The first example of glucose-containing Br?nsted acid synthesis and catalysis: Efficient synthesis of tetrahydrobenzo[α]xanthens and tetrahydrobenzo[α]acridines in water

Article abstract of DOI:10.1016/j.tet.2013.03.029

Glucose sulfonic acid (GSA) was synthesized for the first time and used as an efficient catalyst for the preparation of tetrahydrobenzo[α]xanthens and tetrahydrobenzo[α]acridines via the reaction of aromatic aldehydes, 2-naphthol (or β-naphthylamine), and

Full text of DOI:10.1016/j.tet.2013.03.029

Tetrahedron 69 (2013) 3947e3950
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
The first example of glucose-containing Brønsted acid synthesis and
catalysis: efficient synthesis of tetrahydrobenzo[
tetrahydrobenzo[ ]acridines in water
a]xanthens and
a
Yu Wan a, Xiao-xiao Zhang b, Chao Wang b, Ling-ling Zhao b, Liang-feng Chen b,
,
Gui-xiang Liu b, Shu-ying Huang b, Shu-ning Yue b, Wen-li Zhang b, Hui Wu a
*
a Key Laboratory of Biotechnology on Medical Plant of Jiangsu Province, Xuzhou 221116, PR China
b School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Glucose sulfonic acid (GSA) was synthesized for the first time and used as an efficient catalyst for the
Received 21 December 2012
Received in revised form 25 February 2013
Accepted 8 March 2013
preparation of tetrahydrobenzo[
a]xanthens and tetrahydrobenzo[a]acridines via the reaction of aromatic
aldehydes, 2-naphthol (or -naphthylamine), and dimedone in water. Up to four new bonds and one new
b
ring were formed in one-pot with water as the only by-product in these two reactions. The work opens
up a new and efficient synthesis and application of sugar-containing Brønsted acid.
Ó 2013 Elsevier Ltd. All rights reserved.
Available online 13 March 2013
Keywords:
Glucose sulfonic acid
Catalysis
Tetrahydrobenzo[
Tetrahydrobenzo[
a
a
]xanthens
]acridines
1. Introduction
Organic reactions in water without using of any harmful organic
solvents are of great current interest, because water is an available,
Glucose is an important nature product bearing five hydroxyl
groups. As a cheap and readily available substance, its physiological
and pharmacological activity has been widely investigated.1 How-
ever, its application in synthetic chemistry, especially as a catalyst, is
relatively rare concerned. By far, it is mainly used as: (1) surfactant,2
(2) carrier to extract and separate protein from complex system3
and (3) substrate in asymmetric organic synthesis.4
Although possessing five hydroxyl groups in its framework,
glucose is not active enough to be an organocatalyst. Therefore, it
should be functionalized and introduced in active sites if we want
to use it as catalyst or enhance its catalysis.
In recent years, the use of sulfonic acid-containing catalysts
and reagents has gained increasing attention in organic synthesis
due to their unique properties, such as high reactivity, selectivity,
efficiency, straightforward workup, availability, eco-friendly reaction
conditions, and ability to promote a wide range of reactions.5,6 They
are also non-toxic, non-corrosive, and inexpensive. But the synthesis
of glucose sulfonic acid and its application in organic reactions has
not been reported.
economical, safe, and environmentally benign solvent.7e9
A lot of natural and synthetic compounds containing xanthene
and acridine skeleton display interesting biological and physical
activities, such as antibacterial,10 anti-inflammatory,11 antiviral,12
antimalaria,13 and antitumor.14 Some types of xanthenes have also
been used as antagonists for paralyzing the action of zoxazol-
amine15 and in photodynamic therapy.16 Moreover, these two
kinds of compound can be used as dyes,17 pH-sensitive fluorescent
materials for the visualization of biomolecular assemblies18 and in
laser technologies.19 Simultaneously, the multihydroacridineone
derivatives have been reported to have high fluorescence efficiency
and can be used as fluorescent probes to monitor polymerization
process.20 They also received increasing attention due to their
similar bioactivity to 1,4-dihydropyridine (1,4-DHP), a well-known
compound in calcium channel modulations.21 Therefore, the syn-
theses of xanthene and acridine derivatives are of great importance.
Previously, xanthene and acridine derivatives had been syn-
thesized under reflux for 4e5 h in organic solvents,22e24 or under
microwave irradiation25 in the presence of acid catalysts, such as
BF3$Et2O,26 NaHSO4$SiO2,27 Sr(OTf)2,28 InCl3,29 P2O5,29 I2,30 TBAF,31
p-TSA32 or TEBAC.22 Although they afforded good yields, the limi-
tations of these methods, such as long reaction time (2e18 h),22,23
* Corresponding author. Tel.: þ86 051683403163; fax: þ86 051683403164;
e-mail address: wuhui72@yahoo.com.cn (H. Wu).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.03.029

3948
Y. Wan et al. / Tetrahedron 69 (2013) 3947e3950
harsh reaction conditions, and expensive catalysts were also obvi-
ous. Moreover, these syntheses have been usually carried out in
organic solvents with complex isolation and high toxicity. Conse-
quently, there is a scope of further improvement toward shorter
reaction time and high atom efficiency.33
Table 1, this transformation could not run smoothly in the presence
of catalysts, such as -proline, tartaric acid, camphorsulfonic acid, I2,
L
H2SO4 or TsOH (entries 1e6), so these catalysts could not be
employed as promoters of the reactions. Surprisingly, GSA gave
good results (entries 7e12), which indicated that strong acid con-
dition was the key factor of this reaction. The important role of GSA
may be attributed to its super-acidity and surface-activity, which
may increase the solubility of reactants in water and accelerate the
reaction. While increasing loading of GSA to 5 mol %, the products
of 5d and 6h were afforded in 96% and 98% yields, respectively
(entries 7 and 8), which showed the important role of catalyst
concentration in the reaction. However, the yields decreased un-
expectedly when the molar amount of catalyst was over 7.5 mol %
(entry 9). A possible reason is that the starting material or the
products had been destroyed when excess amount of GSA was
added. It was also realized that the process was efficiently facili-
tated at 90 ꢁC (entries 7 and 10e11). However, elevating the tem-
perature did not enhance the yields of products (entry 12).
In this paper, glucose sulfonic acid (GSA) was synthesized firstly
and used as an efficient catalyst to promote the preparation of
tetrahydrobenzo[
multi-component condensation of aromatic aldehydes, 2-naphthol
(or -naphthylamine), and dimedone in water (Scheme 1).
a]xanthens and tetrahydrobenzo[a]acridines by
b
To explore the application of this method, the scope of the
substrates was evaluated with a variety of aromatic aldehydes
under the optimal condition (Table 2). It showed that this reaction
can afford moderate to high yield and the product can be separated
easily. Higher yields could be given by p-substituted aromatic al-
dehydes (entries 1 and 7e9, Table 2). Whereas o- or m-substituted
substrates could only afford a little bit lower yields. These results
accord with the general rule of organic chemistry. The brief com-
parison of this method with previous ones was shown in Table 3.
The data shown in Table 3 clearly showed the high catalysis of
GSA in the synthesis of these two kinds of compound.
Scheme 1. The synthesis and catalysis of GSA in the preparation of tetrahydrobenzo[a]
xanthens (acridines).
2. Results and discussion
The mechanisms of these two processes were figured in Scheme 2.
It wassupposed that theproduct 5 mayformedvia initial formation of
o-methylene quinine B, which was derived from the 2-naphthol and
aromatic aldehydes catalyzed by GSA. B then reacts with the active
methylene moiety of A to give intermediate C. The cyclization of C
GSA was prepared firstly and the structure was deduced on the
basis of IR, 1H NMR, and 13C NMR spectroscopy. The 1H NMR
spectrum exhibited a singlet at
d
¼6.85 ppm for five sulfonic group.
Comparing with the IR spectrum of glucose, the IR spectrum of GSA
showed a new broad peak at 3445 cmꢀ1 and a new broad peak at
1227 cmꢀ1 arising from sulfonic group. And the pH value of GSA
(0.84) showed its strong acidity.
gives 5. When
tained successfully. Compound 6 is likely formed through the initial
formation of -unsaturated ketone D, which was derived from
dimedone and aromatic aldehydes catalyzed by GSA. D then reacts
with the -naphthylamine to give intermediate E. Intermediate E
b-naphthylamine was used as substrate 6 can be ob-
a, b
Subsequently, the application of GSA in organocatalysis was
investigated on the condensation of aromatic aldehydes, dimedone,
b
and 2-naphthol (or
were optimized based on the yields of 5d and 6h (Table 1). From
b
-naphthylamine). The reaction conditions
turned to provide F via tautomerization, and F is then cyclized to give
6 while one H2O molecules were removed.
Table 2
The synthesis of 5 and 6 catalyzed by GSAa
Table 1
Optimization of the reaction conditionsa
Entry Ar
Time Productb Yieldc (%)
(h)
Mp (ꢁC)
Entry Catalyst
Cat. (mol %) pH of catalystb T (ꢁC) Yieldc (%)
5d 6h
Found Reported Found
Reported
149e150 150e
15230
1
4-OHC6H4
3
5d
96
8230
1
2
3
4
5
6
7
8
L-Proline
5
5.78
1.95
1.77
5.04
1.49
1.74
0.84
0.89
0.80
0.84
0.84
0.84
90
90
90
90
90
90
90
90
90
70
80
100
Nrd Nrd
Nrd Nrd
Nrd Nrd
<10 <10
Tartaric acid
5
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
2-OHC6H4
3-BrC6H4
3,4-(CH3O)2C6H3
3,4,5-(CH3O)3C6H2
2,3-(CH3)2C6H3
4-IC6H4
4-CNC6H4
4-CH3OC6H4
2-BrC6H4
2-OHC6H4
2-CH3OC6H4
3-FC6H4
5.5 5h
5j
3.5 5m
78
84
89
92
88
95
90
98
85
87
91
90
87
93
95
90
165e166
166e167
161e163
148e150
183e185
>300
Camphorsulfonic acid
5
4
I2
5
H2SO4
TsOH
GSAe
GSAe
GSAe
GSAe
GSAe
GSAe
5
5
5
2.5
7.5
5
5
5
35
48
96
86
91
41
70
95
<10
35
98
80
92
60
75
92
3
3
4
6
5
5n
5o
6e
6g
6h
6j
>300
9722
295e296 >30022
>300
9
10
11
12
8
10
8
6k
6l
>300
>300
>300
>300
>300
>300
>300
7
8
5
6m
6o
6r
a
All reactions were carried out in the scale of 2.0 mmol of 2-naphthol (or b-
3-BrC6H4
naphthylamine), dimedone, and 2.0 mmol of 4-hydroxybenzaldehyde (or p-ani-
2,3-(CH3O)2C6H3
3,4,5-(CH3O)3C6H2
2,3-(CH3)2C6H3
saldehyde) and in 2.0 mL of water.
6
6t
b
The pH was measured by pH meter, the working solution (10ꢀ2 mol Lꢀ1) was
7
6u
prepared by dissolving 10 mol % of catalysts in 5 mL of deionized water and diluting
to 100.0 mL with deionized water.
a
All reactions were carried out in the scale of 5 mol % of GSA in 2 mL water at
c
90 ꢁC, and starting materials (1:2:3¼2.0:2.0:2.0 mmol) were completely consumed.
Isolated yields.
No reaction.
Prepared in our lab.
d
b
New products only the old ones were listed in Supplementary data (Table 1).
Isolated yield.
e
c

Y. Wan et al. / Tetrahedron 69 (2013) 3947e3950
3949
Table 3
internal standard and D2O or CDCl3 as solvent. Mass was determined
by using a Bruker TOF-MS high resolution mass spectrometer. The
pH was performed on an AISI-PHB-9901 pH meter. All reagents
were obtained from commercial suppliers and used without further
purification unless otherwise stated. GSA was prepared in our lab.
Organic solvents were dried and distilled prior to use.
The brief comparison of this method with previous ones
Entry Substrate
Catalyst
Solvent
T (ꢁC) Yield Ref.
(%)
a
5a
5f
Benzaldehyde
GSA
Sr(OTf)2
H2O
ClCH2CH2Cl 80
90
94
85
b,c
28
27
29
c
NaHSO4$SiO2 CH2Cl2
38e40 87
b
InCl3
P2O5
d
120
120
90
84
76
92
78
d
4.2. General procedure for the synthesis of glucose sulfonic
acid (GSA)
d
29
a
4-Methoxybenzaldehyde GSA
H2O
ClCH2CH2Cl 80
b,c
Sr(OTf)2
NaHSO4$SiO2 CH2Cl2
28
27
29
29
c
38e40 72
120
120
Chlorosulfonic acid (2.33 g, 20 mmol) was dropped into glucose
(0.90 g, 5 mmol) in anhydrous THF (5 mL) at 0e5 ꢁC under N2
atmosphere, generated HCl was absorbed by NaOH solution. The
mixture was stirred for 12 h at the same temperature. Additional
THF (10 mL) was added to quench the reaction. The solvent was
filtered and evaporated to afford 2.5 g of GSA as colorless oil (78%).
b
InCl3
P2O5
d
76
71
83
90
86
77
91
d
d
p-TSAe
GSA
[bmim]BF4 80
H2O 90
ClCH2CH2Cl 80
32
a
5k
5l
3-Nitrobenzaldehyde
b,c
Sr(OTf)2
28
d
P2O5
d
120
90
29
a
2,4-Dichlorobenzaldehyde GSA
H2O
c
NaHSO4$SiO2 CH2Cl2
38e40 78
27
32
b
n
, cmꢀ1): 3411, 3311, 2944, 2913,
InCl3
P2O5
d
120
120
90
85
78
88
88
93
4.2.1. Glucose. White solid. IR (KBr,
1462, 1112, 1050, 1023, 995, 623; 1H NMR (400 MHz, D2O)
d
d
32
d
:
a
6a
Benzaldehyde
GSA
H2O
H2O
EtOH
3.08e3.12 (t, 1H, OH), 3.25e3.41 (m, 5H, CH), 3.56e3.64 (m, 2H,
CH2), 3.69e3.77 (m, 2H, OH), 4.50e4.52 (d, 1H, OH), 5.10 (s, 1H, OH).
TEBACb
MWIf
100
220
22
25
13C NMR (400 MHz, D2O):
d 95.83, 92.02, 75.87, 75.68, 74.05, 72.69,
a
This work.
b
c
d
e
f
71.40, 71.36, 69.56, 69.52, 60.69, 60.52.
Expensive catalysts.
Noxious solvent.
Low-yielding.
Costly solvent.
Microwave irradiation.
4.2.2. Glucose sulfonic acid (GSA). Colorless oil. IR (KBr, n
, cmꢀ1):
3445, 1473, 1456, 1342, 1227 (vs, st of eSO3), 1055, 883; 1H NMR
(400 MHz, D2O)
d
: 2.96e5.18 (m, 7H, 5CHþCH2), 6.85 (s, 5H,
OSO3H). 13C NMR (400 MHz, D2O):
d
92.33, 88.64, 72.33, 71.86,
70.86, 69.77, 68.16, 67.48, 66.42, 66.14, 64.21, 57.97. The molecular
weight of glucose and GSA cannot be obtained via HRMS may be
because of hydroxyls or sulfonic groups in the glucose or GSA
molecular respectively.
4.3. General procedure for the preparation of compounds 5
and 6
A mixture of aromatic aldehydes (1, 2.0 mmol), dimedone
(2, 2.0 mmol), 2-naphthol or b-naphthylamine (3 or 4, 2.0 mmol) and
5 mol % GSA was stirred in water (2 mL) at 90 ꢁC until completely
(monitored by TLC). After the completion, water (20e25 mL) was
added to quench the reaction and then the reaction mixture was
filtered, concentrated, the precipitate was collected, and purified by
95% EtOH/DMF (8:1).
Scheme 2. Proposed mechanisms.
Acknowledgements
We are grateful to the foundation of the ‘Priority Academic Pro-
gram Development of Jiangsu Higher Education Institutions’, ‘Key
Basic Research Project in Jiangsu University’ (No. 10KJA430050), the
‘Graduate Innovation Project in Jiangsu Province’ (No. CXZZ11_0904,
CXZZ12_0979), ‘The Project of Outstanding Scientific and Techno-
logical Innovation Team for Higher Education Institutions in Jiangsu
Province (Pre-development of medicinal microbial resources)’ for
financial support.
3. Conclusion
In summary, GSA was synthesized firstly and used as efficient
catalyst for the one-pot synthesis of tetrahydrobenzo[ ]xanthens and
tetrahydrobenzo[ ]acridines in water due to its super-acidity and the
surface-activity, which may increase the solubility of reactants in
water and accelerate the reaction. To the best of our knowledge, this
methodology has not been reported. These catalysts not only make
the synthetic process safe and inexpensive, but also afford the prod-
ucts in excellent yield. And the work opens up a new and efficient
synthesis and application of sugar-containing Brønsted acid.
a
a
Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2013.03.029.
4. Experimental section
4.1. General remarks
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