Synthesis of N-Arylpyrazoles by Palladium-Catalyzed Coupling of Aryl Triflates with Pyrazole Derivatives

Abstract

A method for the synthesis of N-arylpyrazoles by palladium-catalyzed coupling of aryl triflates with pyrazole derivatives is described. Using tBuBrettPhos as a ligand, the palladium-catalyzed C−N coupling of a variety of aryl triflates including ortho-substituted ones with pyrazole derivatives proceeded efficiently to give N-arylpyrazole products in high yields. 3-Trimethylsilylpyrazole was found to be an excellent pyrazole substrate for the coupling, and the corresponding product, 1-aryl-3-trimethylsilylpyrazole, also served as a great template for the syntheses of N-arylpyrazole derivatives, as demonstrated by regioselective halogenation at the 3-, 4-, and 5positions of the pyrazole ring. Note pubs.acs.org/joc

Palladium-Catalyzed Synthesis of N,N-Dimethylanilines via Buchwald–Hartwig Amination of (Hetero)aryl Triflates

“…IR (ATR, neat, cm –1 ): 1582 (w), 1491 (w), 1462 (w), 1417 (s), 1293 (w), 1249 (m), 1203 (s), 1136 (s), 1086 (s), 1043 (w), 990 (w), 942 (w), 887 (s), 800 (s), 760 (s), 726 (w), 702 (m), 646 (m), 626 (m), 602 (s), 572 (m), 546 (w), 520 (s), 493 (m), 442 (m). The analytical data is in accordance with that reported in the literature …”

“…The analytical data is in accordance with that reported in the literature. 50 N,N,2-Trimethylaniline Hydrochloride (3x•HCl). Following general procedure B, the use of o-tolyl trifluoromethanesulfonate (1x) afforded the title compound 3x (70 mg, 0.408 mmol, 77%) as a white crystalline solid after purification via column chromatography (n-pentane/EtOAc = 20:1) and treatment with 2 M HCl in Et 2 O. R f = 0.24 (n-pentane/EtOAc = 20:1, UV) free base; 1 H NMR (300 MHz, CDCl 3 ) δ 13.00 (s, 1H), 7.62−7.45 (m, 1H), 7.36−7.23 (m, 3H), 3.23 (s, 6H), 2.84−2.63 (m, 3H).…”

Copper-Promoted One-Pot Sandmeyer-Type Reaction for the Synthesis of N-Aryltriazoles

“…3-Phenyl-1-(p-tolyl)-1H-pyrazole (3ah). 43 Yellow oil, 78.6 mg, 67% yield; 1 H NMR (600 MHz, Chloroform-d) δ = 7.93−7.88 (m, 3H), 7.64 (d, J = 8.2, 2H), 7.42 (t, J = 7.6, 2H), 7.33 (t, J = 7.0, 1H), 7.25 (d, J = 8.4, 2H), 6.74 (d, J = 2.3, 1H), 2.38 (s, 3H). 13…”

Various amide derivatives induced Keggin-type SiW12O404−-based cobalt complexes: assembly, structure, electrochemical sensing and dye adsorption properties

“…For example, Li et al successfully synthesized two new Evans-Showell-based MOCs by introducing dipyrazine-bisamide ligands with varying spacing lengths, which demonstrated excellent catalytic oxidation performance of benzyl alcohol. 17 Currently, some amide derivative ligands containing imidazole, 18 pyrazole, 19 or pyridine groups, 20 featuring flexible, 21 rigid, 22 and semi-rigid linkers, 23 have been involved in the POM-containing system to construct the MOCs with diverse structures and exceptional performances. However, reports on the combination of imidazole-amide derivative with the keggintype POMs are still very limited.…”