Convenient method for the Friedel-Crafts acylation of benzene derivatives using silver nitrate as catalyst

Article abstract of DOI:10.1080/00397911003707139

(Chemical Equation Presented) Friedel-Crafts acylation of benzene derivatives such as anisole, toluene, and xylene has been successively carried out using silver nitrate as the catalyst in the presence of an eco friendly solvent (ethyl alcohol). Both benzoyl chloride and acetyl chloride reacted smoothly under the conditions to afford the corresponding ketones in good yield. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397911003707139

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Convenient Method for the Friedel–Crafts
Acylation of Benzene Derivatives Using
Silver Nitrate as Catalyst
K. M. Lokanatha Rai a , Ebraheem Abdu Musad a , R. L. Jagadish b &
K. N. Shivakumar a
a Department of Studies in Chemistry, University of Mysore,
Manasagangotri, Mysore, India
b Department of Polymer Science, Sir. M. V. P. G. Centre,
Tubinakere, Mandya, India
Published online: 03 Mar 2011.
To cite this article: K. M. Lokanatha Rai , Ebraheem Abdu Musad , R. L. Jagadish & K. N. Shivakumar
(2011) Convenient Method for the Friedel–Crafts Acylation of Benzene Derivatives Using Silver
Nitrate as Catalyst, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 41:7, 953-955, DOI: 10.1080/00397911003707139
To link to this article: http://dx.doi.org/10.1080/00397911003707139
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Synthetic Communications1, 41: 953–955, 2011
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911003707139
CONVENIENT METHOD FOR THE FRIEDEL–CRAFTS
ACYLATION OF BENZENE DERIVATIVES USING
SILVER NITRATE AS CATALYST
K. M. Lokanatha Rai,1 Ebraheem Abdu Musad,1
R. L. Jagadish,2 and K. N. Shivakumar1
1Department of Studies in Chemistry, University of Mysore,
Manasagangotri, Mysore, India
2Department of Polymer Science, Sir. M. V. P. G. Centre, Tubinakere,
Mandya, India
GRAPHICAL ABSTRACT
Abstract Friedel–Crafts acylation of benzene derivatives such as anisole, toluene, and
xylene has been successively carried out using silver nitrate as the catalyst in the presence
of an eco friendly solvent (ethyl alcohol). Both benzoyl chloride and acetyl chloride reacted
smoothly under the conditions to afford the corresponding ketones in good yield.
Keywords Catalyst; Friedel–Crafts; silver nitrate
Friedels–Crafts acylation or alkylation reactions are fundamental and some of the
most important processes in organic synthesis as well as in industrial chemistry.[1]
These reactions are generally carried out using AlCl3 as Lewis acid in the presence
of solvents such as CS2 and nitrobenzene. Various reagents used to acylate or alkyl-
ate the hydrocarbon under Friedel–Crafts conditions include SnCl4, FeCl3, ZnCl2,
ZnO, hafnium(IV) triflate,[2] ytterbium(II) triflate,[3] titanium(IV) chloride triflate,[4]
and bismuth(III)triflate.[5] The results obtained in these reagents are usually good,
but one has to do the reaction under drastic conditions. In addition to this, tedious
workup procedures and use of large amount of acid, which may induce environmen-
tal pollution, remain as severe problems to overcome, especially in large-scale indus-
trial processes.
Under these circumstances, development of more efficient and powerful cata-
lysts is strongly demanded. In this article, we report the Friedel–Crafts acylation
Received December 8, 2009.
Address correspondence to K. M. Lokanatha Rai, Department of Studies in Chemistry, University
of Mysore, Manasagangotri, Mysore 570006, India. E-mail: kmlrai@yahoo.com
953

954
K. M. L. RAI ET AL.
Scheme 1. (a) R¼R0¼H, R00¼Ph; (b) R¼H, R0¼OCH3, R00¼Ph; (c) R¼R0¼CH3, R00¼Ph; (d) R¼H,
R0¼OCH3, R00¼CH3; (e) R¼R0¼CH3, R00¼CH3; (f) R¼H, R0¼CH3, R00¼CH3; and (g) R¼R0¼H,
R00¼CH3.
of benzene, toluene, anisole, and o-xylene using silver nitrate as catalyst in an
ecofriendly solvent, ethanol. This method has distinct advantages over the other
existing methods although the reagent is costlier: it has mild reaction conditions,
shorter reaction time, easy workup procedure, and excellent yields.
Most alkyl halides, when in contact with alcoholic silver nitrate, precipitate sil-
ver chloride, but no reaction occurs when there is aryl halide in the place of alkyl
halides. Recently Ajay Kumar et al.[6] observed that reaction of chloramine-T with
alcoholic silver nitrate followed by addition of alkenes afforded aziridine derivatives.
The probable path for the formation of aziridine involves the generation of highly
reactive nitrene intermediate, which may be formed by eliminating AgCl from
chloramine-T. These results prompted us to utilize silver nitrate as catalyst for
Friedel–Crafts acylation, keeping in mind that reaction of acyl halide with silver
nitrate generates reactive carbocation and we wanted to make it general method
for the synthesis of aryl ketones.
In a typical synthesis, equimolar quantities of benzene and acetyl chloride in
alcohol were treated with an equimolar quantity of well-powdered silver nitrate with
stirring at room temperature (Scheme 1). It was then stirred for 2–3 h. On the usual
workup, it yields 80 to 85% of acetophenone. Formation of ketones (3) were con-
firmed by comparing the synthesized molecules with the standard samples (e.g.,
acetophenone and benzophenone) and others prepared by conventional method
using thin-layer chromatography (TLC) and also by taking respective boiling points
and melting points (Table 1). Further, the products were confirmed by infrared (IR)
and NMR studies.
Table 1. Synthesis of benzophenone
Entry
R
R0
R00
Yield (%)
3a
3b
3c
3d
3e
3f
H
H
H
Ph
Ph
84
80
74
84
71
79
82
OCH3
CH3
OCH3
CH3
CH3
H
CH3
H
Ph
CH3
CH3
CH3
CH3
CH3
H
3g
H

FRIEDEL–CRAFTS ACYLATION
955
EXPERIMENTAL
Melting points were recorded in open capillaries using a Thomus Hoover
apparatus and were uncorrected. The compounds were routinely checked for their
purity by TLC using silica gel-G as adsorbent. IR spectra were recorded on a
Shimadzu Fourier transform (FT) 8300 spectrometer. 1H NMR spectra were
recorded on a Jeol 60-MHz FT NMR spectrometer using CDCl3 as solvent.
Typical Procedure for the Preparation of Benzophenone (3a)
A mixture of benzene (0.66 g, 8.5 mmol), benzoyl chloride (1.44 g, l0.3 mmol),
and silver nitrate (1.69 g, 10 mmole) in ethanol (10 ml) was stirred using a magnetic
stirrer for 2 h. The precipitated silver chloride in the reaction was filtered off. The
filtrate was extracted into ether and washed with 10% NaOH (3 ꢀ 20 ml) and water.
After drying over anhydrous sodium sulfate, the ethereal layer was evaporated in
vacuo. The resultant residue dissolved in chloroform (2 ml) was poured into a flask
containing petroleum ether, and crystals of benzophenone were obtained. Recrystal-
lization from alcohol produces pure crystals of benzophenone in 83% (0.6 g),
mp ¼ 44–46 ꢁC.
ACKNOWLEDGMENT
The project was supported by the AstraZeneca Research Foundation of India,
Bangalore, India.
REFERENCES
1. Olah, A. In Friedel–Crafts and Related Reactions; Interscience: New York, 1964; Vol. III,
Part 1; Heaney, H. In Comprehensive Organic Synthesis; B. M. Trost (Ed.); Pergamon
Press: Oxford, 1991; p. 733.
2. Hachiya, I.; Morikawi, M.; Kobayashi, S. Catalytic Friedel–Crafts acylation reactions
using hafnium triflate as a catalyst in lithium perchlorate–Nitromethane. Tetrahedron Lett.
1995, 409.
3. Kobashi, S.; Hachiya, I. Lanthanide triflates as water-tolerant lewis acids: Activation of
commercial formaldehyde solution and use in the aldol reaction of silyl enol ethers with
aldehydes in aqueous media. J. Org. Chem. 1994, 59, 3590.
4. Izume, T.; Shijna, I.; Hulaiyama, T. An efficient esterification reaction between equimolar
amounts of free carboxylic acids and alcohols by the combined use of octamethylcyclote-
trasiloxane and a catalytic amount of titanium(IV) chloride tris(trifluoromethanesulfo-
nate). Chem. Lett. 1995, 141.
5. Laurent-Robert, H.; Leroux Dubae, J. Enhancement of dienophilic and enophilic reactivity
of the glyoxylic acid by bismuth(III) triflate in the presence of water. Synth. Lett. 1998,
1138.
6. Ajaykumar, K.; Rai, K. M. L.; Umesha, K. B. A new approach for the transformation of
alkenes to pyrrolines via aziridine intermediates. Tetrahedron 2001, 57, 6993–6996.