Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

Abstract

A one-pot iodine-catalyzed multicomponent reaction has been developed for the selective preparation of 5-amino-4-(arylselanyl)-1H-pyrazoles from a diverse array of benzoylacetonitriles, arylhydrazines and diaryl diselenides. The reactions were conducted in MeCN as solvent at reflux temperature under air. The methodology presents a large functional group tolerance to electron-deficient, electron-rich, and bulky substituents and gave the expected products in good to excellent yields. The synthesized 1,3-diphenyl-4-(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis.

Visible Light-Mediated C(sp2)–H Selenylation of Amino Pyrazole and Amino Uracils in the Presence of Rose Bengal as an Organophotocatalyst

“…It was purified by column chromatography [eluent hexane/ethyl acetate = 24:1 (v/v)]. 16 Off-white solid; yield 158 mg (81%); mp 117−119 °C.…”

“…It was purified by column chromatography [eluent hexane/ethyl acetate = 97:3 (v/v)]. 16 Reddish semisolid; yield 158 mg (78%); 1 H NMR (400 MHz, CDCl 3 ): δ 7.84 (d, J = 8.0 Hz, 2H), 7.70 (d, J = 8.0 Hz, 2H), 7.52 (t, J = 8.0 Hz, 2H), 7.38 (t, J = 8.0 Hz, 1H), 7.29 (d, J = 8.0 Hz, 2H), 7.24−7.14 (m, 5H), 4.32 (s, 2H), 2.35 (s, 3H). 13 C { 1 H} NMR (100 MHz, CDCl 3 ): δ 153.…”

“…15 Pires et al developed a three-component reaction of benzoylacetonitriles, arylhydrazines, and diaryl diselenides in the presence of molecular iodine as a catalyst (Scheme 1, eq c). 16 Recently, Fajardo and his group have reported a threecomponent reaction for the synthesis of selenoethers of pyrazoles using Cu 2+ immobilized on alginate-based microspheres (Alg−Cu 2+ ) (Scheme 1, eq d). 17 Cheng's research group reported selenylation of uracils in the presence of sodium iodide and H 2 O 2 in dimethyl sulfoxide (DMSO) medium from the reaction of uracil and diselenides (Scheme 1, eq e).…”

Ultrasound-assisted synthesis of imidazo[1,2-a]pyridines and sequential one-pot preparation of 3-selanyl-imidazo[1,2-a]pyridine derivatives

“…Then, intermediate A undergoes an intramolecular attack of the NH2 to produce imidazo[1,2a]pyridine 3, with water release. In the next step, molecular iodine, formed in the medium, 43,44…”

Efficient multicomponent synthesis of 2-aminopyridines catalysed by basic mesoporous materials

“…Multicomponent reactions (MCRs) have received considerable attention and are known as some of the most important reactions in organic and medicinal chem-istry [1][2][3][4][5][6][7][8][9][10][11]. One-pot multicomponent reactions are the useful path for the fac-ile synthesis of heterocycles with a biological value [12][13][14][15].…”