Abstract
Background: In this current work, a new synthesis strategy was developed to obtain 1,3,4-trisubstituted pyrazoles derivatives.
Methods: A series of 1,3,4-trisubstituted pyrazoles have been prepared via 1,3-dipolar cycloaddition reaction of 3-phenylsydnones with a variety of alkenes derivatives, symmetric and non-symmetric alkynes derivatives, N-phenyl-maleimide, N-benzylmaleimides, and maleic anhydride under conventional manner.
Results: Moreover, in this work, it has been demonstrated that the 4-bromopyrazole intermediates can be further functionalized by a combination of Suzuki-Miyaura crosscoupling reactions with aryl-boronic acids and N-arylation reactions of anilines.
Conclusion: In summary, we have developed a new method to obtain 1,3,4 triarylated pyrazoles through 3-phenylsydnone 1,3-dipolar cycloadditions. By comparing the different reactions, it is apparent that high temperatures and xylene as solvent are key to achieving pyrazoles derivatives. The best yields were observed for symmetric and non-symmetric alkynes as dipolarophiles.
Keywords: Sydnone, pyrazole, 1, 3-dipolar cycloaddition, C-arylation, Suzuki-Miyaura cross-coupling reactions, microwave, N-heterocycle, N-arylations reactions, aryl halides.
Graphical Abstract
[http://dx.doi.org/10.3390/molecules23010134] [PMID: 29329257]
(b) Elguero, J.; Goya, P.; Jagerovic, N.; Silva, A.M.S. Synthesis, characterization and biological screening of some novel sulphur bridged pyrazole, thiazole, coumarin and pyrimidine derivatives. Targets Heterocycl. Syst., 2002, 6, 52-98.
[http://dx.doi.org/10.12691/wjoc-5-1-4]
[PMID: 23757934]
[http://dx.doi.org/10.1016/j.cclet.2008.12.013];
(b) Bondock, S.; Fadaly, W.; Metwally, M.A. Synthesis and antimicrobial activity of some new thiazole, thiophene and pyrazole derivatives containing benzothiazole moiety. Eur. J. Med. Chem., 2010, 45(9), 3692-3701.
[http://dx.doi.org/10.1016/j.ejmech.2010.05.018] [PMID: 20605657]
[http://dx.doi.org/10.1016/j.ejmech.2008.10.020] [PMID: 19056146];
(b) Yewale, S.B.; Ganorkar, S.B.; Baheti, K.G.; Shelke, R.U. Novel 3-substituted-1-aryl-5-phenyl-6-anilinopyrazolo[3,4-d]pyrimidin-4-ones: Docking, synthesis and pharmacological evaluation as a potential anti-inflammatory agents. Bioorg. Med. Chem. Lett., 2012, 22(21), 6616-6620.
[http://dx.doi.org/10.1016/j.bmcl.2012.08.119] [PMID: 23036953];
(c) Bandgar, B.P.; Gawande, S.S.; Bodade, R.G.; Gawande, N.M.; Khobragade, C.N. Synthesis and biological evaluation of a novel series of pyrazole chalcones as anti-inflammatory, antioxidant and antimicrobial agents. Bioorg. Med. Chem., 2009, 17(24), 8168-8173.
[http://dx.doi.org/10.1016/j.bmc.2009.10.035] [PMID: 19896853]
[http://dx.doi.org/10.1016/j.jfluchem.2010.12.009]
[http://dx.doi.org/10.1016/j.ejmech.2009.01.032] [PMID: 19268406]
[http://dx.doi.org/10.1016/j.bmc.2010.05.034] [PMID: 20627597];
(b) Xu, Y.; Liu, X.H.; Saunders, M.; Pearce, S.; Foulks, J.M.; Parnell, K.M.; Clifford, A.; Nix, R.N.; Bullough, J.; Hendrickson, T.F.; Wright, K.; McCullar, M.V.; Kanner, S.B.; Ho, K.K. Discovery of 3-(trifluoromethyl)-1H-pyrazole-5-carboxamide activators of the M2 isoform of pyruvate kinase (PKM2). Bioorg. Med. Chem. Lett., 2014, 24(2), 515-519.
[http://dx.doi.org/10.1016/j.bmcl.2013.12.028] [PMID: 24374270]
[http://dx.doi.org/10.1021/jm00083a017] [PMID: 1548681]
[http://dx.doi.org/10.1016/j.ejmech.2015.09.029] [PMID: 26433616]
[http://dx.doi.org/10.1021/jf802489e] [PMID: 18939848]
[http://dx.doi.org/10.1016/j.bmc.2008.09.070] [PMID: 18945621]
[http://dx.doi.org/10.1021/jf402719z] [PMID: 23972278]
[http://dx.doi.org/10.1016/0008-6215(92)84179-V] [PMID: 1665755]
[http://dx.doi.org/10.1002/anie.197506651]
[http://dx.doi.org/10.1021/ja00039a014]
[http://dx.doi.org/10.1056/NEJM200006293422603] [PMID: 10874062]
[http://dx.doi.org/10.2174/092986711797636090] [PMID: 22050759]
[http://dx.doi.org/10.1021/jm010861y] [PMID: 11606127]
[http://dx.doi.org/10.1002/anie.196305651];
(b) Padwa, A.; Pearson, W.H. Eds.; Synthetic Applications of 1,3-Dipolar Cycloaddition Chemistry Toward Heterocycles and Natural Products; John Wiley & Sons: New York, 2002.
[http://dx.doi.org/10.1002/0471221902];
(c) Mohanan, K.; Martin, A.R.; Toupet, L.; Smietana, M.; Vasseur, J.J. Three-component reaction using the Bestmann-Ohira reagent: A regioselective synthesis of phosphonyl pyrazole rings. Angew. Chem. Int. Ed. Engl., 2010, 49(18), 3196-3199.
[http://dx.doi.org/10.1002/anie.200906781] [PMID: 20349482]
[http://dx.doi.org/10.1016/j.tet.2009.10.085]
[http://dx.doi.org/10.1021/jo902514v] [PMID: 20030356]
[http://dx.doi.org/10.1021/jo301770k] [PMID: 22998610]
[http://dx.doi.org/10.1021/acs.joc.8b00155] [PMID: 29547278]
[http://dx.doi.org/10.1002/ejoc.201500625]
[http://dx.doi.org/10.1016/j.tet.2006.07.011]
[http://dx.doi.org/10.1016/j.ejmech.2007.08.002] [PMID: 17923171]
[http://dx.doi.org/10.1039/C7CC06405E] [PMID: 28959814]