Novel method for the synthesis of 1,3,5-triarylbenzenes from ketones

Article abstract of DOI:10.1080/00397910500283370

Treatment of aryl ketones with p-toluenesulfinic acid and a catalytic amount of tin tetrachloride anhydrous (5%) in 1-pentanol gives good yields of 1,3,5-triarylbenzenes. Copyright Taylor & Francis, Inc.

Full text of DOI:10.1080/00397910500283370

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Novel Method for the Synthesis of
1,3,5‐Triarylbenzenes from Ketones
Xiaobi Jing a , Feng Xu a , Qihua Zhu a , Xinfeng Ren b , Chaoguo Yan a , Li
Wang a & Jinrong Wang a
a College of Chemistry and Chemical Engineering, Yangzhou University,
Yangzhou, China
b College of Chemistry and Chemical Engineering, Shanghai University of
Engineering Science, Shanghai, China
Published online: 20 Aug 2006.
To cite this article: Xiaobi Jing , Feng Xu , Qihua Zhu , Xinfeng Ren , Chaoguo Yan , Li Wang & Jinrong Wang
(2005): Novel Method for the Synthesis of 1,3,5‐Triarylbenzenes from Ketones, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 35:24, 3167-3171
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Synthetic Communicationsw, 35: 3167–3171, 2005
Copyright # Taylor & Francis, Inc.
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910500283370
Novel Method for the Synthesis
of 1,3,5-Triarylbenzenes from Ketones
Xiaobi Jing, Feng Xu, and Qihua Zhu
College of Chemistry and Chemical Engineering, Yangzhou University,
Yangzhou, China
Xinfeng Ren
College of Chemistry and Chemical Engineering, Shanghai University of
Engineering Science, Shanghai, China
Chaoguo Yan, Li Wang, and Jinrong Wang
College of Chemistry and Chemical Engineering, Yangzhou University,
Yangzhou, China
Abstract: Treatment of aryl ketones with p-toluenesulfinic acid and a catalytic amount
of tin tetrachloride anhydrous (5%) in 1-pentanol gives good yields of 1,3,5-
triarylbenzenes.
Keywords: Tin tetrachloride, 1,3,5-triarylbenzene, p-toluenesulfinic acid
INTRODUCTION
Triaryl benzenes are an important class of compounds in electrode and
electroluminescent devices. A simple method yielding these compounds
involves the triple condensation of aryl methyl ketones (1), as shown in
Scheme 1. The reported methods of inducing condensation involve
primarily one of three catalysts: a sulfuric acid and sodium pyrosulfate
mixture, hydrogen chloride and/or hydrochloric acid, or aniline and aniline
Received in Japan May 24, 2005
Address correspondence to Xiaobi Jing, College of Chemistry and Chemical
Engineering, Yangzhou University, Yangzhou 225002, China. E-mail: jingxiaobi@
yahoo.com.cn
3167

3168
X. Jing et al.
Scheme 1. R ¼ (a) C6H5; (b) 4-MeC6H4; (c) 4-MeOC6H4; (d) 4-ClC6H4;
(e) 4-BrC6H4; (f) –Me and (g) 4-NO2C6H4.
hydrochloride[1–3] In isolated cases other catalysts were used, such as
beryllium chloride, sodium ethoxide, and sulfoacetic acid.[4–6] The most
satisfactory results were obtained using acidic catalysts. They are both
inconvenient and unsuitable for synthesis of all but the simplest compounds.
We therefore sought a more efficient and more general method to
convert (1) into (2) and now report that interaction of compounds (1a–
1e) with one equivalent of p-toluenesulfinic acid and a catalytic amount
of tin tetrachloride, anhydrous (5%), in 1-pentanol at reflux temperature
gave different yields of (2a–2e) regardless of whether the starting ketone
contained electron- withdrawing or electron-donating groups. The results
are given in Table 1.
Clearly, p-TsOH/SnCl4 is a potent reagent for the triple condensation
of ketones to yield benzenoids. Table 1 shows that the yields of ketones
containing electron-withdrawing groups are much lower than those of the
ketones containing electron-donating groups. The precise nature of the
reagents responsible for the condensation is not known. Our further
investigations of scope and pathway of this reaction will be reported
separately.
We then examined the reactions of cyclohexanone (3) (Eq. (1)). In this
case, it gave the desired triannulated benzene (4) in yields of 79%.
To improve the yield of the triarylbenzenes, we tried the reaction under
microwave-induced conditions instead of refluxing (Scheme 2). The results
are given in Table 2.
Clearly, the use of a microwave oven is convenient when compared to
other experimental conditions and the reaction proceeds efficiently in a
shorter period of time and with higher yields. In conclusion, the
SnCl4/p-TsOH/pentanol condition we found is effective enough to catalyze

1,3,5-Triarylbenzenes from Ketones
Table 1. Yield of triarylbenzenes from aryl methyl ketones
3169
Entry
t (h)
T (8C)
Yield (%) (2)
Mp (8C)
1a
1b
1c
1d
1e
1f
4
4
110
110
110
120
120
40
82
85
172
179–180
143
246
5.5
7
77
72
7
74
66
263
3
24
—
1g
150
,30
153
Scheme 2. R ¼ (a) C6H5; (b) 4-MeC6H4; (c) 4-MeOC6H4; (d) 4-ClC6H4;
(e) 4-BrC6H4; (f) –Me and (g) 4-NO2C6H4.
the triple condensation of not only aryl methyl ketones but also cyclohexea-
none. Microwave-induced versions of the condensation reaction are more con-
venient because of the short reaction time and better yields of the products.
The further elaboration of in situ generated triarylbenzenes into useful
products in one-pot procedures using microwave irradiation is currently
being investigated.
Table 2. Yield of triarylbenzenes from aryl methyl ketones under
microwave-induced conditions
Entry
t (min)a
Power (W)
Yield (%) (2)
Mp (8C)
3a
3b
3c
3d
3e
3f
3 ꢀ 1
400
400
400
400
400
300
400
86
84
88
80
85
73
55
172
3 ꢀ 1
179–180
143
246
3 ꢀ 1
3 ꢀ 1.5
3 ꢀ 1.5
3 ꢀ 0.5
3 ꢀ 3
263
—
3g
153
aNumber of irradiations for a given time; 2 ꢀ 3 indicates 2
irradiations of 3 min each.

3170
X. Jing et al.
EXPERIMENTAL
Melting points were measured on a Kofler apparatus and are uncorrected.
1
MS measurements were performed on ZAB-HS spectrometer. H NMR and
13C NMR spectra were recorded on Bruker AM-500 and AM-400 instruments.
Chemical shifts refer to TMS on the d scale.
The p-toluenesulfinic acid (1.72 g, 10 mmol) was added to a stirred
solution of (1c) (1.50 g, 10 mmol) in dry 1-pentanol (10 mL). Then, the
catalytic amount of tin tetrachloride anhydrous (5%) was added slowly by a
syringe to the mixture. The mixture was stirred for 5.5 h at 1108C and then
Table 3. Analytical data for the compound 2a–2ga and compound 4b
Compound
1H NMR
MS
13C NMR (100 M)
Mp (8C)
2a
7.81 (3H, s),
7.72 (6H, m),
7.50 (6H, m),
7.41 (3H, m)
7.13 (3H, s),
7.59 (6H, m),
7.27 (6H, m),
2.42 (9H, s)
306 (Mþ);
289; 232;
154; 136
142.4, 141.2, 128.8,
127.5, 127.4, 125.2
172
2b
2c
—
142.2, 138.4, 137.2,
129.5, 127.2,
124.6, 21.1
179–180
143
7.73 (3H, s),
7.59 (6H, d,
—
160.9, 137.6, 128.9,
128.4, 125.2,
114.6, 56.0
J ¼ 7.8), 7.29
(6H, d, J ¼ 7.8),
2.42 (9H, s)
2d
2e
2g
4
7.70 (3H, s),
7.60 (6H, d,
—
—
—
141.8, 139.2, 134.0,
129.1, 128.5, 125.0
246
263
153
216
J ¼ 8.4), 7.46
(6H, d, J ¼ 8.4)
7.66 (3H, s),
7.49 (6H, d,
137.6, 135.6, 132.3,
129.6, 125.2, 122.0
J ¼ 8.4), 7.37
(6H, d, J ¼ 8.4)
8.25 (6H, d,
147.3, 142.7, 137.6,
128.3, 125.2, 124.1
J ¼ 8.5), 7.66
(3H, s), 7.74
(6H, d, J ¼ 8.5)
2.57 (12H, m),
1.77 (12H, m)
240 (Mþ);
225; 212;
199; 183
132.6, 26.8, 23.1
aTrimethylbenzene (2f ) is easily detected by TLC.
bAll the spectra data are in good agreement with those of the literature report.[1]

1,3,5-Triarylbenzenes from Ketones
3171
poured into ethanol (20 mL), stirred, and filtered. Crystallization from EtOH
and CH2Cl2 (1 : 1) gave (2c) (1.15 g), mp 1438C, yield 72%.
All the analytical data for the compounds (2a–2g) and compound (4) are
given in Table 3.
REFERENCES
1. (a) Bernhauer, K. J. Prakt. Chem. 1936, 145, 301; (b) Odell, A. F.; Hines, C. W.
J. Am. Chem. Soc. 1913, 35, 81; (c) Le Feave, R. J. W. J. Chem. Soc. 1938, 1467;
(d) Sampey, J. R. J. Am. Chem. Soc. 1940, 62, 1953; (e) Davis, T.; Armstrong, C.
J. Am. Chem. Soc. 1935, 57, 1583.
2. Skrowaczewska, Z.; Sucharda, E. Roczniki Chem. 1936, 16, 151.
3. Clapp, D.; Morton, A. J. Am. Chem. Soc. 1936, 58, 2172.
4. Bredeteck, H. Ber. 1939, 72B, 1414.
5. Gastaldi, C.; Cerchi, F. Gass. Chim. Ital. 1915, 452, 251.
6. Schneider, W.; Seeback, F. Ber. 1921, 54B, 2298.