Pyridinium Iodochloride: An Efficient Reagent for Iodination of Hydroxylated Aromatic Ketones and Aldehydes

Abstract

Direct iodination of several reactive aromatic compounds like hydroxy substituted acetophenones and aldehydes with pyridinium iodochloride (PyICl) proceeded smoothly to afford the corresponding aromatic iodides in good to excellent yield. Pyridinium iodochloride has been found to be an efficient solid iodinating reagent with no hazardous effect and it can be handled safely.

Synthesis, Evaluation for Cytotoxicity and Molecular Docking Studies of Benzo[c]furan-Chalcones for Potential to Inhibit Tubulin Polymerization and/or EGFR-Tyrosine Kinase Phosphorylation

“…The analytical data and the corresponding nuclear magnetic resonance (NMR) spectra ( 1 H- and 13 C-NMR) of compounds 2a – e and 3a – y have been included in Figure S1 in the Supplementary Materials . 5-Bromo-2-hydroxy-3-iodoacetophenone 1 , used as a precursor in this investigation was prepared in 64% yield in a one-pot operation involving initial bromination of 2-hydoxyacetophenone with 1 equivalent of N -bromosuccinimide (NBS) in acetic acid under reflux for 1.5 h, followed by iodination with N -iodosuccinimide (NIS) in acetic acid under reflux for an additional 1.5 h. This mixed 3,5-dihalogenated-2-hydroxyacetophenone was prepared before by treatment of the commercially available 5-bromo-2-hydroxyacetophenone with pyridinium iodochloride (1 equivalent) in methanol under reflux for 2 h [ 20 ]. Compound 1 was subjected to the Claisen–Schmidt condensation with benzaldehyde derivatives under basic conditions in methanol at room temperature (RT) for 48 h. We isolated the corresponding 5-bromo-2-hydroxy-3-iodochalcones 2a – e in high yields by aqueous work-up and recrystallization.…”

“…111‒112 °C (Lit. [ 20 ] 104–105 °C); ν max (ATR) 441, 539, 670, 779, 862, 968, 1077, 1190, 1233, 1362, 1420, 1581, 1650, 3259 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ) 2.65 (3H, s, CH 3 ), 7.83 (1H, d, J 2.1 Hz, H-4), 8.04 (1H, d, J 2.1 Hz, H-6), 13.07 (1H, s, OH); 13 C NMR (75 MHz, CDCl 3 ) 26.4, 87.6, 111.1, 120.2, 133.1, 147.1, 160.2, and 203.2.…”

Benzofuran–appended 4-aminoquinazoline hybrids as epidermal growth factor receptor tyrosine kinase inhibitors: synthesis, biological evaluation and molecular docking studies

“…Recourse to the literature revealed that 5-bromo-2-hydroxy-3-iodoacetophenone has been prepared before by treatment of the commercially available 5-bromo-2-hydroxyacetophenone with pyridinium iodochloride (1 equiv.) in methanol under reflux for 2 h 19 . We opted for the use of commercially available 2-hydroxyacetophenone 4 (purchased from Sigma-Aldrich) as a substrate for initial halogenation with 1 equivalent of N- bromosuccinimide (NBS) in acetic acid under reflux for 1.5 h to afford 5-bromo-2-hydroxyacetophenone in 59% yield ( Scheme 2 ).…”

“…The resulting precipitate was filtered and recrystallized from EtOH to afford 5 as a brown solid (4.78 g, 93%), mp. 111–112 °C (Lit 19 . 104–105 °C); ν max (ATR) 441, 539, 670, 779, 862, 968, 1077, 1190, 1233, 1362, 1420, 1581, 1650, 3259 cm −1 ; 1 H NMR (CDCl 3 ) 2.65 (3H, s, CH 3 ), 7.83 (1H, d, J = 2.1 Hz, H-4), 8.04 (1H, d, J = 2.1 Hz, H-6), 13.07 (1H, s, OH); 13 C NMR (CDCl 3 ) 26.4, 87.6, 111.1, 120.2, 133.1, 147.1, 160.2, 203.2; HRMS (ES): MH + , found.…”

Synthesis and Transformation of 5-Acetyl-2-aryl-6-hydroxybenzofurans into Furanoflavanone Derivatives

“…These signals distinguished this compound from the isomeric 3-iodo-or the 2,4-dihydroxy-3,5-diiodoacetophenone, which were the main products formed when using other iodinating agents. 21,23,25,32,33 2,4-Dihydroxy-5-iodoacetophenone (5) was, in turn, treated with 1.0 equivalent of N-bromosuccinimide (NBS) in acetic acid at room temperature for 30 minutes to afford 3-bromo-2,4-dihydroxy-5-iodoacetophenone (6) in 85% yield. The 1 H NMR spectrum of this mixed 3,5dihalogenated 2,4-dihydroxyacetophenone revealed the presence of a singlet in the aromatic region at  = 8.25, which corresponds to H-6.…”