Reaction Steps
Betulin (3 g) and p-toluenesulfonyl chloride (2.52 g) were placed in dry pyridine (70 ml) at 3-5° C. After 72 hours at 3-5° C. the solution was poured into 100 ml of cracked ice and the resulting precipitate was washed with water (2×50 ml), 1% HCl (50 ml) and water (2×50 ml) and dried in an oven. Chromatography on a silica column (Ether:Hexane=25:75) gave 2.96 g of allobetulin tosylate as white crystals mp. 180-182.6° C. (dec); IR (KBr) 2944, 2864, 1489, 1451, 1363, 1337, 1174, 1098, 1036, 925, 905, 875, 812, 685, 560 cm−1; 1H NMR (CDCl3) δ 7.8(D, 2H, benz-Tos), 7.37(D, 2H, benz-Tos), 4.22(DD, 1H, 3H), 3.76(D, 1H, 28H, J=11 Hz), 3.52(S, 1H, 19H), 3.39(D, 1H, 28H, J=11 Hz), 2.44(S, 3H, Tos-Me), 0.8, 0.8, 0.83, 0.92, 0.93, 0.96, 0.99, (all S, 7×3H, 23-, 24-, 25-, 26-, 27-, 29-, 30-Me), 0.6-1.86(complex CH—, CH2—, 25H); 13C NMR (CDCl3) δ 144.46, 135.08, 129.88, 129.88, 127.83, 127.83, 91.18, 88.10, 71.42, 55.93, 51.1, 46.98, 41.65, 40.9, 40.76, 38.95, 38.84, 37.16, 36.92, 36.46, 34.29, 33.97, 32.90, 29.03, 27.98, 26.59, 26.43, 25.04, 24.76, 21.86, 21.23, 18.47, 16.67, 16.43, 15.87, 13.69.
