One-pot synthesis of new 3-substituted coumarins by tandem reactions

Article abstract of DOI:10.1002/jhet.5570440130

(Chemical Equation Presented) The synthesis of new 3-substituted coumarins appended to imidazolium, pyridinium, 3-dimethylamino pyridinium, 3-chloro pyridinium and 3-bromo pyridinium salts is reported. These salts were prepared by tandem reactions, follow

Full text of DOI:10.1002/jhet.5570440130

Jan-Feb 2007
193
One-pot Synthesis of New 3-Substituted Coumarins
by Tandem Reactions
Khadidja Bourahlaa, Mustapha Rahmounia, Joan Fraga-Dubreuilb,†,
Jean Pierre Bazureaub,* and Jack Hamelinb
.a) Université de Tiaret, Laboratoire de Synthèse et de Catalyse, 14000-TIARET, Algérie
b) Université de Rennes 1, Laboratoire Sciences Chimiques de Rennes, UMR CNRS 6226,
Groupe Ingénierie Chimique et Molécules pour le Vivant (ICMV), Bât. 10A, Campus de Beaulieu,
Avenue du Général Leclerc, CS 74205, 35042 RENNES Cedex, France
Email: jean-pierre.bazureau@univ-rennes1.fr
Received December 8, 2005
4
NR3
NR3
O
O
tandem reactions
anionic metathesis
O
, Y
X
X
O
OH
1
2
(X = Cl, Br)
6 (Y = BF4, PF6, N(CN)2)
The synthesis of new 3-substituted coumarins appended to imidazolium, pyridinium, 3-dimethylamino
pyridinium, 3-chloro pyridinium and 3-bromo pyridinium salts is reported. These salts were prepared by
tandem reactions, followed by quantitative anionic metathesis. The structure of these new 3-substituted
coumarins was established by NMR (1H, 13C) and high-resolution mass spectrometry.
J. Heterocyclic Chem., 44, 193 (2007).
INTRODUCTION
RESULTS AND DISCUSSION
Coumarins occupy a unique place in the realm of
natural and synthetic organic chemicals, which present a
wide variety of properties [1]. Members of this group
display a broad range of applications as additives to
perfumes and cosmetics [2], as photographic sensitizers
and solar collectors [3], as fluorescent markers in
biochemistry [4], as tuneable dye lasers [5]. Since the
1990's, a large number of in vivo and in vitro studies have
The starting 2-(halogenoacetoxy) benzaldehydes 3a,b
(X = Cl, Br) were readily obtained by modification of the
procedure of Fuson et al. [23] from salicylaldehyde 1 and
chloroacetyl chloride 2a or bromoacetyl bromide 2b in
dichloromethane at room temperature (Scheme I) with
pyridine. After work-up and purification by distillation,
the 2-(chloroacetoxy) benzaldehyde 3a and 2-(bromo-
acetoxy)benzaldehyde 3b were isolated respectively in 78
and 82% yield.
With the desired aldehydes 3a,b in hand, we have
examined the synthesis of coumarins 5 by cyclization of 3
with various N-nucleophiles 4 (i.e. methyl imidazole 4a,
pyridine 4b, 4-dimethylamino pyridine 4c, 3-chloro
pyridine 4d, 3-bromo pyridine 4e). For the preparation of
salts 5, we have developed a one-pot tandem reaction by
addition of a solution of nucleophile 4 in dichloromethane
to the 2-(halogenoacetoxy)benzaldehydes 3a,b. After
refluxing (4 - 48 hours) followed by addition of ethanol in
the crude reaction mixture at room temperature, the
precipitated salts 5 could then be isolated by simple
filtration after washings with the appropriate solvent
(Et2O, AcOEt). The formation of salt 5 by tandem
reactions could be attributed to a nucleophilic substitution
between the starting product 3 and 4 which gave the
intermediate A in the first step, followed by intra-
molecular condensation of the active methylene with the
formyl group. Initial attempts to isolate the intermediate
salt A during the tandem reactions were unsuccessful. The
salts 5(a-j) were characterized by conventional techniques
(1H, 13C NMR) and the purity was controlled by high-
revealed
a diverse array of pharmacological and
biochemical properties like antibacterial [6], inhibitory
properties on human platelet aggregation [7], anti-HIV
activity [8], antimutagenic and antitumor activities [9].
Coumarins are also exploited as intermediates and
building blocks in organic chemistry [10].
For the preparation of coumarins and their derivatives,
various methods have been used, which include Perkin
[11], Wittig [12], Knoevenagel [13], Reformatsky [14]
and Pechmann [15] reactions and more recently
palladium-catalyzed carbonylative annulations [16].
During the last few years, there has been great interest
in 3-substituted coumarins (i.e. 3-carboxy coumarins
[13b], 3-ethoxycarbonyl coumarins [13c], 3-tetrahydro-
thiophenium coumarins [17], 3-phenoxy coumarins [18])
that have been used to synthesize modified cephalosporins
[19], penicillins [20] and fluorescent chromophores [21].
Continuing our work on imidazolium and pyridinium salts
in ionic liquid chemistry [22], we decided to investigate
the synthesis of coumarins substituted in C-3 position by
imidazolium or pyridinium moiety. Herein, we report the
results obtained for the synthesis of new coumarins.
Preparative procedures including characterization (1H,
13C, HRMS) are also presented.

194
K. Bourahla, M. Rahmouni, J. Fraga-Dubreuil, J.P. Bazureau, J. Hamelin
Vol 44
resolution mass spectrometry. The results summarized in
Table I show that 2-(halogenoacetoxy)benzaldehydes 3
react with various nucleophiles 4 to give the 3-substituted
coumarins 5 in yield ranging from 30 to 88% (Table I).
Analysis of the results in Table I show that the choice of
the nucleophilic compound 4 and/or the 2-(halogeno-
In the last step for the preparation of salts 6 by
anion-exchange reactions, the corresponding weakly
-
-
coordinating anions used were BF4 , PF6 and
-
N(CN)2 from the respective commercially available
starting salts NH4BF4, KPF6 and NaN(CN)2. All the
anion-exchange reactions were carried out in dry
acetonitrile stirred at 70°C under nitrogen for 24
hours. Then the insoluble salt (NH4X, KX or NaX
with X = Cl, Br) was filtered off and then dissolved
in de-ionized water. The efficiency of the metathesis
reaction was determined by measuring the chloride
or bromide ion solution using the Mohr's method
[24]. After filtration of the crude reaction mixture of
6 on a pad of Celite® to remove halide contaminants
trapped in the salt, followed by elimination of MeCN
in vacuo, the salts 6 (Table II) were isolated in good
yields (89 – 98%). The potential halide impurities in
salts 6 were evaluated by volumetric titration using a
modified Volhard's method [25] developed in our
laboratory (halide < 100 ppm).
acetoxy)benzaldehydes
3
controls the nucleophilic
substitution versus annulation pathway. In general, the
experimental results can be divided into two groups, those
that gave low or moderate yields (5a: 49%, 5g: 30% and
5i: 35%) from 2-(chloroacetoxy)benzaldehyde 3a with 4a,
4d or 4e and, those that afforded good yields from 2-
(bromoacetoxy)benzaldehyde 3b. In the first case, the
nucleophilic substitution in the tandem reaction was less
favoured with the 2-(chloroacetoxy)benzaldehyde 3a.
Structural assignment of the compounds 5(a-j) is based on
spectroscopic data (1H, 13C NMR). For example, in the 1H
and the 13C NMR spectrum of 5a in D2O solution, the
singlet of H-4 appears at high field (ꢀH-4 8.36 ppm) and
two signals at ꢀC-3 117.40 and ꢀC-4 138.67 ppm that were
assigned to the intracyclic double bond.
Table I
Table II
Product 5
X
Starting 4 Yield of 5
Melting
Product 6
Y-
Starting
Yield of 6
Melting
(%)[a]
point (°C)
salt 5
(%)[a]
point (°C)
5a
5b
5c
5d
5e
5f
5g
5h
5i
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
4a
4a
4b
4b
4c
4c
4d
4d
4e
4e
49
62
88
82
78
78
30
88
35
69
250-252
262-264
220-222
214-215
245-247
235-237
225-227
230-232
> 260
6a
6b
6c
6d
6e
6f
6g
6h
6i
BF4
PF6
N(CN)2
BF4
PF6
N(CN)2
BF4
PF6
N(CN)2
BF4
PF6
5a or 5b
5a or 5b
5a or 5b
5c or 5d
5c or 5d
5c or 5d
5e or 5f
5e or 5f
5e or 5f
5g or 5h
5g or 5h
5g or 5h
89
92
98
96
97
89
98
96
95
98
97
99
224-226
260-262
171-176
> 260
> 260
219-221
250-252
> 260
210-212
220-222
240-242
210-212
5j
> 260
6j
6k
6l
[a] Yield of isolated product.
N(CN)2

Jan-Feb 2007
One-pot synthesis of new 3-substituted coumarins by tandem reactions
195
Table II (continued)
C, 54.43; H, 3.55; Cl, 17.85; O, 24.17. Found: C, 54.45, H, 3.52;
Cl, 17.83, O, 24.2.
Product 6
Y-
Starting
Yield of 6
Melting
point (°C)
2-(bromoacetoxy)benzaldehyde (3b).
Yield 82%, bp
salt 5
(%)[a]
1
125°C/0.5 Torr, H nmr (CDCl3): 4.17 (s, 2H, CH2), 7.22 (dd,
1H, J = 8.2, 0.8 Hz, H-3, Ar), 7;43 (td, 1H, J = 7.6, 0.8 Hz, H-5,
Ar), 7.65 (td, 1H, J = 8, 1.8 Hz, H-4, Ar), 7.88 (dd, 1H, J = 7.6,
1.8 Hz, H-6, Ar), 10.09 (s, 1H, CHO). 13C nmr (CDCl3): ꢀ 25.37
(t, J = 154 Hz), 123.06 (dd, J = 165, 8 Hz, C-3), 126.99 (dd, J
=165, 8 Hz, C-5), 127.76 (dm, J = 24 Hz, C-1), 131.97 (dd, J =
162, 9 Hz, C-6), 135.44 (dd, J = 164, 9 Hz, C-6), 150.67 (m, C-
2), 165.59 (m, CO), 188.73 (dd, J = 180, 5 Hz, CHO). hrms, m/z
241.9773 found (calculated for C9H7O379Br, M+ requires
241.9779). Anal. Calcd. for C9H7BrO3: C, 44.47; H, 2.90; Br,
32.87; O, 19.75. Found: C, 44.41, H, 2.95; Cl, 32.86, O, 19.78.
Standard Procedure for the Synthesis of Compounds (5a)
and (5b). These reactions were carried out under a nitrogen
atmosphere. To the 2-(chloroacetoxy)benzaldehyde (3a) (1 g,
5.04 mmoles) or to the 2-(bromoacetoxy)benzaldehyde (3b) (1g,
4.11 mmoles) was added dropwise over 15 minutes a solution of
N-methyl imidazole (4a) (0.17 g, 5.04 mmoles) for the
preparation of salt (5a) or (0.5 g, 6.17 mmoles) for (5b) in dry
methylene chloride (20 ml) under vigorous magnetic stirring at
41°C. After cooling down to room temperature, ethanol (20 ml)
was added in the reaction mixture and a solid was obtained after
15 minutes of stirring. The precipitated salt (5) was collected by
filtration, washed with diethylether (2 x 5 ml) and dried under
reduced pressure (10-2 Torr) during 2 hours. The compound (5)
was stored in the dark under an inert atmosphere.
6m
6n
6o
BF4
PF6
N(CN)2
5i or 5j
5i or 5j
5i or 5j
99
98
99
224-226
> 260
220-222
[a] Yield of isolated product.
EXPERIMENTAL
General. Melting points were determined on a Kofler melting
point apparatus and were uncorrected. H NMR spectra were
1
recorded on BRUKER AC 300 P (300 MHz) and BRUKER ARX
200 (200 MHz) spectrometers, 13C NMR spectra on BRUKER AC
300 P (75 MHz) spectrometer. Chemical shifts are expressed in
parts per million downfield from tetramethylsilane as an internal
standard. Data are given in the following order: ꢀ value,
multiplicity (s, singlet; d, doublet; t, triplet; q, quartet; m,
multiplet; br, broad), number of protons, coupling constants J is
given in Hertz. The mass spectra (HRMS) were taken respectively
on a MS/MS ZABSpec TOF Micromass (EBE TOF geometry) at
an ionizing potential of 8 eV for the salts 5 and 6 and on a
VARIAN MAT 311 at an ionizing potential of 70 eV for the other
compounds in the Centre Régional de Mesures Physiques de
l'Ouest (CRMPO, Rennes). Acetonitrile was distilled over calcium
chloride after standing overnight and stored over molecular sieves
(3Å). Solvents were evaporated with a BUCHI rotary evaporator.
All reagents were purchased from Acros, Aldrich Chimie, Fluka
France and used without further purification.
1-Methyl-3-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)imida-
zolium chloride (5a). Yield 49%. White needles, mp 250-
1
252°C. H nmr (D2O): ꢀ 3.95 (s, 3H, Me), 7.36 (td, 2H, J = 8.3
Standard Procedure for the Synthesis of 2-(Chloroacetoxy)-
benzaldehyde (3a) and 2-(Bromoacetoxy)benzaldehyde (3b).
Hz, H-6', H-8', Ar), 7.59 (s, 1H, H-4), 7.68 (td, 2H, J = 7.8 Hz,
H-5', H-7', Ar), 7.79 (s, 1H, H-5), 8.36 (s, 1H, H-4', Ar), 9.25 (s,
1H, H-2, Ar). 13C nmr (D2O): ꢀ 36.35 (q, J = 145 Hz), 116.57
(dd, J = 160, 6 Hz, C-8'), 117.44 (m, C-3'), 120.96 (m, C-4a'),
122.28 (dm, J = 200 Hz, C-5), 123.84 (ddd, J = 200, 12, 5 Hz,
C-4), 126.00 (m, C-5'), 129.63 (dm, J = 168 Hz, C-6'), 134.16
(dm, J = 160 Hz, C-7'), 137,03 (dm, J = 225 Hz, C-2), 138.74
(dd, J = 169, 5 Hz, C-4'), 152.52 (m, C-8a'), 158;30 (d, J = 8 Hz,
CO). hrms, m/z 227.0821 found (calculated for C13H11N2O2, C+
requires 227.0821).
1-Methyl-3-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)imida-
zolium bromide (5b). Yield 62%. White needles, mp 262-
264°C. 1H nmr (D2O): ꢀ 4.69 (s, 3H, Me), 7.35 (td, 2H, J = 8.4
Hz, H-6', H-8', Ar), 7.61 (s, 1H, H-4), 7.69 (td, 2H, J = 7.9 Hz,
H-5', H-7', Ar), 7.80 (s, 1H, H-5), 8.36 (s, 1H, H-4', Ar), 9.27 (s,
1H, H-2). 13C nmr (D2O): ꢀ 36.44 (q, J = 145 Hz), 116.56 (dd, J
= 160, 6 Hz, C-8'), 117.40 (m, C-3'), 120.90 (m, C-4a'),
122.31(dm, J = 200 Hz, C-5), 123.94 (ddd, J = 200, 12, 5 Hz, C-
4), 126.03 (m, C-5'), 129.65 (dm, J = 168 Hz, C-6'), 134.17 (dm,
J = 160 Hz, C-7'), 136.98 (dm, J = 225 Hz, C-2), 138.67 (dd, J =
169, 5 Hz, C-4'), 152.47 (m, C-8a'), 158.18 (d, J = 8 Hz, CO).
hrms, m/z 227.0821 (calculated for C13H11N2O2, C+ requires
227,0821).
All these reactions were carried out under
a nitrogen
atmosphere. To a solution of salicylic aldehyde (1) (2 g, 16.37
mmoles) and dry pyridine (1.62 g, 20.47 mmoles) in 30 ml of
dry methylene chloride was added dropwise chloroacetyl
chloride (2a) (2.29 g (20.30 mmoles) or bromoacetyl bromide
(2b) (4.09 g, 20.30 mmoles) over 20 minutes and under vigorous
magnetic stirring at 0°C. The reaction mixture was stirred for 5
hours (from 2a) or 3 hours (from 2b) at room temperature. After
elimination of the insoluble pyridinium salt on a filter paper, 20
ml of a 0.1 M of chlorhydric acid were added in the crude
reaction mixture. After decantation, the aqueous layer was
washed with methylene chloride (2 x 10 ml) then, the resulting
organic layer was washed successively with 20 ml of saturated
sodium hydrogenocarbonate, 10 ml of deionized water and was
dried over magnesium sulphate. The organic solution was
concentrated by rotary evaporation under reduced pressure and
the crude reaction mixture was purified by distillation with a
BÜCHI B-585 microdistillator.
2-(Chloroacetoxy)benzaldehyde (3a). Yield 78% (Litt. [17]
1
36%), bp 120°C/0.5 Torr. H nmr (CDCl3): ꢀ 4.18 (s, 2H, CH2),
7.20 (dd, 1H, J = 8.1, 0.9 Hz, H-3, Ar), 7.41 (td, 1H, J = 7.5,
1.03 Hz, H-5, Ar), 7.63 (td, 1H, J = 7.7, 1.8 Hz, H-4, Ar), 7.83
(dd, 1H, J = 7.5, 1.8 Hz, H-6, Ar), 10.02 (s, 1H, CHO). 13C nmr
(CDCl3): ꢀ 40.88 (t, J = 155 Hz), 123.20 (dd, J = 165, 7.1 Hz, C-
3), 127.06 (dd, J = 165, 7.1 Hz, C-5), 127.64 (dm, J = 26 Hz, C-
1), 132.64 (dd, J = 162, 9 Hz, C-6), 135.53 (dd, J = 164, 8.1 Hz,
C-6), 150.30 (m, C-2), 165.91 (m, CO), 189.04 (dd, J = 180, 5
Hz, CHO). hrms, m/z 198.0081 found (calculated for
C9H7O335Cl, M+ requires 198.0084). Anal. Calcd. for C9H7ClO3:
1-(2-Oxo-4a,8a-dihydro-2H-chromen-3-yl)pyridinium
chloride (5c). The compound (5c) was prepared from 2-
(chloroacetoxy)benzaldehyde (3a) (1 g, 5.04 mmoles) and dry
pyridine (0.4 g, 5.04 mmoles) according to the experimental
procedure used for (5a) after a reaction time of 24 hours under
reflux and washings with ethyl acetate (3 x 20 ml). This
compound was obtained as white needles, mp 220-222°C and
1
88% yield. H nmr (D2O): ꢀ 7.45 (t, 2H, J = 7.6 Hz, H-6', H-8'),

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K. Bourahla, M. Rahmouni, J. Fraga-Dubreuil, J.P. Bazureau, J. Hamelin
Vol 44
7,78 (dd, 2H, J = 14.2, 7.8 Hz, H-5', H-7'), 8.22 (t, 2H, J = 7 Hz,
H-3, H-5), 8.60 (s, 1H, H-4'), 8.79 (t, 1H, J = 7.8 Hz, H-4),
9.02 (d, 2H, J = 5.4 Hz, H-2, H-6). 13C nmr (D2O): ꢀ 116.86 (dd,
J = 165, 6 Hz, C-8), 117.36 (m, C-3'), 126.24 (dm, J = 9 Hz, C-
6'), 128.08 (dm, J = 171 Hz, C-4a'), 128.37 (m, C-5'), 130.38 (m,
C-3, C-5), 135.22 (dm, J = 165 Hz, C-7'), 142.66 (dd, J = 171, 6
Hz, C-2, C-6), 145.35 (dm, J = 185 Hz, C-4), 148.48 (m, C-4'),
153.41 (m, C-8a'), 158.34 (d, J = 8 Hz, CO). hrms, m/z 224.0713
found (calculated for C14H10NO2, C+ requires 224.0712).
This compound was obtained as beige needles, mp 225-227°C
1
and 30% yield. H nmr (D2O): ꢀ 7.45 (d, 2H, J = 7.2 Hz, H-6',
H-8'), 7.80 (t, 2H, J = 7.6 Hz, H-5', H-7'), 8.24 (t, 1H, J = 8.5 Hz,
H-5), 8.65 (s, 1H, H-4'), 8.76 (d, 1H, J = 8.3 Hz, H-4), 9.04 (d,
1H, J = 7 Hz, H-6), 9.27 (s, 1H, H-2). 13C nmr (D2O): ꢀ 116.86
(C-8'), 117.26 (C-3'), 126.35 (C-6'), 127.56 (C-4a'), 128.83 (C-
5'), 130.61 (C-7'), 135.48 (C-5), 136.06 (C-3), 142.98 (C-4),
144.09 (C-6), 144.65 (C-2), 148.25 (C- 4'), 153.51 (C-8a'),
157.88 (CO). hrms, m/z 258.0328 found (calculated for pour
C14H9NO235Cl, C+ requires 258.0322).
1-(2-Oxo-4a,8a-dihydro-2H-chromen-3-yl)pyridinium
bromide (5d). The compound (5d) was prepared from 2-
(bromoacetoxy)benzaldehyde (3b) (1 g, 4.11 mmoles) and dry
pyridine (0.32 g, 4.11 mmoles) according to the experimental
procedure used for (5b) after a reaction time of 24 hours under
reflux and washings with ethyl acetate (3 x 20 ml). This
compound was obtained as white needles, mp 214-216°C and
3-Chloro-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium bromide (5h). The compound (5h) was prepared from
2-(bromoacetoxy)benzaldehyde (3b) (1 g, 4.11 mmoles) and 3-
chloro pyridine (0.47 g, 4.11 mmoles) according to the
experimental procedure used for (5b) after a reaction time of 12
hours under reflux and washings with ethyl acetate (2 x 20 ml).
This compound was obtained as yellow needles, mp 235-237°C
1
82% yield. H nmr (D2O): ꢀ 7.46 (t, 2H, J = 7.8 Hz, H-6', H-8'),
1
and 80% yield. H nmr (D2O): ꢀ 7.47 (d, 2H, J = 7.1 Hz, H-6',
7.79 (dd, 2H, J = 14.2, 7.8 Hz, H-5', H-7'), 8.22 (t, 2H, J = 7.1
Hz, H-3, H-5), 8.59 (s, 1H, H-4'), 8.70 (t, 1H, J = 6.7 Hz, H-4),
9.00 (d, 2H, J = 5.9 Hz, H-2, H-6). 13C nmr (D2O): ꢀ 116.87 (dd,
J = 165, 6 Hz, C-8'), 117.37 (m, C-3'), 126.24 (dm, J = 9 Hz, C-
6'), 127.97 (dm, J = 171 Hz, C-4a'), 128.37 (m, C-5'), 130.37 (m,
C-3, C-5), 135.22 (dm, J = 165 Hz, C-7'), 142.66 (dd, J = 171, 6
Hz, C-2, C-6), 145.36 (dm, J = 185 Hz, C-4), 148.47(m, C-4'),
153.43 (m, C-8a'), 158.37 (d, J = 8 Hz, CO). hrms, m/z 224.0714
found (calculated for C14H10NO2, C+ requires 224.0712).
H-8'), 7.81 (t, 2H, J = 7.5 Hz , H-5', H-7'), 8.26 (t, 1H, J = 8.3
Hz, H-5), 8.63 (s, 1H, H-4), 8.78 (d, 1H, J = 8.5 Hz, H-4'), 9.02
(d, 1H, J = 5.9 Hz, H-6), 9.28 (s, 1H, H-2). 13C nmr (D2O):
ꢀ 116.91 (C-8'), 117.23 (C-3'), 126.33 (C-6'), 127.50 (C-4a'),
128.83 (C-5'), 130.53 (C-7'), 135.51 (C-5), 136.03 (C-3), 142.95
(C-4), 144.08 (C-6), 144.62 (C-2), 148.20 (C- 4'), 153.50 (C-
8a'), 157.92 (CO). hrms, m/z 258.0328 found (calculated for
pour C14H9NO235Cl, C+ requires 258.0322).
3-Bromo-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium chloride (5i). The compound (5i) was prepared from 2-
(chloroacetoxy)benzaldehyde (3a) (1 g, 5.04 mmoles) and 3-
bromo pyridine (0.79 g, 5.04 mmoles) according to the
experimental procedure used for (5a) after a reaction time of 24
hours under reflux. This compound was obtained as beige
needles, mp > 260°C and 35% yield. 1H nmr ((D3C)2SO): ꢀ 7.52
(t, 2H, J = 7.3 Hz, H-6', H-8'), 7.85 (t, 2H, J = 6.8 Hz , H-5', H-
7'), 8.18 (s, 1H, H-5), 8.67 (s, 1H, H-4'), 8.99 (d, 1H, J = 8.4 Hz,
H-4), 9.16 (d, 1H, J = 6 Hz, H-6), 9.52 (s, 1H, H-2). 13C nmr
((D3C)2SO): ꢀ 117.07 (C-8'), 117.59 (C-3'), 122.63 (C-4a'),
126.42 (C-6'), 128.16 (C-3), 129.06 (C-5'), 130.89(C-7'), 135.41
(C-5), 141.96 (C-4), 145.02 (C-6), 146.81 (C-2), 150.97 (C- 4'),
153.61 (C-8a'), 156.95 (CO). hrms, m/z 301.9820 found
(calculated for C14H9NO279Br, C+ requires 301.9817).
4-Dimethylamino-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-
yl)pyridinium chloride (5e). The compound (5e) was prepared
from 2-(chloroacetoxy) benzaldehyde (3a) (1 g, 5.04 mmoles)
and 4-dimethylamino pyridine (0.61 g, 5.04 mmoles) according
to the experimental procedure used for (5a) after a reaction time
of 4 hours under reflux. This compound was obtained as white
needles, mp 245-247°C and 78% yield. 1H nmr (D2O): ꢀ 3.18 (s,
6H, Me), 6.88 (d, 2H, J = 7.9 Hz, H-3, H-5), 7.32 (td, 2H, J =
7.3 Hz, H-6', H-8'), 7.62 (t, 2H, J = 7.2 Hz, H-5', H-7'), 8.01 (d,
2H, J = 7.8 Hz, H-2, H-6), 8.26 (s, 1H, H-4'). 13C nmr (D2O):
ꢀ 40.02 (C-8, C-9), 107.55 (C-8'), 116.53(C-6'), 117.67 (C-5'),
126.03 (C-3'), 127.08 (C-7'), 129.68 (C-4a'), 134.10 (C-3, C-5),
140.07 (C-2, C-6), 141.06 (C-4'), 152.55 (C-4), 156.62 (C-8a'),
158.92 (CO). hrms, m/z: 267.1139 found (calculated for
C16H15N2O2, C+ requires 267.1134).
3-Bromo-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium bromide (5j). The compound (5j) was prepared from 2-
(bromoacetoxy)benzaldehyde (3b) (1 g, 4.11 mmoles) and 3-
bromo pyridine (0.65 g, 4.11 mmoles) according to the
experimental procedure used for (5b) after a reaction time of 12
hours under reflux. This compound was obtained as yellow
4-Dimethylamino-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)-
pyridinium bromide (5f). The compound (5f) was prepared
from 2-(bromoacetoxy)benzaldehyde (3b) (1 g, 4.11 mmoles)
and 4-dimethylamino pyridine (0.5 g, 4.11 mmoles) according to
the experimental procedure used for (5b) after a reaction time of
3 hours under reflux. This compound was obtained as white
needles, mp 235-237°C and 78% yield. 1H nmr (D2O): ꢀ 3.20 (s,
6H, Me), 6.94 (d, 2H, J = 7.9 Hz, H-3, H-5), 7.40 (d, 2H, J = 6.9
Hz, H-6', H-8'), 7.67 (t, 2H, J = 7.5 Hz, H-5', H-7'), 8.05 (d, 2H,
J = 7.8 Hz, H-2, H-6), 8.28 (s, 1H, H-4'). 13C nmr (D2O):
ꢀ 39.88 (C-8, C-9), 107.50 (C-8'), 116.60 (C-6'), 117.79 (C-5'),
125.99 (C-3'), 127.32 (C-7'), 129.63 (C-4a'), 134.08 (C-3, C-5),
140.32 (C-2, C-6), 141.11 (C-4'), 152.73 (C-4), 156.76 (C-8a'),
159.37 (CO). hrms, m/z 267.1134 found (calculated for C16H15
N2O2, C+ requires 267.1134).
1
needles, mp > 260°C and 69% yield. H nmr (D2O): ꢀ 7.47 (t,
2H, J = 8.7 Hz, H-6', H-8'), 7.79 (t, 2H, J = 7.7 Hz , H-5', H-7'),
8.13 (t, 1H, J = 7.9 Hz, H-5), 8.59 (s, 1H, H-4'), 8.90 (d, 1H, J =
8.4 Hz, H-4), 9.03 (d, 1H, J = 6 Hz, H-6), 9.33 (s, 1H, H-2). 13
C
nmr (D2O): ꢀ 116.91 (C-8'), 117.27 (C-3'), 123.04 (C-4a'),
126.29 (C-6'), 128.74 (C-3), 129.08 (C-5'), 130.46 (C-7'), 135.47
(C-5), 142.89 (C-4), 144.28 (C-6), 146.48 (C- 2), 150.95 (C-4'),
153.53 (C-8a'), 157.99 (CO). hrms, m/z 301.9815 found
(calculated for C14H9NO279Br, C+ requires 301.9817).
3-Chloro-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium chloride (5g). The compound (5g) was prepared from
2-(chloroacetoxy)benzaldehyde (3a) (1 g, 5.04 mmoles) and 3-
chloro pyridine (0.57 g, 5.04 mmoles) according to the
experimental procedure used for (5a) after a reaction time of 48
hours under reflux and washings with ethyl acetate (2 x 20 ml).
Typical Procedure for the Preparation of Compounds 6(a-
o) from Chloride or Bromide Salts 5(a-j) by Anionic
Metathesis. A mixture of 3.28 mmoles of chloride or bromide
salt (5) and ammonium tetrafluoroborate (0.34 g, 3.28 mmoles)
or potassium hexafluorophosphate (0.60 g, 3.28 mmoles) or
sodium dicyanamide (0.29 g, 3.28 mmoles) dissolved in 50 ml

Jan-Feb 2007
One-pot synthesis of new 3-substituted coumarins by tandem reactions
197
of dry acetonitrile was stirred vigorously at 70°C under a stream
of nitrogen for 24 hours. After cooling down to room
temperature, the precipitated salt (ammonium chloride, or
potassium chloride, or sodium chloride) was eliminated by
filtration on a filter paper. The resulting filtrate was quickly re-
filtered through a pad of Celite® to remove some residual salt
and finally concentrated by rotary evaporation that gave the
expected salt (6). The compound (6) was further dried under
high vacuum (10-2 Torr) at 60°C for 2 hours. The compound (6)
was stored in the dark under an inert atmosphere.
= 182 Hz, C-4), 147.26 (t, J = 6 Hz, C-4'), 152.16 (m, C-8a'),
155.44 (d, J = 8 Hz, CO). hrms m/z 224.0714 found (calculated
for C14H10NO2, C+ requires 224,0712).
1-(2-Oxo-4a,8a-dihydro-2H-chromen-3-yl)pyridinium hexa-
fluorophosphate (6e). Yield 97%. White needles, mp > 260°C.
1H nmr ((D3C)2SO): ꢀ 7.56 (t, 1H, J = 7.5 Hz, H-8'), 7.67 (d, 1H,
J = 8.3 Hz, H-6'), 7.86 (td, 1H, J = 7.3, 1.1 Hz, H-7'), 7.91 (d,
1H, J = 7.7 Hz, H-5'), 8.41 (t, 2H, J = 7.1 Hz, H-3, H-5), 8.82 (s,
1H, H-4'), 8.88 (t, 1H, J = 7.9 Hz, H-4), 9.27 (d, 2H, J = 6 Hz,
H-2, H-6). 13C nmr ((D3C)2SO): ꢀ 115.56 (dd, J = 166, 8 Hz, C-
8'), 116.48 (m, C-3'), 124.69 (d, J = 9 Hz, C-6'), 126.90 (t, J = 6
Hz, C-4a'), 127.94(m, C-5'), 129.04 (m, C-3, C-5), 133.29 (ddd,
J = 164, 8, 2 Hz, C-7'), 139.64 (dd, J = 171, 5 Hz, C-2, C-6),
144.81 (dm, J = 178 Hz, C-4), 147.21 (t, J = 6 Hz, C-4'), 152.10
(m, C-8a'), 155.37 (d, J = 8 Hz, CO). hrms, m/z 224.0714 found
(calculated for C14H10NO2, C+ requires 224,0712).
1-Methyl-3-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)imida-
zolium tetrafluoroborate (6a). Yield 89%. Beige needles, mp
1
224-226°C. H nmr ((D3C)2SO): ꢀ 4.01 (s, 3H, Me), 7.57 (td,
2H, J = 7.5 Hz, H-6', H-8'), 7.77 (t, 1H, J = 7.8 Hz, H-7'), 7.83
(d, 1H, J = 7.7 Hz, H-5'), 7.91 (s, 1H, H-4), 8.12 (s, 1H, H-5),
8.63 (s, 1H, H-4'), 9.64 (s, 1H, H-2). 13C nmr ((D3C)2SO):
ꢀ 36.22 (q, J = 144 Hz), 116.39 (dd, J = 168, 8 Hz, C-8'), 117.58
(m, C-3'), 121.62 (d, J = 4 Hz, C-4a'), 122.46 (ddd, J = 207,
13.5 Hz, C-4), 123.66 (dm, J = 199 Hz, C-5), 125.59 (dd, J =
160, 8 Hz, C-5'), 129.44 (dm, J = 165 Hz, C-6'), 133.55 (dm, J =
162 Hz, C-7'), 137.28 (dm, J = 222 Hz, C-2), 137.41 (dd, J =
170, 5 Hz, C-4'), 152.43 (m, C-8a'), 156.18 (d, J = 8 Hz, CO).
hrms, m/z 227.0821 found (calculated for C13H11N2O2, C+
requires 227.0821).
1-(2-Oxo-4a,8a-dihydro-2H-chromen-3-yl)pyridinium dicyan-
1
amide (6f). Yield 89%. Brownish needles, mp 219-221°C. H
nmr ((D3C)2SO): ꢀ 7.54 (t, 1H, J = 7.5 Hz, H-8'), 7.65 (d, 1H, J =
8.3 Hz, H-6'), 7.85 (td, 1H, J = 7.6, 1.3 Hz, H-7'), 7.91 (d, 1H, J
= 7.5 Hz, H-5'), 8.41 (t, 2H, J = 7.1 Hz, H-3, H-5), 8.86 (s, 1H,
H-4'), 8.88 (t, 1H, J = 6.9 Hz, H-4), 9.29 (d, 2H, J = 5.8 Hz, H-2,
H-6). 13C nmr ((D3C)2SO): ꢀ 117.14 (dd, J = 168, 8 Hz, C-8'),
118.07 (m, C-3'), 126.25 (d, J = 9 Hz, C-6'), 128.50 (m, C-4a'),
129.45 (m, C-5'), 130.64 (m, C-3, C-5), 134.86 (ddd, J = 164, 8,
2 Hz, C-7'), 141.25 (dd, J = 171, 5 Hz, C-2, C-6), 146.39 (dm, J
= 182 Hz, C-4), 148,80 (t, J = 6 Hz, C-4'), 153.66 (m, C-8a'),
1-Methyl-3-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)imi-
dazolium hexafluorophosphate (6b). Yield 92%. White
1
needles, mp > 260°C. H nmr ((D3C)2SO): ꢀ 4.01 (s, 3H, Me),
7.51 (t, 1H, J = 7.4 Hz, H-8'), 7.59 (d, 1H, J = 8.3 Hz, H-6'), 7.78
(t, 1H, J = 7.6 Hz, H-7'), 7.85 (d, 1H, J = 7.6 Hz, H-5'), 7.93 (s,
1H, H-4), 8.12 (s, 1H, H-5), 8.64 (s, 1H, H-4'), 9.63 (s, 1H, H-
2). 13C nmr ((D3C)2SO): ꢀ 36.24 (q, J = 144 Hz), 116.43 (dd, J =
167, 8 Hz, C-8'), 117.62 (m, C-3'), 121.72 (d, J = 4 Hz, C-4a'),
122.50 (ddd, J = 207, 12, 4 Hz, C-4), 123.71(dm, J = 205 Hz, C-
5), 125.6 (dd, J = 166, 8 Hz, C-5'), 129.47 (dm, J = 162 Hz, C-
6'), 133.56 (dm, J = 163 Hz, C-7'), 137.28 (dm, J = 222 Hz, C-
2), 137.44(dd, J = 169, 5 Hz, C-4'), 152.43 (m, C-8a'), 156.19 (d,
156.95 (d, J = 8 Hz, CO). hrms, m/z 514.1524 (calculated for
-
C30H20N5O4, [2C+, N(CN)2 ]+ requires 514,1515).
4-Dimethylamino-1-(2-oxo-4a,8a-dihydro-2H-chromen-
3-yl)pyridinium tetrafluoroborate (6g). Yield 98%. White
needles, mp 250-252°C. 1H nmr ((D3C)2SO): ꢀ 3.30 (s, 6H, Me),
7.22 (d, 2H, J = 7 Hz, H-3, H-5), 7.51 (t, 1H, J = 7.3 Hz, H-8'),
7.60 (d, 1H, J = 8.4 Hz, H-6'), 7.78 (t, 1H, J = 7.8 Hz, H-7'), 7.84
(d, 1H, J = 7.5 Hz, H-5'), 8.38 (d, 2H, J = 7.2 Hz, H-2, H-6),
8.56 (s, 1H, H-4'). 13C nmr ((D3C)2SO): ꢀ 40.62 (C-8, C-9),
107.82 (C-8'), 116.9 (C-6'), 118.55 (C-5'), 125.97 (C-3'), 128.60
(C-7'), 130.03 (C-4a'), 133.89 (C-3, C-5), 139.24 (C-2, C-6),
142.49 (C-4'), 153.25 (C-4), 156.82 (C-8a'), 157.64 (CO). hrms,
m/z 267.1134 (calculated for C16H15N2O2, C+ requires 267.1136).
4-Dimethylamino-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-
yl)pyridinium hexafluorophosphate (6h). Yield 96%. White
J = 8 Hz, CO). hrms, m/z 599.1294 found (calculated for
-
C26H22N4O4F6P, [2C+, PF6 ]+ requires 599.1284).
1-Methyl-3-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)imida-
zolium dicyanamide (6c). Yield 98%. Beige needles, mp 171-
173°C. 1H nmr ((D3C)2SO): ꢀ 4.02 (s, 3H, Me), 7.48 (td, 1H, J =
8.2, 0.6 Hz, H-8'), 7.58 (d, 1H, J = 8.3 Hz, H-6'), 7.77 (td, 1H, J
= 7.2, 1.5 Hz, H-7'), 7.85 (dd, 1H, J = 7.7, 1.3 Hz, H-5'), 7.96 (t,
J = 1.6 Hz, 1H, H-4), 8.14 (t, J = 1.8 Hz, H-5), 8.68 (s, 1H, H-
4'), 9.67 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 36.29 (q, J = 144
Hz), 116.43 (dd, J = 167, 7 Hz, C-8'), 117.58 (m, C-3'), 121.68
(dd, J = 205, 4 Hz, C-4a'), 122.49 (ddd, J = 203, 13, 5 Hz, C-4),
123.73(dm, J = 202 Hz, C-5), 125.60 (dd, J = 165, 8 Hz, C-5'),
129.46 (dm, J = 162 Hz, C-6'), 133.54 (dm, J = 167 Hz, C-7'),
137.25 (dd, J = 170, 5 Hz, C-4'), 137.45 (dm, J = 222 Hz, C-2),
1
needles, mp > 260°C. H nmr ((D3C)2SO): ꢀ 3.30 (s, 6H, Me),
7.23 (d, 2H, J = 7.8 Hz, H-3, H-5), 7.50 (t, 1H, J = 7.5 Hz, H-8'),
7.59 (d, 1H, J = 8.4 Hz, H-6'), 7.77 (t, 1H, J = 7.5 Hz, H-7'), 7.84
(d, 1H, J = 7.20 Hz, H-5'), 8.39 (d, 2H, J = 7.8 Hz, H-2, H-6),
8.58 (s, 1H, H-4'). 13C nmr ((D3C)2SO): ꢀ 40.62 (C-8, C-9),
107.81 (C-8'), 116.90 (C-6'), 118.55 (C-5'), 125.95 (C-3'),
128.58 (C-7'), 130.02 (C-4a'), 133.87 (C-3, C-5), 139.24 (C-2,
C-6), 142.50 (C-4'), 153.24 (C-4), 156.82 (C-8a'), 157.64 (CO).
hrms, m/z 679.1920 found (calculated for C32H30N4O4F6P, [2C+,
152.44 (m, C-8a'), 156.17 (d, J = 8 Hz, CO). hrms, m/z 520.1735
-
-
(calculated for C28H22N7O4, [2C+, N(CN)2 ]+ requires 520.1733).
1-(2-Oxo-4a,8a-dihydro-2H-chromen-3-yl)pyridinium tetra-
PF6 ]+ requires 679.1909).
4-Dimethylamino-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-
yl)pyridinium dicyanamide (6i). Yield 95%. White needles,
mp 210-212°C. 1H nmr ((D3C)2SO): ꢀ 3.29 (s, 6H, Me), 7.23 (d,
2H, J = 7.5 Hz, H-3, H-5), 7.49 (t, 1H, J = 7.5 Hz, H-8'), 7.57 (d,
1H, J = 8.4 Hz, H-6'), 7.76 (t, 1H, J = 7.8 Hz, H-7'), 7.84 (d, 1H,
J = 7.5 Hz, H-5'), 8.39 (d, 2H, J = 7.2 Hz, H-2, H-6), 8.61 (s, 1H,
H-4'). 13C nmr ((D3C)2SO): ꢀ 40.69 (C-8, C-9), 107.86 (C-8'),
116.88 (C-6'), 118.53 (C-5'), 125.93 (C-3'), 128.49 (C-7'),
130.03 (C-4a'), 133.86 (C-3, C-5), 139.24 (C-2, C-6), 142.47 (C-
4'), 153.22 (C-4), 156.80 (C-8a'), 157.62 (CO). hrms, m/z
1
fluoroborate (6d). Yield 96%. Beige needles, mp > 260°C. H
nmr ((D3C)2SO): ꢀ 7.54 (t, 1H, J = 7.5 Hz, H-8'), 7.65 (d, 1H, J =
8.3 Hz, H-6'), 7.84 (td, 1H, J = 8.6, 1.3 Hz, H-7'), 7.89 (d, 1H, J
= 7.8 Hz, H-5'), 8.37 (t, 2H, J = 7.4 Hz, H-3, H-5), 8.77 (s, 1H,
H-4'), 8.85 (t, 1H, J = 7.9 Hz, H-4), 9.23 (d, 2H, J = 5.6 Hz, H-2,
H-6). 13C nmr ((D3C)2SO): ꢀ 115.60 (dd, J = 168, 8 Hz, C-8'),
116.53 (m, C-3'), 124.76 (d, J = 9 Hz, C-6'); 126.95 (m, C-4a'),
128.01 (m, C-5'), 129.11 (m, C-3, C-5), 133.37 (ddd, J = 164, 8,
2 Hz, C-7'), 139.71 (dd, J = 171, 5 Hz, C-2, C-6), 144.83 (dm, J

198
K. Bourahla, M. Rahmouni, J. Fraga-Dubreuil, J.P. Bazureau, J. Hamelin
-
Vol 44
600.2350 found (calculated for C34H30N7O4, [2C+, N(CN)2 ]+
requires 600.2359).
3-Bromo-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium dicyanamide (6o). Yield 99%. Orange needles, mp
220-222°C. 1H nmr ((D3C)2SO): ꢀ 7.55 (t, 1H, J = 7.3 Hz, H-8'),
7.65 (d, 1H, J = 8.3 Hz, H-6'), 7.86 (t, 1H, J = 7.7 Hz, H-7'), 7.93
(d, 1H, J = 7.5 Hz, H-5'), 8.37 (t, 1H, J = 7.1 Hz, H-5), 8.88 (s,
1H, H-4'), 9.14 (d, 1H, J = 8.2 Hz, H-4); 9.33 (d, 1H, J = 5.7 Hz,
H-6), 9.71 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 117.19 (C-8'),
117.87 (C-3'), 122.40 (C-4a'), 126.36 (C-6'), 128.70 (C-3),
129.18 (C-5'), 130.80 (C-7'), 135.11 (C-5), 141.75 (C-4), 145.48
(C-6), 147.37 (C- 2), 151.01 (C-4'), 153.66 (C-8a'), 156.66 (CO).
hrms, m/z 669.9727 found (calculated for C30H18N5O479Br2,
3-Chloro-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium tetrafluoroborate (6j). Yield 98%. Yellow needles, mp
220-222°C. 1H nmr ((D3C)2SO): ꢀ 7.56 (t, 1H, J = 7.5 Hz, H-8'),
7.67 (d, 1H, J = 8.3 Hz, H-6'), 7.89 (t, 1H, J = 7.4 Hz, H-7'), 7.93
(d, 1H, J = 7.7 Hz, H-5'), 8.43 (t, 1H, J = 8,4 Hz, H-5), 8.80 (s,
1H, H-4'), 9.02 (d, 1H, J = 8.5 Hz, H-4); 9.27 (d, 1H, J = 6.1 Hz,
H-6), 9.64 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 117.19 (C-8'),
117.83 (C-3'), 126.41 (C-6'), 128.80 (C-4a'), 129.13 (C-5'),
130.81 (C-7'), 134.55 (C-5), 135.17 (C-3); 141.75 (C- 4), 145.34
(C- 6), 145.65 (C- 2), 148.35 (C- 4'), 153.68 (C-8a'), 156.51
(CO). hrms, m/z 258.0328 found (calculated for C14H9NO235Cl,
C+ requires 258.0322).
3-Chloro-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium hexafluorophosphate (6k). Yield 97%. Beige needles,
mp 240-243°C. 1H nmr ((D3C)2SO): ꢀ 7.56 (t, 1H, J = 7.4 Hz, H-
8'), 7.67 (d, 1H, J = 8.3 Hz, H-6'), 7.87 (t, 1H, J = 7.5 Hz, H-7'),
7.94 (d, 1H, J = 7.5 Hz, H-5'), 8.45 (t, 1H, J = 7.1 Hz, H-5), 8.88
(s, 1H, H-4'), 9.05 (d, 1H, J = 8.2 Hz, H-4); 9.31 (d, 1H, J = 5.6
Hz, H-6), 9.69 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 117.20 (C-
8'), 117.84 (C-3'), 126.39 (C-6'), 128.74 (C-4a'), 129.15 (C-5'),
130.82 (C-7'), 134.51 (C-5); 135.16 (C-3), 141.78 (C-4), 145.35
(C-6), 145.65 (C-2), 148.34 (C- 4'), 153.67 (C-8a'), 156.62 (CO).
hrms, m/z 258.0324 found (calculated for C14H9NO235Cl, C+
requires 258.0322).
-
[2C+, N(CN)2 ]+ requires 669.9726).
Acknowlegement. We are grateful to the “Accord programme
de Coopération Mixte Inter Universitaire Algéro-Français N° 03
MDU 574” for financial assistance (K.B)”.
REFERENCES AND NOTES
†
Present address: Dr Joan Fraga-Dubreuil, University of
Nottingham, School of Chemistry, University Park, Nottingham, NG7
2RD, UK
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Lassaigne, A. Bonnefoy and B. Musicki, Bioorg. Med. Chem. Lett., 9,
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(2003).
[8] S. Kirkiacharian, D. T. Thuy, S. Siesic, R. Bakhchinian, R.
Kurkjian and T. Tonnaire, Farmaco, 57, 703 (2002).
[9a] S. P. Pillai, S. R. Menon, L. A. Mitscher, C. A. Pillai, and D.
A. Shankel, J. Nat. Prod., 62, 1358 (1999); [b] S. Kawaii, Y. Tomono,
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21, 917, (2001).
3-Chloro-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium dicyanamide (6l). Yield 99%. Beige needles, mp 210-
212°C. 1H nmr ((D3C)2SO): ꢀ 7.53 (t, 1H, J = 7.2 Hz, H-8'), 7.66
(d, 1H, J = 8 Hz, H-6'), 7.86 (t, 1H, J = 7.5 Hz, H-7'), 7.93 (d,
1H, J = 7.1 Hz, H-5'), 8.45 (t, 1H, J = 7.8 Hz, H-5), 8.83 (s, 1H,
H-4'), 9.04 (d, 1H, J = 7.9 Hz, H-4), 9.30 (d, 1H, J = 5.1 Hz, H-
6), 9.69 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 117.19 (C-8'),
117.83 (C-3'), 126.38 (C-6'), 128.73 (C-4a'), 129.15 (C-5'),
130.82 (C-7'), 134.50 (C-5), 135.15 (C-3), 141,78 (C-4), 145.34
(C-6), 145.65 (C-2), 148.33 (C- 4'), 153.67 (C-8a'), 156.61 (CO).
hrms, m/z 582.0728 found (calculated for C30H18N5O435Cl2, [2C+,
N(CN)2 ]+ requires 582.0736).
-
3-Bromo-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium tetrafluoroborate (6m). Yield 99%. Orange needles,
mp 224-226°C. 1H nmr ((D3C)2SO): ꢀ 7.56 (t, 1H, J = 7.5 Hz, H-
8'), 7.67 (d, 1H, J = 8.3 Hz, H-6'), 7.87 (t, 1H, J = 7.8 Hz, H-7'),
7.93 (d, 1H, J = 7.7 Hz, H-5'), 8.35 (t, 1H, J = 7.2 Hz, H-5), 8.80
(s, 1H, H-4'), 9.13 (d, 1H, J = 8.2 Hz, H-4); 9.29 (d, 1H, J = 5.8
Hz, H-6), 9.68 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 117.20 (C-
8'), 117.86 (C-3'), 122.37 (C-4a'), 126.39 (C-6'), 128.77(C-3),
129.15 (C-5'), 130.80 (C-7'), 135.14 (C-5), 141.73 (C-4), 145.48
(C-6), 147.40 (C-2), 151.03 (C- 4'), 153.67 (C-8a'), 156.66 (CO).
hrms, m/z 301.9815 found (calculated for pour C14H9NO279Br, C+
requires 301.9817).
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45, 2283 (1980); [b] J. P. G. Versleijen, A. M. van Lausen and B. L.
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[11a] B. J. Donnelly, D. M. Donnelly and A. M. D. Sullivan,
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Indian J. Chem, Sect. B, 17, 178 (1979).
[12] I. Yavari, R. Heckmat-Shoar and A. Zanouzi, Tetrahedron
Lett., 39, 2391 (1998).
3-Bromo-1-(2-oxo-4a,8a-dihydro-2H-chromen-3-yl)pyri-
dinium hexafluorophosphate (6n). Yield 98%. Yellowish
needles, mp > 260°C. 1H nmr ((D3C)2SO): ꢀ 7.53 (t, 1H, J = 7.1
Hz, H-8'), 7.67 (d, 1H, J = 7.9 Hz, H-6'), 7.86 (t, 1H, J = 7.2 Hz ;
H-7'), 7.93 (d, 1H, J = 7.2 Hz, H-5'), 8.36 (t, 1H, J = 7 Hz, H-5),
8.83 (s, 1H, H-4'), 9.13 (d, 1H, J = 7.9 Hz, H-4), 9.31 (d, 1H, J =
4.9 Hz, H-6), 9.69 (s, 1H, H-2). 13C nmr ((D3C)2SO): ꢀ 117.19
(C-8'), 117.86 (C-3'), 122.38 (C-4a'), 126.38 (C-6'), 128.74 (C-
3), 129.15 (C-5'), 130.79 (C-7'), 135.12 (C-5), 141.74 (C-4),
145.47 (C-6), 147.4 0 (C- 2), 151.01 (C- 4), 153.67 (C-8a'),
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209, 117 (2004).
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Commun., 6, 57 (2005); [b] E. V. O. John and S. S. Israelstom, J. Org.
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Prakt. Chem., 342, 371 (2000).
156.67 (CO). hrms, m/z 748.9270 found (calculated for
-
C28H18N2O4F679Br2P, [2C+, PF6 ]+ requires 748.9275).
[18] P. S. Salunkhe, C. P. Phadke, S. L. Kelkar and M. S. Wadia,

Jan-Feb 2007
One-pot synthesis of new 3-substituted coumarins by tandem reactions
199
Synthesis, 111 (1985).
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Analysis, 3rd ed., Longmans, Green and Co: London, 1961.
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