**3. Materials and Methods**

#### *3.1. General Information*

All organic solvents were dried and distilled by standard methods prior to use. 1H and 13C NMR spectra were recorded on a Bruker AV II-400 spectrometer (BURKERT, Ingelfingen, Germany) at 400 and 100 MHz, respectively. All chemical shifts were reported in δ units with references to the residual solvent resonances of the deuterated solvents for proton and carbon chemical shifts. High Resolution Mass Spectra (HRMS) were obtained on a Thermo Q Exactive™ Focus Hybrid Quadrupole-Orbitrap™ Mass Spectrometer (SCIEX, Framingham, Massachusetts, USA). All other chemicals were purchased from either Aldrich (Sigma-Aldrich, Shanghai, China) or Aladdin Chemical Co. (Aladdin Holdings Group Co., Ltd, Shanghai, China) and used as received, unless otherwise specified.

The optical density at 490 nm of each well was measured using a microplate reader (Molecular devices corporation, Sunnyvale, CA. USA) to calculate the percent of cell viability. The inhibition rates were calculated using GraphPad Prism 7.0 software. The seven tested cell lines were obtained from the laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University.

#### *3.2. Experimental Section of Synthesis*

[2-bromoethyl] 3-hydroxy-12-en-28-oic acid (**2**) [36–38] To a mixture of oleanolic acid (913.4 mg, 2.0 mmol), K2CO3 (552.8 mg, 4.0 mmol), and DMF (40 mL), 1, 2-dibromoethane (513 μL, 6.0 mmol) was slowly added at room temperature, and the mixture was then stirred at 40 ◦C for 4 h. The resulting mixture was cooled to room temperature, then quenched with ice water (50.0 mL), and the insoluble material was removed by a Buchner funnel. The organic layer was separated, and the aqueous layer was extracted with ethyl acetate (50 mL × 3). The organic solutions were combined and dried over anhydrous MgSO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200-300 mesh) using petroleum ether and ethyl acetate (15/1 in *v*/*v*) as eluents to give **2** (957.6 mg, 85% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.30 (s, 1H, H-12), 4.35 (m, 2H, -OC*H*2C-), 3.49 (t, *J* = 5.5 Hz, 2H, BrC*H*2C-), 3.20 (d, *J* = 6.9 Hz, 1H, H-3), 2.87 (d, *J* = 12.2 Hz, 1H, H-18), 1.99 (m, 1H, -O*H*), 1.87 (m, 2H, -C*H*2), 1.72 (m, 3H, H-22, -C*H*, -C*H*2,), 1.62 (m, 6H, 3 × -C*H*2), 1.54 (m, 3H, H-22, -C*H*, -C*H*2), 1.33 (m, 6H, 3 × -C*H*2), 1.18 (s, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.06 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 177.2 (C-28), 143.4 (C-13), 122.6 (C-12), 78.8 (C-3), 63.6 (-*C*O-), 55.2 (C-5), 47.6 (C-9), 46.8 (C-17), 45.7 (C-19), 41.6 (C-14), 41.2 (C-18), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 29.1 (-*C*Br), 28.2 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.0 (C-26), 15.6 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C32H51BrO3 [M+H]+: 563.3100. Found: 563.3054.

[2-((pyrrolidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3a**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), pyrrolidine (1.0 mmol, 82 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. To the resulting mixture another THF solution (4.0 mL) of **2** (0.4 mmol, 225.4 mg) was added dropwise. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (2/1 in *v*/*v*) as eluents to give **3a** (201.3 mg, 80% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.29 (s, 1H, H-12), 4.27 (m, 2H, -OC*H*2C-), 3.92 (t, *J* = 6.9 Hz, 2H, -SC*H*2), 3.66 (t, *J* = 6.8 Hz, 2H, -NC*H*2), 3.59 (m, 2H, -NC*H*2), 3.20 (m, 1H, H-3), 2.87 (dd, *J* = 13.5, 3.4 Hz, 1H, H-18), 2.10 (m, 1H, -O*H*), 1.97 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.87 (m, 2H, -C*H*2), 1.66 (d, *J* = 8.4 Hz, 3H, -NCH2C*H*2C*H*), 1.59 (m, 5H, -NCH2CH2C*H*, 2 × -C*H*2), 1.53 (m, 3H, H-22, -C*H*, -C*H*2), 1.35 (m, 6H, 3 × -C*H*2), 1.16 (d, *J* = 4.0 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 191.7 (-*C*S2), 177.4 (C-28), 143.6 (C-13), 122.5 (C-12), 78.8 (C-3), 62.5 (-*C*O-), 55.2 (-N*C*H2), 55.1 (-N*C*H2), 50.6 (C-5), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.6 (C-14), 41.2 (C-18), 39.3 (C-8), 38.7 (C-1), 38.5 (C-4), 37.0 (C-10), 35.0 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.2 (C-27), 26.1 (-*C*H2), 25.9 (C-30), 24.3 (-*C*H2), 23.7 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.1 (C-26), 15.7 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C37H59NO3S2 [M+H]+: 630.4015. Found: 630.3961.

[2-((2-methylpyrrolidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3b**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 2-methylpyrrolidine (1.0 mmol, 101 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.2 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3b** (213.6 mg, 83% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.30 (s, 1H, H-12), 4.52 (m, 1H, -O*H*), 4.26 (m, 2H, -OC*H*2C-), 3.93 (m, 1H, -NC*H*), 3.73 (m, 1H, -NC*H*), 3.44 (m, 2H, -SC*H*2), 3.21 (m, 1H, H-3), 2.87 (dd, *J* = 13.7, 3.8 Hz, 1H, H-18), 2.25 (m, 1H, -NC*H*), 2.02 (m, 4H, 2 × -C*H*2), 1.81 (m, 3H, H-11, -C*H*, -C*H*2), 1.63 (m, 7H,-NCH2C*H*2, -NCH2C*H*2, H-22, -C*H*, -C*H*2), 1.53 (m, 3H, H-22, -C*H*, -C*H*2), 1.42 (m, 2H, -C*H*2), 1.35 (m, 4H, 2 × -C*H*2), 1.28 (m, 3H, -C*H*3), 1.16 (t, *J* = 4.2 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 191.7 (-*C*S2), 177.5 (C-28), 143.6 (C-13), 122.5 (C-12), 78.9 (C-3), 62.6 (-*C*O-), 61.3 (-N*C*H2CH3), 58.0(-*C*H3), 55.2 (C-5), 50.4 (-N*C*H2), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.7 (C-14), 41.3 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.0 (C-10), 34.8 (-*C*S), 33.9 (C-29), 33.1 (C-22), 32.4 (C-21), 31.3 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.2 (C-27), 25.9 (C-30), 23.7 (C-2), 22.9 (C-11), 21.6 (C-16), 18.6 (-*C*H2), 18.3 (C-6), 17.5 (-*C*H2), 17.1 (C-26), 15.6 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C38H61NO3S2 [M+H]+: 644.4171. Found: 644.4116.

[2-((2,2-dimethylpyrrolidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3c**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 2,2-dimethylpyrrolidine (1.0 mmol, 120 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.9 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). To the resulting solution was added water (15.0 mL), the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3c** (223.5 mg, 85% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.30 (s, 1H, H-12), 4.26 (m, 2H, -OC*H*2C-), 3.83 (t, *J* = 6.8 Hz, 1H, -NC*H*), 3.56 (m, 2H, -SC*H*2), 3.21 (m, 1H, -NC*H*), 2.87 (dd, *J* = 13.6, 3.7 Hz, 1H, H-18), 2.01 (m, 1H, -O*H*), 1.96 (m, 2H, -C*H*2), 1.88 (m, 3H, H-22, -C*H*, -C*H*2), 1.73 (s, 6H, 3 × -C*H*2), 1.63 (m, 8H, 4 × -C*H*2), 1.55 (m, 3H, -C*H*3), 1.46 (m, 3H, -C*H*3), 1.31 (m, 6H, 3 × -C*H*2), 1.16 (t, *J* = 5.6 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.78 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): <sup>δ</sup> 191.4 (-*C*S2), 177.5 (C-28), 143.7 (C-13), 122.5 (C-12), 79.0 (C-3), 69.2 (-N*C*CH3CH3), 62.7 (-*C*O-), 55.2 (-N*C*H2), 53.8 (C-5), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 43.3 (-*C*H2), 41.7 (C-14), 41.3 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.0 (C-10), 34.7 (-*C*S), 33.9 (C-29), 33.2 (C-22), 32.8 (C-21), 32.4 (C-7), 30.7 (C-20), 28.2 (C-15), 27.7 (C-23), 27.2 (C-27), 26.1 (-*C*H2), 25.9 (C-30), 24.8 (-*C*H2), 23.7 (C-2), 23.5 (C-11), 22.9 (C-16), 22.1 (-*C*H2), 18.4 (C-6), 17.1 (C-26), 15.7 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C39H63NO3S2 [M+H]+: 658.4328. Found: 658.4303.

[2-((3-hydroxypyrrolidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3d**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 3-hydroxypyrrolidine (1.0 mmol, 81 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 224.7 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (2/1 in *v*/*v*) as eluents to give **3d** (180.7 mg, 70% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 5.31 (s, 1H, H-12), 4.57 (m, 1H, -O*H*), 4.21 (m, 2H, -OC*H*2C-), 4.03 (m, 2H, -SC*H*2), 3.82 (m, 2H, -NC*H*2), 3.55 (m, 2H, -NC*H*2), 3.20 (m, 1H, H-3), 2.86 (d, *J* = 12.2 Hz, 1H, H-18), 2.15 (m, 1H, -O*H*), 2.05 (m, 2H, -C*H*2), 1.89 (m, 4H, 2 × -C*H*2), 1.67 (m, 6H, 3 × -C*H*2), 1.53 (m, 4H, 2 × -C*H*2), 1.33 (m, 7H, -C*H*OH, 3 × -C*H*2), 1.16 (t, *J* = 3.8 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.97 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (d, *J* = 2.3 Hz, 6H, <sup>2</sup> × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): <sup>δ</sup> 192.5 (-*C*S2), 177.7 (C-28), 143.5 (C-13), 122.5 (C-12), 79.0 (C-3), 70.7 (-*C*OH), 68.8 (-N*C*H2CH), 63.2 (-N*C*H2), 62.5 (-*C*O-), 55.2 (C-5), 52.9 (-*C*H2), 48.6 (C-7), 47.6 (C-9), 46.8 (C-17), 45.8 (C-19), 41.7 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.5 (C-4), 37.0 (C-10), 35.0 (-*C*S), 33.8 (C-29), 32.9 (C-22), 32.4 (C-21), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 23.7 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.1 (C-26), 15.7 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C37H59NO4S2 [M+H]+: 646.3964. Found: 646.3917.

[2-((3-(hydroxymethyl)pyrrolidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3e**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 3-(hydroxymethyl)pyrrolidine (1.0 mmol, 103 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.8 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (1/1 in *v*/*v*) as eluents to give **3e** (181.9 mg, 69% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 5.30 (t, *J* = 3.2 Hz, 1H, H-12), 4.25 (m, 2H, -OC*H*2C-), 3.85 (m, 1H, -O*H*), 3.68 (m, 2H, -SC*H*2), 3.54 (m, 3H, -C*H*2OH, -NC*H*), 3.21 (m, 1H, H-3), 2.86 (dd, *J* = 13.7, 3.9 Hz, 1H, H-18), 2.55 (m, 1H, -NC*H*), 2.22 (m, 1H, -NC*H*), 2.08 (m, 1H, -NC*H*), 1.95 (m, 2H, -C*H*2), 1.84 (m, 3H, -NCH2C*H*, -C*H*2), 1.70 (m, 1H, -O*H*), 1.63 (m, 6H, 2 × -C*H*3), 1.53 (m, 3H, -NCH2C*H*, -C*H*2), 1.42 (m, 3H, H-22, -C*H*, -C*H*2), 1.28 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.21 (s, 1H, -C*H*CH2OH), 1.17 (t, *J* = 3.2 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 192.0 (-*C*S2), 177.6 (C-28), 143.6 (C-13), 122.5 (C-12), 79.0 (C-3), 63.6 (-*C*OH), 62.4 (-*C*O-), 57.5 (-N*C*H2CH), 55.2 (-*C*'OH), 54.5 (-N*C***'**H2CH), 53.1 (-N*C*H2CH2), 50.1 (C-5), 47.6 (C-9), 46.8 (C-17), 45.8 (C-19), 41.7 (C-14), 41.3 (C-18), 39.5 (-*C*CH2OH), 39.3 (C-8), 38.7 (C-1), 38.5 (C-4), 37.0 (C-10), 35.0 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 31.5 (-N*C***'**H2CH2), 30.7 (C-20), 30.2 (-NCH2*C*H2), 28.4 (-*C***'**CH2OH), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 26.6 (-*C***'**CH2OH), 25.9 (C-30), 23.7 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.1 (C-26), 15.7 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C38H61NO4S2 [M+H]+: 660.4120. Found: 660.4069.

[2-((octahydro-1H-isoindole-2-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3f**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), octahydro-1H-isoindole (1.0 mmol, 115 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.5 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3f** (210.4 mg, 77% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 5.20 (s, 1H, H-12), 4.18 (m, 2H, -OC*H*2C-), 3.76 (m, 2H, -SC*H*2), 3.52 (m, 4H, 2 × -NC*H*2), 3.10 (m, 1H, H-3), 2.77 (d, *J* = 11.0 Hz, 1H, H-18), 2.26 (m, 2H, -C*H*2), 2.09 (m, 1H, -O*H*), 1.84 (m, 3H, H-22, -C*H*, -C*H*2), 1.52 (m, 8H, 4 × -C*H*2), 1.44 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.30 (m, 8H, 4 × -C*H*2), 1.18 (m, 4H, 2 × -C*H*2), 1.07 (s, 1H, H-9), 1.04 (s, 3H, -C*H*3), 0.95 (s, 1H, H-5), 0.88 (s, 3H, -C*H*3), 0.83 (s, 3H, -C*H*3), 0.80 (s, 6H, 2 × -C*H*3), 0.67 (s, 3H, -C*H*3), 0.64 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 192.3 (-*C*S2), 177.3 (C-28), 143.5 (C-13), 122.5 (C-12), 78.6 (C-3), 62.5 (-*C*O-), 58.9 (2 × -*C*H2), 55.2 (C-5), 54.5 (2 × -*C*H2), 47.5 (C-9), 46.6 (C-17), 45.7 (C-19), 41.6 (C-14), 41.2 (C-18), 39.3 (C-8), 38.7 (C-1), 37.6 (C-4), 36.9 (C-10), 35.8 (-*C*S), 34.9 (2 × -*C*H2), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.3 (C-7), 30.6 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 26.9 (C-30), 25.9 (C-2), 25.6 (2 × -*C*H2), 23.6 (C-11), 22.6 (C-16), 18.3 (C-6), 17.1 (C-26), 15.7 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C41H65NO3S2 [M+H]+: 684.4484. Found: 684.4430.

[2-((isoindoline-2-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3g**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), isoindoline (1.0 mmol, 113 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 226.4 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3g** (243.9 mg, 90% yield) as a yellowish solid. 1H NMR (400 MHz, CDCl3): δ 7.31 (m, 4H, Ar-*H*), 5.30 (t, *J* = 3.3 Hz, 1H, H-12), 5.20 (s, 2H, -OC*H*2C-), 4.99 (s, 2H, -NC*H*2), 4.32 (m, 2H, -NC*H*2), 3.66 (m, 2H, -SC*H*2), 3.19 (m, 1H, H-3), 2.95 (m, 1H, -O*H*), 2.88 (dd, *J* = 13.7, 4.0 Hz, 1H, H-18), 1.85 (m, 2H, -C*H*2), 1.69 (m, 3H, H-22, -C*H*, -C*H*2), 1.54 (m, 6H, 3 × -C*H*2), 1.42 (m, 3H, H-22, -C*H*, -C*H*2), 1.23 (m, 6H, 3 × -C*H*2), 1.17 (t, *J* = 4.4 Hz, 1H, H-9), 1.12 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.95 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 3H, -C*H*3), 0.86 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3), 0.72 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 192.7 (-*C*S2), 177.5 (C-28), 143.6 (C-13), 135.2 (*Ph*), 134.9 (*Ph*), 128.1 (*Ph*), 127.9 (*Ph*), 122.8 (*Ph*), 122.7 (*Ph*), 122.5 (C-12), 78.9 (C-3), 62.3 (-*C*O-), 60.5 (-N*C*H2), 55.7 (-N*C*H2), 55.1 (C-5), 47.5 (C-9), 46.7 (C-17), 45.8 (C-19), 41.6 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 35.3 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 18.2 (C-6), 17.1 (C-26), 15.5 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C41H59NO3S2 [M+H]+: 678.4015. Found: 678.3996.

[2-((4-methylpiperidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3h**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-methylpiperidine (1.0 mmol, 100 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 224.6 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3h** (199.8 mg, 76% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.23 (s, 1H, H-12), 4.21 (m, 2H, -OC*H*2C-), 3.54 (m, 2H, -SC*H*2), 3.10 (m, 3H, -NC*H*2, H-3), 2.80 (d, *J* = 12.2 Hz, 1H, H-18), 1.89 (m, 1H, -O*H*), 1.80 (m, 2H, -NC*H*2), 1.70 (m, 3H, H-22, -C*H*, -C*H*2), 1.58 (m, 7H, -C*H*CH3, 3 × -C*H*2), 1.46 (m, 4H, 2 × -C*H*2), 1.33 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.20 (m, 6H, 3 × -C*H*2), 1.10 (s, 1H, H-9), 1.06 (s, 3H, -C*H*3), 0.98 (s, 1H, H-5), 0.92 (s, 6H, 2 × -C*H*3), 0.86 (s, 3H, -C*H*3), 0.83 (s, 6H, 2 × -C*H*3), 0.71 (s, 3H, -C*H*3), 0.67 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 194.8 (-*C*S2), 177.5 (C-28), 143.7 (C-13), 122.6 (C-12), 79.1 (C-3), 62.5 (-*C*O-), 55.3 (C-5), 53.6 (-N*C*H2, -N*C*H2), 47.7 (C-9), 46.8 (C-17), 45.9 (C-19), 41.8 (C-14), 41.4 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.1 (C-10), 35.8 (-*C*S), 34.0 (C-29), 33.2 (-NCH2*C*H2, -NCH2*C*H2), 33.1 (C-22), 32.8 (C-21), 32.5 (C-7), 31.0 (-*C*CH3), 30.8 (C-20), 28.2 (C-15), 27.8 (C-23), 27.3 (C-27), 26.0 (C-30), 23.7 (C-2), 23.5 (C-11), 23.0 (C-16), 21.4 (-*C*H3), 18.4 (C-6), 17.2 (C-26), 15.7 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C39H63NO3S2 [M+H]+: 658.4328. Found: 658.4275.

[2-((4-hydroxypiperidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3i**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-hydroxypiperidine (1.0 mmol, 103.5 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2**

(0.4 mmol, 225.4 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (1/1 in *v*/*v*) as eluents to give **3i** (184.6 mg, 70% yield) as a yellow gel. 1H NMR (400 MHz, CDCl3): δ 5.50 (s, 1H, -O*H*), 5.30 (s, 1H, H-12), 4.60 (s, 1H, -C*H*OH), 4.28 (m, 2H, -SC*H*2), 3.61 (m, 2H, -NC*H*2), 3.21 (m, 1H, H-3), 3.08 (s, 2H, -NC*H*2), 2.87 (d, *J* = 11.0 Hz, 1H, H-18), 2.00 (m, 1H, -O*H*), 1.87 (s, 2H, -C*H*2), 1.76 (m, 3H, H-22, -C*H*, -C*H*2), 1.62 (m, 6H, 3 × -C*H*2), 1.53 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.42 (m, 4H, 2 × -C*H*2), 1.27 (m, 6H, 3 × -C*H*2), 1.16 (t, *J* = 3.7 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 194.6 (-*C*S2), 177.4 (C-28), 143.6 (C-13), 122.5 (C-12), 78.9 (C-3), 62.4 (-*C*O-), 55.2 (C-5), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.7 (C-14), 41.3 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.0 (C-10), 35.7 (-*C*S), 33.9 (C-29), 33.1 (C-22), 32.8 (C-21), 32.4 (C-7), 31.0 (-*C*OH), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.2 (C-27), 26.9 (-N*C*H2, -N*C*H2), 25.9 (C-30), 23.7 (C-2), 23.4 (C-11), 22.9 (C-16), 21.3 (-NCH2*C*H2, -NCH2*C*H2), 18.4 (C-6), 17.1 (C-26), 15.6 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C38H61NO4S2 [M+H]+: 660.4120. Found: 660.4080.

[2-((4-(hydroxymethyl)piperidine-1-carbonothioyl)thio)-ethyl] 3-hydroxy-12-en-28-oic acid (**3j**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-(hydroxymethyl)piperidine (1.0 mmol, 115.3 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.9 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (2/1 in *v*/*v*) as eluents to give **3j** (199.3 mg, 74% yield) as a yellow gel. 1H NMR (400 MHz, CDCl3): δ 5.57 (s, 1H, -C*H*CH2OH), 5.31 (s, 1H, H-12), 4.64 (s, 1H, -C*H*OH), 4.26 (m, 2H, -OC*H*2C-), 3.60 (m, 2H, -SC*H*2), 3.51 (m, 2H, -NC*H*2), 3.21 (m, 2H, -NC*H*2), 3.13 (m, 1H, H-3), 2.86 (dd, *J* = 13.5, 3.7 Hz, 1H, H-18), 1.96 (m, 1H, -O*H*), 1.91 (m, 2H, -C*H*2), 1.87 (m, 3H, -O*H*, -C*H*2), 1.63 (m, 6H, 3 × -C*H*2), 1.52 (m, 5H, -C*H*OH, 2 × -CH2), 1.38 (m, 6H, 3 × -C*H*2), 1.27 (m, 4H, 2 × -C*H*2), 1.16 (t, *J* = 4.4 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 194.8 (-*C*S2), 177.5 (C-28), 143.6 (C-13), 122.5 (C-12), 78.9 (C-3), 66.5 (-*C*H2OH), 62.4 (-*C*O-), 55.2 (C-5), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.6 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.5 (C-4), 38.4 (-N*C*H2, -N*C*H2), 37.0 (C-10), 36.6 (-N*C*H2CH2, -N*C*H2CH2), 35.6 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 31.5 (-*C*CH2OH), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.1 (C-26), 15.6 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C39H63NO4S2 [M+H]+: 674.4277. Found: 674.4230.

[2-((2-(2-hydroxyethyl)piperidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3k**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 2-(2-hydroxyethyl)piperidine (1.0 mmol, 128.1 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.6 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue

was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (2/1 in *v*/*v*) as eluents to give **3k** (200.7 mg, 73% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 5.93 (m, 1H, -O*H*), 5.30 (t, *J* = 3.3 Hz, 1H, H-12), 4.55 (m, 1H, -C*H*OH), 4.28 (m, 2H, -OC*H*2C-), 3.62 (m, 3H, -C*H*OH, -SC*H*2), 3.39 (m, 1H, H-3), 3.16 (m, 3H, -NC*H*2, -NC*H*), 2.87 (dd, *J* = 13.7, 3.9 Hz, 1H, H-18), 2.14 (m, 1H, -O*H*), 1.95 (m, 2H, -C*H*2), 1.87 (m, 3H, -CHC*H*2CH2OH, H-22, -C*H*), 1.79 (m, 1H, H-22, -C*H*), 1.70 (m, 6H, 3 × -C*H*2), 1.59 (m, 6H, 3 × -C*H*2), 1.53 (m, 4H, 2 × -C*H*2), 1.38 (m, 6H, 3 × -C*H*2), 1.17 (t, *J* = 4.3 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 196.4 (-*C*S2), 177.4 (C-28), 143.5 (C-13), 122.5 (C-12), 78.8 (C-3), 58.1 (-*C*O-), 56.0 (-N*C*H), 55.2 (C-5), 47.6 (C-9), 46.7 (C-17), 46.0 (C-19), 45.8 (-*C*H2OH), 41.6 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.5 (C-4), 37.0 (C-10), 35.6 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.9 (C-21), 32.7 (C-7), 32.4 (-N*C*H2), 30.7 (C-20), 29.3 (-*C*H2CH2OH), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 25.8 (-NCH*C*H2), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 19.2 (-NCH2CH2*C*H2), 18.3 (C-6), 17.1 (C-26), 17.1 (-NCH2*C*H2), 15.6 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C40H65NO4S2 [M+H]+: 688.4433. Found: 688.4418.

[2-((4-(2-hydroxyethyl)piperidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3l**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-(2-hydroxyethyl)piperidine (1.0 mmol, 130.8 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 226.4 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (2/1 in *v*/*v*) as eluents to give **3l** (195.2 mg, 71% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 5.23 (t, *J* = 3.3 Hz, 1H, H-12), 4.53 (m, 1H, -O*H*), 4.21 (m, 2H, -OC*H*2C-), 3.95 (m, 2H, -SC*H*2), 3.75 (m, 2H, -NC*H*2), 3.53 (m, 2H, -NC*H*2), 3.14 (m, 1H, H-3), 2.79 (dd, *J* = 13.6, 3.7 Hz, 1H, H-18), 2.07 (m, 2H, -C*H*2), 1.90 (m, 1H, -O*H*), 1.81 (m, 3H, -C*H*2, -NCH2CH2C*H*), 1.61 (m, 2H, -C*H*2), 1.56 (m, 6H, 3 × -C*H*2), 1.45 (m, 4H, 2 × -C*H*2), 1.25 (m, 6H, 3 × -C*H*2), 1.10 (t, *J* = 4.6 Hz, 1H, H-9), 1.06 (s, 3H, -C*H*3), 0.98 (s, 1H, H-5), 0.91 (s, 3H, -C*H*3), 0.86 (s, 3H, -C*H*3), 0.83 (s, 6H, 2 × -C*H*3), 0.70 (s, 3H, -C*H*3), 0.67 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 194.5 (-*C*S2), 177.5 (C-28), 143.5 (C-13), 122.5 (C-12), 77.0 (C-3), 62.4 (-*C*O-), 60.4 (-*C*H2OH), 59.6 (-N*C*H2), 55.2 (C-5), 52.3 (-N*C*H2), 50.4 (-*C*H2CH2OH), 47.5 (C-9), 46.7 (C-17), 45.7 (C-19), 41.6 (C-14), 41.2 (C-18), 39.3 (C-8), 38.7 (C-1), 38.5 (C-4), 36.9 (C-10), 35.6 (-CS), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 31.6 (-NCH2*C*H2), 30.7 (C-20), 28.1 (C-15), 27.6 (C-23), 27.1 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 21.1 (-*C*HCH2CH2OH), 18.3 (C-6), 17.1 (C-26), 15.7 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C40H65NO4S2 [M+H]+: 688.4433. Found: 688.4366.

[2-((4-phenylpiperidine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3m**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-phenylpiperidine (1.0 mmol, 164.7 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.2 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted

with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3m** (253.2 mg, 88% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 7.31 (m, 2H, Ar-*H*), 7.21 (m, 3H, Ar-*H*), 5.30 (t, *J* = 3.3 Hz, 1H, H-12), 4.32 (m, 2H, -OC*H*2C-), 3.63 (m, 2H, -SC*H*2), 3.20 (m, 3H, H-3, -NC*H*2), 2.88 (m, 2H, H-18, -NCH2CH2C*H*), 1.99 (m, 1H, -O*H*), 1.96 (m, 2H, -C*H*2), 1.88 (m, 3H, H-22, -C*H*, -C*H*2), 1.64 (m, 8H, 2 × -NC*H*2, 2 × -C*H*2), 1.51 (m, 3H, H-22, -C*H*, -C*H*2), 1.44 (m, 4H, 2 × -NC*H*2), 1.28 (m, 6H, 3 × -C*H*2), 1.17 (t, *J* = 3.6 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.97 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 3H, -C*H*3), 0.89 (s, 3H, -C*H*3), 0.76 (s, 3H, -C*H*3), 0.75 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 195.1 (-*C*S2), 177.5 (C-28), 144.3 (*Ph*), 143.6 (C-13), 128.7 (*Ph*), 126.8 (*Ph*), 122.6 (C-12), 78.9 (C-3), 62.4 (-*C*O-), 55.2 (C-5), 47.6 (C-9), 46.8 (C-17), 45.8 (C-19), 42.6 (-N*C*H2), 41.7 (C-14), 41.3 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.0 (C-10), 35.9 (-*C*S), 34.7 (-NCH2CH2*C*H), 33.9 (C-29), 33.2 (C-22), 32.8 (C-21), 32.4 (C-7), 30.7 (C-20), 28.2 (C-15), 27.7 (C-23), 27.2 (C-27), 27.0 (-NCH2*C*H2), 25.9 (C-30), 25.3 (-NCH2*C*H2), 23.7 (C-2), 23.5 (C-11), 23.0 (C-16), 18.4 (C-6), 17.2 (C-26), 15.7 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C44H65NO3S2 [M+H]+: 720.4484. Found: 720.4450.

[2-((4-methylpiperazine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3n**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-methylpiperazine (1.0 mmol, 112 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.0 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (1/4 in *v*/*v*) as eluents to give **3n** (234.3 mg, 89% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): 5.30 (t, *J* = 3.3 Hz, 1H, H-12), 4.36 (s, 2H, -OC*H*2C-), 4.28 (m, 2H, -NC*H*2), 3.96 (s, 2H, -NC*H*2), 3.61 (m, 2H, -SC*H*2), 3.21 (m, 1H, H-3), 2.87 (dd, *J* = 13.6, 4.0 Hz, 1H, H-18), 2.50 (s, 4H, 2 × -NC*H*2), 2.34 (s, 3H, -C*H*3), 1.97 (m, 1H, -O*H*), 1.87 (m, 2H, -C*H*2), 1.64 (m, 6H, 3 × -C*H*2), 1.53 (m, 3H, H-22, -C*H*, -C*H*2), 1.40 (m, 3H, H-22, -C*H*, -C*H*2), 1.27 (m, 6H, 3 × -C*H*2), 1.16 (t, *J* = 4.3 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.78 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 195.9 (-*C*S2), 177.4 (C-28), 143.6 (C-13), 122.5 (C-12), 78.9 (C-3), 62.3 (-*C*O-), 55.2 (C-5), 54.4 (-N*C*H2), 47.6 (C-9), 46.7 (C-17), 46.4 (-CH2*C*H2), 45.8 (C-19), 45.6 (-N*C*H3), 41.7 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 35.6 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.2 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.1 (C-26), 15.6 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C38H62N2O3S2 [M+H]+: 659.4280. Found: 659.4239.

[2-((4-(2-hydroxyethyl)piperazine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3o**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-(2-hydroxyethyl)piperazine (1.0 mmol, 123 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 224.9 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (1/5

in *v*/*v*) as eluents to give **3o** (195.5 mg, 71% yield) as a yellowish gel. 1H NMR (400 MHz, CDCl3): δ 5.30 (t, *J* = 3.1 Hz, 1H, H-12), 4.33 (s, 1H, -NC*H*), 4.28 (m, 2H, -OC*H*2C-), 3.99 (s, 1H, -NC*H*), 3.69 (m, 2H, -NC*H*2), 3.61 (m, 2H, -SC*H*2), 3.21 (m, 1H, H-3), 2.86 (dd, *J* = 13.7, 4.1 Hz, 1H, H-18), 2.63 (t, *J* = 5.2 Hz, 4H, 2 × -NC*H*2), 2.61 (s, 1H, -O*H*), 1.97 (m, 1H, -O*H*), 1.88 (m, 2H, -C*H*2), 1.66 (m, 2H, -C*H*2), 1.60 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.53 (m, 4H, 2 × -C*H*2), 1.43 (m, 3H, H-22, -C*H*, -C*H*2), 1.33 (m, 4H, 2 × -C*H*2), 1.27 (m, 4H, 2 × -C*H*2), 1.16 (t, *J* = 4.4 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.77 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 196.1 (-*C*S2), 177.5 (C-28), 143.6 (C-13), 122.5 (C-12), 79.0 (C-3), 62.3 (-*C*O-), 59.1 (-N*C*H2CH2OH), 57.9 (-NCH2*C*H2OH), 55.2 (C-5), 52.3 (-N*C*H2CH2), 47.6 (C-9), 46.8 (C-17), 45.8 (C-19), 41.7 (C-14), 41.3 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.0 (C-10), 35.7 (-*C*S), 33.9 (C-29), 33.1 (C-22), 32.4 (C-21), 31.5 (C-7), 30.7(-NCH2*C*H2), 30.2 (C-20), 28.1 (C-15), 27.7 (C-23), 27.2 (C-27), 25.9 (C-30), 23.7 (C-2), 23.4 (C-11), 22.9 (C-16), 18.4 (C-6), 17.1 (C-26), 15.6 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C39H64N2O4S2 [M+H]+: 689.4386. Found: 689.4336.

[2-((4-phenylpiperazine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3p**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-phenylpiperazine (1.0 mmol, 150 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 226.7 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (1/5 in *v*/*v*) as eluents to give **3p** (247.8 mg, 86% yield) as a yellowish solid. 1H NMR (400 MHz, CDCl3): δ 7.30 (m, 2H, Ar-*H*), 6.93 (m, 3H, Ar-*H*), 5.30 (t, *J* = 3.2 Hz, 1H, H-12), 4.49 (s, 2H, -OC*H*2C-), 4.29 (m, 2H, -NC*H*2), 4.10 (m, 2H, -NC*H*2), 3.64 (m, 2H, -SC*H*2), 3.30 (t, *J* = 4.9 Hz, 4H, 2 × -NC*H*2), 3.20 (m, 1H, H-3), 2.87 (dd, *J* = 13.6, 3.9 Hz, 1H, H-18), 1.97 (m, 1H, -O*H*), 1.88 (m, 2H, -C*H*2), 1.67 (m, 4H, 2 × -C*H*2), 1.58 (m, 4H, 2 × -C*H*2), 1.51 (m, 3H, H-22, -C*H*, -C*H*2), 1.35 (m, 7H, H-22, -C*H*, 3 × -C*H*2), 1.17 (t, *J* = 4.0 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.97 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 3H, -C*H*3), 0.89 (s, 3H, -C*H*3), 0.76 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 196.1 (-*C*S2), 177.4 (*Ph*), 150.2 (*Ph*), 143.6 (C-13), 129.3 (*Ph*), 122.5 (C-12), 120.6 (*Ph*), 116.3 (*Ph*), 78.9 (C-3), 62.2 (-*C*O-), 55.2 (C-5), 48.7 (-N*C*H2), 48.2 (-N*C*H2), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.6 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 35.6 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 18.3 (C-6), 17.1 (C-26), 15.6 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C43H64N2O3S2 [M+H]+: 721.4437. Found: 721.4411.

[2-((4-(o-tolyl)piperazine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3q**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-(o-tolyl)piperazine (1.0 mmol, 177.9 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.9 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3q** (246.7 mg, 84% yield) as a yellowish gel. 1H NMR (400 MHz,

CDCl3): δ 7.17 (t, *J* = 7.9 Hz, 1H, Ar-*H*), 6.73 (m, 3H, Ar-*H*), 5.30 (t, *J* = 3.1 Hz, 1H, H-12), 4.46 (s, 2H, -OC*H*2C-), 4.27 (m, 2H, -NC*H*2), 4.10 (s, 2H, -NC*H*2), 3.64 (m, 2H, -SC*H*2), 3.28 (t, *J* = 5.0 Hz, 4H, 2 × -NC*H*2), 3.18 (m, 1H, H-3), 2.87 (dd, *J* = 13.6, 3.8 Hz, 1H, H-18), 2.32 (s, 3H, -C*H*3), 1.97 (m, 1H, -O*H*), 1.87 (m, 2H, -C*H*2), 1.69 (m, 4H, 2 × -C*H*2), 1.58 (m, 5H, H-22, -C*H*, 2 × -C*H*2), 1.51 (m, 3H, H-22, -C*H*, -C*H*2), 1.35 (m, 6H, 3 × -C*H*2), 1.17 (t, *J* = 3.8 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.97 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 3H, -C*H*3), 0.89 (s, 3H, -C*H*3), 0.76 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 195.9 (-*C*S2), 177.4 (C-28), 150.2 (*Ph*), 143.5 (C-13), 139.0 (*Ph*), 129.1 (*Ph*), 122.5 (C-12), 121.5 (*Ph*), 117.1 (*Ph*), 113.4 (*Ph*), 78.8 (C-3), 62.3 (-*C*O-), 55.2 (C-5), 48.8 (-N*C*H2), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.6 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 35.6 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 26.9 (-NCH2*C*H2), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 21.8 (-*C*H3), 18.3 (C-6), 17.1 (C-26), 15.6 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C44H66N2O3S2 [M+H]+: 735.4593. Found: 735.4540.

[2-((4-(m-tolyl)piperazine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3r**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-(m-tolyl)piperazine (1.0 mmol, 174 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 226.1 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3r** (235.0 mg, 80% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 7.16 (t, *J* = 7.9 Hz, 1H, Ar-*H*), 6.72 (m, 3H, Ar-*H*), 5.30 (s, 1H, H-12), 4.40 (s, 2H, -OC*H*2C-), 4.28 (m, 2H, -NC*H*2), 4.11 (m, 2H, -NC*H*2), 3.60 (m, 2H, -SC*H*2), 3.27 (m, 4H, 2 × -NC*H*2), 3.18 (m, 1H, H-3), 2.87 (dd, *J* = 13.5, 3.5 Hz, 1H, H-18), 2.32 (s, 3H, -C*H*3), 1.95 (m, 1H, -O*H*), 1.86 (m, 2H, -C*H*2), 1.62 (m, 7H, H-22, -C*H*, 3 × -C*H*2), 1.51 (m, 3H, H-22, -C*H*, -C*H*2), 1.42 (m, 2H, -C*H*2), 1.32 (m, 6H, 3 × -C*H*2), 1.17 (t, *J* = 3.1 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.96 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 3H, -C*H*3), 0.89 (s, 3H, -C*H*3), 0.75 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 195.9 (-*C*S2), 177.4 (C-28), 150.2 (*Ph*), 143.5 (C-13), 139.0 (*Ph*), 129.1 (*Ph*), 122.5 (C-12), 121.5 (*Ph*), 117.1 (*Ph*), 113.4 (*Ph*), 78.8 (C-3), 62.3 (-*C*O-), 55.2 (C-5), 48.8 (-N*C*H2), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.6 (C-14), 41.3 (C-18), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 35.6 (-*C*S), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 26.9 (-NCH2*C*H2), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 21.8 (-CH3), 18.3 (C-6), 17.1 (C-26), 15.6 (C-24), 15.4 (C-25). HRMS (ESI): *m*/*z* calculated for C44H66N2O3S2 [M+H]+: 735.4593. Found: 735.4537.

[2-((4-(p-tolyl)piperazine-1-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3s**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), 4-(p-tolyl)piperazine (1.0 mmol, 177.1 mg) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.8 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3s** (249.6 mg, 85% yield) as a white solid. 1H NMR (400 MHz, CDCl3): δ 7.10 (d, *J* = 8.3 Hz, 2H, Ar-*H*), 6.84 (d, *J* = 8.5 Hz, 2H, Ar-*H*), 5.30 (t, *J* = 3.3 Hz, 1H, H-12), 4.48 (s, 2H, -NC*H*2), 4.30 (m, 2H, -OC*H*2C-), 4.10 (s, 2H, -NC*H*2), 3.64 (m, 2H, -SC*H*2), 3.23 (m, 4H, 2× -NC*H*2), 3.19 (d, *J* = 4.8 Hz, 1H, H-3), 2.87 (dd, *J* = 13.7, 4.0 Hz, 1H, H-18), 2.28 (s, 3H, -C*H*3), 1.97 (m, 1H, -O*H*), 1.87 (m, 2H, 2× -C*H*2), 1.65 (m, 6H, 3× -C*H*2), 1.50 (m, 4H, 2× -C*H*2), 1.40 (m, 4H, 2× -C*H*2), 1.29 (m, 4H, 2× -C*H*2) 1.17 (t, *J* = 4.1 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.05 (s, 1H, H-5), 0.97 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 3H, -C*H*3), 0.89 (s, 3H, -C*H*3), 0.76 (s, 3H, -C*H*3), 0.74 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 196.0 (-*C*S2), 177.4 (C-28), 148.1 (*Ph*), 143.6 (C-13), 130.3 (*Ph*), 129.8 (*Ph*), 122.5 (C-12), 116.8 (*Ph*), 78.9 (C-3), 62.3 (-*C*O-), 55.2 (C-5), 49.4 (-N*C*H2), 47.6 (C-9), 46.7 (C-17), 45.8 (C-19), 41.7 (C-14), 41.5 (C-18), 41.3 (-NCH2*C*H2), 39.3 (C-8), 38.7 (C-1), 38.4 (C-4), 37.0 (C-10), 35.6 (-CS), 33.8 (C-29), 33.1 (C-22), 32.7 (C-21), 32.4 (C-7), 30.7 (C-20), 28.1 (C-15), 27.7 (C-23), 27.1 (C-27), 25.9 (C-30), 23.6 (C-2), 23.4 (C-11), 22.9 (C-16), 20.5 (-*C*H3), 18.3 (C-6), 17.1 (C-26), 15.6 (C-24), 15.3 (C-25). HRMS (ESI): *m*/*z* calculated for C44H66N2O3S2 [M+H]+: 735.4593. Found: 735.4562.

[2-((thiomorpholine-4-carbonothioyl)thio)ethyl] 3-hydroxy-12-en-28-oic acid (**3t**). To a mixture of CS2 (1.8 mmol, 108 μL), anhydrous K3PO4 (0.8 mmol, 169.1 mg), and THF (8.0 mL), thiomorpholine (1.0 mmol, 94 μL) was slowly added at 0 ◦C, and the reaction mixture was then stirred at 0 ◦C for 0.5 h. Another THF solution (4.0 mL) of **2** (0.4 mmol, 225.1 mg) was added dropwise to the resulting mixture. The reaction mixture was stirred for 12 h at room temperature, then quenched with ice water (15.0 mL), and the insoluble material was removed by a Buchner funnel. After removal of the solvent, the residue was dissolved in ethyl acetate (15.0 mL). Water (15.0 mL) was added to the resulting solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (15.0 mL × 2). The organic solutions were combined and dried over anhydrous Na2SO4. After removal of the solvent, the residue was submitted to column chromatography on silica gel (200–300 mesh) using petroleum ether and ethyl acetate (10/1 in *v*/*v*) as eluents to give **3t** (190.4 mg, 72% yield) as a white gel. 1H NMR (400 MHz, CDCl3): δ 5.29 (s, 1H, H-12), 4.61 (s, 2H, -OC*H*2C-), 4.26 (m, 2H, -NC*H*2), 3.61 (m, 2H, -SC*H*2), 3.21 (m, 1H, H-3), 2.86 (dd, *J* = 13.5, 3.6 Hz, 1H, H-18), 2.75 (m, 4H, 2 × -SC*H*2), 1.97 (m, 1H, -O*H*), 1.88 (m, 2H, -C*H*2), 1.63 (m, 6H, 3 × -C*H*2), 1.53 (m, 3H, H-22, -C*H*, -C*H*2), 1.42 (m, 4H, 2 × -C*H*2), 1.35 (m, 3H, H-22, -C*H*, -C*H*2), 1.27 (m, 4H, 2 × -C*H*2), 1.16 (t, *J* = 3.6 Hz, 1H, H-9), 1.13 (s, 3H, -C*H*3), 1.04 (s, 1H, H-5), 0.98 (s, 3H, -C*H*3), 0.93 (s, 3H, -C*H*3), 0.90 (s, 6H, 2 × -C*H*3), 0.78 (s, 3H, -C*H*3), 0.73 (s, 3H, -C*H*3). 13C NMR (100 MHz, CDCl3): δ 195.9 (-*C*S2), 177.5 (C-28), 143.6 (C-13), 122.6 (C-12), 79.0 (C-3), 62.2 (-*C*O-), 55.3 (C-5), 47.7 (C-9), 46.8 (C-17), 45.8 (C-19), 41.7 (C-14), 41.3 (C-18), 39.4 (C-8), 38.8 (C-1), 38.5 (C-4), 37.1 (C-10), 35.8 (-*C*S), 33.9 (C-29), 33.2 (C-22), 32.8 (C-21), 32.5 (C-7), 30.8 (C-20), 28.2 (C-15), 27.8 (C-23), 27.2 (C-27), 27.0 (-N*C*H2), 25.9 (C-30), 23.7 (C-2), 23.5 (C-11), 23.0 (C-16), 18.4 (C-6), 17.2 (C-26), 15.7 (C-24), 15.4 (C-25), 14.2 (-SCH2). HRMS (ESI): *m*/*z* calculated for C37H59NO3S3 [M+H]+: 662.3735. Found: 662.3673.

#### *3.3. Preliminary Biological Study*

The in vitro cytotoxic activities of the compounds were evaluated by MTT assay against Panc1, A549, Hep3B, Huh-7, HT-29, Hela, LO2. Cell lines were obtained from the Laboratory of Molecular Pharmacology, Southwest Medical University. Briefly, different tumor cells grew in DMEM medium except for A549, which used 1640 medium. Cells ((3–5) × 103 cells/well) were harvested at the log phase of growth and seeded in 96-well plates. After 24 h incubation at 37 ◦C in 5% CO2 to allow cell attachment, cultures were exposed to various concentrations of the isolated compounds for 48 h. Finally, the MTT solution was added. Plates were further incubated for 4 h at 37 ◦C after adding 150 μL/well of DMSO and shaking for 10 min on the shaker platform. The plates were read in a 96-well plate reader at 490 nm wavelength. The results were expressed as IC50 values, and were defined as the concentration at which 50% survival of cells was obtained. Fluorouracil, docetaxel, and cisplatin were co-assayed as positive controls.
