Reaction Steps
To a solution of diisopropyl 6-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-chloroethyl)amino)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)spiro[3.3]hept-5-ene-2,2-dicarboxylate (18 mg, 0.024 mmol) in a solution of borontrifluoride etherate in benzene (BF3.Et2O 2% by volume, 2 mL) at RT, was added morpholine (75 μl, 0.857 mmol) forming a cloudy mixture. The mixture was kept at 80° C. for 2 hours. The reaction was diluted with a saturated solution of ammonium chloride in 0.5 N HCl, organic materials were extracted into ethyl acetate (25 mL) three times. The organic extracts were combined and washed with a solution of sodium bicarbonate, the organic materials were concentrated, and purified by silica gel chromatography eluted with mixture of ethyl acetate and hexanes to give 8.1 mg (40%) of the desired product. MS: m/e 787.6 (M+H)+. 1H NMR (400 MHz, CHLOROFORM-d) δ 5.87 (s, 1H), 5.55-5.49 (m, 1H), 5.15-5.00 (m, 2H), 4.72 (br. s., 1H), 4.59 (br. s., 1H), 3.73 (t, J=4.4 Hz, 4H), 2.70 (s, 4H), 2.59 (d, J=2.3 Hz, 3H), 2.56-2.34 (m, 6H), 2.10 (dd, J=17.9, 6.7 Hz, 1H), 1.92-1.72 (m, 4H), 1.70 (s, 4H), 1.67-1.28 (m, 14H), 1.25 (dd, J=6.3, 5.0 Hz, 14H), 1.15 (m, 5H), 1.10 (m, 5H), 1.07 (m, 5H), 0.97 (s, 3H), 0.82 (s, 3H).
