Three-component one-pot synthesis of dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridines
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Seyed Esmail Sadat-Ebrahimi
Abstract
A series of dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridines has been synthesized using a simple and efficient one-pot, three-component procedure. The products were obtained in good yields in the presence of heterogeneous nanoporous acid catalyst (SBA-Pr-SO3H).
Introduction
Pyrazoles and fused pyrazoles are well-recognized central units in medicine and therapeutics [1]. Among the various fused systems, pyrazolopyridines show promising biological activities as antibacterial [2], antitumor [3], antiviral [4] and anti-inflammatory [5] agents, and antagonists of corticotropin-releasing factor 1 (CRF1) [6], chemokine receptor type 1 (CCR1) [7] and dopamine D3 receptors antagonists [8]. They are also known to be cholesterol forming [9], acetyl-CoA carboxylase (ACC) [10], HIV reverse transcriptase [11], phosphodiesterase 3/4 (PDE3/4) cyclin-dependent 1 (CDK1) [12], and B-Raf kinase inhibitors [13]. Several methods have been devised for the synthesis of substituted pyrazolopyridines [14], [15], [16], [17], [18], [19], [20]. Among them multi-component reactions (MCRs) [21], [22], [23], [24], [25] are of increasing importance because of their convergent, atom-economical and productive nature.
MCRs [26], [27] constitute an important pathway for one-pot construction of polycyclic compounds. This valuable feature has made the MCR chemistry a powerful procedure. Heterogeneous catalysts are often used to resolve growing concerns about environmental issues. In this context, Santa Barbara Amorphous (SBA-15) [28], in which various functional groups could be covalently bound to its mesostructured silica surface, has gained considerable attention. Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) [29] with high acid strength could be regarded as a replacement for conventional homogenous acidic catalysts suffering from various drawbacks, mainly their toxicity and hazards to humans. Considering environmental and industrial aspects, sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) has emerged as an important catalyst in an efficient construction of complex frameworks. In continuation of our interest toward developing new pathways for the synthesis of heterocyclic compounds [30], [31], [32], herein we report the catalytic synthesis of novel compounds incorporating coumarin and pyrazolopyridine moieties.
Results and discussion
The reaction of 4-hydroxycoumarin (1), 3-methyl-1-phenyl-1H-pyrazol-5-amine (2) and benzaldehyde (3a) was selected as a model reaction to establish the appropriate conditions (Scheme 1). The reaction was investigated by utilizing 5 mol% SBA-Pr-SO3H, prepared according to the literature [33], in different solvents at reflux temperature (including ethanol, water, ethanol/water and methanol). The highest yield of 83% of product 4a was obtained for the reaction conducted in ethanol under reflux for 2 h. No improvement in the isolated yield was observed with increasing amounts of the catalyst, up to 20 mol% and no product 4a was observed in the absence of the catalyst. Heating the mixture under reflux in acetic acid furnished product 4a in a comparable yield, but after a long reaction time (18 h). Additional dihydrochromeno[4,3-b]pyrazolo [4,3-e]pyridines 4b–k were obtained in good yields under similar conditions, as shown in Scheme 1. No significant substituent effects were observed for electron-donating groups Me and OMe or electron-withdrawing groups including Cl, Br, NO2 and CN.
Conclusion
Pyrazolo[4,3-e]pyridines 4a–k were synthesized in good yields using our straightforward, one-pot and multi-component procedure.
Experimental
All chemicals were purchased from Merck and Fluka and used without further purification. Melting points were measured with a Kofler hot stage apparatus and are uncorrected. 1H NMR (500 MHz) and 13C NMR (125 MHz) spectra were recorded on a Bruker FT-500 spectrometer in DMSO-d6, using tetramethylsilane as an internal standard. IR spectra were recorded on a Shimadzu 470 spectrophotometer in KBr disks. Mass spectra were obtained using an Agilent Technology mass spectrometer operating at an ionization potential of 70 eV. Elemental analysis was performed using an Elemental Analysen system, GmbH VarioELCHNS. The synthesis of SBA-15 and SBA-Pr-SO3H was performed as described in the literature [33].
General synthesis of compounds 4a–k
A mixture of 4-hydroxycoumarin (1 mmol), an aldehyde (1 mmol), 3-methyl-1-phenyl-1H-pyrazol-5-amine (1 mmol) and 5 mol% SBA-SO3H in ethanol (5 mL) was stirred and heated under reflux. Upon completion, which was indicated by TLC analysis, the mixture was filtered off and the filtrate was cooled to room temperature. The precipitate of 4a–k was collected and purified by silica gel chromatography eluting with petroleum ether/ethyl acetate (8:2). The catalyst was washed with water and acetone. After drying under a reduced pressure, the catalyst could be reused several times without the loss of activity.
8-Methyl-7,10-diphenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4a)
The product was obtained within 2 h in 83% yield as a pale yellow solid; mp 221–222°C; IR: 3400, 1698, 1631, 1535, 1455, 1024, 748, 701 cm-1; 1H NMR: δ 1.93 (s, 3H), 5.19 (s, 1H), 7.15 (t, 1H, J = 7.3 Hz), 7.25–7.30 (m, 4H), 7.35 (d, 1H, J = 8.0 Hz), 7.38–7.43 (m, 2H), 7.57 (t, 2H, J = 7.5 Hz), 7.62 (t, 1H, J = 7.3 Hz), 7.68 (d, 2H, J = 7.0 Hz), 8.06 (d, 1H, J = 8.0 Hz), 9.95 (s, NH); 13C NMR: δ 11.9, 37.3, 101.4, 103.9, 113.9, 116.4, 122.5, 123.6, 123.7, 126.2, 126.6, 127.8, 128.0, 129.3, 131.7, 136.0, 138.7, 143.8, 145.8, 146.0, 152.0, 160.4; MS: m/z 405 ([M]+, 26), 328 (100), 284 (60), 77 (41%). Anal. Calcd for C26H19N3O2: C, 77.02; H, 4.72; N, 10.36. Found: C, 76.94; H, 4.59; N, 10.48.
8-Methyl-10-phenyl-7-(p-tolyl)-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4b)
The product was obtained within 1.5 h in 80% yield as a pale yellow solid; mp 154–156°C; IR: 3348, 1690, 1627, 1551, 1440, 1011, 819 cm-1; 1H NMR: δ 1.93 (s, 3H), 3.69 (s, 3H), 5.13 (s, 1H), 6.82 (d, 2H, J = 8.5 Hz), 7.18 (d, 2H, J = 8.5 Hz), 7.35 (d, 1H, J = 8.0 Hz), 7.38–7.42 (m, 2H), 7.57 (t, 2H, J = 8.0 Hz), 7.62 (t, 1H, J = 7.5 Hz), 7.67 (d, 2H, J = 7.5 Hz), 8.04 (d, 1H, J = 8.0 Hz), 9.94 (s, NH); 13C NMR: δ 11.9, 20.9, 36.4, 101.4, 104.6, 113.7, 114.0, 116.4, 122.8, 123.1, 123.7, 126.2, 128.8, 129.6, 131.3, 136.0, 138.3, 138.7, 143.5, 145.6, 151.3, 157.6, 160.0. Anal. Calcd for C27H21N3O2: C, 77.31; H, 5.05; N, 10.02. Found: C, 77.21; H, 4.96; N, 10.06.
7-(2-Methoxyphenyl)-8-methyl-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4c)
The product was obtained within 2.5 h in 81% yield as a pale yellow solid; mp 202°C; IR: 3236, 1681, 1631, 1536, 1458, 1027, 755, 698 cm-1; 1H NMR: δ 1.93 (s, 3H), 3.78 (s, 3H), 5.50 (s, 1H), 6.82 (t, 1H, J = 7.5 Hz), 6.94 (d, 1H, J = 8.0 Hz), 7.10–7.15 (m, 2H), 7.33 (d, 1H, J = 8.5 Hz), 7.36–7.41 (m, 2H), 7.56 (t, 2H, J = 7.5 Hz), 7.61 (t, 1H, J = 7.5 Hz), 7.65 (d, 2H, J = 8.5 Hz), 8.04 (d, 1H, J = 8.5 Hz), 9.83 (s, NH); 13C NMR: δ 11.7, 31.4, 55.5, 95.4, 101.1, 103.7, 111.3, 114.0, 116.3, 120.4, 122.3, 123.4, 123.5, 126.4, 127.4, 129.2, 129.3, 131.5, 134.2, 136.2, 138.8, 144.6, 145.6, 152.0, 159.8. Anal. Calcd for C27H21N3O3: C, 74.47; H, 4.86; N, 9.65. Found: C, 74.50; H, 4.92; N, 9.71.
7-(4-Methoxyphenyl)-8-methyl-10-phenyl-10,11-dihydrochromeno [4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4d)
The product was obtained within 2 h in 79% yield as a pale yellow solid; mp 196–198°C; IR: 3244, 1711, 1628, 1539, 1457, 1027, 841, 758, 689 cm-1; 1H NMR: δ 1.94 (s, 3H), 3.69 (s, 3H), 5.14 (s, 1H), 6.82 (d, 2H, J = 7.5 Hz), 7.19 (d, 2H, J = 7.5 Hz), 7.34 (d, 1H, J = 8.5 Hz), 7.41 (t, 2H, J = 7.5 Hz), 7.55–7.62 (m, 3H), 7.68 (d, 2H, J = 8.5 Hz), 8.05 (d, 1H, J = 7.5 Hz), 9.89 (s, NH); 13C NMR: δ 11.9, 36.4, 54.9, 101.7, 104.1, 113.4, 113.9, 116.4, 122.5, 123.5, 123.6, 126.5, 128.8, 129.3, 131.6, 135.9, 138.3, 138.7, 143.5, 145.8, 151.9, 157.6, 160.4; MS: m/z 435 ([M]+, 25), 328 (100), 107 (51), 251 (41), 77 (32%). Anal. Calcd for C27H21N3O3: C, 74.47; H, 4.86; N, 9.65. Found: C, 74.56; H, 4.92; N, 9.54.
7-(4-Hydroxy-3-methoxyphenyl)-8-methyl-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4e)
The product was obtained within 2 h in 82% yield as a pale yellow solid; mp 230–232°C; IR: 3351, 1683, 1630, 1541, 1382, 741 cm-1; 1H NMR: δ 1.99 (s, 3H), 3.71 (s, 3H), 5.10 (s, 1H), 6.58 (d, 1H, J = 8.0 Hz), 6.65 (d, 1H, J = 7.3 Hz), 6.91 (s, 1H), 7.35 (d, 1H, J = 8.0 Hz), 7.38–7.42 (m, 2H), 7.57 (t, 2H, J = 7.5 Hz), 7.61 (t, 1H, J = 7.5 Hz), 7.68 (d, 2H, J = 8.0 Hz), 8.04 (d, 1H, J = 8.0 Hz), 8.72 (s, 1H), 9.91 (s, NH); 13C NMR: δ 12.0, 36.7, 55.7, 101.8, 104.3, 112.5, 114.0, 115.3, 116.4, 120.1, 122.4, 123.6, 126.5, 129.3, 131.6, 135.9, 137.4, 138.8, 143.5, 144.9, 145.8, 146.9, 151.9, 160.5. Anal. Calcd for C27H21N3O4: C, 71.83; H, 4.69; N, 9.31. Found: C, 71.74; H, 4.58; N, 9.40.
7-(4-Chlorophenyl)-8-methyl-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4f)
The product was obtained within 3 h in 75% yield as a pale yellow solid; mp 236–237°C; IR: 3189, 1665, 1623, 1530, 1457, 1047, 837, 753 cm-1; 1H NMR: δ 1.93 (s, 3H), 5.22 (s, 1H), 7.32–7.43 (m, 7H), 7.58 (t, 2H, J = 7.5 Hz), 7.63 (t, 1H, J = 7.8 Hz), 7.68 (d, 2H, J = 8.5 Hz), 8.06 (d, 1H, J = 8.0 Hz), 10.02 (s, NH); 13C NMR: δ 11.9, 36.8, 100.9, 103.3, 113.8, 116.4, 122.6, 123.6, 123.7, 126.7, 128.0, 129.3, 129.7, 130.7, 131.8, 136.0, 138.6, 144.0, 144.9, 145.8, 152.0, 160.4. Anal. Calcd for C26H18ClN3O2: C, 70.99; H, 4.12; N, 9.55. Found: C, 70.88; H, 4.21; N, 9.49.
7-(3-Bromophenyl)-8-methyl-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4g)
The product was obtained within 3.5 h in 72% yield as a pale yellow solid; mp 166–168°C; IR: 3230, 1677, 1628, 1534, 1459, 1045, 756, 687 cm-1; 1H NMR: δ 1.94 (s, 3H), 5.23 (s, 1H), 7.25 (t, 1H, J = 7.5 Hz), 7.30 (d, 1H, J = 7.3 Hz), 7.34–7.44 (m, 4H), 7.46 (s, 1H), 7.58 (d, 2H, J = 7.8 Hz), 7.64 (t, 1H, J = 7.5 Hz), 7.69 (d, 2H, J = 8.0 Hz), 8.06 (d, 1H, J = 7.8 Hz), 10.02 (s, NH); 13C NMR: δ 11.9, 37.2, 100.7, 103.2, 113.8, 116.3, 116.5, 121.4, 122.6, 123.1 (2C), 126.7, 127.1, 129.2, 130.3, 131.9, 132.6, 1360, 138.6, 144.1, 145.8, 148.6, 152.0, 160.4. Anal. Calcd for C26H18BrN3O2: C, 64.47; H, 3.75; N, 8.68. Found: C, 64.39; H, 3.82; N, 8.58.
7-(4-Bromophenyl)-8-methyl-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4h)
The product was obtained within 3 h in 78% yield as a pale yellow solid; mp 177–179°C; IR: 3230, 1677, 1628, 1534, 1459, 1045, 756, 687 cm-1; 1H NMR: δ 1.93 (s, 3H), 5.20 (s, 1H), 7.25 (d, 2H, J = 8.5 Hz), 7.36 (d, 1H, J = 8.0 Hz), 7.38–7.43 (m, 2H), 7.45 (d, 2H, J = 8.5 Hz,), 7.57 (t, 2H, J = 7.5 Hz), 7.63 (t, 1H, J = 7.5 Hz), 7.67 (d, 2H, J = 8.5 Hz), 8.05 (d, 1H, J = 8.0 Hz), 10.01 (s, NH); 13C NMR: δ 11.9, 36.9, 100.8, 103.3, 113.8, 116.5, 119.2, 122.6, 123.6, 123.7, 126.7, 129.3, 130.1, 130.9, 131.9, 136.0, 138.6, 144.0, 145.4, 145.8, 152.0, 160.4. Anal. Calcd for C26H18BrN3O2: C, 64.47; H, 3.75; N, 8.68. Found: C, 64.58; H, 3.69; N, 8.58.
8-Methyl-7-(2-nitrophenyl)-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4i)
The product was obtained within 3.5 h in 71% yield as a pale yellow solid; mp 189–191°C; IR: 3339, 1652, 1640, 1559, 1370, 731, 682 cm-1; 1H NMR: δ 1.96 (s, 3H), 5.93 (s, 1H), 7.31 (d, J = 8.0 Hz, 1H), 7.38–7.44 (m, 4H), 7.56–7.62 (m, 4H), 7.71 (d, 2H, J = 8.0 Hz), 7.83 (d, 1H, J = 8.5 Hz), 8.05 (d, 1H, J = 8.0 Hz), 10.09 (s, NH); 13C NMR: δ 12.0, 31.9, 101.0, 102.0, 113.6, 116.5, 120.6, 122.8, 123.1, 124.5, 126.7, 127.4, 129.3, 130.2, 131.6, 133.1, 134.3, 137.0, 139.7, 143.8, 146.0, 148.8, 152.0, 160.5; MS: m/z 450 ([M]+, 19), 328 (100), 284 (42), 122 (23), 77 (54%). Anal. Calcd for C26H18N4O4: C, 69.33; H, 4.03; N, 12.44. Found: C, 69.42; H, 4.11; N, 12.37.
8-Methyl-7-(3-nitrophenyl)-10-phenyl-10,11-dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-one (4j)
The product was obtained within 3 h in 74% yield as a pale yellow solid; mp 244–246°C; IR: 3361, 1701, 1632, 1531, 1455, 1043, 755 cm-1; 1H NMR: δ 1.93 (s, 3H), 5.44 (s, 1H), 7.36 (d, 1H, J = 8.5 Hz), 7.41–7.45 (m, 2H), 7.58–7.62 (m, 3H), 7.65 (t, 1H, J = 7.5 Hz), 7.71 (d, 2H, J = 8.0 Hz), 7.80 (d, 1H, J = 7.5 Hz), 8.05 (d, 1H, J = 7.7 Hz), 8.10 (d, 1H, J = 8.0 Hz), 8.14 (s, 1H), 10.12 (s, NH); 13C NMR: δ 11.9, 37.2, 100.3, 102.9, 113.8, 116.5, 121.4, 122.3, 122.7, 123.7, 123.8, 126.8, 129.4, 129.6, 132.0, 134.7, 136.2, 138.6, 144.4, 145.9, 147.7, 148.0, 152.1, 160.3. Anal. Calcd for C26H18N4O4: C, 69.33; H, 4.03; N, 12.44. Found: C, 69.20; H, 3.97; N, 12.32.
4-(8-Methyl-6-oxo-10-phenyl-6,7,10,11-tetrahydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-7-yl)benzonitrile (4k)
The product was obtained within 3 h in 76% yield as a pale yellow solid; mp 159–161°C; IR: 3303, 2227, 1694, 1631, 1537, 1456, 1041, 843, 763, 688 cm-1; 1H NMR: δ 1.91 (s, 3H), 5.33 (s, 1H), 7.37 (d, 1H, J = 8.0 Hz), 7.40–7.44 (m, 2H), 7.50 (d, 2H, J = 8.5 Hz), 7.58 (t, 2H, J = 7.5 Hz), 7.63–7.69 (m, 3H), 7.75 (d, 2H, J = 8.5 Hz), 8.07 (d, 1H, J = 8.0 Hz), 10.07 (s, NH); 13C NMR: δ 11.9, 37.6, 100.2, 102.7, 109.0, 113.7, 116.5, 118.7, 122.7, 123.7, 124.2, 126.7, 128.9, 129.3, 132.0, 132.1, 136.0, 138.5, 144.4, 145.8, 151.2, 152.0, 160.4; MS: m/z 430 ([M]+, 26), 328 (100), 284 (29), 102 (62), 77 (39%). Anal. Calcd for C27H18N4O2: C, 75.34; H, 4.21; N, 13.02. Found: C, 75.28; H, 4.30; N, 12.95.
Acknowledgments
This study was supported by the research council of Tehran University of Medical Sciences (TUMS) and Iran National Science Foundation (INSF).
References
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Articles in the same Issue
- Frontmatter
- Review
- Constituents from Chloranthaceae plants and their biological activities
- Preliminary Communications
- Design, synthesis and cytotoxicity evaluation of novel (E)-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-1-(pyridin-3-yl)prop-2-en-1-ones as anticancer agents
- Synthesis of first selenodecalines: 2-aryl-4-phenyl octahydroselenochromenes
- Reasearch Articles
- Microwave-assisted and conventional synthesis of novel antimicrobial 1,2,4-triazole derivatives containing nalidixic acid skeleton
- One-pot synthesis of new triazole-sucrose derivatives via click chemistry and evaluation of their antitubercular activity
- One-pot synthesis of 2-hydrazonyl-4-phenylthiazoles via [PDBMDIm]Br-catalyzed reaction under solvent-free conditions
- Three-component one-pot synthesis of dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridines
