PAPER
Carboxylation Method and Its Application for Synthesis of Liquid Crystals
571
Benzoic Acid Ethyl Ester (Table 1, entry 1)
5-Chloro-thiophene-2-carboxylic Acid Ethyl Ester (Table 1, en-
try 8)
1H NMR: = 1.40 (t, J = 7.1 Hz, 2 H), 4.38 (q, J = 7.1 Hz, 3 H), 7.41
(m, 2 H), 7.55 (m, 1 H), 8.05 (m, 2 H).
IR: 2982 (w), 1711 (s), 1426 (s), 1279 (s), 1254 (s), 1090 (s), 1060
(s), 747 (s) cm–1.
13C NMR: = 14.3, 60.9, 128.3, 129.5, 130.6, 132.8, 166.6.
1H NMR: = 1.36 (t, J = 7.3 Hz, 2 H), 4.33 (q, J = 7.3 Hz, 3 H), 6.92
(d, J = 4.0 Hz, 1 H), 7.58 (d, J = 4.0 Hz, 1 H).
13C NMR: = 14.2, 61.4, 127.2, 132.2, 132.8, 137.1, 161.3.
MS: m/z = 150 (47) [M], 122 (60), 106 (14), 105 (base), 78 (6), 77
(67), 51 (19).
HRMS: m/z calcd for C9H10O2: 150.0681; found: 150.0687.
MS: m/z = 192 (12), 190 (36) [M], 164 (11), 162 (33), 147 (39), 145
4-Chloro-benzoic Acid Ethyl Ester (Table 1, entry 2)
IR: 3063 (w), 2983 (w), 1723 (s), 1292 (s), 1256 (s), 1131 (m), 1021
(m), 894 (s), 748 (w) cm–1.
(base), 75 (4), 73 (12).
HRMS: m/z calcd for C7H7ClO2S: 189.9856; found: 189.9873.
1H NMR: = 1.40 (t, J = 7.2 Hz, 2 H), 4.39 (q, J = 7.2 Hz, 3 H), 7.38
(t, m, 1 H), 7.52 (m, 1 H), 7.93 (m, 1 H), 8.02 (t, m, 1 H).
3-Bromo-thiophene-2-carboxylic Acid Ethyl Ester (Table 1, en-
try 9)
IR: 3120 (w), 2985 (w), 2940 (w), 2905 (w), 1720 (s), 1515 (m),
13C NMR: = 14.3, 61.4, 127.7, 129.6, 132.3, 132.8, 134.5, 165.4.
1416 (s), 1279 (m), 1245 (s), 1090 (m), 1080 (m), 767 (m) cm–1.
MS: m/z = 186 (10), 184 (34) [M], 158 (16), 156 (65), 141 (48), 139
(base), 113 (13), 111 (46), 75 (19).
1H NMR: = 1.39 (t, J = 7.2 Hz, 2 H), 4.37 (q, J = 7.2 Hz, 3 H), 7.09
(d, J = 5.4 Hz, 1 H), 7.45 (d, J = 5.4 Hz, 1 H).
HRMS: m/z calcd for C9H9ClO2: 184.0289; found: 184.0291).
MS: m/z = 236 (12), 234 (12) [M], 208 (15), 206 (15), 191 (11), 189
(38), 147 (36), 86 (17), 69 (26), 57 (base), 56 (51).
3-Methoxy-Benzoic Acid Ethyl Ester (Table 1, entry 3)
1H NMR: = 1.38 (t, J = 7.2 Hz, 2 H), 3.86 (s, 3 H), 4.35 (q, J = 7.2
Hz, 3 H), 6.91 (d, J = 8.1 Hz, 2 H), 8.00 (d, J = 8.1 Hz, 2 H).
HRMS: m/z calcd for C7H7BrO2S: 233.9350; found: 233.9347.
1H-Indole-5-carboxylic Acid Ethyl Ester (Table 1, entry 11)
IR: 2982 (w), 1741 (s), 1450 (s), 1378 (s), 1342 (s), 1324 (s), 1241
(s), 1084 (m), 1046 (m), 761 (s) cm–1.
1H NMR: = 1.46 (t, J = 7.2 Hz, 2 H), 4.48 (q, J = 7.2 Hz, 3 H), 6.50
(d, J = 3.5 Hz, 1 H), 7.40 (d, J = 8.8 Hz, 1 H), 7.59 (d, J = 3.5 Hz, 1
H), 7.67 (d, J = 2.1 Hz, 1 H), 8.02 (dd, J = 8.8, 2.1 Hz, 1 H).
13C NMR: = 14.2, 61.3, 127.6, 129.6, 132.3, 132.8, 134.5, 165.4.
MS: m/z = 180 (25) [M], 152 (20), 139 (6), 136 (10), 135 (base), 107
(10), 92 (9), 77 (14).
HRMS: m/z calcd for C10H12O3: 180.0787; found: 180.0805.
Benzo[1,3]dioxole-5-carboxylic Acid Ethyl Ester (Table 1, entry
5)
13C NMR: = 14.3, 63.4, 107.8, 123.5, 126.6, 127.1, 132.1, 133.9,
150.6.
IR: 2983 (w), 1713 (s), 1442 (s), 1258 (s), 1158 (s), 1105 (m), 1037
(m), 761 (s) cm–1.
5-Bromo-thiophene-2-carboxylic Acid Ethyl Ester (Scheme 3)
IR: 3095 (w), 2980 (m), 1710 (s), 1526 (m), 1417 (s), 1322 (m),
1278 (s), 1246 (s), 1081 (w), 808 (w), 744 (m) cm–1.
1H NMR: = 1.36 (t, J = 7.1 Hz, 2 H), 4.33 (q, J = 7.1 Hz, 3 H), 7.06
(d, J = 4.0 Hz, 1 H), 7.54 (d, J = 4.0 Hz, 1 H).
1H NMR: = 1.37 (t, J = 7.1 Hz, 2 H), 4.34 (q, J = 7.1 Hz, 3 H), 6.03
(s, 2 H), 6.83 (d, J = 8.2 Hz, 1 H), 7.47 (d, J = 1.7 Hz, 1 H), 7.65
(dd, J = 8.2, 1.7 Hz, 1 H).
13C NMR: = 14.3, 60.9, 101.7, 107.9, 109.5, 124.6, 125.2, 147.7,
151.5, 166.0.
13C NMR: = 14.2, 61.4, 120.0, 130.8, 133.4, 135.2, 137.1, 161.1.
MS: m/z 194 (42) [M], 166 (24), 165 (18), 150 (13), 149 (base), 121
(21), 65 (10), 63 (12).
MS: m/z = 236 (35), 234 (34) [M], 208 (36), 206 (35), 191 (base),
189 (98), 163 (5), 161 (4), 119 (5), 117 (5), 82 (20).
HRMS: m/z calcd for C10H10O4: 194.0579; found: 194.0592.
HRMS: m/z calcd for C7H7BrO2S: 233.9349; found: 233.9350.
Naphthalene-1-carboxylic Acid Ethyl Ester (Table 1, entry 6)
1H NMR: = 1.47 (t, J = 7.1 Hz, 2 H), 4.49 (q, J = 7.1 Hz, 3 H), 7.56
(m, 2 H), 7.60 (m, 1 H), 7.90 (m, 1 H), 8.02 (m, 1 H), 8.19 (m, 1 H),
8.91 (m, 1 H).
13C NMR: = 14.3, 61.0, 124.4, 125.8, 126.1, 127.5, 127.6, 128.5,
130.0, 131.3, 133.1, 133.8, 167.6.
Thiophene-2,5-dicarboxylic Acid Ethyl Ester (Scheme 3)
IR: 2985 (m), 1713 (s), 1644 (w), 1455 (w), 1369 (w), 1246 (s),
1089 (m), 1051 (w), 1012 (w), 749 (m) cm–1.
1H NMR: = 1.38 (t, J = 7.2 Hz, 4 H), 4.37 (q, J = 7.2 Hz, 6 H), 7.71
(s, 2 H).
13C NMR: = 14.2, 61.7, 132.8, 139.1, 161.6.
MS: m/z = 200 (52) [M], 172 (17), 156 (33), 155 (base), 128 (30),
127 (72), 126 (15), 111 (60), 77 (15).
MS: m/z = 228 (35) [M], 213 (9), 200 (25), 184 (15), 183 (base), 172
(40), 156 (20), 155 (99), 111 (17).
HRMS: m/z calcd for C13H12O2: 200.0837; found: 200.0845.
HRMS: m/z calcd for C10H12O4S: 228.0456; found: 228.0459.
Thiophene-2-carboxylic Acid Ethyl Ester (Table 1, entry 7)
1H NMR: = 1.38 (t, J = 7.0 Hz, 2 H), 4.36 (q, J = 7.0 Hz, 3 H), 7.09
(dd, J = 5.0, 3.8 Hz, 1 H), 7.54 (dd, J = 5.0, 1.3 Hz, 1 H), 7.80 (dd,
J = 3.8, 1.3 Hz, 1 H).
[5-(Biphenyl-4-carbonyl)-thiophen-2-yl]-biphenyl-4-yl-metha-
none (Scheme 5)
1H NMR: = 7.40–7.52 (m, 6 H), 7.66 (d, J = 8.2 Hz, 4 H), 7.74–
7.77 (m, 6 H), 8.02 (d, J = 8.2 Hz, 4 H).
13C NMR: = 14.3, 61.1, 127.6, 132.1, 133.2, 134.1, 162.3.
13C NMR: = 127.3, 128.3, 129.0, 130.0, 133.6, 135.9, 139.7,
145.8, 148.5, 187.5.
MS: m/z = 156 (25) [M], 141 (3), 128 (26), 112 (10), 111 (base), 83
(5), 57 (3).
MS: m/z = 444 (3) [M], 256 (9), 250 (10), 224 (10), 167 (12), 149
(17), 127 (13), 125 (21), 111 (35), 97 (51), 83 (52), 71 (63), 57
(base).
HRMS: m/z calcd for C7H8O2S: 156.0245; found: 156.0259.
UV (CH2Cl2): max ( ) = 322 (12500) nm.
Synthesis 2004, No. 4, 568–572 © Thieme Stuttgart · New York