':5,6-b'')tripyran-2-one, 11,12-dihydro-12-hydroxy-6,6,10,11-tetramethyl-4-propyl-, (10R-(10alpha,11beta,12alpha))- Calanolide A DRG-0308 NSC 650886 NSC 675451