Kinetic and Mechanistic Study of Transition Metal Ion Catalyzed Vilsmeier–Haack Cyclization and Formylation Reactions with Acetanilides

<div><p>Vilsmeier–Haack reactions (VHR) with acetanilides afforded 2-chloro 3-formyl quinoline derivatives. The reactions obeyed second order kinetics with a first order dependence on VHR as well as acetanilide. Significant rate enhancements were observed when transition metal ions such as Cu(II), Ni(II), Co(II), and Cd(II) were used as catalysts in these reactions. The kinetic results in transition metal ion catalyzed reactions coupled with uv-visible spectrophotometric observations substantiated the participation of mixed ligand precursors of the type [M(II)S(VHR)] involving acetanilides and VH reagents in the rate limiting step. Activation parameters were computed and interpreted suitably.</p></div

Ultrasonic and microwave effects in polyethylene glycol-bound metal nitrate initiated nitration of aromatic compounds under acid free conditions

<div><p>ABSTRACT</p><p>Ultrasonic and microwave-assisted practical methods have been developed for the nitration of phenols using metal nitrates in aqueous polyethylene glycol (PEG) media. Solvent is recycled three times for reproducibility. It was recycled with minimum loss and decomposition. Developed protocols were cost effective, simple and efficient, which afforded nitration products in good to excellent yields. The observed hyperchromic/hypochromic shifts in the UV/VIS spectra of metal nitrates in PEG solutions could be due to the plausible <i>in situ</i> formation of “PEG-bound M(II) nitrate” and thereby the release of nitronium ion () during the course of reaction when metal nitrate [M(II)nitrate] is added to PEG. Nitronium thus formed most likely is captured by aromatic compound to afforded nitro aromatics.</p></div