A convenient preparation of 1-vinylpyridinium salts

Article abstract of DOI:10.1055/s-1999-3642

Alkylation of various substituted pyridines with 1,2-dibromo- or 1,2,3- tribromoalkanes provides a new simple route to the corresponding 1 - vinylpyridinium salts. It was established that a correlation, similar to pyridine's quaternization reaction, exists between the reaction time and the product yield and the electronic nature of the substituents in the pyridine ring. The synthesis of 1,1'-vinylenebis-pyridinium salt that is the representative of the new type of quaternary pyridines is described.

Full text of DOI:10.1055/s-1999-3642

PAPER
2131
A Convenient Preparation of 1-Vinylpyridinium Salts
Olegas Eicher-Lorka,* Gytis K.Kupetis, Laimute Rastenyté, Algirdas Matijoöka
Institute of Chemistry, Akademijos 7, 2600 Vilnius, Lithuania
E-mail: lorka@takas.lt
Received 1 April 1999; revised 30 June 1999
plied to pyridine derivatives containing functional groups
sensitive to thionyl chloride (e.g., NH2, OH, CO2R, etc.).
Abstract: Alkylation of various substituted pyridines with 1,2-di-
bromo- or 1,2,3-tribromoalkanes provides a new simple route to the
corresponding 1-vinylpyridinium salts. It was established that a cor-
relation, similar to pyridine’s quaternization reaction, exists be-
tween the reaction time and the product yield and the electronic
nature of the substituents in the pyridine ring. The synthesis of 1,1’-
vinylenebis-pyridinium salt that is the representative of the new
type of quaternary pyridines is described.
We now report on a new efficient synthesis method of the
preparation of the substituted 1-(1-phenylvinyl)pyri-
dinium salts, based on addition of 1,2-dibromo-1-phe-
nylethane to various pyridines, where pyridine derivatives
are both the alkylation substrate and the dehydro-
halogenating agent at the same time (Scheme 1). A corre-
lation, similar to pyridine’s quaternization reaction, exists
between the reaction time and the product yield and the
electronic nature of the substituents in the pyridine ring.
Thus, electron-donating groups tend to accelerate the rate
of reaction (compounds 3a–e), while electron-withdraw-
ing groups cause a reduction in the reaction rate (com-
pounds 3f–m, Scheme 1). These results, combined with
the fact that only compounds 3 and 4 were produced in
the typical procedure, suggest that the quaternization re-
action occurred more slowly than the elimination
reaction. Only at low temperatures and with the excess of
dibromide, a small amount of compound 2 was produced.
For ease of isolation, some of the vinyl-pyridinium
bromides were converted to vinylpyridinium perchlorates
(see experimental).
Key words: pyridines, alkylation, 1,2-dibromides, 1-vinylpyri-
dinium salts, bromine, esters, condensation
1-Vinylpyridinium salts are known as potential mono-
mers for the cationic quaternary polyelectrolytes1 and for
the new photochromic polymers,2 but despite their poten-
tial importance and theoretical interest, they have not been
thoroughly investigated. They are generally prepared by
the dehydrohalogenation of 1-(2-halogenalkyl or 2-halo-
genalkylaryl)pyridinium salts. Ag2O1 or, most often,
NaOH3,4 was used as the dehydrohalogenating reagent. 1-
(2-Arylvinyl)pyridinium salts are prepared from 1-(2-hy-
droxy-2-arylethyl)pyridinium salts via intermediate for-
mation of acetylated5 or benzoylated6 derivatives. In
1973, Relles7 described a general synthesis of 1-(1-arylvi-
nyl)pyridinium salts from pyridine, acetophenone and
thionyl chloride. However, this method could not be ap-
In contrast to the above reaction, where secondary bro-
mine atom was the first to react under the influence of the
phenyl group and where elimination was faster than qua-
Scheme 1
Synthesis 1999, No. 12, 2131–2137 ISSN 0039-7881 © Thieme Stuttgart · New York

2132
O. Eicher-Lorka et al.
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Scheme 2
ternization, the primary bromine atom was the first to re- Treatment of 1,1,2-tribromoethane (12) with an excess of
act in the reaction of various picolines and pyridine 5a–c pyridine for 20 hours at 70°C in the absence of a solvent
with ethyl 2,3-dibromopropionate, and the reaction was gave compound 13 in 32% yield (Scheme 4). This partic-
halted at the first stage to afford bromoalkyl esters 6a–c in ular type of quaternary pyridine derivatives was unknown
good yields. Unsaturated acids 8a–c were synthesized by previously.
a two-step process by first hydrolysing the esters 6a–c
with 46% HBr to 7a–c and then dehydrohalogenation with
corresponding pyridines. Only 3-methylpyridinium unsat-
urated ester 9 was prepared by direct dehydrohalogena-
tion of bromoalkyl ester 6c, other unsaturated esters were
unstable (Scheme 2). It was observed that an exchange re-
action takes place if compounds with pyridine rings dif-
ferent from that of substrate pyridine ring were used as the
Scheme 4
dehydrohalogenating agent. This reaction yielded a mix-
ture of two unsaturated quaternary pyridine acids. This
Compounds 3b and 3d (Scheme 1) with acidic methylene
phenomenon is currently under investigation and will be
groups are unstable and they readily decompose during
published elsewhere.
the workup and purification process. Thus, they were con-
densed with benzaldehydes without any purification to af-
ford 1-(1-phenylvinyl)stilbazolium salts 14 and 15
respectively (Scheme 5).
Reaction of pyridine with 2,3-dibromopropan-1-ol or with
1,2,3-tribomopropane gave only unsaturated compounds
10,11 respectively (Scheme 3). 1H NMR spectra indicated
a clean formation of the (E)-derivatives 8–11 attested by
a 14 Hz coupling constant between the CH=CH group
protons.
Scheme 5
Scheme 3
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A Convenient Preparation of 1-Vinylpyridinium Salts
2133
tone. After filtration of NaBr and removal of the solvent, the prod-
uct was purified by crystallization or was treated with HClO4.
The structures of all products were determined on the ba-
sis of their 1H and 13C NMR spectra and confirmed by IR,
mass spectra and elemental analyses.
1-(1-Phenylvinyl)pyridinium Perchlorate (3a)
After the reaction of 1a (2.45 g, 2.5 mL) with 1,2-dibromo-1-phe-
nylethane (4.0 g) for 6 h and treatment with HClO4 followed by re-
crystallization from H2O, pure 3a•ClO4 was obtained as sand-
coloured crystals; yield: 3.55 g (84%); mp 129–130°C.
In conclusion, a short and efficient synthesis of various 1-
vinylpyridinium salts was realized. This procedure, which
is based on the reaction of various substituted 1,2-dibro-
moalkynes with substituted pyridines can also be recom-
mended for the synthesis of other N-vinyl heterocycles.
IR (KBr): ν = 1624 (C=N+), 1094 cm-1 (ClO4 ).
-
1H NMR (90 MHz, CD3OD): δ = 8.91 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.69 (t, J =7 Hz, 1 H, Py+ 4-H), 8.13 (t, 2 H, J = 7 Hz, Py+ 3,5-H),
7.49 – 7.11 (m, 5 Harom), 6.11 (d, 1 H, J = 3 Hz, =CH trans to C6H5),
5.89 (d, 1 H, J = 3 Hz, =CH cis to C6H5).
13C NMR: δ = 149.60 ( =C), 148.06 (Py+ 4 C), 144.86 (Py+ 2,6-C),
133.05, 131.44, 129.87 (Carom), 128.83 (Py+ 3,5-C), 127.16 (Carom),
116.52 ( =CH2).
Melting points are uncorrected. 1H NMR spectra were recorded on
a Hitachi R-22 spectrometer (90 MHz) in CD3OD with TMS as an
internal standard. 13C NMR spectra were recorded on a Bruker AC-
300 (50.32 MHz) in DMSO-d6 with TMS as an internal standard.
Mass spectra were performed on a Kratos MS-30 (70 eV). IR spec-
tra were recorded as KBr pellets using a FT-IR spectrophotometer
Bomem MB (Hartman and Braun, Canada). Elemental analyses
were performed by the Analytical Laboratory of the Chemistry fac-
ulty of the University of Vilnius. The course of reaction and the pu-
rity of products were followed by TLC analysis using Silufol UV-
254 (Cavalier, Praha) plates, eluent: acetone/CHCl3/EtOH/H2O
(12:10:6:1 v/v). 1,2-Dibromo-2-phenylethane, ethyl 2,3-dibro-
mopropionate, 2,3-dibromopropan-1-ol, 1,2,3-tribromopropane and
pyridines are commercially available and were used without further
purification.
MS (EI): m/z (%) = 182 (13), 105 (100), 103 (10), 79 (54), 77 (55),
52 (28), 39 (8).
Anal. Calcd for C13H12ClNO4: C, 55.43; H, 4.29; N, 4.97. Found C,
55.25; H 4.39; N 4.81.
1H NMR and MS data are in accordance with literature.7
4-Methyl-1-(1-phenylvinyl)pyridinium Bromide (3b)
Reaction of 1b (2.89 g, 3 mL) with 1,2-dibromo-2-phenylethane
(4.0 g) for 5 h afforded 3b in 82% yield (determined by 1H NMR of
the crude reaction mixture). The product was used for further reac-
tion without any purification.
1H NMR (90 MHz, CD3OD): δ = 8.67 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
7.93 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 7.49 – 7.09 (m, 5 Harom), 6.07 (d,
1 H, J = 3 Hz, =CH trans to C6H5), 5.80 (d, 1 H, J = 3 Hz, =CH cis
to C6H5), 2.64 (s, 3 H, CH3).
Exchange of the Br-Anion in Pyridinium Salts by ClO4-Perchlo-
rate Anion; General Procedure
64.5% Aq HClO4 (1 mL) was added to appropriate pyridinium salt
(10 mmol) and was diluted with H2O (5 mL). The separated solid
was filtered and was recrystallized from H2O.
3-Methyl-1-(1-phenylvinyl)pyridinium Perchlorate (3c)
After the reaction of 1c (2.89 g, 3 mL) with 1,2-dibromo-1-phenyl-
ethane (4.0 g) for 11 h and treatment with HClO4 followed by re-
1-(2-Bromo-1-phenylethyl)pyridinium Perchlorate (2)
Pyridine (3.9 g, 4 mL, 50 mmol) was added to a solution of 1,2-di-
bromo-2-phenylethane (26.4 g, 100 mmol) in MeCN (50 mL). The
mixture was stirred for 18 h at 50°C. The solvent was removed in
vacuo and the residue neutralized with satd aq Na2CO3 solution and
dissolved in acetone. After filtration of NaBr and removal of the sol-
vent, the residue was treated with 64.5% HClO4 (5 mL) and
crystallization from H2O gave pure 3c•ClO as sand-coloured crys-
4
tals; yield: 3.64 g (82%); mp 153–154°C.
-
IR (KBr): ν = 1625 (C=N+), 1096 cm-1 (ClO4 ).
1H NMR (90 MHz, CD3OD): δ = 8.84 (s, 1 H, Py+ 2-H), 8.71 (d, 1
H, J = 7 Hz, Py+ 6-H), 8.49 (d, 1 H, J = 7 Hz, Py+ 4-H), 8.00 (t, J =
7 Hz, 1 H, Py+ 5-H), 7.49–7.11 (m, 5 Harom), 6.13 (d, 1 H, J = 3
Hz, =CH trans to C6H5), 5.86 (d, 1 H, J = 3 Hz, =CH cis to C6H5),
2.56 (s, 3 H, CH3).
-
3a•ClO4 formed was filtered. The solvent was removed from fil-
trate in vacuo and the residue was purified by column chromatogra-
phy on silica gel (MeCN/EtOH, 3:1) to give 2 (1.8 g, 10%) as very
hydroscopic material.
2
1H NMR (90 MHz, CD3OD): δ = 4.31, 4.93 (dd, J = 10 Hz, 3J =
MS (EI): m/z (%) = 196 (100), 103 (63), 94 (58), 93 (48), 77 (52),
65 (12), 51 (26), 39 (13).
5Hz, 2 H, CH2Br), 6.8 (dd, 3J =9 Hz, 3J = 5 Hz, 1 H, CH), 7.67–7.84
(m, 5 Harom), 8.13 (t, J = 7 Hz, 2 H, Py+ 3,5-H), 8.67 (t, J = 7 Hz, 1
H, Py+ 4-H), 9.67 (d, 2 H, J = 7 Hz, Py+ 2,6-H).
Anal. Calcd for C14H14ClNO4: C, 56.86; H, 4.77; N, 4.74. Found C,
56.73; H 4.83; N 4.69.
4-Benzyl-1-(1-phenylvinyl)pyridinium Bromide (3d)
Reaction of 1d (5.25 g) with 1,2-dibromo-1-phenylethane (4.0 g)
for 5 h gave 3d in 64% yield (determined by 1H NMR of the crude
reaction mixture). Product was used for further reaction without
any purification.
1H NMR (90 MHz, CD3OD): δ = 8.73 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
7.92 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 7.42–7.04 (m, 10 Harom), 6.04 (d,
1 H, J = 3 Hz, =CH trans to C6H5), 5.79 (d, 1 H, J = 3 Hz, =CH cis
to C6H5), 4.07 (s, 2 H, CH2).
1,1,2-Tribromoethane (12)
A solution of Br2 (8 g, 50 mmol) in CHCl3 (5 mL) was added drop-
wise at –10°C to a stirred solution of vinyl bromide (5.35 g, 50
mmol) in CHCl3 (10 mL) over a period of 3 h. The solution was kept
at r.t. for 12 h, the solvent was evaporated and the residue was dis-
tilled in vacuo to give 12 (11.6 g, 87%) as colorless liquid; bp 77–
78°C/14 Torr (Lit.8 bp 73.1°C/10 Torr).
1H NMR (90 MHz, CD3OD): δ = 3.96 (d, J = 6 Hz, 2 H, CH2), 5.82
(t, 1 H, CH).
MS (EI): m/z (%) = 259 (41), 156 (100), 103 (33), 80 (12), 77 (13),
50 (27), 39 (5).
1-(1-Phenylvinyl)pyridinium Bromides 3a–m; General Proce-
dure
1,2-Dibromo-1-phenylethane (3.96 g, 15 mmol) was added to a so-
lution of 1a–m (31 mmol) in MeCN (15mL). The mixture was re-
fluxed for 5–100 h. The solvent was evaporated and the residue was
neutralized with satd aq Na2CO3 solution and was dissolved in ace-
3-Benzyl-1-(1-phenylvinyl)pyridinium Perchlorate (3e)
After the reaction of 1e (5.25 g) with 1,2-dibromo-1-phenylethane
(4.0 g) for 10 h and treatment with HClO4 followed by recrystalli-
zation from H2O gave pure 3e•ClO as sand-coloured crystals;
yield: 4.02 g (72%); mp 76–77°C.
4
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2134
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IR (KBr): ν = 1618 (C=N+), 1088 cm-1 (ClO4 ).
1H NMR (90 MHz, CD3OD): δ = 9.44 (s, 1 H, Py+ 2 H), 9.26 (d, 1
H, J = 7 Hz, Py+ 6-H), 9.18 (d, 1 H, J = 7 Hz, Py+ 4-H), 8.38 (t, J =
7 Hz, 1 H, Py+ 5-H), 7.44 (s, 5 Harom), 6.29 (d, 1 H, J = 3 Hz, =CH
trans to C6H5), 6.04 (d, 1 H, J = 3 Hz, =CH cis to C6H5), 4.47 (q, J
= 7 Hz, 2 H, CH2), 1.31 (t, J = 7 Hz, 3 H, CH3).
1H NMR (90 MHz, CD3OD): δ = 8.87 (s, 1 H, Py+ 2-H), 8.71 (d, 1
H, J = 7 Hz, Py+ 6-H), 8.46 (d, 1 H, J = 7 Hz, Py+ 4-H), 8.00 (t, J =
7 Hz, 1 H, Py+ 5-H), 7.44–7.02 (m, 10 Harom), 6.09 (d, 1 H, J = 3
Hz, =CH trans to C6H5), 5.87 (d, 1 H, J = 3 Hz, =CH cis to C6H5),
4.22 (s, 2 H, CH2).
MS (EI): m/z (%) = 254 (56), 226 (53), 182 (15), 152 (40), 124 (52),
103 (100), 77 (50), 51 (20), 39 (6).
MS (EI): m/z (%) = 272 (8), 168 (100), 105 (47), 91 (15), 77 (23),
51 (15), 39 (8).
Anal. Calcd for C16H16BrNO2: C, 57.50; H, 4.83; N, 4.19. Found C,
57.35; H 4.99; N 4.00.
Anal. Calcd for C20H18ClNO4: C, 64.61; H, 4.88; N, 3.77. Found C,
64.21; H 4.96; N 3.70.
3-Carboxy-1-(1-phenylvinyl)pyridinium Bromide (3j)
A solution of 3i (5.01 g, 15 mmol) in aq 46.8% HBr (6 mL) was
stirred at 60°C for 10 h. The solvent was evaporated in vacuo and
the residue was washed with acetone (2 × 10 mL). The product was
further purified by recrystallization from MeCN to give pure 3j as
white crystals; yield: 4.23 g (92%); mp 223–224°C (dec.).
4-Benzoyl-1-(1-phenylvinyl)pyridinium Bromide (3f)
Reaction of 1f (5.68 g) with 1,2-dibromo-1-phenylethane (4.0 g) for
18 h and recrystallization of the product from MeCN gave pure 3f
as yellow crystals; yield: 3.52 g (64%); mp 179–180°C.
IR (KBr): ν = 1632 (C=N+), 1670 cm-1 (C=O).
IR (KBr): ν = 1623 (C=N+), 1717 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 9.09 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.24 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 7.95 – 7.31 (m, 10 Harom), 6.15
(d, 1 H, J = 3 Hz, =CH trans to C6H5), 6.00 (d, 1 H, J = 3 Hz, =CH
cis to C6H5).
1H NMR (90 MHz, CD3OD): δ = 9.13 (s, 1 H, Py+ 2-H), 9.03 (d, 1
H, J = 7 Hz, Py+ 6-H), 8.96 (d, 1 H, J = 7 Hz, Py+ 4-H), 8.22 (t, J =
7 Hz, 1 H, Py+ 5-H), 7.13 (s, 5 Harom), 6.15 (d, 1 H, J = 3 Hz, =CH
trans to C6H5), 5.86 (d, 1 H, J = 3 Hz, =CH cis to C6H5).
MS (EI): m/z (%) = 286 (33), 184 (72), 105 (89), 103 (80), 77 (100),
51 (39), 39 (5).
MS (EI): m/z (%) = 227 (72), 123 (54), 105 (67), 103 (100), 80 (31),
77 (64), 51 (40), 39 (12).
Anal. Calcd for C20H16BrNO: C, 65.59; H, 4.40; N, 3.82. Found C,
65.31; H 4.51; N 3.60.
Anal. Calcd for C14H12BrNO2: C, 54.92; H, 3.95; N, 4.57. Found C,
54.89; H 4.02; N 4.37.
4-(2-Phenyl-1-ethenyl)-1-(1-phenylvinyl)pyridinium Bromide
(3g)
Reaction of 1g (5.62 g) with 1,2-dibromo-1-phenylethane (4.0 g)
for 15 h and recrystallization of the product from H2O gave pure 3g
as yellow crystals; yield: 2.57 g (47%); mp 239.5–240.5°C.
4-Amino-1-(1-phenylvinyl)pyridinium Bromide (3k)
Reaction of 1k (2.92 g) with 1,2-dibromo-1-phenylethane (4.0 g)
for 20 h and recrystallization of the product from MeCN gave pure
3k as sand-coloured crystals; yield: 0.83 g (20%); mp 178–180° C.
IR (KBr): ν = 1626 cm-1 (C=N+).
1H NMR (90 MHz, CD3OD): δ = 7.73 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
7.40–7.03 (m, 5 Harom), 6.91 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 5.68 (d,
1 H, J = 3 Hz, =CH trans to C6H5), 5.42 (d, 1 H, J = 3 Hz, =CH cis
to C6H5).
IR (KBr): ν = 1615 cm-1 (C=N+).
1H NMR (90 MHz, CD3OD): δ = 8.69 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.18 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 7.98 (d, 1 H, J = 16 Hz, =CH–
C6H5), 7.78–7.60 (m, 5 Harom), 7.53–7.31 (m, 5 Harom), 7.40 (d, 1 H,
J = 16 Hz, =CH–Py+), 6.04 (d, 1 H, J = 3 Hz, =CH trans to C6H5),
5.82 (d, 1 H, J = 3 Hz, =CH cis to C6H5).
MS (EI): m/z (%) = 196 (100), 103 (85), 94 (77), 80 (49), 77 (36),
67 (18), 51 (14), 39 (10).
MS (EI): m/z (%) = 284 (82), 180 (100), 103 (39), 81 (10), 80 (20),
79 (14), 77 (32), 51 (13), 39 (6).
Anal. Calcd for C13H13BrN2: C, 56.34; H, 4.73; N, 10.11. Found C,
56.22; H 4.89; N 10.08.
Anal. Calcd for C21H18BrN: C, 69.24; H, 4.98; N, 3.85. Found C,
69.02; H 5.10; N 3.71.
3-Bromo-1-(1-phenylvinyl)pyridinium Bromide (3l)
Reaction of 1l (4.90 g,) with 1,2-dibromo-1-phenylethane (4.0 g)
for 40 h and recrystallization of the product from MeCN gave pure
3 l as sand-coloured crystals; yield: 1.79 g (35%); mp 95–96°C.
IR (KBr): ν = 1613 cm-1 (C=N+).
1H NMR (90 MHz, CD3OD): δ = 9.36 (s, 1 H, Py+ 2-H), 8.98 (d, 1
H, J = 7 Hz, Py+ 6-H), 8.87 (d, 1 H, J = 7 Hz, Py+ 4-H), 8.07 (t, J=
7 Hz, 1 H, Py+ 5-H), 7.36 (s, 5 Harom), 6.11 (d, 1 H, J = 3 Hz, =CH
trans to C6H5), 5.87 (d, 1 H, J = 3 Hz, =CH cis to C6H5).
1-(1-Phenylvinyl)-4-(4-pyridyl)pyridinium Bromide (3h)
Reaction of 1h (5.96 g) with 1,2-dibromo-1-phenylethane (4.0 g)
for 18 h and recrystallization of the product from MeCN afforded
pure 3h as sand-coloured crystals; yield: 1.58 g (31%); mp 102–
104°C.
IR (KBr): ν = 1629 cm-1 (C=N+).
1H NMR (90 MHz, CD3OD): δ = 9.04 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.61 (d, 2 H, J = 7 Hz, Py+ 2,6-H), 8.01 (d, 2 H, J = 7 Hz, Py+ 3,5-
H), 7.96 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 7.26 (s, 5 Harom), 6.16 (d, 1
H, J = 3 Hz, =CH trans to C6H5), 5.93 (d, 1 H, J = 3 Hz, =CH cis to
C6H5).
MS (EI): m/z (%) = 260 (19), 181 (10), 157 (79), 103 (100), 78 (62),
51 (42), 39 (9).
Anal. Calcd for C13H11Br2N: C, 45.78; H, 3.25; N, 4.11. Found C,
45.66; H 3.35; N 4.00.
MS (EI): m/z (%) = 259 (41), 156 (100), 103 (33), 80 (12), 77 (13),
50 (27), 39 (5).
3,5-Dibromo-1-(1-phenylvinyl)pyridinium Bromide (3m)
Reaction of 1m (7.34 g) with 1,2-dibromo-1-phenylethane (4.0 g)
for 100 h and recrystallization of the product from MeCN gave pure
3m as sand-coloured crystals; yield: 0.63 g (10%); mp >250°C
(dec.).
Anal. Calcd for C18H15BrN2: C, 63.73; H, 4.46; N, 8.26. Found C,
63.69; H 4.57; N 8.10.
3-Ethoxycarbonyl-1-(1-phenylvinyl)pyridinium Bromide (3i)
Reaction of 1i (4.69 g, 4.23 mL) with 1,2-dibromo-1-phenylethane
(4.0 g) for 22 h and recrystallization from MeCN gave pure 3i as
sand-coloured crystals; yield:1.91 g (38%); mp 162–163°C.
IR (KBr): ν = 1600 cm-1 (C=N+).
1H NMR (90 MHz, CD3OD): δ = 9.36 (s, 2 H, Py+ 2,6-H), 9.20 (s,
1 H, Py+ 4-H), 7.40 (s, 5 Harom), 6.26 (d, 1 H, J = 3 Hz, =CH trans
to C6H5), 5.98 (d, 1 H, J = 3 Hz, =CH cis to C6H5).
IR (KBr): ν = 1610 (C=N+), 1710 cm-1 (C=O).
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A Convenient Preparation of 1-Vinylpyridinium Salts
2135
MS (EI): m/z (%) = 339 (6), 237 (17), 156 (100), 105 (23), 103 (12),
77 (10), 50 (6), 38 (4).
13C NMR: δ = 166.98 (C = O), 147.10 (Py+ 2-C), 145.15 (Py+ 6-C),
142.95 (Py+ 4-C), 138.79 (Py+ 3-C), 127.10 (Py+ 5-C), 62.40
(CH2CHBr), 61.38 (CH2CH3), 43.21 (CHBr), 17.86 (CH3), 13.71
(CH2CH3).
Anal. Calcd for C13H10Br3N: C, 37.18; H, 2.40; N, 3.34. Found C,
37.01; H 2.56; N 3.33.
MS (EI): m/z (%) = 192 (30), 164 (34), 133 (30), 93 (100), 80 (11),
65 (16), 39 (15).
1-(2-Bromo-2-ethoxycarbonylethyl)pyridiniumBromides6a–c;
General Procedure
Anal. Calcd for C11H15Br2NO2: C, 37.42; H, 4.28; N, 3.97. Found
C, 37.33; H 4.35; N 3.87.
Ethyl 2,3-dibromopropionate (2.60 g, 10 mmol) was added to a so-
lution of 5a–c (12 mmol) in MeCN (5 mL). The mixture was stirred
for 5–22 h at the appropriate temperature (see below). The solvent
was evaporated in vacuo and the residue was washed with benzene
(2 × 10 mL).
1-(2-Bromo-2-carboxyethyl)pyridinium Bromides 7a–c; Gener-
al Procedure
A solution of 6a–c (10 mmol) in aq 46.8% HBr (5 mL) was stirred
at 60°C for 10 h. The solvent was evaporated in vacuo and the res-
idue was washed with acetone (2 × 10 mL).
1-(2-Bromo-2-ethoxycarbonylethyl)pyridinium Perchlorate
(6a)
After the reaction of 5a (0.95 g, 1 mL) with ethyl 2,3-dibromopro-
pionate (2.60 g, 1.5 mL) for 6 h at 21°C and treatment with HClO4
1-(2-Bromo-2-carboxyethyl)pyridinium Bromide (7a)
Reaction of 6a (3.59 g) with aq 46.8% HBr (5 mL) and recrystalli-
zation of the product from EtOH gave pure 7a as white crystals;
yield: 2.89 g (93%); mp 162–163°C.
followed by recrystallization from EtOH pure 6a•ClO was ob-
4
tained as white crystals; yield: 2.90 g (81%); mp 75–76°C.
IR (KBr): ν = 1625 (C=N+), 1717 cm-1 (C=O).
IR (KBr): ν = 1620 (C=N+), 1700 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 8.96 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.62 (t, J = 7 Hz, 1 H, Py+ 4-H), 8.02 (t, J = 7 Hz, 2 H, Py+ 3,5-H),
5.36–4.80 (m, 3 H, CH2CHBr), 4.04 (q, J = 7 Hz, 2 H, CH2CH3),
1.20 (t, J = 7 Hz, 3 H, CH3).
13C NMR: δ = 167.00 (C=O), 146.84 (Py+ 4-C), 145.70 (Py+ 2,6-C),
127.96 (Py+ 3,5-C), 62.53 (CH2CHBr), 61.18 (CH2CH3), 43.19
(CHBr), 13.70 (CH3).
1H NMR (90 MHz, CD3OD): δ = 8.89 (d, 2 H, J = 7Hz, Py+ 2,6-H),
8.51 (t, J = 7 Hz, 1 H, Py+ 4-H), 8.00 (t, J = 7 Hz, 2 H, Py+ 3,5-H),
5.67 – 4.71 (m, 3 H, CH2CHBr).
13C NMR: δ = 168.09 (C=O), 146.85 (Py+ 4-C), 145.72 (Py+ 2,6-C),
127.91 (Py+ 3,5-C), 61.28 (CH2CHBr), 44.04 (CHBr).
MS (EI): m/z (%) = 150 (19), 133 (9), 105 (15), 80 (32), 79 (100),
52 (30), 39 (3).
MS (EI): m/z (%) = 178 (6), 152 (11), 105 (21), 80 (40), 79 (100),
71 (10), 52 (42), 45 (8), 39 (5).
Anal. Calcd for C8H9Br2NO2: C, 30.90; H, 2.92; N, 4.50. Found C,
30.89; H 3.01; N 4.40.
Anal. Calcd for C10H13BrClNO6: C, 33.50; H, 3.65; N, 3.91. Found
C, 33.33; H 3.78; N 3.80.
1-(2-Bromo-2-carboxyethyl)-4-methylpyridinium Bromide (7b)
Reaction of 6b (3.53 g) with aq 46.8% HBr (5 mL) and recrystalli-
zation of the product from MeCN gave pure 7b as white crystals;
yield: 2.99 g (92%); mp 107–108°C.
1-(2-Bromo-2-ethoxycarbonylethyl)-4-methylpyridinium Bro-
mide (6b)
Reaction of 5b (1.12 g, 1,2 mL) with ethyl 2,3-dibromopropionate
(2.60 g, 1.5 mL) for 5 h at 21°C and recrystallization from acetone
gave pure 6b as white crystals; yield: 2.08 g (59%); mp 123–124°C.
IR (KBr): ν = 1615 (C=N+), 1710 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 8.82 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
7.87 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 5.33–4.80 (m, 3 H, CH2CHBr),
2.62 (s, 3 H, CH3).
IR (KBr): ν = 1620 (C=N+), 1710 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 8.69 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
7.84 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 5.29–4.71 (m, 3 H, CH2CHBr),
4.18 (q, J = 7 Hz, 2 H, CH2CH3), 2.60 (s, 3 H, CH3), 1.18 (t, J = 7
Hz, 3 H, CH2CH3).
13C NMR: δ = 168.01 (C=O), 160.02 (Py+ 4-C), 144.62 (Py+ 2,6-C),
128.16 (Py+ 3,5-C), 60.49 (CH2CHBr), 43.95 (CHBr), 21.74 (CH3).
MS (EI): m/z (%) = 163 (10), 152 (35), 133 (8), 105 (12), 93 (100),
13C NMR: δ = 166.54 (C=O), 159.89 (Py+ 4-C), 144.56 (Py+ 2,6-C),
128.01 (Py+ 3,5-C), 62.00 (CH2CHBr), 59.92 (CH2CH3), 42.94
(CHBr), 21.57 (CH3), 13.51 (CH2CH3).
80 (60), 79 (53), 71 (14), 65 (40), 51 (17), 39 (19).
Anal. Calcd for C9H11Br2NO2: C, 33.26; H, 3.41; N, 4.31. Found C,
33.22; H 3.41; N 4.28.
MS (EI): m/z (%) = 191 (100), 163 (92), 146 (25), 117 (25), 93 (31),
80 (12), 65 (11), 39 (13).
1-(2-Bromo-2-carboxyethyl)-3-methylpyridinium Bromide (7c)
Reaction of 6c (3.53 g) with aq 46.8% HBr (5 mL) and recrystalli-
zation of the product from EtOH gave pure 7c as white crystals;
yield: 2.89 g (89%); mp 185.5–186.5°C.
Anal. Calcd for C11H15Br2NO2: C, 37.42; H, 4.28; N, 3.97. Found
C, 37.39; H 4.33; N 3.88.
IR (KBr): ν = 1625 (C=N+), 1739 cm-1 (C=O).
1-(2-Bromo-2-ethoxycarbonylethyl)-3-methylpyridinium Bro-
mide (6c)
Reaction of 5c (1.12 g, 1.2 mL) with ethyl 2,3-dibromopropionate
(2.60 g, 1.5 mL) for 22 h at 15°C and recrystallization of the product
from MeCN gave pure 6c as white crystals; yield: 1.66 g (47%); mp
128–129°C.
1H NMR (90 MHz, CD3OD): δ = 8.89 (s, 1 H, Py+ 2-H), 8.82 (d, 1
H, J = 7 Hz, Py + 6-H), 8.40 (d, 1 H, J = 7 Hz, Py+ 4-H), 7.82 (dd, J
= 7Hz, 1 H, Py+ 5-H), 5.31–4.73 (m, 3 H, CH2CHBr), 2.49 (s, 3 H,
CH3).
13C NMR: δ = 168.35 (C=O), 147.11 (Py+ 2-C), 145.15 (Py+ 6-C),
142.97 (Py+ 4-C), 138.88 (Py+ 3-C), 127.16 (Py+ 5-C), 61.20
(CH2CHBr), 44.15 (CHBr), 17.95 (CH3).
IR (KBr): ν = 1638 (C=N+), 1727 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 8.67 (s, 1 H, Py+ 2-H), 8.62 (d, 1
H, J = 7 Hz, Py+ 6-H), 8.31 (d, 1 H, J = 7 Hz, Py+ 4-H), 7.82 (dd, 1
H, Py+ 5-H), 5.36 – 4.67 (m, 3 H, CH2CHBr), 4.11 (q, J = 7 Hz, 2
H, CH2CH3), 2.49 (s, 3 H, CH3), 1.40 (t, J = 7 Hz, 3 H, CH2CH3).
MS (EI): m/z (%) = 150 (39), 133 (9), 93 (100), 80 (51), 66 (50), 53
(10), 39 (19).
Anal. Calcd for C9H11Br2NO2: C, 33.26; H, 3.41; N, 4.31. Found C,
33.16; H 3.56; N 4.20.
Synthesis 1999, No. 12, 2131–2137 ISSN 0039-7881 © Thieme Stuttgart · New York

2136
O. Eicher-Lorka et al.
PAPER
1-[(E)-2-Carboxy-1-ethenyl]pyridinium Bromides 8a–c; Gener-
al Procedure
lization from MeCN to give pure 9 as sand-coloured crystals; yield:
2.25 g (55%); mp 185–186°C (dec.).
Corresponding pyridine 5a–c (30 mmol) was added to a solution of
7a–c (15 mmol) in EtOH (25 mL) and refluxed for 7 h. After evap-
oration to dryness, the residue was washed with acetone (2 × 10
mL).
IR (KBr): ν = 1618 (C=N+), 1652 (C=C), 1716 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 9.16 (s, 1 H, Py + 2-H), 9.07 (d, J
= 7 Hz, 1 H, J = 7 Hz, Py+ 6-H), 8.51 (d, J = 7 Hz 1 H, Py+ 4-H),
8.29 (d, J = 14 Hz, 1 H, =CH–Py+), 8.00 (t, J = 7 Hz, 1 H, Py+ 5-
H), 7.00 (d, J = 14 Hz, 1 H, =CHCO2), 4.16 (q, J = 7 Hz, 2 H,
CH2CH3), 2.53 (s, 3 H, CH3), 1.22 (t, J = 7 Hz, 3 H, CH2CH3).
13C NMR: δ = 163.73 (C=O), 149.10 ( =CH–Py+), 143.19 (Py+ 2-
C), 142.01 (Py+ 6-C), 140.79 (Py+ 4-C), 138.74 (Py+ 3-C), 127.19
(Py+ 5-C), 119.04 ( =CHCO2), 61.32 (CH2CH3), 17.75 (CH3), 13.97
(CH2CH3).
1-[(E)-2-Carboxy-1-etheny])pyridinium Bromide (8a)
Reaction of pyridine 5a (2.37 g, 2.4 mL) with 7a (4.67 g) and re-
crystallization of the product from propan-2-ol gave pure 8a as pale
lilac crystals; yield: 1.17 g (34%); mp 188–189°C (dec.).
IR (KBr): ν = 1610 (C=N+), 1640 (C=C), 1695 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 9.17 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.62 (t, J = 7 Hz, 1 H, Py+ 4-H), 8.27 (d, J = 14 Hz, 1 H, = CHPy+),
8.11 (t, J = 7 Hz, 2 H, Py+ 3,5-H), 6.91 (d, J = 14 Hz, 1 H,
=CHCO2H).
MS (EI): m/z (%) = 192 (21), 164 (24), 135 (20), 108 (39), 93 (100),
80 (7), 66 (18), 51 (5), 39 (16).
Anal. Calcd for C11H14BrNO2: C, 48.55; H, 5.19; N, 5.15. Found C,
48.38; H 5.28; N 5.09.
13C NMR: δ = 164.73 (C=O), 148.56 ( =CHPy+), 145.63 (Py+ 4-C),
142.99 (Py+ 2,6-C), 128.08 (Py+ 3,5-C), 120.68 ( =CHCO2H).
MS (EI): m/z (%) = 150 (4), 80 (27), 79 (100), 70 (10), 52 (55), 39
(8).
1-[(E)-3-Hydroxyprop-1-en-1-yl]pyridinium Bromide (10)
Adapting the general procedure for the preparation of 3a–m, pyri-
dine (2.45 g, 2.5 mL, 31 mmol) and 2,3-dibromopropan-1-ol (3.27
g, 1.6 mL, 15 mmol) were reacted to give 10; sand-coloured crys-
tals; yield: 1.43 g (44%); mp 156–157°C (MeCN).
Anal. Calcd for C8H8BrNO2: C, 41.17; H, 3.50; N, 6.09. Found C,
41.59; H 3.60; N 6.00.
1-[(E)-2-Carboxy-1-ethenyl]-4-methylpyridinium Bromide (8b)
Reaction of 5b (2.79 g, 2.9 mL) with 7b (4.88 g) and recrystalliza-
tion of the product from acetone/H2O (30:1) gave pure 8b as pale
lilac crystals; yield: 1.50 g (41%); mp 155–156°C (dec.).
IR (KBr): ν = 1088 (C–C–O), 1624 cm-1 (C=N+).
1H NMR (90 MHz, CD3OD): δ = 9.00 (d, J = 7 Hz, 2 H, Py+ 2,6-H),
8.49 (t, J =7 Hz, 1 H, Py + 4-H), 8.00 (t, J = 7 Hz, 2 H, Py+ 3,5-H),
7.44 (dt, 3J = 14Hz, 4J = 2 Hz,1 H =CH–Py+), 6.78 (dt, 3J = 14Hz,
IR (KBr): ν = 1615 (C=N+), 1640 (C=C), 1705 cm-1 (C=O).
3
4
4J = 2 Hz, 1 H =CHCH2), 4.27 (dd, J = 4 Hz, J = 2 Hz,2 H,
1H NMR (90 MHz, CD3OD): δ = 8.98 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
8.22 (d, 1 H, J = 14 Hz, =CHPy+), 7.93 (d, 2 H, J = 7 Hz, Py+ 3,5-
H), 6.84 (d, 1 H, J = 14 Hz, =CHCO2H), 2.67 (s, 3 H, CH3).
13C NMR: δ = 165.22 (C=O), 160.66 (Py+ 4-C), 141.86 ( =CHPy+),
141.15 (Py+ 2,6-C), 128.30 ( =CHCO2H), 127.57 (Py+ 3,5-C), 21.73
(CH3).
CH2OH).
13C NMR: δ = 146.20 (Py+ 4-C), 142.02 (Py+ 2,6-C), 133.18
( =CH–Py+), 129.95 ( =CHCH2), 127.98 (Py+ 3,5-C), 58.36
(CH2OH).
MS (EI): m/z (%) = 136 (8), 117 (7), 105 (6), 80 (29), 79 (100), 52
(21), 39 (7).
MS (EI): m/z (%) = 163 (2), 93 (100), 80 (21), 65 (21), 51 (12), 39
(26).
Anal. Calcd for C8H10BrNO: C, 44.47; H, 4.66; N, 6.48. Found C,
44.33; H 4.77; N 6.41.
Anal. Calc for C9H10BrNO2: C, 44.29; H, 4.13; N, 5.74. Found C,
44.13; H 4.18; N 5.70.
1-[(E)-3-(Pyridinium-1-yl)prop-1-en-1-yl]pyridinium Dibro-
mide (11)
1-[(E)-2-Carboxy-1-ethenyl]-3-methylpyridinium Bromide (8c)
Reaction of 5c (2.79 g, 2.9 mL) with 7c (4.88 g) and recrystalliza-
tion from EtOH gave pure 8c as white crystals; yield: 2.53 g (69%);
mp 190–191°C (dec.).
Prepared by reacting pyridine (3.64 g, 3.7 mL, 46 mmol) and 1,2,3-
tribromopropane (4.20 g, 2.65 mL, 15 mmol) as desribed for 10.
The product was treated with HClO4 and further purified by recrys-
tallization from MeCN to give pure 11 as sand-coloured crystals;
yield: 2.47 g (46%); mp 218–219°C (dec.).
IR (KBr): ν = 1621 (C=N+), 1659 (C=C), 1714 cm-1 (C=O).
1H NMR (90 MHz, CD3OD): δ = 9.09 (s, 1 H, Py+ 2-H), 8.98 (d,J =
7 Hz, 1 H, Py + 6-H), 8.46 (d, 1 H, J = 7 Hz, Py+ 4-H), 8.20 (d,
J = 14 Hz, 1 H, =CH–Py+), 7.96 (dd, J = 7Hz, 1 H, Py + 5-H), 6.90
(d, 1 H, J = 14 Hz, =CHCO2H), 2.51 (s, 3 H, CH3).
13C NMR: δ = 165.12 (C=O), 149.00 ( =CH–Py+), 142.86 (Py+2-C),
142.03 (Py+ 6-C), 140.74 (Py+ 4-C), 138.89 (Py+ 3-C), 127.30 (Py+
5-C), 120.38 ( =CHCO2H), 17.89 (CH3).
IR (KBr): ν = 1624 (C=N+), 1680 (C=C).
1H NMR (90 MHz, CD3OD): δ = 9.24–9.04 (m, 4 H, Py+ 2,6-H),
8.71–8.44 (m, 2 H, Py+ 4-H), 8.09 (br d t, 4 H, Py+ 3,5-H), 7.96 (d,
J = 14 Hz, 1 H, =CH–Py+), 7.11 (dt, 1 H, 3J = 14 Hz, 4J = 6.5 Hz, 1
H =CHCH2), 5.62 (d, 3J = 6.5 Hz, 2 H, CH2).
13C NMR: δ = 147.57, 146.38 (Py+ 4-C), 145.10, 142.51 (Py+ 2,6-
C), 136.39 ( =CH–Py+), 128.29, 128.07 (Py+ 3,5-C), 124.38
( =CHCH2), 58.46 (CH2).
MS (EI): m/z (%) = 164 (4), 93 (100), 80 (29), 66 (48), 51 (8), 39
(27).
MS (EI): m/z (%) = 79 (100), 50 (25), 39 (8).
Anal. Calcd for C9H10BrNO2: C, 44.29; H, 4.13; N, 5.74. Found C,
44.10; H 4.25; N 5.59.
Anal. Calcd for C13H14Br2N2: C, 43.61; H, 3.94; N, 7.82. Found C,
43.53; H 4.05; N 7.79.
1-[(E)-2-Ethoxycarbonyl-1-ethenyl]-3-methylpyridinium Bro-
mide (9):
3-Methylpyridine (2.79 g, 2.9 mL, 30 mmol) was added to a solu-
tion of 6c (5.30 g, 15 mmol) in EtOH (25 mL) and stirred for 48 h
at 50°C. After evaporation to dryness, the residue was washed with
acetone (2 × 10 mL). The product was further purified by recrystal-
1-[2-(Pyridinium-1-yl)-1-ethenyl]pyridinium Dibromide (13)
A mixture of pyridine (1.3 mL, 16 mmol) and 1,1,2-tribromoethane
(0.5 mL, 5 mmol) was heated at 70°C for 22 h. The mixture was left
in the freezer overnight. The solid was filtered and recrystallized
from EtOH to give 13 (550 mg, 32%) as lilac crystals; mp >250 °C
(dec.).
Synthesis 1999, No. 12, 2131–2137 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
A Convenient Preparation of 1-Vinylpyridinium Salts
2137
IR (KBr): ν = 1625 cm-1 (C=N+).
hyd EtOH (5 mL). The mixture was refluxed for 4 h. H2O (30 mL)
was added to the mixture and left overnight at r.t. The precipitate
was filtered, dried and washed with hot hexane (2 × 20 mL). The
residue was extracted with benzene (3 × 20 mL). The precipitate
which was formed after the addition of hexane (20 mL) to the ben-
zene solution was collected by filtration and gave 15 (0.68 g, 28%)
as metallic violet crystals; mp 155–160°C (dec.).
1H NMR (90 MHz, CD3OD): δ = 9.12 (d, J = 7 Hz, 4 H, Py+ 2,6-
H), 8.67 (t, J = 7 Hz, 2 H, Py+ 4 H), 8.63 (s, 2 H, =CH), 8.14 (t, J =
7 Hz, 4 H, Py+ 3,5-H).
13C NMR: δ = 150.26 (Py+ 4 C), 144.90 (Py+ 2,6-C), 134.79 ( =CH–
Py+), 129.89 (Py+ 3,5-C).
IR (KBr): ν = 1616 cm-1 (C=N+).
MS (EI): m/z (%) = 181 (12), 154 (4), 82 (100), 79 (98), 52 (35), 39
(6).
1H NMR (90 MHz, CD3OD): δ = 8.31 (d, 2 H, J = 7 Hz, Py+ 2,6-H),
7.89 (s, 1 H, C=CH), 7.70 (d, 2 H, J = 7 Hz, Py+ 3,5-H), 7.58–6.24
(m, 14 Harom), 5.91 (d, 1 H, J = 3 Hz, =CH trans to C6H5), 5.69 (d,
1 H, J = 3 Hz, =CH cis to C6H5), 2.82 (s, 6 H, CH3).
Anal. Calcd for C12H12Br2N2: C, 41.89; H, 3.52; N, 8.14. Found C,
41.77; H 3.62; N 8.02.
4-[2-(2-Hydroxyphenyl)-1-ethenyl]-1-(1-phenylvinyl)pyridini-
um Bromide (14)
13C NMR: δ = 159.98 (Carom), 158.12 (Py+ 4-C), 151.13 (CH=CPh),
147.53 (CH2=C), 142.76 (Py+ 2,6-C), 141.36, 137.42, 133.34,
129.94, 129.59, 128.96, 128.33, 126.36, 122.20, 111.05 (Carom),
132.80 ( =CHPh), 115.41 (C=CH2), 39.92 (CH3).
Piperidine (0.3 mL) was added to a solution of 3b (2.3 g of the crude
product) and 2-hydroxybenzaldehyde (0.74 g, 6 mmol) in anhyd
EtOH (5 mL). The mixture was refluxed for 3 h. H2O (30 mL) was
added to the solution and was left overnight at r.t. The precipitate
was filtered and was purified by crystallization from EtOH to give
14 (0.67 g, 35%) as yellow solid; mp 214–216 °C (dec.).
MS (EI): m/z (%) = 403 (1), 300 (83), 285 (61), 271 (40), 228 (18),
174 (82), 168 (73), 105 (100), 103 (81), 91 (43), 80 (40), 77 (99), 63
(23), 51 (63), 39 (20).
IR (KBr): ν = 1618 cm-1 (C=N+).
Anal. Calcd for C29H27BrN2: C, 72.05; H, 5.63; N, 5.79. Found C,
71.88; H 5.79; N 5.60.
1H NMR (90 MHz, CD3OD): δ = 8.62 (d, J = 7 Hz, 2 H, Py+ 2,6-
H), 8.09 (d, J = 7 Hz,2 H, Py+ 3,5-H), 7.98 – 6.56 (m, 9 Harom and
CH=CH), 6.16 (d, J = 3 Hz, 1 H, =CH trans to C6H5), 5.82 (d, J = 3
Hz,1 H, =CH cis to C6H5).
References
(1) Duling, I.N.; Price, C.C. J. Am. Chem. Soc. 1962, 84, 578.
(2) Nambu, Y.; Gan, Y.; Tanaka, Ch.; Endo, T. Tetrahedron Lett.
1990, 31, 891.
(3) Katritzky, A.R.; Rubio-Teresa, O.; Patel, R.C. Chem. Scripta
1982, 20, 147.
(4) Katritzky, A.R.; Mokrosz, M.J. Heterocycles 1984, 22, 505.
(5) Krohnke, F.; Wolff, I.; Jentrsch, G. Chem. Ber. 1951, 84, 399.
(6) King, L.C.; Brownell, W.B. J. Am. Chem. Soc. 1950, 72, 2507.
(7) Relles, H.M. J. Org. Chem. 1973, 38, 1570.
(8) Potechin, A.A In Svoistva organicheskih soedinenij, Chimija:
Leningrad, 1984, 437.
13C NMR: δ = 157.31 (2-OHC6H4, 2-C), 155.48 (Py+ 4-C), 147.68
(CH2=C), 143.57 (Py+ 2,6-C), 138.60 (C6H5, 1-C), 132.80
( =CHPhOH), 131.81 (2-OHC6H4, 1-C), 130.21 (2-OHC6H4, 4-C),
129.01 (C6H5, 4-C), 128.97 (C6H5, 3,5-C), 126.39 (C6H5, 2,6-C),
123.53 (Py+ 3,5-C), 122.34 (2-OHC6H4, 6-C), 121.65 ( =CH–Py),
119.24 (2-OHC6H4, 5-C), 116.40 (2-OHC6H4, 3-C), 115.78
(C=CH2).
MS (EI): m/z (%) = 299 (11), 195 (90), 167 (20), 103 (72), 93 (100),
77 (41), 65 (10), 51 (10), 39 (13).
Anal. Calcd for C21H18BrNO: C, 66.33; H, 4.77; N, 3.68. Found C,
66.20; H 4.88; N 3.56.
Article Identifier:
1437-210X,E;1999,0,12,2131,2137,ftx,en;Z03099SS.pdf
4-[2-(4-Dimethylaminophenyl)-1-phenyl-1-ethenyl]-1-(1-phe-
nylvinyl)pyridinium Bromide (15)
Piperidine (0.3 mL) was added to a solution of 3d (3.2 g of the crude
product) and 4-dimethylaminobenzaldehyde (0.9 g, 6 mmol) in an-
Synthesis 1999, No. 12, 2131–2137 ISSN 0039-7881 © Thieme Stuttgart · New York