%0 Journal Article
%T Microwave Assisted Solvent-Free Synthesis of Some Imine Derivatives
%A Yunus Bekdemir
%A K邦rˋat Efil
%J Organic Chemistry International
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/816487
%X Some imine derivatives (1a每7d) were synthesized using a rapid and an environmentally friendly method with reaction of aromatic aldehydes (a每d) and aromatic amines (1每7) (in 1ˋ:ˋ1 molar ratio) in the presence of -ethoxyethanol as a wetting reagent (2 drops) under solvent-free conditions using microwave heating. 1. Introduction Compounds containing the 每C=N每 (azomethine group) structure are known as Schiff bases, usually synthesized from the condensation of primary amines and active carbonyl groups [1]. The reaction is acid-catalyzed and is generally carried out by refluxing the carbonyl compound and amine, with an azeotroping agent if necessary, and separating the water as formed [2]. Schiff bases are well known for their biological applications as antibacterial, antifungal, anticancer, and antiviral agents; furthermore, they have been used as intermediates in medical substrates and as ligands in complex formation with some metal ions [1, 3]. The synthesis of imines was firstly reported by Hugo Schiff in 1864 and they have been known since then [4]. The imine compounds have been prepared using molecular sieves [5, 6], infrared irradiation [7], Mg(ClO4)2 [8], P2O5/SiO2 [9], ZnCl2 [10], CaO under microwave power [11], ethyl lactate as a tunable solvent [12], K10 clay [13], TiCl4 [14], alumina [15], CeCl3 7H2O [16], ultrasound irradiation [17], polymer-supported [18], nanotube TiO2 (in sunlight) [19], and Ti(OEt)4 [20, 21]. The present work reveals the comparative aspects of condensation of some aromatic amines with aldehyde derivatives using microwave and conventional methods. The amine and aldehyde compounds as starting materials, -ethoxyethanol ( -EE) as wetting reagent and microwave power as an effective source of heating are used in this study. The corresponding imine compounds were prepared in high yields and short reaction times using this effective and environment friendly method. 2. Results and Discussion In this work, we synthesized quickly and efficiently a series imine derivatives (1a每7d) by condensation of some aromatic amines (1每7) and aldehyde derivatives such as salicylaldehyde (a), p-chlorobenzaldehyde (b), p-methoxybenzaldehyde (c) and cinnamaldehyde (d) under microwave-assisted solvent-free conditions using -EE as wetting reagent. -EE that is a polar molecule quickly absorbs microwaves and therefore heats up and heats around effectively. As a result, -EE, which increases the polarity of the reaction medium, has an active role in the heating of the reaction medium by microwaves. The general reaction was summarized in Scheme 1. In addition,
%U http://www.hindawi.com/journals/oci/2014/816487/