Part 148 in the Series “Studies on Novel Synthetic Methodologies:” Selective Acetylation of Alcohols, Phenols and Amines and Selective Deprotection of Aromatic Acetates using Silica-Supported Phosphomolybdic Acid

Synthesis of amphiphilic resveratrol lipoconjugates and evaluation of their anticancer activity towards neuroblastoma SH-SY5Y cell line

Resveratrol, a polyphenol present in grapes and other edible plants, possesses several important pharmacological activities, including anticancer activity. Nevertheless, its therapeutic use is still limited because of some unfavourable physicochemical and pharmacokinetic properties, mainly, poor cellular uptake and too rapid metabolism resulting in elimination from the body. To meet these drawbacks, some resveratrol conjugates would be useful, which would possess improved stability, uptake and bioavailability than the lead compound, and the ability to release it once it is internalized into the cell. In this paper we report a synthetic strategy which allowed us to obtain new amphiphilic resveratrol derivatives starting from different selectively protected resveratrol phosphoramidites or even from the resveratrol triphosphoramidite. Specifically, resveratrol was conjugated through phosphate bridge(s) to different lipophilic groups related to membrane lipids, such as cholesteryl or diacylglycero moieties. All the new lipoconjugates were tested towards human neuroblastoma SH-SY5Y cells and proved to be significantly more active than resveratrol, with a concentration-dependent activity.

Efficient and Rapid Solvent-Free Acetylation of Alcohols, Phenols, and Thiols Using Catalytic Amounts of Sodium Acetate Trihydrate

Under solvent-free conditions, different alcohols and phenols were efficiently acetylated at room temperature within short time periods by using acetic anhydride in the presence of catalytic quantities of sodium acetate trihydrate, which is a very inexpensive and mild reagent. Thiols were also shown to behave equally well under the same conditions. Chemoselective protection of less hindered alcohols in the presence of bulkier homologues and phenols in the presence of alcohols was achieved using competitive experiments.

Metal Acetate/Metal Oxide in Acetic Acid: An Efficient Reagent for the Chemoselective N-Acetylation of Amines under Green Conditions

The use of catalytic amount of metal acetate or metal oxide in acetic acid is a new and highly efficient acetylating system for chemoselective N-acetylation of primary and secondary amines in excellent yields under reflux condition. No other solvent is required. The noted features of this method include mild reaction conditions, use of innocuous reagents, excellent yields, convenient work-up, and reuse of catalyst.