“…Dehydroabietic acid (21) (1R,4aR,10aR )-1,4a-Dimethyl-7-isopropyl-1,2, 3,4,4a,9,10,10a-octahydrophenanthrene-1-isocyanate (24) was prepared according to the literature procedure: 24 (1R,4aR,10aR )-1,4a-Dimethyl-7-isopropyl-1,2,3,4, 4a,9,10,10a-octahydrophenanthrene-1-amine (25). To a solution of compound 24 (2 g, 6.7 mmol) in benzene (50 mL), 35% HCl (5 mL) was added.…”