Chemoselective Synthesis of Tetraketones in Water Catalyzed by Nanostructured Diphosphate Na2CaP2O7

Full text of DOI:10.1080/00304948.2018.1462055

Organic Preparations and Procedures International
The New Journal for Organic Synthesis
ISSN: 0030-4948 (Print) 1945-5453 (Online) Journal homepage: http://www.tandfonline.com/loi/uopp20
Chemoselective Synthesis of Tetraketones in
Water Catalyzed by Nanostructured Diphosphate
Na CaP O
2
2 7
Behrooz Maleki, Massomeh Raei, Heshmatollah Alinezhad, Reza Tayebee &
Alireza Sedrpoushan
To cite this article: Behrooz Maleki, Massomeh Raei, Heshmatollah Alinezhad, Reza Tayebee
&
Alireza Sedrpoushan (2018) Chemoselective Synthesis of Tetraketones in Water Catalyzed by
Nanostructured Diphosphate Na CaP O , Organic Preparations and Procedures International, 50:3,
2
2
7
288-300, DOI: 10.1080/00304948.2018.1462055
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Organic Preparations and Procedures International, 50:288–300, 2018
Copyright Ó Taylor & Francis Group, LLC
ISSN: 0030-4948 print / 1945-5453 online
DOI: 10.1080/00304948.2018.1462055
Chemoselective Synthesis of Tetraketones in Water
Catalyzed by Nanostructured Diphosphate
Na CaP O
2
2 7
1
Behrooz Maleki, Massomeh Raei, Heshmatollah Alinezhad,
1
2
1
Reza Tayebee, and Alireza Sedrpoushan
3
1
Department of Chemistry, Hakim Sabzevari University, Sabzevar, 96179-
7
6487, Iran
Faculty of Chemistry, University of Mazandaran, P.O. Box 47416-95447,
2
Babolsar, Iran
3
Institute of Industrial Chemistry, Iranian Research Organization for Science
and Technology, Tehran, Iran
1
Green chemistry has now attained the status of a major scientific discipline and studies in
this area have led to the development of cleaner and more benign chemical processes,
with many new technologies being developed each year. Much effort has been devoted to
the use of non-traditional solvents for chemical synthesis. In addition to solvent-free
2
–3
4
5
media, these unconventional media include water, supercritical CO , perfluorinated
2
6
7–9
solvents and ionic liquids. The use of water as a medium for organic reactions is one
of the latest challenges for modern organic chemists. It will be a major step forward to
carry out organic reactions in water for environmental and economic reasons. Further-
more, because of its high polarity, high surface tension, high specific heat capacity and
1
0–13
network of hydrogen bonds, water plays a significant role in many reactions.
Another aspect of green chemistry is the development of reusable and heterogeneous
catalysts under environmentally friendly conditions. From the viewpoint of green chemis-
try, good recovery and reusability of the catalyst are highly preferable. These concepts are
at the center of chemical activity, and research on high selectivity is the driving force for
the conception of all new catalytic processes. At present, it is well known that a heteroge-
neous catalyst must have three characteristics: high activity, selectivity and stability.
Nanotechnologies constitute an invaluable tool in catalysis. Considerable progress has
been made, but many challenges that deal with the control of the localization of active
1
4–17
sites still exist.
Arylmethylene bis-(3-hydroxy-2-cyclohexene-1-one) derivatives (tetraketones) are
important substrates used as precursors in the syntheses of xanthenes and acridinediones
1
for laser dye technology. These compounds have also shown potent activity as antioxi-
8
1
dants, lipoxygenase inhibitors, and a new clinical class of tyrosinase inhibitors against
9
2
0
important dermatological disorders including hyper-pigmentation and skin melanoma.
Received August 28, 2016; in final form November 2, 2017.
Address correspondence to Behrooz Maleki, Department of Chemistry, Hakim Sabzevari
University, Sabzevar, 96179-76487, Iran. E-mail: malekibehrooz@gmail.com
288

Tetraketones
289
Tetraketones are synthesized through Knoevenagel condensations and Michael additions
of aldehydes with cyclohexane-1,3-diones, dimedones or other 1,3-cyclic diketones. They
were first reported by Merling in 1894 in the preparation of cyclohexane-1,3-dione from resor-
2
1
22
cinol. Vorlander and Kalkow reported a practical synthesis of tetraketones as early as 1899.
Several reports of the attempts to carry out an efficient synthesis of tetraketones have
appeared in the literature. The most commonly exploited method is condensation of aromatic
aldehydes (1 mmol) with 1,3-cyclohexanediones (2 mmol) under a variety of conditions. This
reaction has been carried out using a number of catalysts, such as sodium dodecylsulfate
2
3
24
25
26
(SDS), HClO –SiO or PPA–SiO , molecular iodine, L-histidine in an ionic liquid,
SmCl , polyvinylpyrrolidone(PVP)-stabilized nickel nanoparticles, KF/Al O , catalyst-
4 2 2
2
3
0–31
7
28
29
2 3
3
32–33
free,
triethylbenzylammonium chloride (TEBA),
35
FeCl .6H O/TMSCl/[bmim]
3 2
34
36
BF4], In(OTf) , Yb(OTf) -SiO , cetyltrimethylammonium bromide (CTMAB), nano-
37
[
particles of Pd, choline chloride/urea (2:1), silica/HBF4, ultrasonic conditions, water,
3 3 2
8
3
39
40
41
42
43
and hexafluoro-2-propanol. Many of these catalysts have such disadvantages as the use of
hazardous organic solvents, pollution discharge, high reaction temperatures, low yields, long
reaction times, the utilization of expensive reagents of toxic metals and harsh reaction condi-
tions, tedious workup conditions, the need to use high catalyst loading, a need for a large excess
of the reagents and catalysts. There is still interest in developing green, economical, and mild
methods to produce the desirable tetraketones in high yields and short reaction times. Also,
desirable catalysts are waste-free, easily prepared, and efficiently re-used.
4
4–54
In continuation of our efforts toward the development of greener methodologies,
we now report that the reaction of aldehydes with 1,3-cyclohexanediones proceeds at
reflux in H O using nanostructured diphosphate Na CaP O (DIPH) as a basic heteroge-
neous catalyst in excellent yields and without the formation of by-products (Scheme 1).
2
2
2 7
R
OH
OH
O
R1 Nanostructured Na CaP O
2 7
2
R1
R1
R1
RCHO +
R1
H O/ Reflux
2
R1
O O
O
R = CH , H
1
3
1
2
3a-r
Scheme 1 Synthesis of arylmethylene bis-(3-hydroxy-2-cyclohexene-1-ones) “tetraketones.”
The synthesis of the nanostructured diphosphate Na CaP O (DIPH) in powder state has
2 2 7
been carried out from Na CO , CaCO and NH H PO in proportions 1:1:2, respectively
4
2
3
3
4
2
5
5–58
in a well-documented procedure.
To achieve optimum reaction conditions in a model reaction, a mixture of 3-nitrobenzal-
dehyde (1 mmol) and dimedone (2 mmol), was stirred in water (3 mL) in the presence of dif-
ferent amounts of Na CaP O under various temperature conditions (Table 1, Entries 1–6). As
2
2 7
it can be seen in Table 1, 20 mol% of Na CaP O was sufficient to catalyze the reaction under
2
2 7
reflux conditions. The expected tetraketone was obtained in 95% yield within 5 min (Table 1,
Entry 2). We also tested this amount of catalyst (20 mol% of Na CaP O ) in the presence of
different solvents (5 mL). As shown as Table 1, water is a more suitable medium.
2
2 7
The scope and the generality of the present method were then further demonstrated
by the reaction of different aldehydes with dimedone or 1,3-cyclohexandione (Table 2).
In all cases good yields and selectivity were obtained. As shown in Table 2, aromatic

2
90
Maleki et al.
Table 1
Optimization of reaction conditions for synthesis of 3 g
NO2
OH
CHO
O
O
OH
Me Conditions
Me
+
Me
Me
Me
Me
NO2
O O
3g
1
2
Entry
Catalyst (mol%)
Na CaP O (20)
Na CaP O (20)
Conditions
Time (min)
Yield (%)
1
2
3
4
5
6
7
8
9
Water/rt
Water/Reflux
140
5
82
95
85
85
85
88
90
86
72
2
2 7
2
2 7
0
Water/90 C
Na CaP O (20)
2 2 7
60
90
10
5
0
Water/80 C
Na CaP O (20)
2 2 7
Na CaP O (15)
2 2 7
Water/Reflux
Water/Reflux
Na CaP O (25)
2 2 7
Na CaP O (20)
2 7
Ethanol/Reflux
Methanol/Reflux
Water/Reflux
20
20
180
2
Na CaP O (20)
2
2 7
a
–
a
This reaction was carried out in the absence of any catalyst.
aldehydes with electron withdrawing and electron-donating groups as well as heteroaro-
matic and aliphatic aldehydes were employed. The nature of the substituents on the aro-
matic ring showed no obvious effect on this conversion; all products were obtained in
high yields in relatively short reaction times.
Synthetically, chemoselectivity in chemistry is regarded as one of the most important
aspects of organic reactions. In all cases, the desired products (3 a-r) were obtained in
high yields as the major products. For example, none of the corresponding xanthene was
ˊ
formed on heating 2,2 -[(3-nitrophenyl)-methylene] bis-(3-hydroxy-5,5-dimethyl-2-
cyclohexen-1-one) (3 g, 1 mmol) in the presence of nanostructured diphosphate
Na CaP O (20 mol%) in refluxing water (1 ml); only starting material was recovered.
2
2 7
The scope of the methodology was studied in the preparation of 7 a and 8 a by using
,3-cyclopentanedione (5) or 1,3-indanedione (6) as one of the components (Scheme 2).
1
ˊ
In order to illustrate the efficacy of our procedure, results for the preparation of 2,2 -
arylmethylene bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives reported
previous-ly are compared with our data (Table 3). Our process using nanostructured
diphosphate Na CaP O offers several advantages such as excellent yields, a simple pro-
2
2 7
cedure, short reaction times, facile work-up and recyclability.
We believe that the surface of Na CaP O presents multiple catalytic active sites.
2
2 7
The basic sites (oxygens of P O group and CaO octahedra) may abstract the proton
2
7
6
from the dimedone or 1,3-cyclohexandione. The acidic sites (phosphorus of the P O
2
7
C
2C
group, Na and Ca cations) probably induce the polarization of the CDO bond and
facilitate domino Knoevenagel condensation/Michael addition reaction leading to the
tetraketones.

Tetraketones
291
Table 2
Synthesis of tetraketone derivatives
0
Mp ( C)
Yield (%) Time (min) Found Lit.
93 10 188–190 186–188
Entry
1
Products (3 a-r)
2
7
OH
OH
Me
Me
Me
Me
O O
3
a
2
7
2
OMe
92
10
144–146 146–148
OH
OH
Me
Me
Me
Me
O O
Br
3
b
2
8
3
93
10
157–159 158–159
OH
OH
Me
Me
Me
Me
O O
3
c
(
Continued on next page)

2
92
Maleki et al.
Table 2
Synthesis of tetraketone derivatives (Continued)
0
Mp ( C)
Entry
4
Products (3 a-r)
Yield (%) Time (min) Found Lit.
2
2
2
7
8
1
Cl
90
90
94
10
10
5
143–145 142–144
166–168 167–168
190–192 194–196
OH
OH
Me
Me
Me
Me
O O
F
3
d
5
OH
OH
Me
Me
Me
Me
O O
3
e
6
NO2
OH
OH
Me
Me
Me
Me
O O
3
f
(
Continued on next page)

Tetraketones
293
Table 2
Synthesis of tetraketone derivatives (Continued)
0
Mp ( C)
Entry
7
Products (3 a-r)
NO2
Yield (%) Time (min) Found Lit.
2
7
95
5
201–203 201–203
OH
OH
Me
Me
Me
Me
O O
3
g
2
7
8
OMe
90
10
175–177 178–180
OMe
OH
OH
OH
Me
Me
Me
Me
O O
3
h
2
4
9
Cl
91
15
184–186 185–187
OH
Me
Me
Me
Me
O O
Me
3
i
2
7
1
0
86
20
140–142 139–141
OH
OH
Me
Me
Me
Me
O O
3
j
(
Continued on next page)

2
94
Maleki et al.
Table 2
Synthesis of tetraketone derivatives (Continued)
0
Mp ( C)
Entry
Products (3 a-r)
Yield (%) Time (min) Found Lit.
2
8
1
1
N(CH3)2
87
20
193–195 195–196
OH
OH
OH
Me
Me
Me
Me
O O
3
k
2
7
1
2
90
10
140–142 139–141
O
OH
Me
Me
Me
Me
OO
3
l
2
7
1
3
86
25
203–205
204
OH
OH
OH
OH
Me
Me
Me
Me
O O
H
3
m
3
0
1
4
84
40
191–193 192–193
Me
Me
Me
Me
O O
3
n
(
Continued on next page)

Tetraketones
295
Table 2
Synthesis of tetraketone derivatives (Continued)
0
Mp ( C)
Yield (%) Time (min) Found Lit.
81 50 182–183 182–184
Entry
15
Products (3 a-r)
3
0
CH3
OH
OH
Me
Me
Me
Me
O O
3
o
3
0
1
6
92
10
206–208 207–208
OH
OH
O O
Br
3
p
q
r
3
1
1
7
91
10
238–240 240–241
OH
OH
O O
3
2
8
1
8
92
5
193–195 194–196
NO2
OH
OH
O O
3

2
96
Maleki et al.
HO
OH
O
O
O
O
CHO
5
Nanostructured Na CaP O
2 7
O O
(7a, 10 min, 92% yield)
(mp. 220-222 C; lit. 222-223 C)
or
2
or
+
H O/Reflux
0
42
0
2
1
HO
OH
6
O O
(
8a, 10 min, 90% yield)
0
42
0
(
mp. 159-160 C; lit. 156-158 C)
Scheme 2. Reaction of benzaldehyde with 1,3-cyclopentadione or 1,3-indandione.
The reusability of the catalyst was also investigated. The same model reaction mentioned
above was again studied under the optimized conditions. After the completion of the reac-
tion, acetone was added to the reaction mixture to dissolve the product. Then the catalyst
ꢀ
was removed by filtration and washed with acetone and calcined at 500 C for 1 h before
re-use. It was re-used directly in the model reaction to give 3 g in yields of 95%, 92%,
8
9% for three consecutive runs at 5 min.
Table 3
Comparison of the efficiency of various catalysts in the synthesis of tetraketone
derivatives
Entry Tetraketones
3 a
Conditions
Time (min) Yield (%)
1
HClO –SiO /acetonitrile/reflux [24]
4
360
30
54
91
86
86
2
SmCl /water/rt [27]
3
KF/Al O /solvent-free/rt [29]
2
840
2880
3
Catalyst-free/solvent-free/rt [30]
p-Dodecylbenzenesulfonic acid/water/us/25-
0
0 C [42]
3
HFIP/ reflux [43]
60
180
10
89
90
93
91
90
91
88
88
94
Present work
SmCl /water/rt [27]
2
3 g
30
10
3
PVP-Ni NPs/ ethylene glycol/rt [28]
KF/Al O /solvent-free/rt [29]
840
2880
25
2
3
Catalyst-free/water/rt [31]
Pd(0) NPs/water/rt [38]
p-Dodecylbenzenesulfonic acid/water/us/25-
60
0
3
0 C [42]
HFIP/ reflux [43]
Present work
140
5
95
95

Tetraketones
297
In conclusion, novel synthetic nanostructured diphosphate (Na CaP O ) in the presence
2
2 7
of water is an excellent catalyst for the synthesis of tetraketone derivatives via the con-
densation of aldehydes and 1,3-cyclic dicarbonyl compounds. The current method offers
many advantages. These include high efficiency, high yields, short reaction times, free-
dom from waste, operational simplicity, facile separation and re-use of the catalyst from
the reaction medium.
Experimental Section
All reagents were obtained from commercial sources and were used without purification.
1
IR spectra were recorded as KBr pellets on a Shimadzu 435-U-04 spectrophotometer. H
1
3
and C NMR spectra were determined on a Bruker DRX-300 Avance spectrometer in
DMSO-d or CDCl . Melting points were determined using an Electrothermal 9200 appa-
ratus and are uncorrected. Scanning electron microscopy (SEM) images were obtained
6
3
5
5-58
with a Philips CM . The synthesis of catalyst has been previously described.
0
1
General Procedure for the Synthesis of Arylmethylene bis-(3-Hydroxy-2-cyclohexene-
-one)
1
The catalyst, Na CaP O (20 mol%), was added to a mixture of the aldehyde (1 mmol),
2
2 7
dimedone or 1,3-cyclohexandione (2 mmol), and 3 ml of water in a 5 ml flask fitted with
a reflux condenser. The resulting mixture was heated to reflux for the appropriate time
(
(
see Table 2) with stirring. After the completion of the reaction as determined by TLC
silica gel; hexane-ethyl acetate, 4:1), acetone (2 ml) was added and the mixture stirred
for 2 min. The catalyst was removed by filtration and washed with acetone and calcined
ꢀ
at 500 C for 1 h before re-use. After concentration of the filtrate, the residue was purified
by recrystallization (8 ml, EtOH 96%) to afford the pure arylmethylene bis-(3-hydroxy-2-
1
cyclohexene-1-one) derivatives. The products were identified by their melting points, H-
NMR, and IR.
Spectral Data for Selected Compounds
1
,2’-(Phenylmethylene)-bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) (3 a): H
2
NMR (400 MHz, CDCl ): d 1.10 (s, 6 H, 2CH ), 1.23 (s, 6 H, 2CH ), 2.17–2.48 (m, 8 H,
3
3
3
4
CH ), 5.54 (s, 1 H, CH), 7.08–7.28 (m, 5 H, Ar-H), 11.91 (s, 1 H, OH).
2
2
,2’-(4-Methoxyphenylmethylene)-bis-(3-hydroxy-5,5- dimethyl-2-cyclohexene-
1
1
-one) (3b): H NMR (400 MHz, CDCl ): d 1.02 (s, 6 H, 2CH ), 1.15 (s, 6 H, 2CH ),
3 3 3
2
.21–2.40 (m, 8 H, 4CH ), 3.70 (s, 3 H, OCH ), 5.41 (s, 1 H, CH), 6.72–6.75 (d, 2 H,
2 3
Ar-H), 6.93–6.91 (d, 2 H, Ar-H), 11.84 (s, 1 H, OH).
,2’-(4-Chlorophenylmethylene)-bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-
2
one) (3 d): H NMR (400 MHz, CDCl ): d 1.02 (s, 6 H, 2CH ), 1.14 (s, 6 H, 2CH ),
1
3
3
3
2
2
.21–2.41 (m, 8 H, 4CH ), 5.40 (s, 1 H, CH), 6.93–6.95 (d, 2 H, Ar-H), 7.14–7.17 (d,
2
H, Ar-H), 11.80 (s, 1 H, OH).
2
one) (3f): H NMR (400 MHz, CDCl ): d 1.04 (s, 6 H, 2CH ), 1.16 (s, 6 H, 2CH ), 2.24–
,2 ’-(4-Nitrophenylmethylene)-bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-
1
3
3
3
2
.44 (m, 8 H, 4CH ), 5.57 (s, 1 H, CH), 7.03-7.51(m, 4 H, Ar-H), 11.87 (s, 1 H, OH).
2
2
one) (3 g): H NMR (400 MHz, CDCl ): d 1.05 (s, 6 H, 2CH ), 1.20 (s, 6 H, 2CH ), 2.24–
,2 ’-(3-Nitrophenylmethylene)-bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-
1
3
3
3
2
.45 (m, 8 H, 4CH ), 5.47 (s, 1 H, CH), 7.32–7.98 (m, 4 H, Ar-H), 11.79 (s, 1 H, OH).
2

2
98
Maleki et al.
2
one) (3j): H NMR (400 MHz, CDCl ): d 1.02 (s, 6 H, 2CH ), 1.15 (s, 6 H, 2CH ), 2.22
,2 ’-(4-Methylphenylmethylene)-bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-
1
3
3
3
(s, 3 H, CH ), 2.25–2.40 (m, 8 H, 4CH ), 5.42 (s, 1 H, CH), 6.89–6.91 (d, 2 H, Ar-H),
3 2
6
.99–7.19 (d, 2 H, Ar-H), 11.83 (s, 1 H, OH).
,2 ’-(Furan-2-ylmethylene)-bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)
2
3 l): H NMR (400 MHz, CDCl ): d 1.10-1.18 (d, 12 H, 2CH ), 2.36 (s, 8 H, 4CH ),
1
(
3 3 2
5
OH).
.39 (s, 1 H, CH), 5.95 (s, 1 H, CH), 6.30 (s, 1 H, CH), 7.26 (s, 1 H, CH), 12.17 (s, 1 H,
1
,2 ’-(Phenylmethylene)-bis-(cyclopentane-1,3-dione) (7 a): HNMR (CDCl3,
2
4
2
00 MHz): d 2.60-2.66 (m, 8 H, 4CH ), 5.37 (s, 1 H, CH), 7.11-7.24 (m, 5 H), 8.17 (brs,
2
H, OH).
1
2,2 ’-(Phenylmethylene)-bis-(1 H-indene-1,3(2 H)-dione) (8 a): HNMR (CDCl ,
3
00 MHz): d 3.94 (t, 1 H), 4.28 (d, 2 H), 7.19 (t, 1 H), 7.22 (t, 1 H), 7.38 (d, 2 H),7.79-
4
7
.83 (m, 4 H), 7.89-7.94 (m, 4 H).
Acknowledgments
The authors thank the Research Council of Hakim Sabzevari University for partial sup-
port of this work.
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