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Organic & Biomolecular Chemistry
δ 165.0, 135.9, 133.0, 132.6, 129.9, 128.6, 128.1, 122.4, 67.1; 6.89–7.13 (m, 1H), 5.80–5.98 (m, 1H), 5.16 (s, 2H), 1.89 (dd, J =
HRMS (ESI): calc. for [(C14H11BrO2)H] (M + H) 291.0021, found 6.88, 1.7 Hz, 3H); 13C NMR (50 MHz, CDCl3): δ 166.1, 145.0,
291.0021.
Benzyl 3-chlorobenzoate (2i). Yield: 86%; 1.5 g; colorless for [(C11H12O2)H] (M + H) 177.0916, found 177.0910.
liquid; IR (CHCl3, cm−1): νmax 3105, 2920, 2810, 1715, 1580,
Benzyl propionate (2q). Yield: 90%; 2.51 g; colorless liquid;
136.3, 128.6, 128.2, 128.2, 122.7, 66.0, 18.1; HRMS (ESI): calc.
1417; 1H NMR (200 MHz, CDCl3): δ 7.96–8.15 (m, 2H), IR (CHCl3, cm−1): νmax 2958, 2934, 2839, 1713, 1606, 1511,
7.49–7.62 (m, 1H), 7.34–7.45 (m, 5H), 5.36 (s, 2H); 13C NMR 1462, 1373, 1258, 1167, 1098, 1029, 847, 769, 741, 721;
(50 MHz, CDCl3): δ 166.3, 136.1, 133.0, 130.2, 129.8, 128.7, 1H NMR (200 MHz, CDCl3): δ 7.32–7.36 (m, 6H), 5.11 (s, 2H),
128.6, 128.4, 128.2, 128.2, 127.9, 66.7; HRMS (ESI): calc. for 2.37 (q, J = 7.3 Hz, 2H), 1.16 (t, J = 7. 6 Hz, 3H); 13C NMR
[(C14H11ClO2)H] (M + H) 247.0526, found 247.0522.
(50 MHz, CDCl3): δ 166.2, 136.1, 133.0, 129.8, 128.5, 128.4,
Benzyl 3,4-dimethoxybenzoate (2j). Yield: 90%; 1.47 g; 128.2, 66.7, 27.6, 9.2; HRMS (ESI): calc. for [(C10H12O2)H]
colorless liquid; IR (CHCl3, cm−1): νmax 2981, 2910, 1711, 1575, (M + H) 165.0916, found 165.0917.
1135, 763; 1H NMR (200 MHz, CDCl3): δ 7.70 (dd, J = 8.5,
Benzyl thiophene-3-carboxylate (2r). Yield: 92%; 1.79 g;
2.1 Hz, 1H), 7.56 (d, J = 2.3 Hz, 1H), 7.29–7.49 (m, 5H), 6.86 (d, colorless liquid; IR (CHCl3, cm−1): νmax 3027, 2923, 1712, 1524,
J = 8.2 Hz, 1H), 5.34 (s, 2H), 3.93 (s, 3H), 3.92 (s, 3H); 13C NMR 1417, 1374, 1356, 1273,1258, 1094; 1H NMR (200 MHz, CDCl3):
(50 MHz, CDCl3): δ 165.9, 152.9, 142.2, 136.0, 128.5, 128.2, δ 7.77–7.95 (m, 1H), 7.50–7.65 (m, 1H), 7.32–7.48 (m, 5H),
128.1, 125.0, 106.9, 106.7, 66.7, 60.8, 56.1; HRMS (ESI): calc. 7.06–7.18 (m, 1H), 5.34 (s, 2H); 13C NMR (50 MHz, CDCl3):
for [(C16H16O4)H] (M + H) 273.1127, found 273.1132.
δ 161.9, 135.9, 134.0, 133.8, 133.6, 132.4, 128.6, 128.3, 128.2,
Benzyl 3,4,5-trimethoxybenzoate (2k). Yield: 92%; 1.41 g; 127.9, 127.7, 66.7; HRMS (ESI): calc. for [(C12H10O2S)H]
colorless liquid; IR (CHCl3, cm−1): νmax 3050, 2911, 1710, 1616, (M + H) 219.0480, found 219.0490.
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1400; H NMR (200 MHz, CDCl3): δ 7.21–7.49 (m, 7H), 5.35 (s,
Benzyl nicotinate (2s). Yield: 90%; 1.79 g; colorless gum;
2H), 3.81–3.96 (m, 9H); 13C NMR (50 MHz, CDCl3): δ 165.9, IR (CHCl3, cm−1): νmax 3102, 2987, 2897, 1720, 1624, 1528,
152.9, 148.4, 136.1, 130.0, 128.4, 128.2, 127.9, 123.5, 122.4, 1325, 1014; H NMR (200 MHz, CDCl3): δ 9.26 (s, 1H), 8.77 (d,
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111.9, 110.0, 66.3, 55.7; HRMS (ESI): calc. for [(C17H18O5)H] J = 3.5 Hz, 1H), 8.31 (dt, J = 8.0, 2.0 Hz, 1H), 7.25–7.50 (m, 6H),
(M + H) 303.1232, found 303.1232.
5.39 (s, 2H); 13C NMR (50 MHz, CDCl3): δ 164.9, 153.4,
1,2-Dibenzyl phthalate (2l). Yield: 92%; 2.37 g; colorless 151.0137.1, 135.5, 128.7, 128.5, 128.3, 126.0, 123.2, 67.1;
liquid; IR (CHCl3, cm−1): νmax 2971, 1811, 1720, 1541, 1410; 1H HRMS (ESI): calc. for [(C13H11NO2)H] (M + H) 214.0868, found
NMR (200 MHz, CDCl3): δ 7.67–7.79 (m, 2H), 7.47–7.58 (m, 214.0873.
2H), 7.27–7.37 (m, 10H), 5.20 (s, 4H); 13C NMR (50 MHz,
CDCl3): δ 167.1, 135.5, 132.0, 131.0, 129.0, 128.5, 128.4, 128.3,
General experimental procedure for the preparation of methyl
esters (3a–q)
67.3; HRMS (ESI): calc. for [(C22H18O4)H] (M + H) 347.1283,
found 347.1285.
In an oven dried round bottom flask containing 4-nitrobenz-
1,4-Dibenzyl phthate (2m). Yield: 90%; 2.32 g; colorless aldehyde 1a (1 g, 6.61 mmol) and titanium superoxide as cata-
liquid; IR (CHCl3, cm−1): νmax 3071, 2911, 1720, 1611, 1580, lyst (0.1 g, 10 wt%) in dry MeOH (1.32 mL, 33.05 mmol) was
1051; 1H NMR (200 MHz, CDCl3): δ 8.07–8.14 (m, 4H), added TBHP in decane (5–6 M) (2.4 mL, 13.22 mmol) in a
7.33–7.46 (m, 10H), 5.37 (s, 4H); 13C NMR (50 MHz, CDCl3): dropwise manner under a nitrogen atmosphere. Then the flask
δ 165.5, 135.7, 134.0, 129.7, 128.7, 128.5, 128.3, 67.1; HRMS was stirred at 25 °C for 6 h. After the complete disappearance
(ESI): calc. for [(C22H18O4)H] (M
347.1283.
+
H) 347.1283, found of aldehyde ( judged by TLC; using DNP solution), the reaction
mixture was filtered through a sintered funnel using CH2Cl2 as
Benzyl cinnamate (2n). Yield: 80%; 1.4 g; colorless liquid; an eluent. Then the organic layer was extracted with CH2Cl2,
IR (CHCl3, cm−1): νmax 3027, 2983, 2923, 1712, 1617, 1307, dried over anhydrous Na2SO4, and evaporated under reduced
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1278, 1162, 805, 767; H NMR (200 MHz, CDCl3): δ 7.72 (d, J = pressure. The crude product was purified by column chromato-
16.0 Hz, 1H), 7.28–7.54 (m, 11H), 6.47 (d, J = 16.0 Hz, 1H), 5.24 graphy over silica (230–400 mesh) using petroleum ether/ethyl
(s, 2H); 13C NMR (50 MHz, CDCl3): δ 166.6, 145.2, 136.1, 134.4, acetate (19 : 1 v/v) as an eluent to give methyl 4-nitrobenzoate
130.4, 128.9, 128.6, 128.4, 128.2, 118.0, 66.3; HRMS (ESI): calc. (3a).
for [(C16H14O2)H] (M + H) 239.1072, found 239.1075.
Methyl 4-nitrobenzoate (3a). Yield: 88%; 1.0 g; colorless
Benzyl acrylate (2o). Yield: 88%; 2.54 g; colorless liduid; IR liquid; IR (CHCl3, cm−1): νmax 2810, 1718, 1620, 1524, 1105;
(CHCl3, cm−1): νmax 2931, 2848, 1720, 1621, 1580, 1515, 1421; 1H NMR (200 MHz, CDCl3): δ 8.24 (m, 4H), 3.97 (s, 3 H);
1H NMR (200 MHz, CDCl3): δ 7.35–7.44 (m, 6H), 6.48 (dd, J = 13C NMR (50 MHz, CDCl3): δ 164.9, 150.3, 135.3, 130.5, 123.3,
17.2, 1.7 Hz, 1H), 6.18 (dd, J = 17.3, 10.2 Hz, 1H), 5.87 (dd, J = 52.6; HRMS (ESI): calc. for [(C8H7NO4)H] (M + H) 182.0453,
10.2, 1.6 Hz, 1H), 5.21 (s, 3H); 13C NMR (50 MHz, CDCl3): found 182.0455.
δ 165.7, 135.8, 130.9, 128.5, 128.3, 128.2, 66.2; HRMS (ESI):
calc. for [(C10H10O2)H] (M + H) 163.0759, found 163.0760.
Benzyl (E)-but-2-enoate (2p). Yield: 88%; 2.21 g; colorless 3050, 2980, 2910, 1716, 1615, 1548, 1258; H NMR (200 MHz,
liquid; IR (CHCl3, cm−1): νmax 3010, 2971, 2882, 1725, 1652, CDCl3): δ 7.98 (d, J = 8.8 Hz, 2H), 6.90 (d, J = 8.8 Hz, 2H), 3.87
1568, 1312; 1H NMR (200 MHz, CDCl3): δ 7.34 (s, 5H), (s, 3H), 3.86 (s, 3H); 13C NMR (50 MHz, CDCl3): δ 166.5, 163.2,
Methyl-4-methoxybenzoate (3b). Yield: 82%; 1.0 g; colorless
solid; mp.: 49–51 °C (lit.4k mp. 49 °C); IR (CHCl3, cm−1): νmax
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