Molecules 2018, 23, 2235
12 of 17
Methyl 4-(4-chlorophenyl)-4-oxobutanoate (23a) [72]. Synthesized according to the general procedure.
Reaction conditions: 3-(4-Chlorobenzoyl)propionic acid (1 mmol, 212.6 mg), MeOH (0.5 mL), NBS
(0.070 mmol, 12.5 mg), 70 ◦C, 20 h. Purification: Not necessary. Yield: 224 mg of white solid (99%);
1H-NMR (300 MHz, CDCl3)
2.70 (t, J = 6.6 Hz, 2H); 13C-NMR (76 MHz, CDCl3)
δ
7.90–7.81 (m, 2H), 7.41–7.33 (m, 2H), 3.64 (s, 3H), 3.22 (t, J = 6.6 Hz, 2H),
196.8, 173.2, 139.6, 134.8, 129.4, 128.9, 51.8, 33.3,
δ
27.9; hRMS (ESI) for C12H18O2: calculated m/z = 249.0294 (MNa+); found m/z = 249.0297 (MNa+).
2-Fluoroethyl benzoate (1b) [73]. Synthesized according to the general procedure. Reaction conditions:
◦
benzoic acid (1 mmol, 122.1 mg), 2-fluoroethanol (0.5 mL), NBS (0.07 mmol, 12.5 mg), 70 C, 40 h.
Purification: Preparative TLC (CH2Cl2/MeOH = 200:1). Yield: 160 mg of colourless oil (95%); 1H-NMR
(300 MHz, CDCl3)
(76 MHz, CDCl3)
δ
8.20–7.86 (m, 2H), 7.60–7.52 (m, 1H), 7.49–7.37 (m, 2H), 4.85–4.44 (m, 4H); 13C-NMR
166.4, 133.3, 129.8, 128.5, 81.5 (d, J = 170.6 Hz), 63.9 (d, J = 20.2 Hz); 19F NMR
δ
(285 MHz, CDCl3) δ 5.03 (tt, J = 47.4, 28.6 Hz); hRMS (ESI) for C9H9FO2: calculated m/z = 169.0665
(MH+); found m/z = 169.0668 (MH+).
Isopropyl benzoate (1c) [74]. Synthesized according to the general procedure. Reaction co◦nditions:
benzoic acid (1 mmol, 122.1 mg), isopropanol (0.5 mL), NBS (0.07 mmol, 12.5 mg), 70 C, 20 h.
Purification: Not necessary. Yield: 12 mg of colourless oil (7%); 1H-NMR (300 MHz, CDCl3)
δ 8.09–7.99
(m, 2H), 7.59–7.50 (m, 1H), 7.47–7.38 (m, 2H), 5.26 (hept, J = 6.3 Hz, 1H), 1.37 (d, J = 6.3 Hz, 6H);
13C-NMR (76 MHz, CDCl3) δ 166.3, 132.8, 131.1, 129.6, 128.4, 68.5, 22.1.
2-Fluoroethyl octanoate (2b) [75]. Synthesized according to the general procedure. Reaction conditions:
◦
octanoic acid (1 mmol, 158.5
Purification: Not necessary. Yield: 175 mg of yellow oil (92%); 1H-NMR (300 MHz, CDCl3)
(m, 4H), 2.36 (t, J = 7.5 Hz, 2H), 1.71–1.57 (m, 2H), 1.42–1.19 (m, 8H), 0.88 (t, J = 7.1 Hz, 3H); 13C-NMR
(76 MHz, CDCl3) 173.7, 81.5 (d, J = 170.3 Hz), 63.2 (d, J = 20.1 Hz), 34.2, 31.7, 29.1, 29.0, 25.0, 22.7,
µL), 2-fluoroethanol (0.5 mL), NBS (0.07 mmol, 12.5 mg), 70 C, 20 h.
δ
4.73–4.20
δ
14.1; 19F-NMR (285 MHz, CDCl3)
δ 4.86 (tt, J = 47.4, 28.7 Hz); hRMS (ESI) for C10H19FO2: calculated
m/z = 191.1447 (MH+); found m/z = 191.1446 (MH+).
Isopropyl octanoate (2c) [76]. Synthesized according to the general procedure. Reaction conditions
◦
octanoic acid (1 mmol, 158.5
µ
L), isopropanol (0.5 mL), NBS (0.07 mmol, 12.5 mg), 70 C, 20 h.
Purification: Not necessary. Yield: 149 mg of colourless oil (80%); 1H-NMR (300 MHz, CDCl3)
δ 5.00
(hept, J = 6.3 Hz, 1H), 2.25 (t, J = 7.5 Hz, 2H), 1.67–1.55 (m, 2H), 1.35–1.25 (m, 8H), 1.23 (d, J = 6.3 Hz,
6H), 0.88 (t, J = 7.0 Hz, 3H); 13C-NMR (76 MHz, CDCl3)
δ 173.4, 67.3, 34.8, 31.7, 29.2, 29.0, 25.1, 22.7,
21.9, 14.1; hRMS (ESI) for C11H22O2: calculated m/z = 187.1698 (MH+); found m/z = 187.1703 (MH+).
n-Butyl benzoate (1d) [77]. Synthesized according to the general procedure. Reaction conditions: benzoic
◦
acid (1 mmol, 122.1 mg), n-butanol (0.5 mL), NBS (0.07 mmol, 12.5 mg), 70 C, 20 h. Purification:
Preparative TLC (CH2Cl2/MeOH = 200:1). Yield: 134 mg of colourless oil (75%); 1H-NMR (300 MHz,
CDCl3)
δ 8.10–7.99 (m, 2H), 7.58–7.49 (m, 1H), 7.42 (t, J = 7.5 Hz, 2H), 4.32 (t, J = 6.6 Hz, 2H), 1.84–1.66
(m, 2H), 1.56–1.39 (m, 2H), 0.98 (t, J = 7.4 Hz, 3H); 13C-NMR (76 MHz, CDCl3)
δ 166.7, 132.8, 130.6,
129.6, 128.4, 64.9, 30.9, 19.4, 13.8; hRMS (ESI) for C11H14O2: calculated m/z = 179.1072 (MH+); found
m/z = 179.1070 (MH+).
n-Butyl octanoate (2d) [
]. Synthesized according to the general procedure. Reaction conditions octanoic
◦
acid (1 mmol, 158.5
µL), n-butanol (1 mmol, 92
µL), NBS (0.07 mmol, 12.5 mg), 70 C, 15 h. Purification:
Not necessary. Yield: 190 mg of colourless oil (95%); 1H-NMR (300 MHz, CDCl3)
δ 4.07 (t, J = 6.6 Hz,
2H), 2.29 (t, J = 7.5 Hz, 2H), 1.70–1.52 (m, 4H), 1.47–1.21 (m, 10H), 0.94 (t, J = 7.3 Hz, 3H), 0.87 (t,
J = 6.9 Hz, 3H); 13C-NMR (76 MHz, CDCl3)
δ 174.0, 64.1, 34.4, 31.8, 30.8, 29.2, 29.0, 25.1, 22.7, 19.2, 14.1,
13.7; hRMS (ESI) for C12H24O2: calculated m/z = 201.1855 (MH+); found m/z = 201.1857 (MH+).
n-Octyl benzoate (1f) [58]. Synthesized according to the general procedure. Reaction conditions: benzoic
◦
1
acid (1 mmol, 122.1 mg), n-octanol (1 mmol, 158
µ
L), NBS (0.07 mmol, 12.5 mg), 70 C, 20 h. Purification:
Preparative TLC (CH2Cl2/Hexane = 1:1). Yield: 134 mg of white solid (57%); H-NMR (300 MHz,