5034
F. K. Hansen et al. / Bioorg. Med. Chem. Lett. 22 (2012) 5031–5034
11. Alvaro-Gracia, J. M. Rheumatology 2004, 43, i21.
12. Celotti, F.; Laufer, S. Pharmacol. Res. 2001, 43, 429.
13. Kulkarni, S. K.; Singh, V. P. Curr. Top. Med. Chem. 2007, 7, 251.
14. Kumar, P.; Kalonia, H.; Kumar, A. Br. J. Pharmacol. 2011, 164, 644.
15. Laufer, S. A.; Augustin, J. J.; Dannhardt, G.; Kiefert, W. J. Med. Chem. 1994, 37,
1894.
16. Laufer, S.; Tries, S.; Augustin, J.; Dannhardt, G. Arzneimittelforschung 1994, 44,
629.
17. Rotondo, S.; Dell’Elba, G.; Krauze-Brzosko, K.; Manarini, S.; Martelli, N.; Pecce,
R.; Evangelista, V.; Cerletti, C. Eur. J. Pharmacol. 2002, 453, 131.
18. Rotondo, S.; Dell’Elba, G.; Manarini, S.; Cerletti, C.; Evangelista, V. Eur. J.
Pharmacol. 2006, 546, 95.
DMSO-d6), (ppm): 105.0, 123.4, 124.3, 125.7, 130.4, 133.8, 139.0, 155.9, 166.3.
Anal. Calcd for C9H5ClO3S: C, 47.28; H, 2.20; S, 14.02. Found: C, 47.25; H, 2.30;
S, 14.04.
24. Preparation of 3-acetoxybenzo[b]thiophene-2-carboxylic acid 6. Concentrated
sulfuric acid (1 drop) was added to a mixture of 3-hydroxybenzo[b]thiophene-
2-carboxylic acid 4a (389 mg, 2 mmol) and acetic anhydride (613 mg, 6 mmol).
The temperature of the reaction mixture was slowly raised to 60 °C using an oil
bath and stirred at this temperature for 1 h. Afterward, the reaction was
poured into ice water (50 mL) and the mixture was extracted with CH2Cl2
(3 Â 50 mL). The combined organic layers were dried over MgSO4 and
evaporated under reduced pressure to give
a crude product, which was
subsequently purified by column chromatography using CH2Cl2/ethyl acetate
(8:2) as eluent to provide pure 6. Pink solid, Yield: 51%; Mp: 137 °C; IR mmax
(KBr) cmÀ1: 3590–2428 (COOH), 1774, 1683 (C@O); 1H NMR (400 MHz, DMSO-
d6), d (ppm): 2.41 (s, 3H), 7.49–8.07 (m, 4H); 13C NMR (400 MHz, DMSO-d6), d
(ppm): 20.9, 122.5, 123.9, 125.8, 128.6, 120.8, 133.0, 137.2, 144.8, 162.4, 168.7;
Anal. Calcd for C11H8O4S: C, 55.93; H, 3.41; S, 13.57. Found: C, 55.55; H, 3.55; S,
13.88.
19. Cuniberti, B.; Odore, R.; Barbero, R.; Cagnardi, P.; Badino, P.; Girardi, C.; Re, G.
Vet. J. 2012, 191, 327.
20. Goossens, L.; Berthommé, I. Prakt. Tierarzt 2008, 82, 1014.
21. Kurz, T.; Geffken, D.; Mesaros R. (BioAgency AG), WO 2005/082873 A2, 2005.
22. Preparation of methyl 3-hydroxybenzo[b]thiophene-2-carboxylate 3a.
A
suspension of thiosalicylic acid (7.71 g, 50 mmol) in a mixture of methanol
and sulfuric acid (95:5, 125 mL) was refluxed under nitrogen for 18 h. The
reaction mixture was evaporated under reduced pressure and water (100 mL)
was added. Subsequently, solid NaHCO3 was added until pH ꢀ9 and the
mixture was extracted with CH2Cl2 (3 Â 50 mL). The combined organic layers
were dried over MgSO4 and evaporated under reduced pressure. The residue
was dissolved in THF (100 mL). Next, methyl chloroacetate (6.51 g, 60 mmol),
N,N-diisopropylethylamine (7.75 g, 60 mmol) and potassium iodide (0.33 g,
2 mmol) were added and the reaction mixture was stirred for 2 days at room
temperature. Upon completion of the reaction according to TLC analysis, the
precipitate was removed by filtration and the filtrate was concentrated under
reduced pressure. The residue was treated with 1 N NaOH (50 mL) and
extracted with CH2Cl2 (3 Â 50 mL). The combined organic layers were washed
with 1 N HCl (2 Â 50 mL), dried over MgSO4 and evaporated. The crude oil was
crystallized from diethyl ether/hexane to afford 2. White solid, Yield: 73%; Mp:
49 °C; IR mmax (KBr) cmÀ1: 1745, 1701 (C@O); 1H NMR (400 MHz, DMSO-d6),
(ppm): 3.65 (s, 3H), 3.85 (s, 3H), 3.97 (s, 2H), 7.25–7.91 (m, 4H); 13C NMR
(400 MHz, DMSO-d6), (ppm): 33.9, 52.6, 52.7, 125.0, 126,3, 131.2, 133.2, 12.5,
140.0, 166.4, 170.0; Anal. Calcd for C11H12O4S: C, 54.99; H, 5.03; S, 13.34.
Found: C, 54.90; H, 5.16; S, 13.31.
25. Beck, J. R. J. Org. Chem. 1973, 38, 4086.
26. Dunn, A. D.; Norrie, R. J. Heterocycl. Chem. 1987, 24, 85.
27. Preparation of 6-chloro-3-hydroxybenzo[b]thiophene-2-carbohydrazide 11.
Hydrazine hydrate (7 mL) was added to a solution of 3c (2.43 g, 10 mmol) in
methanol (20 mL) under ice cooling. The mixture was then refluxed for 4 h.
After completion of the reaction (monitored by TLC), the mixture was acidified
with 2 N HCl to pH 4 under ice cooling. The precipitated product was collected,
washed with cold water (10 mL) and recrystallized from methanol. Pale yellow
solid, Yield: 70%; Mp: 127 °C; IR mmax (KBr) cmÀ1 3310 (NH); 1H NMR
:
(400 MHz, DMSO-d6), (ppm): 7.43 (s, 2H), 7.80–8.10 (m, 3H), 8.04 (s, 1H), 9.43
(s, 1H); 13C NMR (400 MHz, DMSO-d6), (ppm): 102.7, 131.4, 133.9, 138.2,
155.1, 122.8, 124.8, 126.4, 163.5.
General procedure for the synthesis of compounds 12a, b. The respective ketone
(10 mmol) was added to a suspension of 11 (1.21 g, 5 mmol) in MeOH (10 mL)
and the mixture was heated under reflux for 1 h. After cooling, the precipitated
solid product was collected by filtration and recrystallized from EtOH.
6-Chloro-3-hydroxy-N’-(propan-2-ylidene)benzo[b]thiophene-2-carbohydrazide
12a. White solid, Yield: 90%; Mp: 254 °C; IR m
max (KBr) cmÀ1: 3156 (NH), 1625
(C@O); 1H NMR (400 MHz, DMSO-d6), (ppm): 1.98 (s, 3H), 2.07 (s, 3H); 7.43–
8.09 (m, 3H), 11.15 (s, 1H), 13.29 (s, 1H); 13C NMR (400 MHz, DMSO-d6),
(ppm): 17.5, 24.5, 101.1, 126.3, 128.2, 133.0, 142.8, 122.3, 123.5, 125.0, 161.4,
167.7; Anal. Calcd for C12H11ClN2O2S: C, 50.98; H, 3.92; N, 9.91; S, 11.34.
Found: C, 50.72; H, 4.08; N, 9.77; S, 11.50.
Methyl 2-((2-methoxy-2-oxoethyl)thio)benzoate
2 (7.21 g, 30 mmol) was
dissolved in dry toluene (60 mL), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU,
4,57 g, 30 mmol) was added and the reaction mixture was stirred at room
temperature for 24 h. Afterward, 1 N HCl (20 mL) was added and the biphasic
mixture was stirred for 5 min. The layers were separated and the aqueous layer
was extracted with diethyl ether (3 Â 20 mL). The combined organic layers
were dried over MgSO4 and evaporated under reduced pressure. The crude oil
crystallized upon scratching with a glass rod, hexane (10 mL) was added and
the solid was collected and washed with hexane (3 Â 5 mL). White solid, Yield:
28. The COX-1/2 and 5-LOX assays were performed as described previously.29–32
For clarity a brief summary of the procedures is given below:
COX-1 inhibition was determined by using platelets isolated from bovine
blood, incubated with the test substance, and stimulated by the Ca ionophor
A23187. The inhibition of COX-1 was assessed by quantitative HPLC
determination of the formation of 12-hydroxyheptadecatrienoic acid.29,30 5-
LOX inhibition was investigated by using bovine polymorpho-nuclear
leucocytes, incubated with the test substance, and stimulated by the Ca
ionophor A23187. The inhibition of 5-LOX was assessed by quantitative HPLC
determination of the formation of leukotriene B4.29,30
98%; Mp: 106 °C; IR mmax (KBr) cmÀ1 3290 (OH), 1665 (C@O); 1H NMR
:
(400 MHz, DMSO-d6), (ppm): 3.86 (s, 3H), 7.44–7.95 (m, 4H), 10.39 (s, 1H); 13
C
NMR (400 MHz, DMSO-d6), (ppm): 52.3, 103.4, 123.1, 123.7, 125.0, 129.1,
131.8, 137.9, 156.2, 164.4; Anal. Calcd for C10H8O3S: C, 57.68; H, 3.87; S, 15.40.
Found: C, 57.73; H, 3.68; S, 15.39.
23. General procedure for the preparation of compound 4a–d and 10a, b. A solution of
potassium tert-butoxide (1.12 g, 10 mmol) in DMSO (10 mL) was stirred at
room temperature. After 10 min, the respective methyl ester (1 mmol) was
added and the reaction mixture was stirred at room temperature. Upon
completion (TLC analysis), ice water (40 mL) was added and the mixture was
acidified with 1 N HCl until pH 1. The precipitate was collected and washed
with water (5 mL), cold diethyl ether (2 mL) and hexane (5 mL) and
recrystallized from an appropriate solvent.
COX-2 inhibition was determined by using aliquots of human blood samples,
containing sodium heparin. The samples were incubated in absence and
presence of LPS and the test substances as described.31,32
29. Dannhardt, G.; Lehr, M. J. Pharm. Pharmacol. 1992, 44, 419.
30. Scholz, M.; Ulbrich, H. K.; Soehnlein, O.; Lindbom, L.; Mattern, A.; Dannhardt, G.
Bioorg. Med. Chem. 2009, 17, 558.
31. Panara, M. R.; Greco, A.; Santini, G.; Sciulli, M. G.; Rotondo, M. T.; Padovano, R.;
Digiamberardino, M.; Cipollone, F.; Cuccurullo, F.; Patrono, C.; Patrignani, P. Br.
J. Pharmacol. 1995, 116, 2429.
32. Patrignani, P.; Panara, M. R.; Greco, A.; Fusco, O.; Natoli, C.; Iacobelli, S.;
Cipollone, F.; Ganci, A.; Creminon, C.; Maclouf, J.; Patrono, C. J. Pharmacol. Exp.
Ther. 1994, 271, 1705.
6-Chloro-3-hydroxybenzo[b]thiophene-2-carboxylic acid 4c. White solid, Yield:
62%; Mp: 154 °C; IR
m
max (KBr) cmÀ1: 3500–2400 (COOH, OH), 1655 (C@O); 1
H
NMR (400 MHz, DMSO-d6), d (ppm): 3.75 (br s, 1H) 7.48 (dd, J = 8.5, 1.6 Hz, 1H)
7.89 (d, J = 8.5 Hz, 1H) 8.07–8.26 (m, 1H), 10.33 (br s, 1H); 13C NMR (400 MHz,