Synthesis of 3-(4-(phenyldiazenyl)phenoxy)propane-1-thiol (1)
Compound A: 4-(allyloxy)phenyl-2-phenyldiazene: In a dried three neck round bottom flask, 4-(phenyldiazenyl)phenol (1.58 g, 8 mmol, 1 eq.), 3-bromoprop-1ene (0.7 mL, 0.97 g, 8 mmol, 1 eq.) and potassium t-butoxide (1 g, 10.4 mmol, 1.3 eq.) were dissolved in 20 mL of dry THF. The reaction mixture was stirred at reflux for 16 hours after what it was cool down to room temperature. The solvent was evaporated under reduced pressure and the residue dissolved in 100 mL CH2Cl2. The organic phase was washed with distilled water (3 × 60 mL). The organic phase was dried over MgSO4 and the solvent was evaporated under reduced pressure. The product was purified by flash chromatography on silica with ethyl acetate / heptane (1:9) as eluent. The product was collected as an orange solid, 1.525 g, yield 80%. 1H NMR (400 MHz, CDCl3) δ = 4.62 (t, 2H, O-CH2), 5.39 (m, 2H, =CH2), 6.08 (m, 1H, =CH-), 7.04 (d, 2H, Ar-H), 7.50 (m, 3H, Ar-H), 7.91 ppm (m, 4H, Ar-H).
Compound B: 3-(4-phenyldiazenyl)phenoxy)propyl-ethanethioate: In a dried three neck round bottom flask, compound A (1 g, 4.2 mmol, 1 eq.) and AIBN (1.45 g, 8.8 mmol, 2.1 eq.) were dissolved in 20 mL of dry toluene. Thioacetic acid (0.63 mL, 0.67 g, 8.8 mmol, 2.1 eq.) was added dropwise to the mixture under stirring. The reaction mixture was stirred at reflux for 16 hours. The reaction was then cool down to room temperature and diluted with 60 mL of toluene. The organic phase was washed with saturated NaHCO3 solution in water (60 mL) and distilled water (2 × 60 mL). The organic phase was dried over MgSO4 and the solvent was evaporated under reduced pressure. The product was purified by flash chromatography on silica with ethyl acetate / heptane (1:9) as eluent. The product was collected as an orange solid, 1 g, yield 76%. 1H NMR (400 MHz, CDCl3) δ = 2.12 (m, 2H, C-CH2-C), 2.36 (s, 3H, -COCH3), 3.09 (t, 2H, CH2-S), 4.10 (t, 2H, O-CH2), 7.01 (d, 2H, Ar-H), 7.50 (m, 3H, Ar-H), 7.88 ppm (m, 4H, Ar-H).
3-(4-(phenyldiazenyl)phenoxy)propane-1-thiol (1): Compound B (0.5 g, 1.6 mmol, 1 eq.) was dissolved in 40 mL of degassed MeOH under N2 followed by 2 g (9 eq) of K2CO3. 2 mL of HCl (37%) (14 eq.) were added dropwise and the reaction mixture was refluxed for 3 h. The reaction was then cool down to room temperature and the excess HCl was neutralized with a NaOH solution in water (1M). 100 mL of CH2Cl2 were added to the reaction mixture and the organic phase was washed with distilled water (2 × 100 mL). The organic phase was collected and dried over MgSO4 and the solvent was evaporated under reduced pressure. The product was purified by flash chromatography on silica with ethyl acetate / heptane (1:15) as eluent. The product was collected as an orange solid, 0.260 g, yield 60%. 1H NMR (400 MHz, CDCl3) 1.42 (t, 1H, -SH), 2.12 (m, 2H, C-CH2-C), 2.76 (m, 2H, S-CH2), 4.16 (t, 2H, O-CH2), 7.02 (d, 2H, Ar-H), 7.50 (m, 3H, Ar-H), 7.92 ppm (m, 4H, Ar-H). 13C NMR (100 MHz, CDCl3) 21.30 (CH2-S), 33.34 (C-CH2-C), 66.06 (CH2-O), 114.81 (CAr), 122.68 (CAr), 124.87 (CAr), 129.14 (CAr), 130.49 (CAr), 147.15 (CAr-N), 152.85 (CAr-N), 161.41 ppm (CAr-O)
Synthesis of 3-(4-((4-( tert -butyl)phenyl)diazenyl)phenoxy)propane-1-thiol (2)
Compound D: 3-(4-((4-(tert-butyl)phenyl)diazenyl)phenoxy)propyl ethanethioate: In a dried three neck round bottom flask, 4-(4’(-tert-butyl)phenyldiazenyl)phenol (1.1 g, 4.3 mmol, 1 eq.), 3-bromoprop-1ene (0.7 mL, 0.52 g, 4.3 mmol, 1 eq.) and potassium t-butoxide (0.54 g, 5.6 mmol, 1.3 eq.) were dissolved in 20 mL of dry THF. The reaction mixture was stirred at reflux for 16 hours after what it was cool down to room temperature. The solvent was evaporated under reduced pressure and the residue dissolved in 100 mL CH2Cl2. The organic phase was washed with distilled water (3 × 60 mL). The organic phase was dried over MgSO4 and the solvent was evaporated under reduced pressure. The product was purified by flash chromatography on silica with ethyl acetate / heptane (1:9) as eluent. The product was collected as an orange solid, 0.74 g, yield 58%. 1H NMR (400 MHz, CDCl3) δ = 1.38 (s, 9 H, CH3), 4.62 (t, 2H, O-CH2), 5.41 (m, 2H, =CH2), 6.08 (m, 1H, =CH-), 7.03 (d, 2H, Ar-H), 7.53 (d, 2H, Ar-H), 7.83 (d, 2H, Ar-H), 7.91 ppm (d, 2H, Ar-H).
Compound E: 3-(4-((4-(tert-butyl)phenyl)diazenyl)phenoxy)propane-1-thiol: In a dried three neck round bottom flask, compound A (0.74 g, 2.5 mmol, 1 eq.) and AIBN (0.87 g, 5.3 mmol, 2.1 eq.) were dissolved in 10 mL of dry toluene. Thioacetic acid (0.38 mL, 0.40 g, 5.3 mmol, 2.1 eq.) was added dropwise to the mixture under stirring. The reaction mixture was stirred at reflux for 16 hours. The reaction was then cool down to room temperature and diluted with 30 mL of toluene. The organic phase was washed with saturated NaHCO3 solution in water (30 mL) and distilled water (2 × 30 mL). The organic phase was dried over MgSO4 and the solvent was evaporated under reduced pressure. The product was purified by flash chromatography on silica with ethyl acetate / heptane (1:20) as eluent. The product was collected as an orange solid, 0.64 g, yield 72%. 1H NMR (400 MHz, CDCl3) δ = 1.37 (s, 9 H, CH3), 2.11 (m, 2H, C-CH2-C), 2.35 (s, 3H, -COCH3), 3.08 (t, 2H, CH2-S), 4.09 (t, 2H, O-CH2), 6.99 (d, 2H, Ar-H), 7.52 (d, 2H, Ar-H), 7.82 (d, 2H, Ar-H), 7.90 ppm (d, 2H, Ar-H).
3-(4-(phenyldiazenyl)phenoxy)propane-1-thiol (2): Compound B (0.6 g, 1.7 mmol, 1 eq.) was dissolved in 45 mL of degassed MeOH under N2 followed by 2.1 g (9 eq) of K2CO3. 2.7 mL of HCl (37%) (19 eq.) were added dropwise and the reaction mixture was refluxed for 3 h. The reaction was then cool down to room temperature and the excess HCl was neutralized with a NaOH solution in water (1M). 100 mL of CH2Cl2 were added to the reaction mixture and the organic phase was washed with distilled water (2 × 100 mL). The organic phase was collected and dried over MgSO4 and the solvent was evaporated under reduced pressure. The product was purified by flash chromatography on silica with ethyl acetate / heptane (1:15) as eluent. The product was collected as an orange solid, 0.330 g, yield 62%. 1H NMR (400 MHz, CDCl3): 1.38 (s, 9 H, CH3), 1.42 (t, 1H, -SH), 2.12 (m, 2H, C-CH2-C), 2.76 (m, 2H, S-CH2), 4.16 (t, 2H, O-CH2), 7.02 (d, 2H, Ar-H), 7.50 (m, 3H, Ar-H), 7.92 ppm (m, 4H, Ar-H). 13C NMR (100 MHz, CDCl3): 21.35 (CH2-S), 31.44 (CH3), 33.40 (CtBu), 35.10 (C-CH2-C), 66.08 (CH2-O), 114.81 (CAr), 122.40 (CAr), 124.72 (CAr), 126.09 (CAr), 147.33 (CAr-N), 150.83 (CAr-N), 154.03 (CAr-tBu), 161.21 ppm (CAr-O)