## 2 Materials and Methods
### Synthesis
Methyl 3\(\alpha\)-[2-thio-(1-(((HH-indol-3-yl)methyl)-1,3-dihydro-2H-benzo[d]imidazole]-acetoxy-5\(\beta\)-cholan-24-oate (**5**)  
Oil, 90%, \({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) \(\delta\): 8.24 (s, 1H, NH), 7.65-7.60 (m, 2H, aromatic), 7.35-7.30 (m, 2H, aromatic), 7.22-7.10 (m, 4H, aromatic), 7.202 (d, \(J\) = 2.6 Hz, 1H, aromatic), 5.50 (s, 2H, CH\({}_{2}\)-10\({}^{\prime}\)), 4.80-4.72 (m, 1H, 3B-H), 4.18 (s, 2H, CH\({}_{2}\)-27), 3.67 (s, 3H, CH\({}_{3}\)-25), 0.92 (d, \(J\) = 6.4 Hz, 3H, CH\({}_{3}\)-21), 0.90 (s, 3H, CH\({}_{3}\)-19), 0.63 (s, 3H, CH\({}_{3}\)-18). \({}^{13}\)C NMR (101 MHz, CDCl\({}_{3}\)) \(\delta\): 174.81 (C-24), 168.29 (C-26), 150.44 (C-2\({}^{\prime\prime}\)), 143.44 (C-8\({}^{\prime\prime}\)), 136.41 (C-7\({}^{\prime\prime}\)), 136.28 (C-9\({}^{\prime}\)), 125.91 (C-8\({}^{\prime}\)), 123.32 (C-5\({}^{\prime\prime}\)), 122.57 (C-4\({}^{\prime\prime}\)), 122.01 (C-2\({}^{\prime}\)), 121.85 (C-6\({}^{\prime}\)), 120.10 (C-5\({}^{\prime}\)), 118.61 (C-3\({}^{\prime\prime}\)), 118.39 (C-4\({}^{\prime}\)), 111.40 (C-3\({}^{\prime}\)), 110.79 (C-7\({}^{\prime}\)), 109.43 (C-6\({}^{\prime\prime}\)), 76.22 (C-3), 56.38, 55.9(cm\({}^{-1}\)): 3379, 2948, 2867, 1735, 1448, 1376, 1247, 1192, 1169. ESI-MS (MeOH): C\({}_{45}\)H\({}_{57}\)N\({}_{3}\)O\({}_{6}\)S \(m/z\) 769 [M+H]\({}^{+}\), 791 [M+Na]\({}^{+}\), 807 [M+K]\({}^{+}\). Methyl 3\(\alpha\)-[2-thio-(1-((1H-indol-3-yl)methyl)-1,3-dihydro-2H-benzo[d]imidazole]-acetoxy-7\(\alpha\),12\(\alpha\)-dihydroxy-5B-cholan-24-oate (7)  
Oil, 89%, 1H NMR (400 MHz, CDCl\({}_{3}\)) 8: 8.36 (s, 1H, NH), 7.62-7.59 (m, 2H, aromatic), 7.36-7.30 (m, 2H, aromatic), 7.24-7.09 (m, 4H, aromatic), 7.05 (d, \(J\) = 2.6 Hz, 1H, aromatic), 5.49 (d, \(J\) = 1.0 Hz, 2H, CH\({}_{2}\)-10\({}^{\prime}\)), 5.09 (s, 1H, 12B-H), 4.89 (s, 1H, 7B-H), 4.63-4.59 (m, 1H, 3B-H), 4.22 (s, 2H, CH\({}_{2}\)-27), 3.66 (s, 3H, CH\({}_{3}\)-25), 2.12 (s, 3H, s, 3H, 7-OAc), 1.98 (s, 2H, s, 3H, 12-OAc), 0.90 (s, 3H, CH\({}_{3}\)-19), 0.81 (d, \(J\) = 6.4 Hz, 3H, CH\({}_{3}\)-21), 0.72 (s, 3H, CH\({}_{3}\)-18). \({}^{13}\)C NMR (101 MHz, CDCl\({}_{3}\)) 8: 174.50 (C-24), 170.57 (C-28), 170.43 (C-30), 168.28 (C-26), 150.41 (C-2\({}^{\prime\prime}\)), 143.36 (C-8\({}^{\prime\prime}\)), 136.42 (\(7^{\prime\prime}\)), 136.30 (C-9\({}^{\prime}\)), 125.92 (C-8\({}^{\prime}\)), 123.33 (C-5\({}^{\prime\prime}\)), 122.59 (C-4\({}^{\prime\prime}\)), 122.06 (C-2\({}^{\prime}\)), 121.93 (C-6\({}^{\prime}\)), 120.13 (C-5\({}^{\prime}\)), 118.57 (C-3\({}^{\prime\prime}\)), 118.24 (C-4\({}^{\prime}\)), 111.41 (C-3\({}^{\prime}\)), 110.70 (C-7\({}^{\prime}\)) 109.46 (C-6\({}^{\prime\prime}\)), 75.85 (C-12), 75.38 (C-3), 70.63 (C-7), 51.49 (C-25), 47.37, 45.07, 43.40, 40.88, 40.31, 37.73, 35.16, 34.59, 34.51, 34.43, 34.29, 31.18, 30.88, 30.76, 28.90, 27.15, 26.66, 25.54, 22.79 (C-19), 22.46, 21.48, 21.37, 17.49 (C-21), 12.19 (C-18). FT-IR (KBr) \(\
u_{\rm max}\) (cm\({}^{-1}\)): 3380, 2948, 2870, 1732, 1437, 1377, 1249, 1169. ESIMS (MeOH): C\({}_{47}\)H\({}_{59}\)N\({}_{3}\)O\({}_{8}\)S \(m/z\) 828 [M+H]\({}^{+}\), 849 [M+Na]\({}^{+}\)]\({}^{+}\). Methyl 3\(\alpha\)-[8-thio-1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione]acetoxy-5\(\beta\)-cholan-24-oate (8)  
Solid, m.p. 139-140 \({}^{\circ}\)C, 78%, 1H NMR (400 MHz, CDCl\({}_{3}\)) 8: 4.83-4.73 (m, 1H, 3\(\beta\)-H), 4.02 (s, 2H, CH\({}_{2}\)-27), 3.90 (s, 3H, CH\({}_{3}\)-14\({}^{\prime}\)), 3.67 (s, 3H, CH\({}_{3}\)-25), 3.53 (s, 3H, CH\({}_{3}\)-12\({}^{\prime}\)), 3.39 (s, 3H, CH\({}_{3}\)-10\({}^{\prime}\)), 0.93 (s, 3H, CH\({}_{3}\)-19), 0.92 (d, \(J\) = 6.52 Hz, 3H, CH\({}_{3}\)-21), 0.64 (s, 3H, CH\({}_{3}\)-18).