Chemoselective C-benzoylation of phenols by using ALCl3under solvent-free conditions

Article abstract of DOI:10.4314/bcse.v29i2.14

Substituted phenols were chemo-selectively reacted with benzoylchloride in presence of aluminum chloride under solvent-free condition to afford the corresponding 2′-hydroxy aryl benzophenones in excellent yields (72-96%). Naphthol benzoylation resulted in lower yields as compared to phenols. Both reactions completed in 5-10 min with quantitative yields providing excellent control over regioselectivity of products.

Full text of DOI:10.4314/bcse.v29i2.14

Bull. Chem. Soc. Ethiop. 2015, 29(2), 319-325.
Printed in Ethiopia
DOI: http://dx.doi.org/10.4314/bcse.v29i2.14
ISSN 1011-3924
 2015 Chemical Society of Ethiopia
SHORT COMMUNICATION
CHEMOSELECTIVE C-BENZOYLATION OF PHENOLS BY USING ALCl3 UNDER
SOLVENT-FREE CONDITIONS
Sunil V. Gaikwad, Beena R. Nawghare and Pradeep D. Lokhande*
Department of Chemistry, Savitribaiphule Pune University, Pune 411007, India
(Received December 19, 2013; revised April 17, 2015)
ABSTRACT. Substituted phenols were chemo-selectively reacted with benzoylchloride in presence of
aluminum chloride under solvent-free condition to afford the corresponding 2'-hydroxy aryl benzophenones in
excellent yields (72-96%). Naphthol benzoylation resulted in lower yields as compared to phenols. Both reactions
completed in 5-10 min with quantitative yields providing excellent control over regioselectivity of products.
KEY WORDS: Chemoselective C-acylation, F-C reaction, Fries rearrangement
INTRODUCTION
Friedel-Crafts acylation and benzoylation reactions are of great important in both academic
research and industrial processes to synthesize aromatic ketones [1, 2]. Traditional Friedel-
Crafts acylation or benzoylation reactions employ acid chlorides and Lewis acids (AlCl3 [3],
ZnCl2 [4], BiCl3 [5], FeCl3 [6]) or Brønsted acid [7] with aromatic compounds. Hydroxyaryl
ketones [8] are versatile intermediates in the synthesis of biologically active chalcones [9]
flavones [10], pyrazolines [11], and indazoles [12]. O-hydroxydiaryl ketones exhibit protein
kinase B inhibitor [13], cyclin-dependent kinase inhibitor [14] and cysteine protease modulator
activities [15]. 4'-Hydroxy and 2'-hydroxypropiophenone are used as intermediates in
manufacturing perfumes, pharmaceuticals and as UV adsorbents [1]. Hydroxydiaryl ketone
moieties occur in natural products such as cotoin [16], balanol [17] and daunorubicin [18] or
they are used as building blocks for the synthesis of various pharmaceutical compounds.
In this work, benzoylation of phenolic compounds was carried out following the two steps of
O-benzoylation and then Fries rearrangement of aryl benzoates (Scheme 1). Fries rearrangement
employs using anhydrous AlCl3 [19], CH3SO3H [20], Bi(OTf)3 [21], ZrCl4 [22], Zeolite H-beta
[23]. Direct Friedel-Crafts acylation of phenols using acetyl chloride (chemoselective reaction)
has been done by Bi(OTf)3 [21] or Hf(OTf)4 [24] in PhMe-MeNO2 as solvent at 110 oC for 5-6 h
o
in moderate yield (64-69%) and Sc(OTf)3 in LiClO4-MeNO2 at 50 C for 6 h into 62% yield
[25a]. Furthermore ortho and para propionylation of simple phenols was carried out by
propionylchloride in presence of Zeolite H-beta [23] as catalyst under solvent free condition at
o
140 C for 6 h in 81% yield, and benzoylation of anisole was achieved by benzoylchloride in
presence of B2O3-ZrO2 in nitro benzene as solvent at 150 oC for 22 h [25b] or by I2-DMF at 140
oC for 12 h in 67% [25c]. To the best of our knowledge there is no previous report for direct C-
benzoylation of phenols and naphthol using AlCl3 under solvent free conditions. The use of
aluminum chloride is significant because, it has low cost, commercially available, easy to handle
and easy of work-up. On the other hand, avoiding the solvent reduces number of components in
reaction, stops any solvent emission problems, and gets around any solvent recycling
requirements. Herein we describe a Friedel-Craft benzoylation of substituted phenols, through a
modified benzoylation procedure that gives O-substituted benzophenones regioselectively with
excellent yields. The objective of the present work is elimination of esterification step (step 1,
__________
*Corresponding author. E-mail: pdlokhande@chem.unipune.ac.in; sunilunipune2012@gmail.com

320
Sunil V. Gaikwad et al.
Scheme 1) in conjunction with absence of solvent, e.g. nitrobenzene, toluene, dichloromethane,
nitro methane, etc., and low reaction time.
EXPERIMENTAL
o
1H-NMR (300 MHz) spectra were recorded on a Varian VXR 300 instrument at 293 K in
CDCl3. Chemical shift values were recorded in δ units (ppm) relative to Me4Si as internal
standard. Melting points were determined by using a Buchi melting point apparatus. Infrared
spectra (IR) were recorded using KBr pellets on a Perkin-Elmer 240C analyzer. Thin layer
chromatography (TLC) was performed on silica gel 60 PF254 plates or aluminum oxide plates
from Merck.
Procedure for benzoylation of substituted 4-chlorophenol. To a mixture of 4-chlorophenol (7.8
mmol, 1 g) and anhydrous AlCl3 (9.3 mmol, 1.24 g) stirred at 110 °C, benzoyl chloride (9.3
mmol, 1.31 g) was added in several portions, very carefully holding the temperature under 110
oC. After completion, the mixture was poured into ice water and then concentrated HCl (2-4
mL) was added subsequently. The suspension was stirred vigorously for 5-10 min. The crude
desired products were obtained as yellow solids, after filtration crude product was purified by
crystallization in ethanol/methanol and yield of product was recorded as 93%.
5-Chloro-2-hydroxyphenyl)(phenyl)methanone (Table 2, Entry 1). Color; yellow solid, m.p. 97-
o
1
99 C; H-NMR (300 MHz, CDCl3) δ = 11.91 (s, D2O exchangeable, 1H) 7.036 (d, J = 9 Hz,
1H) 7.56 (s, 1H) 7.46 (d, J = 2.4 Hz, 1H) 7.67 (d, J = 6.8 Hz, 2H) 7.51 (t, J = 6.2 Hz, 1H) 7.37
(d, J = 2.8 Hz, 2H); 13C-NMR (75 MHz, CDCl3); 200.56, 161.65, 137.15, 136.14, 132.36,
129.10, 128.55, 123.34, 120.05, 119.69.
(3,5-Dichloro-2-hydroxyphenyl)(4-methoxyphenyl)methanone (Table 2, Entry 3 ). White solid,
o
1
Yield: 88%, m.p. 111-113 C; IR: 1690, 3460 cm-1, H-NMR (300 MHz, CDCl3) δ = 12.44 (s,
1H, D2O exchangeable), 6.88 (s, 1H) 7.32 (s, 1H), 7.35 (d, J = 7.2 Hz, 2H), 7.2 (d, J = 7.8 Hz,
2H), 2.31 (s, 3H); 13C-NMR (75 MHz, CDCl3) δ = 183.0, 154.1, 154.0, 132.9, 131.1, 128.8,
128.4, 127.6, 124, 129, 127.9, 20.0.
(2-Hydroxy-5-methylphenyl)(phenyl)methanone (Table 2, entry 4). Yellow liquid; (C14H12O2);
mp: 81-83 oC; IR: 1695, 3398 cm-1, 1H-NMR (300 MHz, CDCl3) δ = 2.47 (s, 3H) 6.71(d, J = 8.1
Hz, 1H) 6.89 (d, J = 6.78 Hz, 2H) 7.1 (d, J = 8.4 Hz, 1H) 7.27(d, J = 8.1 Hz, 1H) 7.49-7.45 (m,
3H) 12.15 (s, 1H).
(3,5-Dichloro-2-hydroxyphenyl)(phenyl)methanone ( Table 2, entry 6 ). Yellow solid, m.p. =
o
1
97-99 C, IR; 1698, 3214 cm-1; H-NMR (300 MHz, DMSO-d6), δ = 10.6 (s, 1H) 8.15 (d, J =
7.8Hz, 2H), 7.77(d, J = 7.2Hz, 2H), 7.628 (t, 2H) 7.54 (s, 1H); 13C-NMR (300 MHz, DMSO-d6),
δ = 218.0, 163.9, 145.9, 134.9, 131.5, 130.2, 129.8, 129.6, 129.4, 128.9, 127.9, 127.4, 125.9.
Procedure for benzoylation of 1-naphtol [26 ]. To a mixture of 1-naphthol (7 mmol, 1 g) and
o
anhydrous AlCl3 (10 mmol, 1.38 g) stirred at 50 C, benzoyl chloride (10 mmol, 1.46 g) was
added in several portions, very carefully holding the temperature under 50 °C. After completion,
the mixture was poured into ice water and then concentrated HCl (2-4 mL) was added
subsequently. The suspension was stirred vigorously for 5-10 min. The crude desired products
were obtained as yellow solids after filtration crude product was purified by crystallization in
ethanol/methanol and yield of product was recorded as 55%.
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321
(1-Hydroxynaphthalen-2-yl)(phenyl)methanone (Table 3, Entry 1) [27]. Yellow solid; m.p. 72-
74 oC; IR 3020, 1630, 1600, 1570 cm-1; 1H-NMR (300 MHz, CDCl3) δ = 6 13.92 (s, 1 H), 8.54
(m, 1H), 7.42-7.79 (m, 10H); 13C-NMR (75 MHz, CDCl3) δ = 201.4, 163.9, 138.2, 137.3, 131.6,
130.3, 129.1, 128.3, 127.4, 125.9, 125.8, 124.5, 117.9, 112.5.
(2-Hydroxynaphthalen-1-yl)(phenyl)methanone ( Table 3, Entry 2) [28]. White solid; m.p. = 74-
76 oC, IR: 3350, 1647; 1H NMR (300 MHz, CDCl3): 7.14 (t, J = 8.0Hz, 1H), 7.33-7.21 (m, 3H),
7.40 (t, J = 7.56 Hz, 2H), 7.54 (t, J = 7.6 Hz, 1H), 7.54 (d, J = 8.0 Hz, 2H), 7.75 (d, J = 8.0 Hz,
1H), 7.93 (d, J = 8.8 Hz, 1H), 13.10 (s, 1H).
o
(2-Methoxyphenyl)(phenyl)methanone (Table 3, Entry 5) [29]. Yellow solid, m.p. = 57-59 C,
IR 3354, 1650, 2918 cm-1; 1H NMR (300 MHz, CDCl3) δ: 3.72 (s, 3H), 6.99-7.05 (m, 2H), 7.36
(dd, J = 1.7, 7.5 Hz, 1H), 7.41-7.49 (m, 3H), 7.55 (m, 1H), 7.81 (dd, J = 1.25, 8.5 Hz, 2H); 13C
NMR (75 MHz, CDCl3) δ: 55.6, 111.5, 120.5, 128.2, 128.9, 129.6, 129.9, 131.9, 133.0, 127.8,
157.4, 196.5.
RESULT AND DISCUSSION
For comparison of ortho-benzoylation via conventional method and AlCl3-solvent free initially,
we attempted the C-benzoylation of p-chlorophenol 1, as model reaction, via conventional
method (Scheme 1). The p-chlorophenol was treated with benzoyl chloride
2 in
dichloromethane at reflux for three hours (Scheme 1, step 1). After extraction (with DCM and
dil. NaOH for removing of unreacted phenol), 4-chlorophenyl benzoate 3 was obtained. Fries
rearrangement of 3 was accomplished by 2.5 equiv AlCl3 at 140 oC for one hour (Scheme 1, step
2). After workup the 5-chloro-2-hydroxybenzophenone 4 was isolated. We calculated overall
yield of step 1 and step 2, and it was obtained 64%.
OH
O
OH
Ph
Step 1
O
Ph
Step 2
Ph Cl
AlCl3, 140oC, 1h
2.5eq
DCM, ref, 3h
O
Cl
Cl
Cl
O
1
2
3
4
Scheme 1. Preparation of hydroxyaryl ketones via conventional method.
Direct Friedel-Crafts of p-chlorophenol using benzoyl chloride and aluminum chloride
under solvent free condition, was accomplished with different equivalent of AlCl3 at the 100-
o
110 C temperature, which summarized in (Table 1) which the best condition was obtained by
1.2 equivalents AlCl3 at 110 oC with 93% yield.
OH
OH
O
AlCl3(1.2eq)
10 min
Cl
O
Ph
Cl
110 0C
Cl
Ph
1eq
1.2 eq
93%
1
2
4
In a typical procedure, 1 equivalent of p-chlorophenol and 1.2 equivalent aluminum chloride
o
were mixed at room temperature. The mixture was heated at 110 C (Scheme 2) followed by
addition of 1.2 equivalents of benzoylchloride dropwise with grinding for 10 min. Then ice-
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Sunil V. Gaikwad et al.
water was added slowly to quench the reaction. The solid product was isolated by filtration and
recrystallized from methanol. The obtained yield was 93% (Table 2, entry 1). By these results,
we found that for C-benzoylation of phenols, neither esterification step nor solvent needed.
Furthermore, this method has excellent yield with low reaction time and easy to workup. A
number of phenols have been converted to corresponding 2-hydroxy benzophenones (Table 2).
The sterically hindered phenols, such as 2,4-dibromophenol 2-bromo-4-chlorophenols have also
afforded to the desired benzophenone in excellent yields. As well as p-methoxy benzoylchloride
reacted efficiently with 2,4-dichlorophenol and resulted into 81% yield. Interestingly, only 2-
benzoyl-1-napthol 8 was obtained as a sole product by benzoylation of α-naphthol 7 in 50%
o
yield, and 1-benzoyl-2-naphthol 10 also was formed from β-naphthol 9 at 45 C in 55% yield
(Scheme 3, Table 3).
R1
R1
OH
O
OH
AlCl3 (1.2eq)
110 oC, 10min
Ph
Ph
Cl
R2
R2
O
5
2
6
Scheme 2. C-benzoylation of substituted phenols using benzoyl chloride and AlCl3 under
solvent free condition.
Table 1. Chemoselective benzoylation of p-chlorophenol in several equivalent of AlCl3 at different
temperatures.
Entry
Equiv AlCl3
Temp. oC
80
110
80
110
90
110
80
Yield %
43
51
61
73
75
85
86
93
1
2
3
4
5
6
7
8
0.6
0.6
0.8
0.8
1.0
1.0
1.2
1.2
110
Table 2. Physico-chemical properties of 2-hydroxybenzophenone.
Entry
1
2
3
4
5
6
7
8
R1
H
H
Cl
H
Br
Br
H
R2
Cl
Br
Cl
Me
Cl
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
m.p. (oC) (lit.)
Yield (%)
93
91 (93) [30]
110 [31]
113 (115)
81 (82) [32]
80 (80) [30]
99 (99) [30]
80 (84) [33]
146 [34]
110
91
88
90
89
88
70
70
75
Br
OMe
OH
Cl
Me
H
H
9
Cl
Me
OH
Me
4-MeOC6H4
Ph
10
11
12
38 [35]
62
78
65
78
Ph
H
4-MeOC6H4
-
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323
Benzoylation of arenes by the above procedure such as toluene, benzene, bromobenzene,
chlorobenzene anisole has been achieved in quantitative yield (Table 3). It is important that the
benzoylation of these substrates was not possible with organo metallic reagents. The
benzoylation of nitrobenzene resulted into lower yields of product, naphthalene and anthracene
o
acylated at 30 C in good yields. The major problem for the use of anhydrous AlCl3 in F-C
benzoylation with electron rich substrate is formation of the strong complexation with Lewis
acids, which retard the progress of reaction. While in the presence of activated phenols, the
reaction completes smoothly within ten minutes to give quantitative yields. On the other hand in
conventional method, the amount of acid chlorides used are in excess than stoichiometric
amount of Lewis acids are required while in the present procedure only stoichiometric amount
of aluminum chloride and acid chlorides are used.
OH
OH O
OH
O
AlCl3 (1.2 eq)
50oC, 15 min
Ph
+
Ph Cl
O
Ph
7
2
8, 55%
Trace
Ph
O
OH
OH
O
OH
AlCl3 (1.2 eq)
45oC, 15 min
+
O
Ph Cl
Ph
Trace
9
10, 50%
Scheme 3. Benzoylation of α- and β-naphthol.
Table 3. Physico-chemical properties of naphthyl benzophenone and aryl benzophenone by using
benzoylchloride and AlCl3 under solvent free condition.
Entry
Substrate
1-Naphthol
2-Naphthol
Toluene
Chlorobenzene
Anisole
1,2-Dichlorobenzene
Nitrobenzene
Anthracene
Yield %
50
55
85
87
80
85
77
72
Reported m.p. (oC)
74 (73) [27]
76
30 (18) [26]
97 (96) [36]
57 (61) [36]
104
135 (136) [37]
142 (145) [38]
102 (104) [39]
1
2
3
4
5
6
7
8
9
1-Chloro-2-nitrobenzene
90
CONCLUSION
We have compared C-benzoylation of phenols by conventional method (esterification of
phenols and Fries rearrangement of aryl benzoate) and direct C-benzoylation by AlCl3 under
solvent free condition. With this procedure, the benzoylation occurs chemoselectively at
benzenoyd ring. Furthermore, the products were obtained with high degree of purity. The
reaction completes just within 10 minutes, into excellent yield and avoid from solvent. This
renew economical process will be useful for all those laboratories where organo metallic
reagents are not accessible.
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Sunil V. Gaikwad et al.
ACKNOWLEDGEMENTS
SVG is thankful to UGC meritorious fellowship (Fellowship No. UGC letter No F.4-
3/2006(BSR) dated Dec 2011 (BSR)], UGC‐New Delhi and BCUD, University of Pune) for
financial support.
REFERENCES
1. Jensen, R.; Goldman, G. in Friedel-Crafts and Related Reactions, Olah, G. (Ed.), Vol. III,
Wiley Interscience: New York; 1964; p 1319.
2. Franck, H.G.; Stadelhofer, J.W. Industrial Aromatic Chemistry, Springer-Verlag: Berlin;
1998.
3. (a) Olah, G.A. Friedel-Crafts Chemistry, Wiley-Interscience: London; 1973. (b) Heancy, H.
in Comprehensive Organic Synthesis, Trost, B.M.; Fleming, I. (Eds.), Vol. 2, Pergamon
Press: Oxford; 1991, pp. 733-752.
4. (a) Cornelis, A.; Laszlo, P.; Wang, S. Tetrahedron lett. 1993, 34, 3839. (b) Cornelis, A.;
Gerstmans, A.; Laszlo, P.; Mathy, A.; Zieba, I. Catal. Lett. 1990, 6, 103-109. (c) Clark, J.H.;
Culle, S.R.; Barlow, S.J.; Bastock, T.W. J. Chem. Soc., Perkin Trans. 1994, 2, 1117.
5. Le Roux, C.; Roques, N.; Dubac, J. Tetrahedron Lett. 2003, 44, 2037.
6. (a) Effenberger, F.; Steegmuller, D. Chem. Ber. 1988, 121, 117. (b) Pearson, D.E.; Buehlr,
C.A. Synthesis 1972, 10, 533. (c) Effenberger, F.; Steegmuller, D.; Null, V.; Ziegler, T.
Chem. Ber. 1988, 121, 125.
7. (a) Sato, Y.; Yato, M.; Ohwada, T.; Saito, S.; Shudo, K. J. Am. Chem. Soc. 1995, 117, 3037.
(b) Olah, G.A. Angew. Chem., Int. Ed. Engl. 1993, 32, 767.
8. Kotali, A.; Harris, P.A. Org. Prep. Proceed. Int. 1994, 26, 159.
9. (a) Smith, J.; Thomson, R.H. J. Chem. Soc. 1960, 346. (b) Choudarry, B.M.; Yadav, J.;
Kantam, M.L. Tetrahedron Lett. 2005, 46, 1369.
10. (a) Lokhande, P.D.; Sakate, S.S.; Taksande, K.N.; Navghare, B.R. Tetrahedron Lett. 2005,
46, 1573. (b) Nawghare, B.R.; Funde, S.; Raheem, A.L; Lokhande, P.D. Chin. J. Chem.
2012, 30, 1695. (c) Nawghare, B.; Gaikwad, S.V.; Abdul, R.; Lokhande, P.D. J. Chil. Chem.
Soc. 2014, 59, 1986.
11. (a) Waghmare, B.Y.; Sakate, S.S. Indian J. Chem. 2005, 44B, 2338. (b) Lokhande, P.D.;
Nawghare, B.R. Indian J. Chem. 2012, 51B, 328. (c) Lokhande, P.D. Nawghare, B.R. Synth.
Commun, 2013, 43, 1955. (d) Nawghare, B.R.; Gaikwad, S.V.; Pawar, B.V.; Lokhande, P.D.
Bull. Chem. Soc. Ethiop. 2014, 28, 469.
12. (a) Lokhande, P.D, Sakate, S.S.; Taksande, K.N.; Nawghare, B.R. Tetrahedron Lett. 2005,
46, 1573. (b) Lokhande, P.D.; Nawghare, B.R.; Sakate, S.S. J. Heterocycl. Chem. 2014,
51, 291. (c) Lokhande, P.D.; Raheem, A.; Sabale, S.T.; Chabukswar, A.R.; Jagdale, S.C.
Tetrahedron Lett. 2007, 48, 6890.
13. Breitenlechner, C.W.; Gassei, M.; Bossemeyer, D.; Huber, R.; Engh, R.A.; Masjost, B. J.
Med. Chem. 2005, 48, 163.
14. Takada, Y.; Aggarwal, B.B. J. Biol. Chem. 2004, 279, 4750.
15. Arad, D.; Elias, Y. WO Patent 9930699, 1999; Chem. Abstr. 1999, 131, 58409.
16. Merza, J.; Aumond, M.C.; Rondeau, D.; Dumontet, V.; Leray, A.M.; Seraphin, D.;
Richomme, P. Phytochemistry 2004, 65, 2915.
17. Denieul, M.P.; Laursen, B.; Hazell, R.; Skrydstrup, T. J. Org. Chem. 2000, 65, 6052.
18. Zhu, L.; Cao, X.; Chen, W.; Zhang, G.; Sun, D.; Wang, P.G. Bioorg. Med. Chem. 2005, 13,
6381.
19. Traven, V.F. Molecules 2004, 9, 50.
20. Commarieu, A.; Hoelderich, W.; Laffitte, J.A.; Dupont, M.P. J. Mol. Cat. A: Chemical
2002, 182-183, 137.
21. Ollevier, T.; Desyroy, V.; Asim, M.; Brochu, M.C. Synlett 2004, 15, 2794.
Bull. Chem. Soc. Ethiop. 2015, 29(2)

Short Communication
325
22. Harrowven, D.C.; Dainty, R.F. Tetrahedron Lett. 1996, 37, 7659.
23. Chaube, V.D.; Moreau, P. Finiels, A.; Ramaswamy, A.V.; Singh, A.P. J. Mol. Cat. A:
Chemical 2001, 174, 255.
24. Kobayashi, S.; Moriwaki, M.; Hachiya, I. Tetrahedron Lett. 1996, 37, 2053.
25. (a) Kobayashi, S.; Moriwaki, M.; Hachiya, I. Bull. Chem. Soc. Jpn. 1997, 70, 267. (b) Patil,
P.T.; Malshe, K.M.; Kumar, P.; Dongare, M.K.; Kemnitz, E. Catal. Commun. 2002, 3, 411.
(c) Guenadil, F.; Aichaoui, H.; Lambert, D.M.; McCurdy, C.R.; Poupaert, J.H. Lett. Org.
Chem. 2008, 5, 665.
26. Wawrzyniak, P.; Heinicke, J. Tetrahedron Lett. 2006, 47, 8921.
27. Li, W.; Lai, H.; Ge, Z.; Ding, C.; Zhou, Y. Synth. Commun. 2007, 37, 1595.
28. (a) Singh, A.K.; Sonar, S.M. Synth. Commun. 1985, 15, 1113. (b) Li, W.‐m.; Lai, H.‐q.; Ge,
Z.‐h.; Ding, C.‐r.; Zhou, Y. Synth. Commun. 2007, 47, 1595. (c) Huffman, J.W.; Wu, M.-J.;
Lu, J. J. Org. Chem. 1998, 63, 4510.
29. (a) Khedkar, M.V.; Tambade, P.J.; Qureshi, Z.S.; Bhanage, B. M. Eur. J. Org. Chem. 2010,
36, 6981. (b) Ettlinger, M.G. J. Am. Chem. Soc., 1950, 72, 8, 3666.
30. Shastri, R.A. Ind. J. Heterocycl. Chem. 2009, 19, 73.
31. Kwon, E.M.; Kim, C.G.; Goh, A.R.; Park, J.; Jong, G.J. Bull. Korean Chem. Soc. 2012, 33,
1939.
32. Commarieu, A.; Hoelderich, W.; Laffitte, J.A.; Dupont, M.P. J. Mol. Cat. A: Chemical.
2002, 182-183, 137.
33. Robert, M. Handbook of Hydroxybenzophenones, Kluwer Academic Publisher: New York;
2000; pp. 35-468.
34. (a) Shigeo, T.; Akio, T. Bull. Inst. Chem. Res., Kyoto Univ. 1991, 69, 5. (b) Li, W.-m.; Lai,
H.-q.; Ge, Z.-h.; Ding, C.-r.; Zhou, Y. Synth. Commun. 2007, 37, 1595.
35. (a) Dean, F.M.; Herbin, G.A.; Matkin, D.A.; Price, A.W.; Robinson, M.L. J. Chem. Soc.,
Perkin Trans. I, 1980, 1986. (b) Montfort, B.; Laude, B.; Vebrel, J.; Cerutti, E.; Bull. Soc.
Chim. France 1987, 5, 848.
36. (a)Yoh-ichi, M.; Kazuhiro, S.; Takanao, M. Tetrahedron Lett. 2004, 45, 4723. (b)
Venkatesan, C.; Jaimol, T.; Moreau, P.; Finiels, A.; Ramaswamy, A.V.; Singh, A. Catal.
Lett. 2001, 75, 119. (c) Huang, Y.C.; Majumdar, K.K.; Cheng, C.H. J. Org. Chem. 2002, 67,
1682.
37. Jeff, W.L.; David, T.; Stille, J.K. J. Org. Chem. 1983, 48, 4634.
38. (a) Hajipour, A.R.; Zarei, A.; Khazdooz, L.; Ruoho, A.E. Synth. Commun. 2009, 39, 2702.
(b) Tamaki, T. J. Chem. Soc., Chem. Commun. 1976, 335.
39. David, R.; Lide, G.; Milne, W.A. Handbook of Data on Organic Compounds, 3rd ed., CRC
Press: Boca Raton, Florida; 1993.
Bull. Chem. Soc. Ethiop. 2015, 29(2)