Transition-Metal Catalyst Free Oxidative Radical Arylation of N-Methylpyrrole

Abstract

This study represents an expansion of the application of catalysis in air through conventional coupling and free radical processes. A reactive free aryl radical intermediate was generated via the oxidation of an activated Ar–NH–NH 2 bond by air as a simple and readily available oxidant. For this purpose, the usability of phenylhydrazine and phenylhydrazine hydrochloride salt reagents for the direct arylation of pyrrole with aryl radicals was investigated. The facile coupling of N -methylpyrrole with aryl radicals was easily applied for the convenient direct synthesis of C-2 arylated pyrroles without a transition-metal catalyst.

Determination of the inhibitory effects of N-methylpyrrole derivatives on glutathione reductase enzyme

“…The synthetic process started from the reaction of phenylhydrazine hydrochloride salt with NaOH to rapidly forma free phenylhydrazine, a slow oxidation with air to produce aryl radical 15 . Aryl radical X reacted with N-methyl pyrrole at room temperature to form allyl radical X which was supported by radical resonance after that losing a single electron loosing with air oxidation and eliminating a proton resulted acrylate pyrrole 16 .…”

“…These reactions were in moderate yield (70–91%) under room temperature ( Figure 4 ). The reaction times were from 50 to 60 hours 16 .…”

UVA- and Visible-Light-Mediated Generation of Carbon Radicals from Organochlorides Using Nonmetal Photocatalyst

“…The solid thus obtained was purified by chromatography on silica gel (hexane/ethyl acetate/Et3N = 100/20/0.2) to give the product (3. 33 4-(3,6-bis(dimethylamino)-9H-carbazol-9yl)-3-trifluoromethylbenzoate (CAR4) K3PO4 (385.8 mg, 1.82 mmol, 3.0 equiv) was added to a sealed tube and flamedried under vacuum. CuI (23.1 mg, 0.12 mmol, 0.2 equiv), N,N-dimethyl-1,2-ethandiamine (19.6 L、0.18 mmol, 0.3 equiv) and THF (2.2 mL) were added.…”

Tetramethylammonium Fluoride Tetrahydrate-Mediated Transition Metal-Free Coupling of Aryl Iodides with Unactivated Arenes in Air

“…The coupling reaction with pyrrole (entry 12) or 1-methylpyrrole (entry 13) gave only the 2-substituted coupling product. [64][65][66] We then applied these reaction conditions for carrying out the intramolecular cyclization of aryl ethers using 1-(benzyloxy)-2-iodo-3-nitrobenzenes 3 and 5, and 2-iodo-1-nitro-3-phenoxybenzene 7 as the substrates (Chart 3). The reaction produced fused three-ring compounds at 150°C in moderate to good yields.…”