316
J Biol Inorg Chem (2011) 16:313–323
1,2-Dimethyl-4-oxo-1,4-dihydropyridin-3-yl
benzenesulfonate
H), 7.82 (d, J = 7.6 Hz, 1 H), 7.03 (d, J = 9.2 Hz, 1 H),
6.25 (d, J = 7.6 Hz, 1 H), 3.68 (s, 3H), 2.31 (s, 3H). 13C
NMR (100 MHz, CDCl3) d = 169.35, 154.98, 144.00,
142.61, 141.42, 140.76, 138.54, 129.69, 122.24, 118.15,
116.78, 59.63, 13.29.
3-Hydroxy-1,2-dimethylpyridin-4(1H)-one (ZBG-3; 0.5 g,
3.6 mmol) was reacted with benzenesulfonyl chloride
(0.51 mL, 4.0 mmol) in 40 mL of pyridine to afford 1,2-
himethyl-4-oxo-1,4-dihydropyridin-3-yl benzenesulfonate
7-Oxocyclohepta-1,3,5-trien-1-yl benzenesulfonate
1
(PZBG-3a) in 43% yield (0.43 g, 1.5 mmol). H NMR
(500 MHz, CDCl3) d = 8.19 (d, J = 6.9 Hz, 2H), 7.66 (t,
J = 7.5 Hz, 1H), 7.57 (t, J = 7.5 Hz, 2H), 7.23 (d,
J = 8 Hz, 1H), 6.34 (d, J = 8.1 Hz, 1H), 3.63 (s, 3H,
NCH3), 2.49 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3)
d = 171.3, 144.8, 140.7, 139.9, 137.3, 134.3, 129.0, 128.9,
118.3, 41.8, 14.7. ESI-MS(?): m/z 280.09 [M ? H]?.
2-Hydroxycyclohepta-2,4,6-trienone
(ZBG4;
0.2 g,
1.7 mmol) was reacted with benzenesulfonyl chloride
(0.63 mL, 4.9 mmol) in 5 mL of pyridine to afford 7-
oxocyclohepta-1,3,5-trien-1-yl benzenesulfonate (PZBG-
1
4a) in 76% yield (0.33 g, 1.3 mmol). H NMR (400 MHz,
DMSO) d = 7.95 (d, J = 7.6 Hz, 2H), 7.80 (t, J = 7.6 Hz,
1H), 7.67 (t, J = 8 Hz, 2H), 7.43–7.37 (m, 2H), 7.25 (t,
J = 8.4 Hz, 1H), 7.14–7.09 (m, 2H). 13C NMR (100 MHz,
CDCl3) d = 179.24, 154.79, 141.19, 138.21, 136.37,
136.33, 135.57, 131.96, 130.92, 130.27, 128.76. ESI-
MS(?): m/z 262.97 [M ? H]?, 279.72 [M ? NH4]?,
284.99 [M ? Na]?.
1,2-Dimethyl-4-oxo-1,4-dihydropyridin-3-yl
4-methylbenzenesulfonate
ZBG-3 (0.2 g, 1.4 mmol) was reacted with p-toluenesul-
fonyl chloride (0.82 g, 4.3 mmol) in 10 mL of pyridine
to afford 1,2-dimethyl-4-oxo-1,4-dihydropyridin-3-yl 4-
methylbenzenesulfonate (PZBG-3b) in 86% yield (0.35 g,
1.2 mmol). 1H NMR (500 MHz, CDCl3) d = 7.99 (d,
J = 8.4 Hz, 2H), 7.40 (d, J = 7.6 Hz, 1H), 7.33 (d,
J = 8 Hz, 2H), 6.40 (d, J = 7.2 Hz, 1H), 3.64 (s, 3H), 2.42
(s, 3H), 2.41 (s, 3H). 13C NMR (100 MHz, CDCl3)
d = 170.71, 145.67, 145.54, 141.48, 134.07, 129.72,
128.96, 126.07, 117.53, 42.25, 22.00, 14.7. ESI-MS(?):
m/z 294.05 [M ? H]?, 315.97 [M ? Na]?.
7-Oxocyclohepta-1,3,5-trien-1-yl
4-methylbenzenesulfonate
ZBG4 (0.2 g, 1.7 mmol) was reacted with p-toluenesul-
fonyl chloride (0.41 g, 2.0 mmol) in 10 mL of pyridine to
afford 7-oxocyclohepta-1,3,5-trien-1-yl 4-methylbenzene-
sulfonate (PZBG-4b) in 63% yield (0.04 g, 0.1 mmol). 1H
NMR (400 MHz, CDCl3) d = 7.92 (d, J = 8.4 Hz, 2H),
7.46 (d, J = 9.2 Hz, 1H), 7.35 (d, J = 8.4 Hz, 2H),
7.26–7.16 (m, 2H), 7.13–7.06 (m, 1H), 6.98 (t, J = 10 Hz,
1H), 2.45 (s, 3H). 13C (125 MHz, CDCl3) d = 179.41,
155.15, 145.50, 141.23, 136.32, 134.61, 133.41, 130.81,
130.00, 129.60, 128.59, 21.78. ESI-MS(?): m/z 277.21
[M ? H]?, 293.99 [M ? NH4]?.
1,2-Dimethyl-4-oxo-1,4-dihydropyridin-3-yl
4-nitrobenzenesulfonate
ZBG-3 (0.2 g, 1.5 mmol) was reacted with 4-nitro-
benzenesulfonyl chloride (0.488 g, 2.2 mmol) in 10 mL of
pyridine to afford 1,2-dimethyl-4-oxo-1,4-dihydropyridin-
3-yl 4-nitrobenzenesulfonate (PZBG-3c) in 50% yield
(0.23 g, 0.7 mmol). 1H NMR (400 MHz, CDCl3)
d = 8.41–8.34 (m, 4H), 7.26 (d, J = 7.6 Hz, 1H), 6.33 (d,
J = 7.6 Hz, 1H), 3.67 (s, 3H), 2.53 (s, 3H). 13C NMR
(100 MHz, CDCl3) d = 170.9, 150.9, 144.9, 143.2,
140.9, 140.1, 130.4, 124.0, 118.4, 41.9, 14.6. ESI-MS(?):
m/z 325.11 [M ? H]?, 346.96 [M ? Na]?.
7-Oxocyclohepta-1,3,5-trien-1-yl
4-nitrobenzenesulfonate
ZBG4 (0.2 g, 1.7 mmol) was reacted with 4-nitro-
benzenesulfonyl chloride (1.1 g, 4.9 mmol) in 5 mL of
pyridine. Addition of 10 mL of water allowed for precip-
itation of 7-oxocyclohepta-1,3,5-trien-1-yl 4-nitroben-
zenesulfonate (PZBG-4c) in 71% yield (0.38 g, 1.2 mmol)
without the need for further purification. 1H NMR
(400 MHz, DMSO) d = 8.45 (d, J = 8.8 Hz, 2H), 8.22 (d,
J = 8.8 Hz, 2H), 7.52 (d, J = 9.2 Hz, 1H), 7,46 (dd,
J1 = 10.2 Hz, J2 = 3.6 Hz, 1 H), 7.31 (dd, J1 = 9.8 Hz,
J2 = 2 Hz, 1 H), 7.15 (dd, J1 = 10.6 Hz, J2 = 3.6 Hz, 1
H). 13C (100 MHz, CDCl3) d = 179.09, 154.86, 151.50,
141.95, 141.27, 138.59, 136.87, 132.06, 131.48, 130.42,
125.42. ESI-MS(?): m/z 308.01 [M ? H]?, 324.73
[M ? NH4]?.
1,2-Dimethyl-4-oxo-1,4-dihydropyridin-3-yl
2,4-dinitrobenzenesulfonate
ZBG-3 (0.10 g, 0.73 mmol) was reacted with 2,4-dini-
trobenzenesulfonyl chloride (0.3 g, 1.1 mmol) in 10 mL of
pyridine to afford 1,2-dimethyl-4-oxo-1,4-dihydropyridin-
3-yl 2,4-dinitrobenzenesulfonate (PZBG-3d) in 23% yield
(0.07 g, 0.2 mmol). 1H NMR (400 MHz, CDCl3) d = 8.83
(d, J = 2.8 Hz 1H), 8.37 (dd, J1 = 9.6 Hz, J2 = 2.8 Hz, 1
123