Selective Acetylation of 2-Naphthol to 2-Naphthyl Acetate with Ni Homogeneous Catalysts: An Environmentally Friendly Protocol

Ateeq Rahman

doi:10.11648/j.sjc.20170504.11

Abstract

An efficient, selective and simple route for the synthesis of 2-Naphthyl acetate has been developed. In reflux conditions the acetylation of 2-naphthol acetylation with a catalytic amount of Nickel nitrate catalysts afforded 2-Naphthyl acetate in moderate to excellent yields. Nickel nitrate showed the best catalytic performance compared to other Nickel salts. Different weights of nickel salts have been evaluated for the title reaction with 30mg NiNO3 afforded the Best conversions. Different acylating reagents were evaluated acetic acid, acetyl chloride and acetic anhydride, and it was observed that acetic acid was the best acetylating reagent. The protocol has advantages including short reaction times, high chemoselectivity towards acylated product simple work-up. Additionally, nickel nitrate, other additives are not required to enhance the reactions.

Highlights

Acetylation is one of the fundamental reactions in organic chemistry and can be carried out by a wide variety of reagents [1]
The aim of this paper is to present the results of acetylation 2-naphthol, and study catalytic activity of nickel nitrate and other nickel salts
A model reaction have been evaluated for acetylation reaction with NiSiO2 catalysts and various homogeneous nickel catalysts for the title reaction showed that Ni-nitrate 30 mg is the active catalysts for the title reaction when acetic acid is used as acylating agent

Summary

Introduction

Acetylation is one of the fundamental reactions in organic chemistry and can be carried out by a wide variety of reagents [1]. Typical procedures employ an acid chloride as the acylating reagent, which is usually prepared from a carboxylic acid and thionyl chloride, releasing HCl and SO2 as by-products. It would be preferable if carboxylic acids are used in place of acid chlorides because the use of carboxylic acids as acylating agents produces water as the sole by-product. Tributyl phosphine was introduced as a less basic catalyst than amines in the acetylation of alcohols [28,29] Other metal salts such as LiClO4 [36], CoCl2 [37], and Mg(ClO4)2 [38] have been successfully have been reported to show catalytic activity toward the acetylation of alcohols with acid anhydride. Cu(OTf) (TfCF3SO2) [23], Er(OTf)3 [24], Al(OTf)3 [25], Ti-Cl3(OTf) [9], Ce(OTf)3 [21], Ateeq Rahman et al.: Selective Acetylation of 2-Naphthol to 2-Naphthyl Acetate with Ni Homogeneous Catalysts: An Environmentally Friendly Protocol

Objectives

Results

Conclusion