Application of poly(vinylphenyltrimethylammonium tribromide) resin as an efficient polymeric brominating agent in the α-bromination and α-bromoacetalization of acetophenones

Article abstract of DOI:10.1080/00397911.2019.1631348

The applications of a new supported tribromide reagent based on poly(vinylbenzyltrimethylammonium hydroxide) resin (Amberlite 717) were reported. This supported tribromide resin was used directly in α-bromination and α-bromoacetalization of acetophenones without any other catalyst under mild conditions. The effects of solvents and the amount of the supported tribromide resin on the reactions were investigated. Under the optimal conditions, most of α-bromo and α-bromoacetal of acetophenones were selectively obtained in excellent yields.

Full text of DOI:10.1080/00397911.2019.1631348

Synthetic Communications
An International Journal for Rapid Communication of Synthetic Organic
Chemistry
ISSN: 0039-7911 (Print) 1532-2432 (Online) Journal homepage: https://www.tandfonline.com/loi/lsyc20
Application of
poly(vinylphenyltrimethylammonium tribromide)
resin as an efficient polymeric brominating agent
in the α-bromination and α-bromoacetalization of
acetophenones
Bingbing Han, Zubiao Zheng, Dongcheng Zheng, Lei Zhang, Peng Cui, Jianjun
Shi & Changjiang Li
To cite this article: Bingbing Han, Zubiao Zheng, Dongcheng Zheng, Lei Zhang, Peng Cui, Jianjun
Shi & Changjiang Li (2019): Application of poly(vinylphenyltrimethylammonium tribromide) resin
as an efficient polymeric brominating agent in the α-bromination and α-bromoacetalization of
acetophenones, Synthetic Communications, DOI: 10.1080/00397911.2019.1631348
To link to this article: https://doi.org/10.1080/00397911.2019.1631348
View supplementary material
Published online: 24 Jun 2019.
Submit your article to this journal
Article views: 3
View Crossmark data
Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=lsyc20

V
R
SYNTHETIC COMMUNICATIONS
https://doi.org/10.1080/00397911.2019.1631348
Application of poly(vinylphenyltrimethylammonium
tribromide) resin as an efficient polymeric brominating
agent in the a-bromination and a-bromoacetalization of
acetophenones
Bingbing Han, Zubiao Zheng, Dongcheng Zheng, Lei Zhang, Peng Cui,
Jianjun Shi, and Changjiang Li
Department of Chemistry, Huangshan University, Huangshan, China
ABSTRACT
ARTICLE HISTORY
The applications of a new supported tribromide reagent based on pol-
y(vinylbenzyltrimethylammonium hydroxide) resin (Amberlite 717) were
reported. This supported tribromide resin was used directly in a-bromi-
nation and a-bromoacetalization of acetophenones without any other
catalyst under mild conditions. The effects of solvents and the amount
of the supported tribromide resin on the reactions were investigated.
Under the optimal conditions, most of a-bromo and a-bromoacetal of
acetophenones were selectively obtained in excellent yields.
Received 3 May 2019
KEYWORDS
a-Bromination; a-bromoace-
talization; tribromide resin;
polymeric brominat-
ing agent
GRAPHICAL ABSTRACT
O
O
O
O
Br
PVBMATB resin
Br
or
R
R
R
methanol or
ethylene glycol
3
1
2
2 2
R : H, p-Br, p-Cl, m-Br, o-Cl, p-NO , m-NO , biphenyl, 4'-Br-biphenyl, p-Me, p-MeO.
cyclohexanone, 3-pentanone
Introduction
Development of a safe, simple, and efficient synthetic method for the widely used key
organic intermediates from commercially available reagents is one of the major chal-
lenges in organic synthesis. a-Bromo and a-bromoacetal of acetophenones are signifi-
cant synthons used for the synthesis of a variety of biologically active heterocyclic
[
1]
[2]
compounds, especially triazole fungicides,
a,b-unsaturated ketones,
and enol
[
2 ]
ether. c A number of various bromination protocols of carbonyl compounds have
been developed, including the use of molecular bromine or its complexes in the pres-
ence of protic or Lewis acid. Alternative brominating agents, such as copper(II) brom-
[
3]
[
4]
[5]
[6]
ide, N-bromo reagents, dioxane-dibromide, and organic ammonium tribromides
CONTACT Zubiao Zheng
zhengzb@hsu.edu.cn
Department of Chemistry, Huangshan University, 44 Daizhen
Road, Huangshan 245041, Anhui, China.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lsyc.
Supplemental data for this article can be accessed on the publisher’s website.
ß 2019 Taylor & Francis Group, LLC

2
B. HAN ET AL.
7]
[
(OATB),
have been increasingly used for a-bromination of carbonyl compounds
resulting in easier handling and increased selectivity of the reaction. Organic ammo-
nium tribromides are preferable owing to hazards associated with bromine and the
other advantages are involving their solid form, high stability, maintenance of desired
stoichiometry and mild reaction condition. Hitherto, several organic ammonium tribro-
[
8]
mides have been reported, such as tetramethylammonium tribromide, tetrabutylam-
[
9]
[10]
monium tribromide,
tribromide.
pyridinium tribromide,
phenyltrimethylammonium
[
11]
However, recovery and recycling of expensive quaternary ammonium
salts are also poor during the post-processing, and in some cases, a substantial quater-
nary ammonium salts get extracted along with the organic products.
Anion exchange resin is a kind of insoluble polymer, and the utilization of it as sup-
[
12]
ports in the organic synthesis has acquired a wide interest in recent years,
because of
[
13]
the ease of work-up and product purification, and minimized environmental damages.
Amberlite 717 (CAS: 9002-24-8, poly(vinylbenzyltrimethylammonium hydroxide)
[
14]
is
one of the strongly basic anion exchange resins, which has been extensively used as a dis-
[
15]
infectant for industrial and domestic water
and is much cheaper than quaternary
ammonium salts. For example, the price of Amberlite 717 was about ten times lower than
that of benzyltrimethylammonium bromide and seven times lower than tetramethylam-
monium bromide in 2019, according to the product catalog of Aladdin.
Herein, to overcome the problem of high cost, recovery, and recycling of organic
ammonium bromides reagents, we wish to report the applications of
Poly(vinylbenzyltrimethylammonium tribromide) (PVBMATB) resin from Amberlite
717, as a novel polymeric brominating agent in the a-bromination and one-pot a-bro-
moacetalization of acetophenones.
Results and discussion
Organic ammonium tribromides represent an important class of bromination reagents, which
are more stable than the liquid bromine because of their crystalline nature, and hence their
storage, transport, and use are easy. However, production of these reagents utilizing volatile
organic molecular bromine and ammonium bromide is unsafe for human health and the
2
ꢀ [16]
[21]
environment. There are a few interesting reagents like NH Br–LDH–WO
,
4
4
[17]
[18]
[19]
[20]
HBr–H O ,
NaBr–NaIO4,
KBr-selectfluoro,
KBr-oxone,
and NaBr–NaBrO3,
2
2
which have been developed to afford bromohydrins and their derivatives.
Amberlite 717 (Poly(vinylbenzyltrimethylammonium hydroxide) is a common
strongly basic anion exchange resin, which was brought directly from Aladdin. It was
changed to bromide form through exchange reaction with an aqueous solution of HBr
(3 equiv.). And then, poly(vinylphenyltrimethylammonium bromide) resin was treated
with 1/3 equiv. of KBrO , and the color of resin converted from golden to red. After fil-
3
tration, poly(vinylbenzyltrimethylammonium tribromide) resin (PVBMATB) was
obtained with almost 100% yield (Scheme 1 and Figure 1). The capacity of the
PVBMATB resin was determined isometrically to be 2.5 mmol/g of resin. Interestingly
the resin could be stored for 1 year in a glass dryer without any loss of its activity.
In the preliminary experiments, our initial objective was to identify an appropriate
solvent for regioselective a-monobromination of acetophenone with PVBMATB resin.

V
R
SYNTHETIC COMMUNICATIONS
3
CH CH2
CH CH2
CH CH2
HBr
HBr+KBrO3
CH N(CH ) OH
CH N(CH ) Br
CH N(CH ) Br
2 3 3 3
2
3 3
2
3 3
n
n
n
Scheme 1. Preparation of poly(vinylbenzyltrimethylammonium tribromide) resin(PVBMATB resin).
HBr+KBrO3
Figure 1. Amberlite 717 resin(poly(vinylbenzyltrimethylammonium hydroxide) supported tribromide.
a
Table 1. Effect of solvents on the a-bromination of 1a with PVBMATB resin .
b
Entry
Solvent
Selectivity(2a/3a/4a/1a)
1
2
3
4
5
6
7
a
THF
22/0/0.2/78
51/0/16/33
30/0/35/35
63/13/4/20
46/11/12/42
52/0/15/39
40/24/2/34
CH
2
CH
3
CH
3
Cl
2
CN
OH
C
2
H
5
OH
CHOH
Ethylene glycol
3 2
(CH )
The reaction was performed with 2.5 mmol of acetophenone (1a), 1.0 g of PVBMATB resin, 5 mL
ꢁ
of solvent at 30 C for 6 h.
b
The ratio of 2a/3a/4a/1a was determined by GC.
a
Table 2. Effect of water on the a-bromination of 1a with PVBMATB resin .
b
Entry
V
Methanol/Vwater(mL)
Selectivity(2a/3a/4a/1a)
1
2
3
4
5
6
a
3/2
4/1
4.4/0.6
4.5/0.5
4.7/0.3
4.9/0.1
42/0/8/50
57/0/14/30
82/0/6/12
92/0/8/0
76/0/6/18
65/0/7/28
The reaction was performed with 2.5 mmol of acetophenone (1a), 1.0 g of PVBMATB resin, 5 mL
of the mixture of methanol and water at 65 C for 1 h.
ꢁ
b
The ratio of 2a/3a/4a/1a was determined by GC.
For this purpose, acetophenone 1a was chosen as the test substrate for the reaction with
g of PVBMATB resin in various solvents and the results are summarized in Table 1.
When tetrahydrofuran (THF), CH Cl , or CH CN was used as a solvent, the reaction
1
2
2
3
completed within 6 h to give low reaction activity of a-monobromination. In the above
study, the best results were observed in methanol. For example, using methanol as a
solvent, the selectivity of 2a could reach 63/4 (entry 4, Table 1). However, 13% of
a-bromoacetal of acetophenone were observed. When ethylene glycol was used, 24% of
a-bromoacetal of acetophenone(2-bromomethyl)-2-phenyl-1,3-dioxolane, 3a) were
observed (entry 5, Table 1).

4
B. HAN ET AL.
Table 3. Effect of PVBMATB resin on the a-bromination of acetophe-
a
none 1a .
b
Entry
m
PVBMATB resin (g)
Selectivity(2a/4a/1a)
1
2
3
4
5
a
0.8
0.9
1.0
1.1
1.2
74/2/24
87/11/2
92/8/0
84/12/0
80/14/0
The reaction was performed with 2.5 mmol of acetophenone (1a), 5 mL of the mixture of
methanol and water at 65 C for 1 h.
ꢁ
b
The ratio of 2a/4a/1a was determined by GC.
Table 4. Effect of PVBMATB resin on the a-bromoacetalization
a
of 1a in ethylene glycol .
Entry
mPVBMATB resin (g)
Yield of 3a
1
2
3
4
5
a
0.8
0.9
1.0
1.1
1.2
59
65
74
97
83
The reaction was performed with 2.5 mmol of acetophenone (1a), 5 mL of
ethylene glycol at room temperature for 24 h.
Secondly, it was essential to reduce the a-bromoacetalization and improve the a-bro-
mination reactivity of acetophenone. When a little water was added to the reaction sys-
tem, the product of a-bromoacetalization of acetophenone determined by GC
disappeared (Table 2). So, the amount of water was further investigated. we found that
a mixture of 0.5 mL of water and 4.5 mL of methanol was the best solvent for the max-
ꢁ
imum selectivity of the desired product 2a (92:8) at 65 C for 1 h (entry 4, Table 2).
The effect of PVBMATB resin (g) on the a-bromination of acetophenone (1a,
2
.5 mmol) was also investigated (Table 3). When 0.8 g of PVBMATB resin was added to
the reaction mixture and the ratio of the a-monobromination product was only 74%
entry 1, Table 3). Increased the amount of PVBMATB resin to 1.0 g, the ratio could
(
increase to 92% (entry 3, Table 3). When a larger amount PVBMATB resin was added,
the a,a-dibromination product increased rapidly. The optimal a-bromination condition
for yield generation requires 2.5 mmol of 1a, 1 g of PVBMATB resin, 4.5 mL of metha-
ꢁ
nol, and 0.5 mL of water at 65 C for 1 h.
When the reaction was performed in the presence of ethylene glycol, PVBMATB
resin could transform from acetophenone to the corresponding a-bromoacetal deriva-
tives without any other catalyst. The effects of amount of PVTATB (g) to acetophenone
(1a, 2.5 mmol) on the rate of reaction were investigated, and the results were summar-
ized in Table 4. The optimum amount (g) of PVBMATB resin to acetophenone (mmol)
was found to be 1.1:2.5.
To investigate the scope of these protocols, the optimized conditions of a-bromination
and a-bromoacetalization were then applied to the synthesis of a variety of substituted aceto-
phenones. The results are listed in Table 5. When 1b and 1c with a halogen atom on the
para-position of benzene ring, were selected, the yields of 2b and 2c were 96 and 95%,
respectively (entries 2 and 3, Table 5), and 3b and 3c were 91 and 96%, respectively. When
2-chloroacetophenone (1d) was used as the tested substrate, the yields of a-bromination and
a-bromoacetalization were only 60 and 85% (entries 4, Table 5), which could be attributed

V
R
SYNTHETIC COMMUNICATIONS
5
a,b
Table 5. a-Bromination and a-bromoacetalization of 1 with PVBMATB resin
.
a
a-Bromination was performed with 2.5 mmol of 1, 1.0 g of PVBMATB resin, 5 mL of the mixture of methanol and water
at 65 C for 1 h; a-bromoacetalization was performed in 5 mL of ethylene glycol at room temperature for 24 h.
ꢁ
b
Isolated yield.
c
ꢁ
The reaction was carried at 45 C.
d
e
2
equiv. of PVBMATB resin was added.
The product was too complex for further separation.

6
B. HAN ET AL.
to the steric effect of ortho-chlorine atom. When 2e and 2f was prepared from 1e and 1f
with a strong electron-withdrawing group (–NO ) on the benzene ring, the yields were only
2
77 and 89%; however, the reactivity of a-bromoacetalization (1e and 1f) was very low, it
may be the result of the low solubility of 1e and 1f in ethylene glycol at room temperature.
ꢁ
So, when the reaction temperature was increased to 45 C, 3e and 3f could be obtained with
excellent yields (96 and 93%) (entry 5 and 6, Table 5); the same process was also used to
prepare 3g and 3h, the yields of a-bromoacetalization were 96, and 95%, respectively (entries
7
, and 8, Table 5), respectively. When 1i, with an electron-donating group (–CH ) on the
3
benzene ring, was tested, both a-bromination and a-bromoacetalization were also good, with
the yields of 2i and 3i reaching 91 and 88%, respectively (entries 9, Table 5). In the case of
substrates with a strong electron donation group (–OCH ), such as 1j, the product of a-bro-
3
mination (2j) could reach 93%, however, the main product of a-bromoacetalization was 2-
bromomethyl-2-(3-bromo-4-methoxyphenyl)-1,3-dioxolane (3j), and the yield was 97% when
2
equiv. of PVBMATB resin was added (entry 10, Table 5). In our new chemical processes,
a-bromination and a-bromoacetalization of acetophenones with electron-withdrawing or
electron-donating groups on the para-position of benzene ring were preformed in excellent
yields. When 2-acetylpyridine (1k) was tested, a-bromination products of 2k could be
obtained with a 96% yield, and the a-bromoacetalization was too complex to further separ-
ation (Entry 11, Table 5). Cyclohexanone (1l) and 3-pentanone (1m) were also selected as
test substrates, 2l, 2m, 3l, and 3m could be obtained with 53, 87, 92 and 90% yields, respect-
ively (entry 12, and 13, Table 5).
Finally, in all of these applications workup of the reaction was easy. When the reaction
was completed, the color of the resin turned from red to golden, and the resin of poly (vinyl-
phenyltrimethylammonium bromide) could be recycled from the reaction mixture via sim-
ple filtration. The recovered resin could be converted into their tribromide form in very
high yield as stated in the experimental part. It was also observed that the recycled resin,
after recycling at least 3 times, could be used without any loss in the efficiency.
In summary, we developed a simple and green method to prepare poly(vinylbenzyltri-
methylammonium tribromide) resin from Amberlite 717 with the aqueous solution of
HBr and KBrO , and demonstrated that the resin is a useful novel polymeric brominat-
3
ing reagent in the a-bromination and bromoacetalization of acetophenones without any
other catalyst. In the proposed system, the in situ generation of HBr from the reaction
of PVBMATB resin and acetophenones catalyzed the a-bromination and caused further
acetalization of the reaction. The advantages of PVBMATB resin are: low price of raw
materials, stability, high efficiency, simple filterability and reusability, and the reaction
processes have confirmed its high application value.
Experimental section
Representative procedure for preparation of poly(vinylbenzyltrimethylammonium
tribromide) resin
Amberlite 717 (10 g, 50 wt%) was washed three times with 30 mL of deionized water.
The resin was added to an aqueous solution of HBr (65 mL, 10%) for 5 h, and then an
aqueous solution of KBrO (1.5 g, 9 mmol) was added to the mixture over a period of
3
30 min. The reaction took place immediately and the solution became yellow with a

V
R
SYNTHETIC COMMUNICATIONS
7
concurrent golden resin of poly(vinylbenzyltrimethylammonium bromide) supported
tribromide. The red resin with tribromide (PVBMATB resin) was filtered, washed 3
times with water and dried in a glass dryer at room temperature. The isolated yield of
PVBMATB resin was almost 100%. The recycling procedure of the recovered resin was
the same as the preparation of PVBMATB resin.
Representative procedure for preparation of a-bromoacetophenone
A mixture of 2.5 mmol of 1a, 4.5 mL methanol, and 0.5 mL of water was stirred for
5
min, and then 1 g of PVBMATB resin was added, and the mixture was stirred 1 h
ꢁ
at 65 C. Afterward, the resin of poly(vinylbenzyltrimethylammonium bromide) was
recycled through filtration and washed with ether. The combined organic layer was
washed twice by water (20 mL), and dried over anhydrous Na SO . After filtration,
2
4
the solvent was removed under reduced pressure, and the residual was treated with
silica gel column chromatography (Petroleum ether/AcOEt ¼ 20/1, v/v) to generate
[
22]
the product. 2-bromo-1-phenyl ethanone (2a):
Yield 91%, white solid; m.p.:
ꢁ ꢁ
8–50 C (lit: 48–49 C); H NMR (500 MHz, CDCl ) d 4.44 (s, 2H, CH Br),
3 2
.60–7.62 (m, 2H, ArH), 7.68–7.70 (m, 1H, ArH), 8.00–8.03 (m, 2 H, ArH). IR (KBr,
cm ): 3055, 3002, 2953, 1694, 1598, 1449, 1390, 1283, 1198, 1092, 993, 746,
87, 624.
1
4
7
ꢀ1
6
Representative procedure for preparation of a-bromoacetal of acetophenone
A mixture of 2.5 mmol of 1a, and 5 mL ethylene glycol was stirred for 5 min, and then
1
.1 g of PVBMATB resin was added, and the mixture was stirred 24 h at room tempera-
ꢁ
ture or 45 C. Afterward, the resin of poly(vinylbenzyltrimethylammonium bromide)
was recycled through filtration and washed with ether. The combined organic layer was
washed twice by water (20 mL), and dried over anhydrous Na SO . After filtration, the
2
4
solvent was removed under reduced pressure, and the residual was treated with alumina
chromatography (Petroleum ether/AcOEt ¼ 20/1, v/v) to generate the product. 2-bro-
[
23]
ꢁ
1
momethyl-2-phenyl-1,3-dioxolane (3a):
Yield 97%, white solid, m.p.: 56–58 C, H
NMR (500 MHz, CDCl ) d 3.66 (s, 2H), 3.88–3.91 (m, 2H), 4.17–4.20 (m, 2H),
3
ꢀ
1
7
1
.32–7.38 (m, 3H), 7.52 (d, 2H, J ¼ 7.5 Hz); IR (KBr, cm ): 3011, 2885, 1627, 1485,
470, 1447, 1220, 1169, 1039, 1029, 997.
Funding
The authors thank the Natural Science Foundation of Anhui Province and Education
Department of Anhui Province – Provincial Foundation for Excellent Young Talents of Colleges
and Universities of Anhui Province for financial support [1808085MB28, gxyq2018081].
References
[1] Baldwin, B. C.; Wiggins, T. E. Pestic. Sci. 1984, 15, 156–166.

8
B. HAN ET AL.
[
2] (a) Eaton, P. E. J. Am. Chem. Soc. 1961, 84, 2344–2348. (b) Piers, E. Grierson, J. R. Lau,
C. K. Nagakura, I. Can. J. Chem. 2011, 60, 210–223;(c) Park, H. S.; Kim, S. H.; Park,
M. Y.; Kim, Y. H. Tetrahedron Lett. 2001, 42, 3729–3732.
[
3] (a) Kimpe, N. D.; Stevens, C. Tetrahedron, 1995, 51, 2387–2402.(b) Vra ꢀz i ꢀc , D.; Jereb, M.;
Laali, K.; Stavber, S. Molecules, 2013, 18, 74–96.(c) Attanasi, O. A.; Berretta, S.; Favi, G.;
Filippone, G. P.; Mele, G.; Moscatelli, G.; Saladino, R. Org. Lett. 2006, 8, 4291–4293.(d)
Bovonsombat. P.; Ali, R.; Khan, C.; Leykajarakul, J.; Pla–on, K.; Aphimanchindakul, S.;
Pungcharoenpong, N.; Timsuea, N.; Arunrat, A.; Punpongjareorn, N. Tetrahedron, 2010,
66, 6928–6935.(e) Lee, A. S. Y.; Wang, S. H.; Chang, Y. T. J. Chin. Chem. Soc. 2014, 61,
364–368.(f) Zhou, B.; Chen, Z. Z.; Zheng, Z. B.; Han, B. B.; Zou, X. Z. Synth. Commun.
2012, 42, 1445.
[
4] (a) Sharley, J. S.; P ꢁe rez, A. M. C.; Ferri, E. E.; Miranda, A. F.; Baxendal, I. R. Tetrahedron,
2
016, 47, 2947–2954.(b) Mali, J. K.; Mali, D. A.; Telvekar, V. N. Tetrahedron Lett. 2016,
5
7, 2324–2326.
[
5] (a) Wu, P.; Xu, S.; Xu, H.; Hu, H.; Zhang, W. Tetrahedron Lett. 2017, 58, 618–621.(b)
Guha, S.; Rajeshkumar, V.; Kotha, S. S.; Sekar, G. Org. Lett. 2015, 46, 406–409.(c) Han,
B. B.; Zheng, Z. B.; Wu, F.; Wang, A. D. Synth. Commun. 2017, 47, 2387–2394.(d) Arbuj,
S. S.; Waghmode, S. B.; Ramaswamy, A. V. Tetrahedron Lett. 2007, 48, 1411–1415.(e)
Reddy, B. M.; Kumar, V. V. R.; Reddy, N. C. G.; Rao, S. M. Chin. Chem. Lett. 2014, 25,
179–182.
[
6] (a) Paul, S.; Gupta, V.; Gupta, R.; Loupy, A. Tetrahedron lett. 2003, 44, 439–442.(b)
Chaudhuri, S. K.; Roy, S.; Saha, M.; Bhar, S. Synth. Commun. 2007, 37, 271–274.(c)
Pasaribu, S. J.; Williams, L. R.; Aust. J. Chem. 1973, 26, 1327–1331.
[7] (a) Udavant, R. N.; Yadav, A. R.; Shinde, S. S. Eur. J. Org. Chem. 2018, 2018,
3432–3436.(b) Moghaddam, F. M.; Masoud, N.; Foroushani, B. K.; Saryazdi, S.; Ghonouei,
N.; Daemi, E. Sci. Iran. 2013, 20, 598–602.
[
[
8] Avramoff, M.; Weiss, J.; Sch €a chter, O. J. Org. Chem. 1963, 28, 3256–3258.
9] Gopinath, R.; Haque, S. J.; Patel, B. K. J. Org. Chem. 2002, 67, 5842–5845.
[
[
[
10] (a) Bliman, D.; Pettersson, M.; Bood, M.; Grøtli, M. Tetrahedron Lett. 2014, 55,
2
5
929–2931.(b) Martinez–Solorio, D.; Jennings, M. P. Tetrahedron Lett. 2008, 49,
175–5178.
11] (a) Sayama, S. Tetrahedron Lett. 2006, 47, 4001–4005.(b) Muthyala, M. K.; Kumar, A. J.
Heterocyclic chem. 2012, 49, 958–964.(c) Jordan, A. D.; Luo, C.; Reitz, A. B. J. Org. Chem.
2
003, 68, 8693–8696.
12] (a) Vahdat, S.; Khaksar, S. Res. Chem. Intermediate. 2014,41, 1–10.(b)
Ghorbani–Choghamarani, A.; Goudarziafshar, H.; Zamani, P. Chin. Chem. Lett. 2011, 22,
1207–1210.(c) Cacchi, S.; Caglioti, L. Synthesis, 1979, 1, 64–66.(d) Bongini, A.; Cainelli,
G.; Contento, M.; Manescalchi, F. Synth. 1980, 2, 143–146.
[
[
13] (a) Alexandratos, S. D. J. Chem. Technol. Biot. 2018, 93, 20–27.(b) Alexandratos, S. D.
Ind. Eng. Chem. Res. 2009, 48, 388–398.(c) Hodge, P.; Houghton, M. P.; Chakiri, A. React.
Funct. Polym. 2012, 72, 967–972.
14] (a) Tsai, T. H.; Maes, A. M.; Vandiver, M. A.; Versek, C.; Seifert, S.; Tuominen, M.;
Liberatore, M. W.; Herring, A. M.; Coughlin, E. B. J. Polym. Sci. Pol. Phys. 2013, 51,
1751–1760.(b) Vandiver, M. A.; Caire, B. R.; Pandey, T. P. Li, Y.F. J. Membrane Sci. 2016,
4
97, 67–76.
[
[
15] Nagireddi, S.; Golder, A. K.; Uppaluri, R. J. Water Process Eng. 2018, 22, 227–238.
16] (a) Solladi ꢁe –Cavallo, A.; Lupattelli, P.; Bonini, C. J. Org. Chem. 2005, 70, 1605–1611.(b)
Ros, A.; Magriz, A.; Dietrich, H.; Fern ꢁa ndez, R.; Alvarez, E.; Lassaletta, J. M. Org. Lett.
2
006, 8, 127–130.
[
17] (a) Podgor ꢀs ek, A.; Stavber, S.; Zupan, M.; Iskra, J. Green Chem. 2007, 9, 1212–1218.(b)
Suryakiran, N.; Peddikotla, P.; Reddy, T. S.; Kondempudi, C. M.; Rajesh, K. M.;
Venkateswarlu, Y. Tetrahedron Lett. 2007, 48, 877–881.
[
[
18] Dewkar, G. K.; Narina, S. V.; Sudalai, A. Org. Lett. 2003, 5, 4501–4504.
19] Patil, R. D.; Joshi, G.; Adimurthy, S.; Ranu, B. C. Tetrahedron Lett. 2009, 50, 2529–2532.

V
R
SYNTHETIC COMMUNICATIONS
9
[
20] Madabhushi, S.; Jillella, R.; Mallu, K. K. R.; Godala, K. R.; Vangipuram, V. S. Tetrahedron
Lett. 2013, 54, 3993–3996.
[
21] Agrawal, M. K.; Adimurthy, S.; Ganguly, B.; Ghosh, P. K. Tetrahedron 2009, 65,
2791–2797.
[
[
22] Mohan, R. B.; Reddy, N. C. G. Synth. Commun. 2013, 43, 2603–2614.
23] Zheng, Z.; Han, B.; Wu, F.; Shi, T.; Liu, J.; Zhang, Y.; Hao, J. Tetrahedron 2016, 72,
7738–7743.