# Design, Synthesis, and Cell Lines Studies of Oleanolic Acid--Hydrogen Sulfide Donor Hybrids
## 2 Materials and Methods
### General Procedure for the Synthesis of Targeted Compounds
#### 2.1.2 General Procedure for the Preparation of **4a-d**  
The corresponding dibromoalkane (3.0 mmol), KOH (1.0 mmol) and KI (0.1 mmol) were added to OA (1.0 mmol) which was dissolved in anhydrous tetrahydrofuran (20 mL) solution. The reaction solution was heated to reflux and whisked until the end of the reaction. The solvent was removed under vacuum. The remainder was diluted with water and extracted with EtOAc. The organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and evaporated under reduced pressure. The resulting crude product was purified by flash chromatography on silica gel column to provide the target compound **4a-d**, respectively. _Oleanolic acid 28-[4-(4-carbamothiolphenoxy)] butyrate_ **(4a)**. Yield: 24%. Oil: 1\({}^{1}\)H NMR (CDC1\({}_{3}\), 300 MHz) \(\delta\) ppm 7.65 (d, 2H, \(J\) = 8.5 Hz, Ar-H), 6.93 (d, 2H, \(J\) = 8.5 Hz, Ar-H), 5.27 (brs, 1H, 12-H), 4.09 (t, 2H, \(J\) = 6.8 Hz, 1\({}^{\prime}\)-H), 4.03 (t, 2H, \(J\) = 6.8 Hz, 4\({}^{\prime}\)-H), 3.20 (m, 1H, 3-H), 2.87 (br d, 4H, \(J\) = 11.8 Hz, 18-H), 1.18-2.20 (m, 26H, methylene and methine protons), 1.13 (s, 3H, 29-H), 0.98 (s, 3H, 30-H), 0.92 (s, 3H, 26-H), 0.90 (s, 3H, 23-H), 0.87 (s, 3H, 25-H), 0.77 (s, 3H, 27-H), 0.72 (s, 3H, 24-H), OH and NH2 show no signal; \({}^{13}\)C NMR (CDC1\({}_{3}\), 75 MHz) \(\delta\) ppm 177.8, 162.2, 143.8, 134.0, 122.4, 115.2, 79.0, 67.7, 63.6, 55.2, 47.6, 46.8, 45.8, 41.7, 41.3, 39.3, 38.7, 38.4, 37.0, 33.8, 33.1, 32.5, 32.4, 31.4, 30.7, 30.1, 28.1, 27.6, 27.1, 25.8, 23.6, 23.4, 23.0, 18.3, 17.0, 15.6, 15.3; HRMS (ESI) Calcf for C4H62 NO4S [M + H]\({}^{+}\) 664.4394, found: 664.4387. _Oleanolic acid 28-[4-(5-thioxo-5H-1,2-dithiol-3-yl) phenoxyl] butyrate_ **(4b)**. Yield: 57%. Brown yellow solid, m.p. : 109.1-111.0 \({}^{\circ}\)C: \({}^{1}\)H NMR (CDC1\({}_{3}\), 300 MHz) \(\delta\) ppm 7.61 (d, 2H, \(J\) = 8.4 Hz, Ar-H), 7.40 (s, 1H, 8\({}^{\prime\prime}\)-H), 6.96 (d, 2H, \(J\) = 8.4 Hz, Ar-H), 5.28 (brs, 1H, 12-H), 4.10 (t, 2H, \(J\) = 6.8 Hz, 1\({}^{\prime}\)-H), 4.05 (t, 2H, \(J\) = 6.8 Hz, 4\({}^{\prime}\)-H), 3.20 (m, 1H, 3-H), 2.87 (br d, 1H, \(J\) = 12.4 Hz, 18-H), 1.13-2.80 (m, 26H, methylene and methine protons), 1.13 (s, 3H, 29-H), 0.98 (s, 3H, 30-H), 0.92 (s, 3H, 26-H), 0.90 (s, 3H, 23-H), 0.87 (s, 3H, 25-H), 0.77 (s, 3H, 27-H), 0.72 (s, 3H, 24-H), OH shows no signal; \({}^{13}\)C NMR (CDC1\({}_{3}\), 75 MHz) \(\delta\) ppm 215.1, 177.7, 162.3, 147.1, 143.8, 134.6, 128.6, 124.0, 122.4, 115.4, 79.0, 67.8, 63.6, 55.2, 47.6, 46.8, 45.8, 41.7, 41.4, 39.3, 38.8, 38.4, 37.0, 33.9, 33.1, 32.7, 32.5, 31.5, 30.7, 30.2, 28.1, 27.7, 27.2, 25.9, 23.7, 23.4, 23.0, 18.3, 17.1, 15.6, 15.3; HRMS (ESI) Calcf for C43H61O4S [M + H]\({}^{+}\) 737.3726, found: 737.3723. _Oleanolic acid 28-[4-(4-carbonamothiolphenoxy)] valerate_ **(4c)**. Yield: 21%. Oil: 1\({}^{1}\)H NMR (CDC1\({}_{3}\), 400 MHz) \(\delta\) ppm 7.66 (d, 2H, \(J\) = 8.5 Hz, Ar-H), 6.93 (d, 2H, \(J\) = 8.5 Hz, Ar-H), 5.30 (brs, 1H, 12-H),4.05 (t, 2H, \(J\) = 6.8 Hz, 1\({}^{\prime}\)-H), 4.03 (t, 2H, \(J\) = 6.8 Hz, 5\({}^{\prime}\)-H),3.20 (m, 1H, 3-H), 2.87 (brd, 1H, \(J\) = 11.8 Hz, 18-H), 1.12-2.20 (m, 28H, methylene and methine protons), 1.11 (s, 3H, 29-H), 0.98 (s, 3H, 30-H), 0.95 (s, 3H, 26-H), 0.93 (s, 3H, 23-H), 0.90 (s, 3H, 25-H), 0.80 (s, 3H, 27-H), 0.78 (s, 3H, 24-H), OH and NH2 show no signal; \({}^{13}\)C NMR (CDC1\({}_{3}\), 100 MHz) \(\delta\) ppm 177.8, 162.2, 143.8, 134.0, 122.3, 115.2, 109.4, 79.0, 68.2, 63.9, 55.2, 47.6, 46.8, 45.9, 41.7, 41.3, 39.3, 38.7, 38.4, 37.0, 33.8, 33.1, 32.5, 31.6, 30.7, 28.7, 28.1, 27.5, 27.2, 26.9, 25.9, 23.6, 23.4, 22.7, 18.3, 17.1, 15.6, 15.3; HRMS (ESI) Calcf for C43H61O4S [M + H]\({}^{+}\) 751.3883, found: 751. _Oleanolic acid 28-[4-(5-thioxo-5H-1,2-dithiol-3-yl) phenoxyl] valerate_ **(4d)**. Yield: 26%. Reddish brown solid, m.p.