J.K. Augustine et al. / Tetrahedron 64 (2008) 688e695
693
5.3.1. Methyl-2-chloro-6-formylpyridine-4-carboxylate 2a
Following the general protocol for hydrolysis, 78 g of 1a
provided 31.7 g of 2a as white solid affording 70% yield;
mp 68e69.8 ꢀC; Rf (10% EtOAc/hexane) 0.40; nmax (KBr)
1736, 1712, 1310, 1217, 761, 683 cmꢁ1. [Found: C, 48.10;
H, 3.06; N, 6.96. C8H6ClNO3 requires C, 48.14; H, 3.03; N,
7.02%.] dH (CDCl3, 400 MHz) 10.06 (1H, s, CHO), 8.40
(1H, s, Ph), 8.13 (1H, s, Ph), 4.02 (3H, s, COOMe); dC
(100.6 MHz, CDCl3) 190.8, 163.4, 153.6, 152.9, 141.5,
128.3, 119.4, 53.3.
5.3.7. Methyl-3-formylthiophene-2-carboxylate 2g22
Following the general protocol for hydrolysis, 34 g of 2g
was isolated as light brown solid affording 91% yield; mp
52.5e54.4 ꢀC; dH (400 MHz, DMSO-d6) 10.46 (1H, s,
CHO), 7.94e7.93 (1H, dd, J 5.1, 0.7 Hz, Ph), 7.53e7.51
(1H, dd, J 5.2, 0.5 Hz, Ph), 3.89 (3H, s, COOMe); dC
(100.6 MHz, DMSO-d6) 186.5, 161.1, 143.8, 138.2, 132.7,
127.0, 52.9.
5.3.8. Methyl-4-formylbenzoate 2h23
Following the general protocol for hydrolysis, 7.3 g of 2h
was isolated as colourless liquid affording 81% yield; dH
(400 MHz, DMSO-d6) 10.1 (1H, s, CHO), 8.13e8.11 (2H, d,
J 8.2 Hz, Ph), 8.03e8.00 (2H, dd, J 8.4, 1.2 Hz, Ph), 4.34e
4.32 (2H, q, CH2Me), 1.34e1.31 (3H, t, CH2Me); dC
(100.6 MHz, DMSO-d6) 193.3, 165.4, 139.5, 135.0, 130.2,
130.0, 61.7, 14.5.
5.3.2. Methyl-6-formylpyridine-3-carboxylate 2b19
Following the general protocol for hydrolysis, 8.5 g of 2b
was isolated as white solid affording 72% yield; mp 115e
116.7 ꢀC; dH (400 MHz, DMSO-d6) 10.16 (1H, s, CHO),
9.38e9.37 (1H, d, J 1.2 Hz, Ph), 8.50e8.47 (1H, dd, J 8.0,
1.2 Hz, Ph), 8.06e8.03 (1H, dd, J 8.0, 0.5 Hz, Ph), 4.01
(3H, s, COOMe); dC (100.6 MHz, DMSO-d6) 192.5, 164.8,
154.9, 151.1, 138.3, 129.2, 121.1, 52.8.
5.3.9. Methyl-4-formyl-1-naphthoate 2i24
Following the general protocol for hydrolysis, 10 g of 2i
was isolated as white solid affording 90% yield; mp 95.8e
97.5 ꢀC; dH (400 MHz, DMSO-d6) 10.50 (1H, s, CHO),
9.19e9.17 (1H, d, J 8.4 Hz, Ph), 8.63e8.61 (1H, d, J
8.2 Hz, Ph), 8.25e8.19 (2H, m, Ph), 7.82e7.73 (2H, m, Ph),
3.98 (3H, s, COOMe); dC (100.6 MHz, DMSO-d6) 194.5,
167.4, 134.5, 133.8, 133.8, 130.7, 130.7, 129.5, 128.6,
128.3, 126.1, 124.8, 53.2.
5.3.3. Ethyl-6-formylpyridine-2-carboxylate 2c
Following the general protocol for hydrolysis, 27 g of 2c
was isolated by column chromatography as white solid afford-
ing 77% yield; mp 37.5e39.6 ꢀC; Rf (10% EtOAc/hexane)
0.30; nmax (KBr) 1735, 1709, 1292, 1216, 1165 cmꢁ1. [Found:
C, 60.41; H, 5.11; N, 7.78. C9H9NO3 requires C, 60.33; H,
5.06; N, 7.82%.] dH (400 MHz, DMSO-d6) 10.01 (1H, s,
CHO), 8.32e8.30 (1H, dd, J 7.7, 1.2 Hz, Ph), 8.30e8.21
(1H, m, Ph), 8.14e8.11 (1H, dd, J 7.6, 1.2 Hz), 4.42e4.37
(2H, q, OCH2Me), 1.36e1.33 (3H, t, CH2Me); dC
(100.6 MHz, DMSO-d6) 193.0, 164.0, 152.3, 148.2, 139.4,
128.9, 124.6, 61.6, 14.1.
5.3.10. 2,2-Dimethyl-4-oxo-4H-1,3-benzodioxine-6-
carbaldehyde 2j
Following the general protocol for hydrolysis, 7 g of 2j was
isolated as white solid affording 79% yield; mp 113e114 ꢀC;
Rf (10% EtOAc/hexane) 0.55; nmax (KBr) 1740, 1687, 1614,
1268, 1197 cmꢁ1. [Found: C, 64.21; H, 4.95. C11H10O4
requires C, 64.08; H, 4.89%.] dH (400 MHz, DMSO-d6) 9.98
(1H, s, CHO), 8.42 (1H, s, Ph), 8.17e8.15 (1H, dd, J 8.5,
1.8 Hz, Ph), 7.32e7.30 (1H, d, J 8.5 Hz, Ph), 1.73 (6H, s,
CMe2); dC (100.6 MHz, DMSO-d6) 191.2, 159.6, 159.4,
136.5, 132.1, 131.3, 118.5, 113.1, 107.3, 25.3.
5.3.4. Methyl-5-formylthiophene-2-carboxylate 2d20
Following the general protocol for hydrolysis, 190 g of 1d
afforded 78 g of 2d as yellow solid in 76% yield; mp
81e82 ꢀC; dH (400 MHz, DMSO-d6) 9.98 (1H, s, CHO),
7.85e7.84 (1H, d, J 3.9 Hz, Ph), 7.75e7.74 (1H, d, J
3.9 Hz, Ph), 3.95 (3H, s, COOMe); dC (100.6 MHz, DMSO-
d6) 183.3, 161.9, 147.7, 140.9, 135.0, 133.3, 52.8.
5.3.11. 2,2-Dimethyl-4-oxo-4H-1,3-benzodioxine-7-
carbaldehyde 2k
5.3.5. Methyl-5-formylisoxazole-3-carboxylate 2e21
Following the general protocol for hydrolysis, 19 g of 2e
was isolated as white solid affording 72% yield; mp 72e
73 ꢀC; dH (400 MHz, DMSO-d6) 10.04 (1H, s, CHO), 7.37
(1H, s, Ph), 4.04 (3H, s, COOMe); dC (100.6 MHz, DMSO-
d6) 177.5, 168.9, 159.1, 156.7, 108.8, 53.3.
Following the general protocol for hydrolysis, 11 g of 2k
was isolated as white solid affording 87% yield; mp 109e
111 ꢀC; Rf (10% EtOAc/hexane) 0.55; nmax (KBr) 1738, 1701,
1444, 1389, 1298 cmꢁ1. [Found: C, 64.16; H, 4.87. C11H10O4
requires C, 64.08; H, 4.89%.] dH (400 MHz, DMSO-d6) 10.05
(1H, s, CHO), 8.08e8.06 (1H, d, J 7.8 Hz, Ph), 7.70e7.68
(1H, dd, J 7.9, 1.4 Hz, Ph), 7.60 (1H, s, Ph), 1.72 (6H, s,
CMe2); dC (100.6 MHz, DMSO-d6) 192.7, 160.0, 156.2,
142.6, 130.7, 123.1, 118.6, 117.7, 107.4, 25.6.
5.3.6. Methyl-2-bromo-5-formylfuran-4-carboxylate 2f
Following the general protocol for hydrolysis, 197.8 g of 2f
was isolated as white solid affording 87% yield; mp 58.3e
58.7 ꢀC; Rf (10% EtOAc/hexane) 0.45; nmax (KBr) 1721,
1676, 1473, 1245, 1066 cmꢁ1. [Found: C, 36.17; H, 2.21.
C7H5BrO4 requires C, 36.08; H, 2.16%.] dH (400 MHz,
DMSO-d6) 9.89 (1H, s, CHO), 7.22 (1H, s, Ph), 3.86 (3H, s,
COOMe); dC (100.6 MHz, DMSO-d6) 177.5, 160.7, 153.3,
130.6, 127.6, 114.6, 52.8.
5.3.12. Methyl-3-formyl-4-nitrobenzoate 2l25
Following the general protocol for hydrolysis, 14 g of 2l
was isolated as white solid affording 90% yield; mp 71.5e
73 ꢀC; dH (400 MHz, DMSO-d6) 10.23 (1H, s, CHO), 8.39e
8.38 (1H, d, J 1.5 Hz, Ph), 8.38e8.35 (1H, dd, J 8.2, 1.9 Hz,