2253-69-2Relevant academic research and scientific papers
Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
Hui, Zi,Jiang, Songwei,Qi, Xiang,Ye, Xiang-Yang,Xie, Tian
, (2020/05/18)
The microwave-accelerated Claisen rearrangement of allyl aryl ethers was investigated, in order to gain insight into the scope of the catalysts, solvents, temperatures, and substrates. Among the catalysts examined, phosphomolybdic acid (PMA) was found to greatly accelerate the reaction in NMP, at temperatures ranging from 220 to 300 °C. This method was found to be useful for preparing several intermediates previously reported in the literature using precious metal catalysts such as Au(I), Ag(I), and Pt(II). Additionally, substrates bearing bromo and nitro groups on the aryl portion required careful tailoring of the reaction conditions to avoid complex product profiles.
Boosting effect of ortho-propenyl substituent on the antioxidant activity of natural phenols
Marteau, Clémentine,Guitard, Romain,Penverne, Christophe,Favier, Dominique,Nardello-Rataj, Véronique,Aubry, Jean-Marie
, p. 418 - 427 (2015/10/19)
Seven new antioxidants derived from natural or synthetic phenols have been designed as alternatives to BHT and BHA antioxidants. Influence of various substituents at the ortho, meta and para positions of the aromatic core of phenols on the bond dissociation enthalpy of the ArO-H bond was evaluated using a DFT method B3LYP/6-311++G(2d,2p)//B3LYP/6-311G(d,p). This prediction highlighted the ortho-propenyl group as the best substituent to decrease the bond dissociation enthalpy (BDE) value. The rate constants of hydrogen transfer from these phenols to DPPH radical in a non-polar and non-protic solvent have been measured and were found to be in agreement with the BDE calculations. For o-propenyl derivatives from 2-tert-butyl-4-methylphenol, BHA, creosol, isoeugenol and di-o-propenyl p-cresol, fewer radicals were trapped by a single phenol molecule, i.e. a lower stoichiometric number. Reaction mechanisms involving the evolution of the primary phenoxyl radical ArO are proposed to rationalise these effects.
EFFECT OF METAL IONS IN ORGANIC SYNTHESIS. XXXV SIMPLE AND CONVENIENT AROMATIC ALKYLATION OF SOME ALKENYLPHENOL DERIVATIVES WITH tert-ALKYL METHYL ETHERS IN THE PRESENCE OF TIN(IV) CHLORIDE
Attanasi, Orazio A.,Filippone, Paolino,Balducci, Sandro
, p. 487 - 489 (2007/10/02)
A very mild, simple and convenient method for the aromatic alkylation of some alkenylphenol derivatives with tert-alkyl methyl ethers to give sterically hindered phenols useful as antioxidants is reported.The reaction occurs with good yields at room temperature and is promoted by tin(IV) chloride.
