J IRAN CHEM SOC (2014) 11:653–658
DOI 10.1007/s13738-013-0336-z
ORIGINAL PAPER
Nano silica phosphoric acid: an efficient catalyst for the one-pot
synthesis of amidoalkyl naphthols under solvent-free condition
•
A. Bamoniri B. F. Mirjalili S. Nazemian
•
Received: 1 March 2013 / Accepted: 25 August 2013 / Published online: 6 September 2013
ꢀ Iranian Chemical Society 2013
Abstract 1-Amidoalkyl-2-naphthols were prepared via
one-pot multi-component reaction of 2-naphthol, alde-
hydes, and amides in the presence of nano silica phosphoric
acid under solvent-free condition at 80 ꢁC. Short reaction
times, high yields, and easy work-up are the advantages of
this protocol.
further led to renaissance of MCRs. Nevertheless, great
efforts have been made to find and develop new MCRs. In
a point of view of the conservation of the environment
combining with economic aspects, all chemists demand the
application of metal ion-free, environmentally safe and
convenient reagents in the multi-component reactions [5].
Amidoalkyl naphthols are precursors for the synthesis of
1-aminomethyl-2-naphthols which exhibit important car-
diovascular, bradycardiac [6], and hypertensive [7] activi-
ties. Previously, some acid catalysts such as [bmim]HSO4
[8], cyanuric chloride [9], sulphamic acid [10, 11], silica-
supported molybdatophosphoric acid [12], H3PW12O40
[13], H4SiW12O40 [14], I2 [15], [TEBSA][HSO4] [16],
KHSO4 [17], P2O5 [18], silica sulfuric acid [19], zirconyl
(IV) chloride [20], HClO4ꢀSiO2 [21] and thiamine hydro-
chloride [22] were applied.
Keywords Amidoalkyl naphthol ꢀ Multi-
component reaction ꢀ Heterogeneous catalyst ꢀ
Solvent-free condition
Introduction
One-pot multi-component reactions (MCRs) by virtue of
their convergence, productivity, facile execution and high
yield have attracted considerable attention in recent years
[1]. There has been tremendous development in three or
four component reaction especially the Passerini [1], Big-
nelli [2], Ugi [3] and Mannich [4] reactions, which have
Silica phosphoric acid (SPA) [23] is an efficient and
reusable catalyst. It was prepared by reaction of silica
chloride with dry phosphoric acid. It is noted that, silica
chloride was prepared via reaction of silica gel and thionyl
chloride. By using nano silica gel instead of silica gel,
according to above pathway, nano silica phosphoric acid
(nano-SPA) was prepared. The particle size of nano-SPA
was measured by SEM and TEM photography (Fig. 1).
The acidic capacity of nano-SPA was presented
10.32 mmol g-1. It was determined via titration of 0.2 g of
nano-SPA with standard solution of NaOH.
The manuscript has been presented at the ‘‘1st National Conference
on Multi-Component Reaction’’ in Institute of Science and High
Technology and Environmental sciences, Graduate University of
Advanced Technology, Kerman, Iran, 2012.
Electronic supplementary material The online version of this
material, which is available to authorized users.
The FT-IR (ATR) spectra of silica chloride, nano-SPA
and H3PO4•SiO2 were shown in Fig. 2. In all ATR spectra,
the Si–O–H and Si–O–Si stretching bands are appeared in
the range of 900–1,100 cm-1. In silica chloride spectrum,
the Si–Cl stretching band is appeared in 700 cm-1. In ATR
spectra of nano-SPA and H3PO4•SiO2, the P–O–H, P=O,
P–O stretching bands are appeared in 910–1,040, 1,637 and
2,400–2,800 cm-1, respectively. According to above data,
A. Bamoniri (&) ꢀ S. Nazemian
Department of Organic Chemistry, Faculty of Chemistry,
University of Kashan, Kashan, Islamic Republic of Iran
e-mail: bamoniri@kashanu.ac.ir
B. F. Mirjalili
Department of Chemistry, College of Science, Yazd University,
Yazd, Islamic Republic of Iran
123
Bamoniri
