Aromatization of hantzsch 1,4-dihydropyridines using barium manganate

Article abstract of DOI:10.1081/SCC-100104821

Barium manganate has been used as an inexpensive and convenient reagent for efficient oxidation of a variety of 1,4-dihydropyridine derivatives to pyridine derivatives in refluxing benzene with excellent yields.

Full text of DOI:10.1081/SCC-100104821

This article was downloaded by: [Korea University]
On: 27 December 2014, At: 01:13
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer
House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An International Journal
for Rapid Communication of Synthetic Organic
Chemistry
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/lsyc20
AROMATIZATION OF HANTZSCH 1,4-
DIHYDROPYRIDINES USING BARIUM MANGANATE
a
a
a
Hamid R. Memarian , Majid M. Sadeghi & Ahmad R. Momeni
a
Faculty of Sciences, Department of Chemistry , University of Esfahan , Esfahan, 81744,
Iran
Published online: 09 Nov 2006.
To cite this article: Hamid R. Memarian , Majid M. Sadeghi & Ahmad R. Momeni (2001) AROMATIZATION OF HANTZSCH
1,4-DIHYDROPYRIDINES USING BARIUM MANGANATE, Synthetic Communications: An International Journal for Rapid
Communication of Synthetic Organic Chemistry, 31:15, 2241-2244, DOI: 10.1081/SCC-100104821
To link to this article: http://dx.doi.org/10.1081/SCC-100104821
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of
the Content. Any opinions and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied
upon and should be independently verified with primary sources of information. Taylor and Francis shall
not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other
liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

SYNTHETIC COMMUNICATIONS, 31(15), 2241–2244 (2001)
AROMATIZATION OF HANTZSCH
1
,4-DIHYDROPYRIDINES USING
BARIUM MANGANATE
Hamid R. Memarian,* Majid M. Sadeghi,
and Ahmad R. Momeni
University of Esfahan, Faculty of Sciences,
Department of Chemistry, 81744 Esfahan, Iran
ABSTRACT
Barium manganate has been used as an inexpensive and con-
venient reagent for efficient oxidation of a variety of 1,4-dihy-
dropyridine derivatives to pyridine derivatives in refluxing
benzene with excellent yields.
In the course of our study on the chemistry of 1,4-dihydropyridine-
1
,5-diesters (DHP), known as Hantzsch esters, especially oxidation and
3
photooxidation of these compounds, we were interested in developinga
convenient method for the oxidation of these compounds. Several oxidizing
2
agents and methods such as potassium permanganate, solid supported
3
pyridinium chlorochromate (PCC), silica gel supported ferric nitrate, nitric
4
5
6
oxide,
nitrate, manganes dioxide, ceric ammonium nitrate, tert-butylhydro-
2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ),
6
bismuth
7
8
9
peroxide, clay supported cupric nitrate accompanied by ultrasound-promo-
1
tion, usingthe system HNO 3/bentonite in the absence of solvent by
0
*
Correspondingauthor.
2
241
Copyright & 2001 by Marcel Dekker, Inc.
www.dekker.com

ORDER
REPRINTS
2
242
MEMARIAN, SADEGHI, AND MOMENI
1
irradiation of the sample in a microwave oven, manganese triacetate
1
12
1
3
or photochemical reactions have been introduced in the literature for this
purpose. However, some of these methods suffer from disadvantages such as
low yield of product, the use of strongoxidants, longreaction time, the
requirement of severe conditions and the need of excess of the oxidants.
Barium manganate has been used as a versatile oxidant in organic
synthesis e.g. for converting alcohols to their corresponding carbonyl
1
4–16
compounds
pondingazo compounds.
compounds using3-carboxypyridinium chlorochromate (CPCC) and nico-
or for oxidative couplingof aromatic amines to their corres-
1
4,17
Recently we reported on oxidation of the title
1
8
1
9
tinium dichromate (NDC). In continuation to this work we used barium
manganate for oxidation of 1,4-dihydropyridines.
As shown in Table oxidation of 3, 5 and 6 with secondary alkyl
and benzylic groups at C-4 accompanied by expulsion of these substituents
and formation of product 14, while in other cases the retention of
4-substituent in product have been observed. A change of ratio of oxidant:
DHP from 2:1 to 1.5:1 and 1:1 causes a decrease of the rate of oxidation.
The advantage of using barium manganate for the oxidation of 1,4-dihydro-
pyridines and also a comparison with other oxidizinga ge nts and also to
CPCC and NDC, is our observation that a heterogeneous system due to low
solubility of barium manganate was prepared, therefore an easy work up
was expected and also due to its high reactivity, shortening of reaction times
and high yield of products have been observed.
EXPERIMENTAL
1
,4-Dihydropyridines (1–13) and barium manganate were prepared
1
,13,14
accordingto described procedures. A mixture of 1,4-dihydropyridine
(1 mmol) and barium manganate (2 mmol) in benzene (5 ml) was refluxed for

ORDER
REPRINTS
HANTZSCH 1,4-DIHYDROPYRIDINES
2243
Table. Oxidation of 1,4-Dihydropyridines (1–13) with Barium Manganate in
RefluxingBenzene
a,b
Compound
R
Product
Time (min.)
Yield (%)
1
2
3
4
5
6
7
8
9
0
1
2
3
H
CH
14
15
14
16
14
14
17
18
19
20
21
22
23
3
30
45
75
45
40
25
60
130
100
15
15
30
95
90
94
94
87
85
95
92
90
90
93
86
91
3
(CH ) CH
3
2
C
C
6
H
H
5
6
5
CH
2
C H CHCH
6
5
3
2,5-(CH
2-NO
3-NO
3
O)
2
C
6
H
3
2
C
C
6
H
H
4
2
6
4
1
1
1
1
4-NO -C H
2
6
4
2-Furyl
5-Methyl-2-furyl
2-Thienyl
a
Isolated yield.
b
All products were identified by comparison with authentic samples (IR,
H NMR, m.p.).
1
the time given in Table. The reaction was followed by TLC. The mixture
was filtered and then washed with benzene. The filtrate was evaporated and
purified by PLC. The products were characterized by comparison of their
1
spectral (IR, H NMR) and physical data with the authentic samples.
REFERENCES
1
2
. Hantzsch, A. Ann. 1882, 215, 1.
. Vanden Eynde, J.J.; D’Orazio, R. and Van Haverbeke, Y. Tetrahedron
1
994, 50, 2479.
. Vanden Eynde, J.J.; Mayence, A. and Maquestiau, A. Tetrahedron
992, 48, 463.
3
1
4
5
. Khadilkar, B. and Borkar, S. Synth. Commun. 1998, 28, 207.
. Itoh, T.; Nagata, K.; Matsuya, Y.; Miyazaki, M. and Ohsawa, A.
J. Org. Chem. 1997, 62, 3582 and references cited therein.
. Vanden Eynde, J.J.; Delfosse, F.; Mayence, A. and Van Haverbeke, Y.
Tetrahedron 1995, 51, 6511.
6
7
8
. Mashraqui, S.H. and Karnik, M.A. Synthesis 1998, 713.
. Pfister, J.R. Synthesis 1990, 689.

ORDER
REPRINTS
2
244
MEMARIAN, SADEGHI, AND MOMENI
9. Chavan, S.P.; Dantale, S.W.; Kalkote, U.R.; Jyothirmai, V.S. and
Kharul, R.K. Synth. Commun. 1998, 28, 2789.
1
1
0. Maquestiau, A.; Mayence, A. and Vanden Eynde, J.J. Tetrahedron
Lett. 1991, 32, 3839.
1. Garcia, O.; Delgado, F.; Cano, A.C. and Alvarez, C. Tetrahedron Lett.
1993, 34, 623 and references cited therein.
12. Varma, R.S. and Kumar, D. Tetrahedron Lett. 1999, 40, 21.
13. Memarian, H.R.; Sadeghi, M.M. and Momeni, A.R. Indian J. Chem.
1
999, 38B, 800 and references cited therein.
4. Firouzabadi, H. and Mostafavipoor, Z. Bull. Chem. Soc. Jpn. 1983,
6, 914.
1
1
5
5. Kwan Soo, K.; SangJae, C. In Haen,g C. and Chi Sun, H.
Tetrahedron Lett. 1989, 30, 2559.
6. Girdhari Lal, A. J. Inst. Chem. 1987, 59, 181.
1
1
7. Nobuo, W.; Yusuke, K. and Kaori, O. Tokyo Kogyo Koto Senmon
Gakko Kenkyu Hokokusho 1989, 21, 93; Chem. Abstr. 114, 23463q.
8. Mohammadpoor-Baltork, I.; Sadeghi, M.M.; Memarian, H.R. and
Pairow, R. J. Chem. Res. (S) 2000, 40.
1
1
9. Sadeghi, M.M.; Mohammadpoor-Baltork, I.; Memarian, H.R. and
Sobhani, S. Synth. Commun. 2000, 30, 1661.
Received in Japan July 5, 2000

Request Permission or Order Reprints Instantly!
Interested in copying and sharing this article? In most cases, U.S. Copyright
Law requires that you get permission from the article’s rightsholder before
using copyrighted content.
All information and materials found in this article, including but not limited
to text, trademarks, patents, logos, graphics and images (the "Materials"), are
the copyrighted works and other forms of intellectual property of Marcel
Dekker, Inc., or its licensors. All rights not expressly granted are reserved.
Get permission to lawfully reproduce and distribute the Materials or order
reprints quickly and painlessly. Simply click on the "Request
Permission/Reprints Here" link below and follow the instructions. Visit the
U.S. Copyright Office for information on Fair Use limitations of U.S.
copyright law. Please refer to The Association of American Publishers’
(AAP) website for guidelines on Fair Use in the Classroom.
The Materials are for your personal use only and cannot be reformatted,
reposted, resold or distributed by electronic means or otherwise without
permission from Marcel Dekker, Inc. Marcel Dekker, Inc. grants you the
limited right to display the Materials only on your personal computer or
personal wireless device, and to copy and download single copies of such
Materials provided that any copyright, trademark or other notice appearing
on such Materials is also retained by, displayed, copied or downloaded as
part of the Materials and is not removed or obscured, and provided you do
not edit, modify, alter or enhance the Materials. Please refer to our Website
User Agreement for more details.
Order now!
Reprints of this article can also be ordered at
http://www.dekker.com/servlet/product/DOI/101081SCC100104821