Reactivity of antipyrine and haloantipyrines in Pd-catalyzed CH bond arylations. Issue 17 (23rd April 2020)

• Record Type: Journal Article
• Authors: Sasmal, Arpan; Bera, Jitendra K.; Doucet, Henri; Soulé, Jean-François
• Is Part Of: Tetrahedron letters. Volume 61:Issue 17(2020)
• Publication Date: 2020-04-23
• Subjects: Palladium -- Catalysis -- Pyrazolone -- CH Bond -- Arylation; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2020.151798
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Antipyrine can be efficiently coupled with halide halides. 4-Iodopyrine was employed in Pd-catalyzed CH bond arylation of heterocycles. CH bond activation was developed instead of classical Suzuki-reaction. Sustainable solvent and silver-free conditions have been developed. Abstract: We reported herein the Pd-catalyzed direct arylation of antipyrine using Pd(OAc)2 as catalyst associated with KOAc as inexpensive base. In most cases, diethyl carbonate was used a sustainable solvent. The reaction tolerated a wide range of functional groups on the aryl bromide partners (e.g., nitrile, nitro, chloro, fluoro, formyl, acetyl, propionyl, benzoyl, ester, methyl, methoxy). In addition, some nitrogen-containing heteroaryl bromides were also efficiently coupled with antipyrine. We also demonstrated that in contrast to 4-bromoantipyrine, 4-iodoantipyrine could be employed as an efficient heteroaryl source in Pd-catalyzed CH bond arylation of 5-membered ring heteroarenes.