Chinese Journal of Chemistry, 2009, 27, 815—820 Full Paper * E-mail: hrshaterian@hamoon.usb.ac.ir Received July 13, 2008; revised September 13, 2008; accepted October 10, 2008. Project partially supported by the Sistan and Baluchestan University Research Council. © 2009 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Preparation and Application of Perchloric Acid Supported on Alumina (Al 2 O 3 -HClO 4 ) to the Synthesis of α-(α-Amidobenzyl)-β-naphthols SHATERIAN, Hamid Reza* KHORAMI, Fahimeh AMIRZADEH, Azita GHASHANG, Majid Department of Chemistry, Faculty of Sciences, University of Sistan and Baluchestan, PO Box 98135-674, Zahedan, Iran Preparation of perchloric acid supported on alumina and its primary application as a solid supported heteroge- neous catalyst to the synthesis of α-(α-amidobenzyl)-β-naphthols by a one-pot, three-component condensation of benzaldehydes, β-naphthol and acetamide or benzamide under thermal solvent-free conditions were described. The present methodology offers several advantages such as simple procedure, shorter reaction time, and excellent yields. Keywords perchloric acid supported on alumina, amidoalkyl naphthol, heterogeneous catalyst, multi-component reaction Introduction Catalytic technologies play a key role in the eco- nomic development and development of the chemicals industry and add to around 20% of world Gross Na- tional Product (GNP). 1 A major emerging and chal- lenging part of heterogeneous catalysis is that of envi- ronmental pollution control, with contraction legislation on the release of waste and toxic emissions having seri- ous implications for the chemical industry. 1 Many of these processes were focused on product yield, disre- garding the environmental impact of inorganic waste and toxic by-products formed during the reaction. 1 Tightening legislation on the emission of hazardous pollutants is driving the industry toward the implemen- tation of innovative “clean technology” including the use of alternative heterogeneously catalyzed processes. 2 In this research, Al 2 O 3 -HClO 4 as the solid heterogene- ous Brønsted acid catalyst deserves special mention, which is safe, easy to handle, and environmentally be- nign with fewer disposal problems. Compounds bearing 1,3-amino oxygenated func- tional groups are ubiquitous to a variety of biologically important natural products and potent drugs including a number of nucleoside antibiotics and HIV protease in- hibitors, such as ritonavir and lipinavir. 3,4 In this re- search, we present an advance in the context of syn- thetic methodology towards a class of biologically im- portant molecules; it is noteworthy that 1-(α-amido- benzyl)-2-naphthols can convert to important biological active 1-(α-amidobenzyl)-2-naphthol derivatives by amide hydrolysis reaction. The hypotensive and brady- cardiac effects of these compounds have been evalu- ated. 3,4 The preparation of 1-amidoalkyl-2-naphthols can be carried out by condensation of aryl aldehydes, 2-naphthol and acetonitrile or amide in the presence of Lewis or Brønsted acid catalysts such as montmorillo- nite K10 clay, 5 Ce(SO 4 ) 2 , 6 iodine, 7 K 5 CoW 12 O 40 •3H 2 O, 8 p-TSA, 9 sulfamic acid, 10,11 zirconyl(IV) chloride, 12 sil- ica sulfuric acid, 13 cation-exchanged resins, 14 SiO 2 - HClO 4 15 and SiO 2 -FeCl 3 . 16 Herein we show that 1-(α-amidobenzyl)-2-naphthols can be produced by three-component condensation of benzaldehydes, β-naphthol and acetamide or benzamide using perchloric acid supported on alumina (Al 2 O 3 -HClO 4 ) as an environmentally friendly hetero- geneous catalyst under thermal solvent-free conditions (Scheme 1). Experimental All reagents were purchased from Merck or Aldrich and used without further purification. All yields refer to isolated products after purification. Products were char- acterized by comparison with authentic samples and by spectroscopy data (IR, 1 H NMR spectra). The NMR spectra were recorded on a Bruker Avance DPX 300 or 500 MHz instrument in DMSO-d 6 relative to TMS. IR spectra were recorded on a JASCO FT-IR 460plus spectrophotometer. Elemental analyses for C, H, and N were performed using a Heraeus CHN-O-Rapid ana- lyzer. Mass spectra were recorded on an Agilent tech-