Solvent-free C-benzoylation and N-benzoylation reactions using

Article abstract of DOI:10.1080/00397911.2010.515363

An ecofriendly and efficient microwave-irradiated solvent-free benzoylation method was developed. The procedure for C-benzoylation used 50 mol% AlCl ₃ as a Lewis acid catalyst at 130°C and was completed in 10 min. The isolated yield was between 71% and 100%. N-benzoylation was conducted in a catalyst-free environment at 130°C in 10 min. The isolated yield was between 80% and 100%. Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397911.2010.515363

This article was downloaded by: [University of Delaware]
On: 06 October 2014, At: 01:51
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic Organic
Chemistry
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/lsyc20
Solvent-Free C-Benzoylation and N-
Benzoylation Reactions Using Microwave
Heating
Mohammad Al-Masum a , Maya Chen Wai a & Henry Dunnenberger a
a Department of Chemistry , Tennessee State University , Nashville ,
Tennessee , USA
Published online: 29 Jun 2011.
To cite this article: Mohammad Al-Masum , Maya Chen Wai & Henry Dunnenberger (2011) Solvent-Free
C-Benzoylation and N-Benzoylation Reactions Using Microwave Heating, Synthetic Communications:
An International Journal for Rapid Communication of Synthetic Organic Chemistry, 41:19, 2888-2898,
DOI: 10.1080/00397911.2010.515363
To link to this article: http://dx.doi.org/10.1080/00397911.2010.515363
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the
“Content”) contained in the publications on our platform. However, Taylor & Francis,
our agents, and our licensors make no representations or warranties whatsoever as to
the accuracy, completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content
should not be relied upon and should be independently verified with primary sources
of information. Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising
out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Conditions of access and use can be found at http://www.tandfonline.com/page/terms-
and-conditions

Synthetic Communications1, 41: 2888–2898, 2011
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2010.515363
SOLVENT-FREE C-BENZOYLATION AND
N-BENZOYLATION REACTIONS USING
MICROWAVE HEATING
Mohammad Al-Masum, Maya Chen Wai, and
Henry Dunnenberger
Department of Chemistry, Tennessee State University,
Nashville, Tennessee, USA
GRAPHICAL ABSTRACT
Abstract An ecofriendly and efficient microwave-irradiated solvent-free benzoylation
method was developed. The procedure for C-benzoylation used 50 mol% AlCl3 as a Lewis
acid catalyst at 130 ꢀC and was completed in 10 min. The isolated yield was between
71% and 100%. N-benzoylation was conducted in a catalyst-free environment at 130 ꢀC
in 10 min. The isolated yield was between 80% and 100%.
Keywords Catalyst-free and solvent-free N-benzoylation; microwave heating; solvent-
free AlCl3-catalyzed C-benzoylation
INTRODUCTION
Benzoylation is an important organic transformation for the synthesis of
aromatic ketones, which are common building blocks found in many natural pro-
ducts and active pharmaceutical ingredients.[1] Microwave-enhanced synthesis is a
Received January 11, 2010.
Address correspondence to Mohammad Al-Masum, Department of Chemistry, Tennessee State
University, 3500 John A. Merritt Blvd., Boswell 201, Nashville, TN 37209, USA. E-mail: malmasum@
tnstate.edu
2888

C-BENZOYLATION AND N-BENZOYLATION
2889
Scheme 1.
present-day green chemistry method that is getting increasing interest in both aca-
demic and industrial research laboratories. Very few papers have reported for
microwave-enhanced benzophenone synthesis in minutes instead of using conven-
tional heating for hours.[2–8] In this work, we report a solvent-free, microwave-
enhanced C-benzoylation and N-benzoylation procedure (Scheme 1).
RESULTS
To employ more environmentally friendly procedures, a solvent-free procedure
was developed for C-benzoylation using AlCl3 as catalyst and microwave
irradiation. Generally, reacting 50 mol% (0.25 mmol) of AlCl3 with 0.5 mmol of
benzoyl chloride derivative and 2.0 mmol of phenyl derivative gave the great yields.
Several control experiments were conducted to test the effectiveness of this newly
developed procedure. When the reaction was conducted procedurally in the micro-
wave in the absence of a catalyst, no transformation occurred. When the reaction
was performed at room temperature for 1 h with the catalyst, 28% transformation
occurred. Conventional heating in an oil bath for 1 h with the catalyst resulted in
47% isolated yield of product after column chromatography. Progress of these con-
trol experiments was monitored by gas chromatography–mass spectrometry
(GC-MS). Table 1 lists the successful C-benzoylation transformations and the corre-
sponding yields. In addition to the positive results listed in Table 1, several experi-
ments were conducted using other reagent combinations and did not produce the
expected outcome. For example, anthracene and allyl benzene with all combinations
of the benzylating reagents 1a–e as well as ferrocene with p-chlorobenzoyl chloride
or p-nitrobenzoyl chloride under these conditions resulted in decomposition or
oligomerization.
Benzoyl halide derivatives were treated with amine derivatives for N-benzoyla-
tion reactions. The same reaction with or without AlCl3 produced similar yields,
suggesting that the presence of the Lewis acid has no beneficial effect on the
reaction progress. Progress of these control experiments were monitored by GC-MS.
Table 2 lists the successful N-benzoylation transformations and the corresponding
yields. All the reaction were conducted on a 0.5-mmol scale and the molar
ratios tested were 1:1, 1:2, 1:4, 2:1, and 4:1 benzoyl halide to phenyl or amine
derivatives.

2890

2891

2892
M. AL-MASUM, M. C. WAI, AND H. DUNNENBERGER
Table 2. Microwave-irradiated solvent-free and catalyst-free N-benzoylationa
Entry
1
Benzoyl halide 1
Amine derivative 4
Product 5
Yields (%)
100
2
4a
4a
4a
97
3
4
5
81
64
1a
1b
100
6
7
8
9
4b
4b
4b
4b
91
80
90
99
1c
1d
aAll reactions were run at least two times. The products were purified by silica-gel chromatography
using hexane=ethyl acetate (5=1) as the eluent.

C-BENZOYLATION AND N-BENZOYLATION
2893
PROCEDURE
C-Benzoylation
In a typical C-benzoylation experiment, 0.5 mmol of PhCOCl, 2.0 mmol of
toluene, and 0.25 mmol AlCl3 are added to a 10-mL argon atmosphere reaction vial.
The reaction was run in dry condition under argon atmosphere. After adding a cata-
lytic amount of anhydrous AlCl3 followed by benzene derivative, benzoyl chloride
was added. In some cases, HCl gas fumes were clearly observed before the reaction
vial was set up in microwave reactor. The microwave conditions utilized were 300 W
at 130 ꢀC for 10 min reaction time. Following the completion of the reaction in the
microwave, the product was allowed to cool to room temperature before it was
extracted with ethyl acetate (3 ꢁ 10 mL). The combined extracts were washed with
concentrated ammonium chloride and concentrated sodium chloride. Sodium sulfate
was used as the primary drying agent for the product extracts, and a rotary vapor
was utilized to remove any excess organic solvent. GC-MS was used to check the
presence of the desired product. The crude product was subjected to silica-gel chro-
matography using hexane=ethyl acetate (50=1) as the eluent for purification. The
pure product was dried in vacuo, and the percentage yield was determined by
1
spectral analysis. Both H NMR and 13C NMR were used to analyze the structure
of the desired product. These data were compared to reported literature values.
N-Benzoylation
In a typical N-benzoylation reaction, 0.5 mmol of PhCOCl and 1.0 mmol of
aniline were added to a 10-ml microwaveable reaction vial flushed with argon
gas. The microwave conditions used are the same as C-benzoylation reactions,
which is 300 W at 120 ꢀC for 10 min reaction time. The N-benzoylation products also
were purified by silica-gel chromatography using hexane=ethyl acetate (5=1) as the
eluent.
SPECTRAL DATA
Compound 3a
LRMS: Calculated for C14H12O Mþ 196. Found: 196. 1H NMR (CDCl3,
300 MHz) d 2.36 (s, 3H, -CH3), 7.19 (d, 2H, -C6H4), 7.22 (d, 2H, -C6H4), 7.40 (d,
2H, -C6H4), 7.48 (d, 2H, -C6H4), 7.70 (d, 2H, -C6H4); 13C NMR (CDCl3,
75.0 MHz) d 128.1, 128.9, 130.1, 130.3, 132.1, 134.8, 137.9, 143.2, 196.5; mp
59–60 ꢀC; literature mp 59 ꢀC.[9a]
Compound 3b
LRMS: Calculated for C15H14O Mþ 210. Found: 210. 1H NMR (CDCl3,
300 MHz) d 2.36 (s, 6H, 2 ꢁ -CH3), 7.20 (d, 4H, -C6H4), 7.62 (d, 4H, -C6H4); 13C
NMR (CDCl3, 75.0 MHz) d 21.6, 128.8, 130.1, 135.1, 142.9, 196.3; mp 92–93 ꢀC;
literature mp 90–93 ꢀC.[9b]

2894
M. AL-MASUM, M. C. WAI, AND H. DUNNENBERGER
Compound 3c
LRMS: Calculated for C15H14O Mþ 226. Found: 226. 1H NMR (CDCl3,
300 MHz) d 2.36 (s, 3H, -CH3), 3.80 (s, 3H, -CH3), 6.88 (d, 2H, -C6H4), 7.19 (d,
2H, -C6H4), 7.59 (d, 2H, -C6H4), 7.73 (d, 2H, -C6H4); 13C NMR (CDCl3,
75.0 MHz) d 21.5, 55.4, 113.4, 113.6, 128.8, 130.3, 132.4, 135.4, 142.5, 162.9,
195.3; mp 94–95 ꢀC; literature mp 94–95 ꢀC.[9c]
Compound 3d
1
LRMS: Calculated for C14H11OCl Mþ 231. Found: 231. H NMR (CDCl3,
300 MHz) d 2.35 (s, 3H, -CH3), 7.18 (d, 2H, -C6H4), 7.36 (d, 2H, -C6H4), 7.62 (m,
4H, -C6H4); 13C NMR (CDCl3, 75.0 MHz) d 21.6, 128.4, 129.0, 130.1, 131.2,
134.4, 136.1, 138.5, 143.4, 195.1; mp 121–123 ꢀC; literature mp 123–125 ꢀC.[9d]
Compound 3e
1
LRMS: Calculated for C14H11OCl Mþ 241. Found: 241. H NMR (CDCl3,
300 MHz) d 2.35 (s, 3H, -CH3), 7.21 (d, 2H, -C6H4), 7.60 (d, 2H, -C6H4), 7.79 (d,
2H, -C6H4), 8.31 (d, 2H, -C6H4); 13C NMR (CDCl3, 75.0 MHz) d 21.6, 123.3,
125.3, 129.2, 130.4, 131.2, 133.4, 143.1, 144.4, 149.4, 194.3; mp 120–121 ꢀC; literature
mp 122–124 ꢀC.[9e]
Compound 3f
1
LRMS: Calculated for C17H14OFe Mþ 290. Found: 290. H NMR (CDCl3,
300 MHz) d 4.21 (m, 2H, -C5H5), 4.59 (m, 2H, -C5H5), 4.90 (m, 5H, -C5H5), 7.60
(m, 5H, -C6H5); 13C NMR (CDCl3, 75.0 MHz) d 70.2, 71.4, 72.6, 78.0, 128.0,
128.2, 131.4, 139.7, 199.2; mp 123–124 ꢀC; literature mp 123–126 ꢀC.[9f]
Compound 3g
1
LRMS: Calculated for C18H16OFe Mþ 304. Found: 304. H NMR (CDCl3,
300 MHz) d 2.36 (s, 3H, -CH3), 4.13 (s, 5H, -C5H5), 4.50 (s, 2H, -C5H4), 4.83 (s,
2H, C5H4), 7.20 (d, 2H, -C6H4) 7.75 (d, 2H, -C6H4); 13C NMR (CDCl3,
75.0 MHz) d 21.5, 70.1, 71.4, 72.3, 78.3, 128.2, 128.8, 137.0, 142.0, 198.7.
Compound 3h
1
LRMS: Calculated for C18H16O2Fe Mþ 320. Found: 320. H NMR (CDCl3,
300 MHz) d 3.82 (s, 3H, -CH3), 4.13 (s, 5H, -C5H5), 4.49 (m, 2H, -C5H4), 4.83 (m,
2H, -C5H4), 6.90 (d, 2H, -C6H4), 7.88 (d, 2H, -C6H4); 13C NMR (CDCl3,
75.0 MHz) d 29.6, 70.1, 71.5, 72.1, 113.3, 130.4, 162.3.
Compound 3i
LRMS: Calculated for C17H11O Mþ 232. Found: 232. 1H NMR (CDCl3,
300 MHz) d 7.45 (m, 7H, -C10H7), 7.77 (m, 5H, -C6H5); 13C NMR (CDCl3,

C-BENZOYLATION AND N-BENZOYLATION
2895
75.0 MHz) d 124.2, 125.5, 126.3, 127.1, 128.2, 128.3, 129.3, 130.3, 130.8, 131.2, 132.1,
133.1, 134.6, 135.1, 136.2, 138.1, 197.9.
Compound 3j
LRMS: Calculated for C18H15O Mþ 246. Found: 246. 1H NMR (CDCl3,
300 MHz) d 2.30 (d, 3H, -CH3), 7.13 (m, 4H, -C10H5), 7.40 (m, 3H, -C10H7), 7.84
(m, 4H, -C6H4); 13C NMR (CDCl3, 75.0 MHz) d 21.6, 124.2, 125.7, 126.2, 127.2,
128.1, 129.0, 130.2, 131.5, 132.1, 133.5, 135.0, 135.5, 136.5, 143.1, 144.1, 196.4.
Compound 3k
1
LRMS: Calculated for C18H15O2 Mþ 262. Found: 262. H NMR (CDCl3,
300 MHz) d 3.74 (s, 3H, -OCH3), 6.81 (m, 4H, -C12H7), 7.39 (m, 3H, -C10H7),
7.75 (m, 2H, -C6H5), 8.13 (m, 2H, -C6H5); 13C NMR (CDCl3, 75.0 MHz) d 36.4,
91.9, 113.5, 124.3, 125.5, 126.2, 127.6, 128.2, 129.1, 130.7, 131.1, 132.5, 133.4,
136.7, 196.8.
Compound 3l
1
LRMS: Calculated for C17H12OCl Mþ 266. Found: 266 H NMR (CDCl3,
300 MHz) d 7.41 (m, 7H, -C12H7), 7.68 (m, 2H, -C6H5), 7.82 (m, 2H, -C6H5);
13C NMR (CDCl3, 75.0 MHz) d 124.2, 125.4, 126.5, 127.3, 128.4, 128.6, 129.3,
130.7, 131.7, 132.1, 133.9, 135.7, 136.54, 139.6, 196.6.
Compound 5a
LRMS: Calculated for C14H13ON Mþ 211. Found: 211. 1H NMR (acetone-d6,
300 MHz) d 4.61 (d, J ¼ 5.7 Hz, 2H, -CH2), 6.46 (s, 1H, -NH) 7.65 (m, 10H,
-aromatic); 13C NMR (acetone-d6, 75.0 MHz) d 43.9, 127.8, 129.1, 129.5 132.0,
135.7, 167.4; mp 111–115 ꢀC; literature mp 111–116 ꢀC.[9g]
Compound 5b
LRMS: Calculated for C15H15ON Mþ 225. Found: 225. 1H NMR (acetone-d6,
300 MHz) d 2.98 (s, 3H, -CH3), 4.58 (d, J ¼ 5.6 Hz, 2H, -CH2), 7.59 (m, 9H, aro-
matic), 8.20 (s, 1H, -NH); mp 138–140 ꢀC; literature mp 133–136 ꢀC.[9g]
Compound 5c
LRMS: Calculated for C15H15O2N Mþ 241. Found: 241. 1H NMR
(acetone-d6, 300 MHz) d 3.83 (s, 3H, -OCH3), 4.58 (d, 2H, J ¼ 5.7 Hz, 2H, -CH2),
7.44 (m, 9H, aromatic), 8.20 (s, 1H, -NH); 13C NMR (acetone-d6, 75.0 MHz) d
43.9, 55.80, 114.3, 129.0, 140.9, 167.0; mp 126–128 ꢀC; literature mp 128 ꢀC.[9h]

2896
M. AL-MASUM, M. C. WAI, AND H. DUNNENBERGER
Compound 5d
LRMS: Calculated for C14H12ONCl Mþ 245. Found: 245. 1H NMR
(acetone-d6, 300 MHz) d 4.59 (d, J ¼ 5.7 Hz, -CH2), 7.65 (m, 9H, aromatic), 8.38
(s, 1H, -NH); 13C NMR (acetone-d6, 75.0 MHz) d 44.0, 105.7, 127.8, 128.5, 129.3,
129.9, 137.6, 140.5, 166.2; mp 165–167 ꢀC; literature mp 165–167 ꢀC.[9i]
Compound 5e
LRMS: Calculated for C13H11ON Mþ 197. Found: 197. 1H NMR (THF,
300 MHz) d 6.52 (m, 2H, aromatic), 6.9 (m, 2H, aromatic), 7.25 (m, 2H, aromatic),
7.42 (m, 2H, -C6H5), 7.85 (m, 2H, aromatic), 9.40 (s, 1H, -NH); 13C NMR
(acetone-d6, 75.0 MHz) d 121.0, 124.5, 128.3, 129.5, 132.3, 136.3, 140.3, 166.4; mp
162–166 ꢀC; literature mp 163 ꢀC.[9j]
Compound 5f
LRMS: Calculated for C14H13ON Mþ 211. Found: 211. 1H NMR (acetone-d6,
300 MHz) d 3.00 (m, 3H, -CH3), 7.48 (m, 9H, aromatic), 9.53 (s, 1H, -NH-); 13C
NMR (acetone-d6, 75.0 MHz) d 21.4, 121.0, 124.4, 128.4, 129.8, 133.4, 140.4,
142.7, 166.2.
Compound 5g
LRMS: Calculated for C14H13O2N Mþ 227. Found: 227. 1H NMR
(acetone-d6, 300 MHz) d 3.87 (s, 3H, -OCH3), 7.51 (m, 9H, aromatic) 9.49 (s, 1H,
-NH); 13C NMR (acetone-d6, 75.0 MHz) d 55.8, 114.4, 120.8, 120.9, 124.3, 129.4,
130.2, 140.5, 163.3; mp 168–170 ꢀC; literature mp 170–171 ꢀC.[9k]
Compound 5h
LRMS: Calculated for C13H10ONCl Mþ 232. Found: 232. 1H NMR
(acetone-d6, 300 MHz) d 7.56 (m, 9H, aromatic), 9.66 (s, 1H, -NH).
Compound 5i
1
LRMS: Calculated for C13H10O3N2 Mþ 242. Found: 242. H NMR (THF,
300 MHz) d 7.08–8.32 (m, 9H, aromatic, 9.71 (s, 1H, -NH); 13C NMR (THF,
75.0 MHz) d, 121.0, 124.3, 124.9, 129.5, 129.7, 140.1, 142.2, 164.5; mp 209–212 ꢀC;
literature mp 210 ꢀC.[9l]
CONCLUSION
In summary, this ecofriendly benzoylation procedure has important practical
significance in synthesizing benzophenone derivatives.

C-BENZOYLATION AND N-BENZOYLATION
2897
ACKNOWLEDGMENT
Financial support from U.S. Department of Education Title III grant to
Tennessee State University is acknowledged.
REFERENCES
1. (a) Palomer, A.; Pascual, J.; Cabre, M.; Borras, L.; Gonzalez, G.; Aparici, M.; Carabaza,
A.; Cabre, F.; Garcia, M. L.; Mauleon, D. Structure-based design of cyclooxygenase-2 sel-
ectivity into ketoprofen. Bioorg. Med. Chem. Lett. 2002, 12, 533; (b) Kawamura, M.; Cui,
D. M.; Shimada, S. Friedel–Crafts acylation reaction using carboxylic acids as acylating
agents. Tetrahedron 2006, 62, 9201; (c) Paul, S.; Nanda, P.; Gupta, R. PhCOCl-Py=basic
alumina as versatile reagent for benzoylation in solvent-free conditions. Molecules 2003,
8, 374; (d) Ianni, A.; Waldvogel, S. R. Reliable and versatile synthesis of 2-aryl-substituted
cinnamic acid esters. Synthesis 2006, 2103; (e) Repichet, S.; Le Roux, C.; Roques, N.;
Dubac, J. BiCl3-catalyzed Friedel–Crafts acylation reactions: Bismuth(III) oxychloride as
a water insensitive and recyclable procatalyst. Tetrahedron Lett. 2003, 44, 2037; (f)
Barbier-Baudry, D.; Bouazza, A.; Desmurs, J. R.; Dormond, A.; Richard, S. UraniumIV
and uranyle salts, efficient and reusable catalysts for acylation of aromatic compounds.
J. Mol. Catal. 2000, 164, 195; (g) Lidstrom, P.; Tierney, J.; Wathey, B.; Westman, J.
Microwave-assisted organic synthesis—A review. Tetrahedron 2001, 57, 9225.
2. De la Hoz, A.; Diaz-Ortiz, A.; Moreno, A.; Langa, F. Cycloadditions under microwave-
irradiation conditions: Methods and applications. Eur. J. Org. Chem. 2000, 3659.
3. Elander, N.; Jones, R.; Lu, Y.; Stone-Elander, S. Microwave-enhanced radiochemistry.
Chem. Soc. Rev. 2000, 29, 239.
4. Deshayes, S.; Liagre, M.; Loupy, A.; Luche, J.; Petit, A. A. Microwave activation in
phase-transfer catalysis. Tetrahedron 1999, 55, 10851.
5. Varma, R. S. Solvent-free organic syntheses using supported reagents and microwave
irradiation. Green Chem. 1999, 1, 43.
6. Loupy, A.; Petit, A.; Hamelin, J.; Texier-Boullet, F.; Jacquault, P.; Mathe, D. New
solvent-free organic synthesis using focused microwaves. Synthesis 1998, 1213.
7. Caddick, S. Microwave-assisted organic reactions. Tetrahedron 1995, 51, 10403.
8. Abramovitch, R. A. Applications of microwave energy in organic chemistry: A review.
Org. Prep. Proced. Int. 1991, 23, 683.
9. (a) Snyder, H. R.; Elston, C. T. Polyphosphoric acid as a reagent in organic chemistry. VII.
Acylation. J. Am. Chem. Soc. 1955, 77, 364; (b) Aldrich Handbook of Fine Chemicals;
Aldrich: St. Louis, MO, 2009–2010; 1113; (c) Belluti, F.; Piazzi, L.; Bisi, A.; Gobbi, S.;
Bartolini, M.; Cavalli, A.; Valenti, P.; Rampa, A. Design, synthesis, and evaluation of ben-
zophenone derivatives as novel acetylcholinesterase inhibitors. Eur. J. Med. Chem. 2009,
44, 1341; (d) Rao, M. L. N.; Venkatesh, V.; Banerjee, D. Atom-efficient cross-coupling
reactions of triarylbismuths with acyl chlorides under Pd(0) catalysis. Tetrahedron 2007,
63, 12917; (e) Jin, T.-S.; Yang, M.-N.; Feng, G.-L.; Li, T.-S. Synthesis of diaryl ketones
catalyzed by Al2O3-ZrO2=S2O2-8 solid superacid. Synth. Commun. 2004, 34, 479; (f) Yang,
D.; Liu, Z.; Li, Y.; Chen, B. Convenient synthesis of aryl ferrocenyl ketone via palladium-
catalyzed carbonylation coupling. Synth. Commun. 2007, 37, 3759; (g) Petricci, E.;
Munaini, C.; Radi, M.; Corelli, F.; Botta, M. Microwave-assisted acylation of amines, alco-
hols, and phenols by the use of solid-supported reagents (SSRs). J. Org. Chem. 2004, 69,
7880; (h) Kokare, N. D.; Nagawade, R. R.; Rane, V. P.; Shinde, D. B. Organophosphorus
esters of 1-hydroxy-2-phenylbenzimidazole: synthesis and utilization as novel peptide coup-
ling reagents. Synthesis 2007, 766; (i) Shen, X.-X.; Liu, Q.; Xing, R.-G.; Zhou, B.

2898
M. AL-MASUM, M. C. WAI, AND H. DUNNENBERGER
Reduction of N-(alkoxy(aryl)methyl)benzamide compounds by a Hantzsch ester 1,4-dihy-
dropyridine using Pd=C as a catalyst. Catal. Lett. 2008, 126, 361; (j) Pu, Y. J.; Vaid, R. K.;
Bioni, S. K.; Towsley, R. W.; Doecke, C. W.; Mitchell, D. A practical method for functio-
nalized peptide or amide bond formation in aqueous-ethanol media with EDC as activator.
Org. Process Res. Dev. 2009, 13, 310; (k) Li, X.; Zhang, Y. Facile preparation of amides
from azo compounds by SmI2. Ind. J. Chem., Sect. B 2006, 45B, 1576; (l) Bahrami, K.;
Khodaei, M. M.; Farrokhi, A. H2O2=SOCl2: A useful reagent system for the conversion
of thiocarbonyls to carbonyl compounds. Tetrahedron 2009, 65, 7658.