Efficient Approach for the Tritylation of Alcohols Using Recyclable Lewis Acid-Based Ionic Liquid (EMIM·AlCl₄)

Abstract

A new efficient approach has been reported for the tritylation of primary alcohols over secondary alcohols using triphenyl methyl alcohol and 4-monomethoxyl trityl alcohols in the presence of imidazolium-based ionic liquid 1-ethyl-3-methylimidazolium tetrachloroaluminate as catalyst. At room temperature, 5 mol % of catalyst in dichloromethane and acetonitrile solvent has been shown to be excellent for the tritylation of benzyl alcohol and various other alcohols The method was compatible with Fmoc/acetyl protecting group of amino and tert -butyldiphenylsilyl ether protecting group of alcohol. Moreover, the catalyst was reused for three to four catalytic cycles with little loss of catalytic activity. Excellent yields, reusability, chemoselectivity, and easy workup are advantages of this protocol.

Regioselective Protection and Deprotection of Nanocellulose Molecular Design Architecture: Robust Platform for Multifunctional Applications

“…The presence of an ionic liquid with a [bmim] + cation and a [PF 6 ] − anion weakens the entanglement and chemical bonding between cellulose chains and other components increasing the interaction between the hydroxyl group and trityl chloride (Figure 2). In addition, as reported by Chaubey et al, 51 the ionic liquid had the ability to generate phenyl carbocations, allowing nucleophilic substitution with hydroxyl-containing compounds to synthesize a tritylated product. At the same time, similar HST parameters of pyridine and 4,4M_Tr 3 Cl allowed the trityl chloride access the hydroxyl groups (Figure 3).…”

Discovery of Dolastatinol: A Synthetic Analog of Dolastatin 10 and Low Nanomolar Inhibitor of Tubulin Polymerization

“…The direct preparation of peptidols on Barlos’ 2-chlorotrityl resin was previously reported . Moreover, trityl ethers derived from alcohols or Fmoc amino acid alcohols can be easily formed in solution under mild reaction conditions . However, the esterification of the 2-chlorotrityl chloride (Cl-Trt) resin with Fmoc amino acids proceeds quickly without byproduct formation. − Thus 5 was subjected to reduction of the carboxylic group using an asymmetrical anhydride method with ethyl chloroformate and NaBH 4 as the reducing reagent.…”