Oxidative reactivity of S-nitrosoglutathione with Hantzsch 1,4-dihydropyridine.

Article abstract of DOI:10.1021/ol990367c

[formula: see text] S-Nitrosoglutathione oxidized 4-substituted Hantzsch 1,4-dihydropyridines in CH3CN/H2O or CH3CN/phosphate aqueous buffer solution to give aromatic products in various yields.

Full text of DOI:10.1021/ol990367c

ORGANIC
LETTERS
2000
Vol. 2, No. 6
741-742
Oxidative Reactivity of
S-Nitrosoglutathione with Hantzsch
1,4-Dihydropyridine
Yu-Zhu Mao, Mei-Zhong Jin, Zhong-Li Liu, and Long-Min Wu*
National Laboratory of Applied Organic Chemistry, Lanzhou UniVersity,
Lanzhou, Gansu 730000, China
nlaoc@lzu.edu.cn
Received November 18, 1999
ABSTRACT
S-Nitrosoglutathione oxidized 4-substituted Hantzsch 1,4-dihydropyridines in CH CN/H Oor CH CN/phosphate aqueous buffer solution to give
3
2
3
aromatic products in various yields.
Nitric oxide (NO) is an endogenous compound of the body
involved in a variety of biological processes,1 including
immunity-regulating functions, physiological control of blood
pressure, and neurotransmission. Authentic NO in vivo has
only a 0.1 s half-life.2 Nitrosothiols (RSNO), which are
formed in vivo from the reaction of NO with protein or
nonprotein thiols, can increase the effective tissue half-life
of NO.3 RSNO is commonly referred to as a NO-donor and
is found in various biological systems, such as in human
plasma, airways, white blood cells, and rat cerebellum.4 Ni-
trosoglutathione (GSNO) has been shown to be one of the
most aboundant RSNOs,4c,5,6 e.g., 0.3 µM in bronchial lavage
fluid and 0.7 µM in brain, and to exhibit depressor action.7
4-Substituted Hantzsch 1,4-dihydropyridines (DHP) are
analogues of NADH coenzymes8 and an important class of
drugs which are potent blockers of calcium (Ca2+) currents.9
Therefore, the oxidation of DHP has recently attracted more
attention from chemists.10 To explore the reaction between
GSNO and DHP is certainly of biological significance.
In a representative experiment, an anaerobic CH3CN/H2O
solution of 0.02 mmol of DHP11 (1) and 0.04 mmol of
GSNO12 was stirred for about 10 h at room temperature under
Ar, giving an aromatic product, Hantzsch pyridine (2)
(Scheme 1). GSNO was converted to the disulfide (GSSG),
Scheme 1
(1) (a) Murad, F. Angew. Chem., Int. Ed. 1999, 38, 1857. (b) Furchgott,
R. F. Angew. Chem., Int. Ed. 1999, 38, 1871. (c) Ignarro, L. J. Angew.
Chem., Int. Ed. 1999, 38, 1883. (d) Pfeiffer, S.; Mayer, B.; Hemmens, B.
Angew. Chem., Int. Ed. 1999, 38, 1714.
(2) Stamler, J. S.; Simmon, D. I.; Osborne, J. A.; Mullins, M. E.; Jaraki,
O.; Mihel, T.; Singel, D. J.; Loscalzo, J. Proc. Natl. Acad. Sci. U.S.A. 1992,
89, 444.
(3) Rubbo, H.; Radi, R.; Trujillo, M.; Telleri, R.; Kalyanaraman, B.;
Barnes, S.; Kirk, M.; Freeman, B. A. J. Biol. Chem. 1994, 269, 26066.
(4) (a) Stamler, J. S.; Jaraki, O.; Osborne, J.; Simon, D. I.; Keaney, J.;
Vita, J.; Singel, D. J.; Valeri, C. R.; Loscalzo, J. Proc. Natl. Acad. Sci.
U.S.A. 1992, 89, 7674. (b) Clancy, R. M.; Levartovsky, D.; Leszczynskapi-
ziak, J.; Yegudin, J.; Abramson, S. B. Proc. Natl. Acad. Sci. U.S.A. 1994,
91, 3680. (c) Gaston, B.; Reilly, J.; Drazen, J. M.; Fackler, J.; Ramdev, P.;
Arnelle, D. R.; Mullins, M. E.; Sugarbaker, D. J.; Chee, C.; Singel, D. J.;
Loscalzo, J.; Stamler, J. S. Proc. Natl. Acad. Sci. U.S.A. 1993, 90, 10957.
(5) Jia, L.; Bonaventura, C.; Bonaventura, J.; Stamler, J. S. Nature 1996,
380, 221.
the oxidized species of glutathione. In most cases, the peak
for DHP on GC disappeared completely at the end of the
reaction. The experimental results are summarized in Table
(6) Kluge, I.; Guttek-Amlser, U.; Zollinger, M.; Do, K. Q. J. Neurochem.
1997, 69, 2599.
(7) Craven, P. A.; DeRuberties, F. R. Biochim. Biophys. Acta 1983, 745,
310.
10.1021/ol990367c CCC: $19.00 © 2000 American Chemical Society
Published on Web 02/26/2000

believe that the reaction between GSNO and DHP occurred
via an electron-transfer mechanism as shown in Scheme 2.
Table 1. Oxidation of DHP with GSNO in CH3CN/H2O under
an Ar Atmosphere
substrate
R
ratioa time (h) productb yield (%)c
Scheme 2
Ia
Ib
Ic
Id
Ig
If
Ig
Ih
Ii
H
CH3
(CH3)2CH
CHdCHPh
Ph
F-Ph
p-methoxy-Ph
m-hydroxy-Ph
3,4-dihydroxy-Ph 2:1
2:1
2:1
2:1
2:1
2:1
2:1
2:1
2:1
6
5
IIa
IIb
IIa
IId
IIe
IIf
IIg
IIh
IIi
100
100
50
60
70
60
100
60
10
10
10
10
8
10
13
0
a Molar ratio of GSNO to DHP. b Determined by 1H NMR. c Compared
to authentic samples by GC.
1. Under the indicated conditions, the corresponding 4-sub-
stituted Hantzsch pyridine (2) was the uniquely identifiable
oxidation product derived from the substrate, with the
exception of Ic where only the dealkylation product was
obtained. The products were easily separated by extraction.
Under other conditions where oxygen was present or water
was replaced by phosphate buffer at pH 7.4 with 10 mM
EDTA to eliminate the decomposition of GSNO catalyzed
by metal ions such as Cu+, Fe 2+, or Hg2+,13 results as similar
to those shown in Table 1 were obtained. Increased molar
ratios of GSNO to DHP in the CH3CN/buffer solution
affected the oxidation product yield and significantly short-
ened the reaction time. This observation ruled out oxidation
of DHP by NO, which was generated from the decomposition
of RSNO in aqueous solution. Therefore, we reasoned that
GSNO might participate as the oxidant in the reaction,
although we considered an alternative heterolytic mechanism
where GSNO homolytic cleavage13 of the S-N bond
proceeded with release of NO.3,14 Reactions of GSNO with
DHP were also performed in sodium dodecyl sulfate (SDS)
micelles (0.5 M), prepared in water containing 10 mM
EDTA. Results similar to those shown in Table 1 were
obtained.
The reaction might commence with a one-electron transfer
from dihydropyridine to GSNO, yielding the radical cation
(3) of DHP and the anion of GSNO, GSNO-. The subsequent
radical coupling upon protonation of GSNO- 17would give
an unstable dihydroxyhydrazine that could eliminate hypo-
nitrous acid, HONdNOH, to form the disulfide, GSSG.
HONdNOH then decomposes into N2O.3,18 N2O was de-
tected by GC-MS. It is reasonable that radical 3 lost a proton
to give aminyl radical (4), which then reacted with GSNO
to form pyridine (2) and GSN(‚)OH. The later species
proceeded by the same reaction pathway shown in Scheme
2. The stoichiometry of reactions showed there was an
approximately equal molar relationship between dihydro-
pyridine (1), GSNO, and pyridine (2). This implies that N2O
or hyponitrous acid might react with DHP and N2 might be
the final gaseous product, although further work will be
necessary to confirm this proposal.
The present results might be of both biological and
chemical significance. First, because of the mild oxidative
reactivity of GSNO which enhances selectivity, this reaction
could be used for a biommetic model for reduction of
NADH. Second, our results reveal an example of the
oxidation of DHP by a S-nitrosothiol, which is pertinent to
the chemical behavior of GSNO and the metabolism of 1,4-
dihydripyridine-based drugs. We believe that the present
work will stimulate investigations of the chemical features
of GSNO and its role in biological and medicinal chemistry.
To our knowledge, two mechanisms for the oxidation of
NADH analogues, hydride transfer8b,15 or electron transfer,16
are possible. On the basis of our experimental results, we
(8) (a) Mauzeral, D.; Westheimer, F. H. J. Am. Chem. Soc. 1955, 77,
2261. (b) Abeles, R. J.; Hutton, R. F.; Westheimer, F. H. J. Am. Chem.
Soc. 1957, 79, 712.
(9) Triggle, D. J.; Langs, D. A.; Janis, R. A. Med. Res. ReV. 1989, 9,
123.
(10) Varma, R. S.; Kumar, D. Tetrahedron Lett. 1999, 40, 21 and
references therein.
(11) For preparation, see: Love, B.; Snader, K. M. J. Org. Chem. 1965,
30, 1914.
(12) For preparation, see: Hart,T. W. Tetrahedron Lett. 1985, 26, 2013.
(13) (a) Butler, A. R.; Williams, D. L. H. Chem. Soc. ReV. 1993, 22,
223. (b) Mayer, B.; Schrammel, A.; Klatt, P.; Koesling, D.; Schmidt, K. J.
Biol. Chem. 1995, 270, 17355. (c) Gorren, A. C. F.; Schrammel, A.;
Schmidt, K.; Mayer, B. Arch. Biochem. Biophys. 1996, 330, 219. (d) Dicks,
A. P.; Swift, H. R.; Williams, D. L. H.; Butler, A. R.; Alsadoni, H. H.;
Cox, B. G. J. Chem. Soc., Perkin Trans. 2 1996, 481. (e) McAninly, J.;
Williams, D. L. H.; Askew, S. C.; Butler, A. R.; Russell, C. J. Chem. Soc.,
Chem. Commun. 1993, 1758.
Acknowledgment. We thank the National Science Foun-
dation of China (Research Grant 29672016) and the National
Foundation of Gansu Province for financial support.
OL990367C
(17) (a) Barton, D. H. R.; Blair, I. A.; Magnus, P. D.; Norris, R. K. J.
Chem. Soc., Perkin Trans. 1 1973, 1031. (b) Church, D. F.; Pryor, W. A.
J. Org. Chem. 1980, 45, 2866. (c) Pryor, W. A.; Church, D. F.; Govindan,
C. K.; Crank, G. J. Org. Chem. 1982, 47, 156.
(14) (a) Park, J. W. Biochem. Biophys. Res. Commun. 1988, 152, 916.
(b) Stamler, J. S. Cell 1994, 78, 36.
(15) Meijer, L. H. P.; Pandit, U. K. Tetrahedron 1985, 41, 467.
(16) Fukuzumi, S. AdV. Electron-Transfer Chem. 1992, 2, 67.
(18) (a) Bonner, F. T.; Ravid, B. Inorg. Chem. 1975, 14, 558. (b) Gallup,
G. A. Inorg. Chem. 1975, 14, 563.
742
Org. Lett., Vol. 2, No. 6, 2000