Q-6 Alkaloid R, C,HNO, is a secondary base. It showed a strong IR band at 1716 cm' and 'H NMR signals at 2.09 ppm (3H, s), 2.53 (2H, d), 2.96 (1H, multiplet) and at 2.0 (1H, broad). In addition to these signals, 'C NMR and DEPT spectra showed other four CH, groups and a quaternary carbon signal at 207.1 ppm. H-H COSY showed that the other four CH2 groups are coupling to each other, and one of them couples to the CH at 2.96 ppm. Alkaloid R reacted with sodium borohydride to give compound D that showed a broad IR band at 3500 cm Compound R underwent iodoform reaction to give a carboxylic acid and showed a positive DNP test. Finally, when alkaloid R was subjected to two successive Hofmann degradations followed by hydrogenation after each stage, 2-octanone was produced. What are the structures of compound and compound D? (10 marks) R