One-pot electrochemical synthesis of acid anhydrides from alcohols

Article abstract of DOI:10.1134/S1070363217110330

One-pot indirect electrochemical oxidation of alcohols in the methylene chloride–aqueous solution of sodium hydrocarbonate two-phase system in the presence of potassium iodide, 4-acetylamino-2,2,6,6-tetramethylpiperidin-1-oxyl, and 2,6-lutidine results in

Full text of DOI:10.1134/S1070363217110330

ISSN 1070-3632, Russian Journal of General Chemistry, 2017, Vol. 87, No. 11, pp. 2733–2735. © Pleiades Publishing, Ltd., 2017.
Original Russian Text © V.P. Kashparova, E.N. Papina, I.I. Kashparov, I.Yu. Zhukova, I.B. Ilchibaeva, E.Sh. Kagan, 2017, published in Zhurnal Obshchei
Khimii, 2017, Vol. 87, No. 11, pp. 1911–1913.
LETTERS
TO THE EDITOR
One-Pot Electrochemical Synthesis
of Acid Anhydrides from Alcohols
a
a,b
a,b
V. P. Kashparova , E. N. Papina , I. I. Kashparov ,
b
a
a
I. Yu. Zhukova , I. B. Ilchibaeva , and E. Sh. Kagan *
a
Platov South-Russian State Polytechnic University, ul. Prosveshcheniya 132, Novocherkassk, 346428 Russia
*
e-mail: kagan29@mail.ru
b
Don State Technical University, Rostov-on-Don, Russia
Received August 21, 2017
Abstract―One-pot indirect electrochemical oxidation of alcohols in the methylene chloride–aqueous solution
of sodium hydrocarbonate two-phase system in the presence of potassium iodide, 4-acetylamino-2,2,6,6-
tetramethylpiperidin-1-oxyl, and 2,6-lutidine results in the formation of the corresponding acid anhydrides with
yield up to 80%. The reaction occurs at room temperature and is complete after passing 6 F/mol of electricity.
Keywords: alcohol, electrochemical oxidation, carboxylic acid anhydride, nitroxyl radical, pyridine base
DOI: 10.1134/S1070363217110330
We have earlier demonstrated that the oxidation of
alcohols 1 with the 4-acetylamino-2,2,6,6-tetramethyl-
piperidin-1-oxyl (2)–iodine–pyridine catalytic system
results in the formation of the corresponding
symmetrical esters 3 in good yield [1]. In this study,
we found that anhydride of the corresponding acid 5 is
formed in up to 80% yield (along with the aldehyde 4
and ester 3) under the same conditions except for
generation of iodine via electrochemical oxidation of
iodide ions (Scheme 1).
To the best of our knowledge, the method suggested
in this study is the first example of alcohols oxidation
into anhydrides using nitroxyl radicals, even though
examples of direct oxidation of alcohols and aldehydes
into esters, amides, and nitriles have been reported [2–5].
The composition of the reaction products depended
in the amount of electricity passed through the system
and the nature of the used pyridine base (pyridine, 2,6-
lutidine, 2-methyl-5-ethylpyridine, 2,4,6-trimethylpyri-
dine, or 4-acetylpyridine). 2,6-Lutidine was found the
best catalyst in the reaction of indirect electrochemical
oxidation of alcohols into the corresponding acid
anhydrides. The changes in the composition of the
reaction mixture in comparison with the oxidation with
molecular iodine could be explained by the reactions in
the electrolyte resulting in the formation of the acid. It
Acid anhydrides form an important class of organic
compounds, conventional synthesis of which includes
several stages and requires the use of toxic reactants
such as sulfuryl or thionyl chloride, phosgene, etc.
Therefore, development of more convenient and green
methods of anhydrides synthesis is a critical issue.
Scheme 1.
NHCOCH3
O
O
O
O
H
Pt-anode
KI, Py
+
+ R
+
R
OH
R
OR
R
O
R
N
O
2
1
3
4
5
2
733

2
734
KASHPAROVA et al.
Scheme 2.
_
2
CH CONH
N
O
+ I2
2 CH CONH
+
N
O
+ 2I
3
3
2
6
O
OH
H O
2
6
R
OH
R
H
R
OH
1
4
_
CH CONH
N
OH
3
7
O
O
6
RCOOH
O
N+
NHCOCH3
R
C+
O
_
R
O
R
R
O
5
OH
is known that the oxidation of alcohols with oxo-
ammonium salts is accompanies by the formation of
the corresponding acids upon even slight variation of
the reaction conditions [6].
6 F/mol of electricity, aldehyde 4 was oxidized into the
acid anhydride 5 with 100% yield (with respect to the
reacted aldehyde, the conversion of the latter being 70
to 85%). If the corresponding aldehyde was used
instead of the alcohol, the anhydride yield was 75%
The suggested mechanism of the anhydride formation
is shown in Scheme 2. In the course of the reaction, the
oxoammonium salt 6 is reduced into the hydroxylamine
(
100% with respect to the reacted aldehyde). After
passing more than 6 F/mol of electricity, the reaction
was slowed down, and side products were formed.
7
, oxidation of which yields the starting radical 2, and
the catalytic cycle is closed. The reaction occurred
stepwise. At the first stage of alcohol 1 oxidation (after
passing 2.2 F/mol of electricity), aldehyde 4 was
formed in 95% yield. At the second stage, after passing
The suggested method of one-pot indirect electro-
chemical oxidation of alcohols was tested with a series
of aliphatic, aromatic, and heteroaromatic alcohols (see
the table).
Indirect electrochemical oxidation of alcohols with the 4-acetylamino-2,2,6,6-teteramethylpiperidin-1-oxyl–potassium iodide
a
catalytic system in the presence of 2,6-lutidine
b
Composition of the reaction mixture after passing 6 F/mol of electricity, %
Alcohol
aldehyde
ester
anhydride
acid
2.5
n-Hexanol
n-Heptanol
n-Octanol
n-Nonanol
25.5
30.9
13.3
28.6
78.5
5.9
4.0
4.1
6.0
7.2
0
66.1
62.0
80.6
62.7
9.5
0
3.1
2.0
2.7
4.8
0
2
-Phenylethanol
c
Methoxybenzyl alcohol
98.0
c
2
-Thiophenemethanol
97.0
0
0
0
d
5
-Hydroxymethylfurfurol
75.0
0
0
0
a
b
c
The reaction conditions are given in the general procedure of alcohols oxidation. Gas chromato–mass spectrometry data. After passing
4
d
F/mol of electricity. After passing 4 F/mol of electricity, 25% are the condensation products [7].
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 11 2017

ONE-POT ELECTROCHEMICAL SYNTHESIS
2735
General procedure of alcohols oxidation. Electro-
lysis was performed in a membrane-free 150 mL
electrolyzer equipped with a water jacket, thermo-
performed using the equipment of Center for
Collective Usage “Nanotechnologies” of Platov South-
Russian State Polytechnic University.
2
meter, and mechanical stirrer. Anode (20 cm ) and
2
cathode (10 cm ) were made of platinum plates.
REFERENCES
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methylpiperidin-1-oxyl (0.004 mol, 0.85 g), and
1
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10.1134/S1070363216110049
0
.004 mol of the corresponding pyridine base
dissolved in 40 mL of methylene chloride were put in
the electrolyzer. 0.06 mol (5.0 g) of NaHCO and
3
2
3
4
5
. Kelly, C.B., Lambert, K.M., Mercadante, M.A., Ovian, J.M.,
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0
.01 mol (1.7 g) of KI dissolved in 80 mL of distilled
water (рН of the aqueous phase 8.6) were then added.
2
The synthesis was performed at current density 0.05 A/cm
. Gaspa, S., Porcheddu, A., and De Luca, L., Tetrahedron
Lett., 2016, vol. 57, p. 3433. doi 10.1016/
j.tetlet.2016.06.115
(
current 1 A) and was complete after passing 6 F/mol
of electricity. After the reaction was complete, the
electrolyte was treated with concentrated solution of
sodium thiosulfate to remove excess of iodine. The
aqueous and organic layers were separated. The
aqueous layer was acidified with dilute hydrochloric
acid to pH 5 and extracted with methylene chloride
. Reddy, K.R., Venkateshwar, M., Maheswari, C.U., and
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(
2×20 mL); the organic phases were combined and
analyzed by means of gas chromato-mass spectrometry
as described elsewhere [1].
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and Bailey, W.F., Org. Lett., 2012, vol. 14, p. 4034. doi
1
0.1021/ol301884a
ACKNOWLEDGMENTS
7. Kashparova, V.P., Klushin, V.A., Leontyeva, D.V.,
Smirnova, N.V., Chernyshev, V.M., and Ananikov, V.P.,
Chem. Asian J., 2016, vol. 11, p. 2578. doi 10.1002/
asia.201600801
This study was financially supported by the Russian
Science Foundation (project no. 16-13-10444) and
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 11 2017