and maintained at 120 ЊC for 16 h. After filtration, the filtrate
was evaporated and the obtained crude product was recrystal-
lized from ethanol. Yield 18%, mp 160.5–161.5 ЊC. δH(400
MHz, CDCl3) 7.34 (1H, ddd, 5Љ-H), 7.45 (1H, t, phenyl 4-H),
7.53 (2H, t, phenyl 3,5-H), 7.81 (1H, dd, 5-H), 7.88 (1H, td, 4Љ-
H), 7.94 (1H, t, 4-H), 7.99 (1H, t, 4-H), 8.18 (2H, d, phenyl 2,6-
H), 8.47 (1H, dd, 5Ј-H), 8.60 (1H, dd, 3Љ-H), 8.65–8.70 (2H, m,
3,3Ј-H), 8.72 (1H, dd, 6Љ-H); HRMS(FAB): found m/z 310.1366
([M + H]+); calc. for C21H15N3 + H: 310.1344.
15 ml) was added 2-acetylpyridine (2.5 g, 21 mmol) and the
mixture was stirred for 30 min. The resulting precipitate was
filtered off, dissolved in dichloromethane and washed once
with water. The organic phase was dried over sodium sulfate
and evaporated to dryness.
Recrystallization from ethanol gave 4-bromo-2Ј-azachalcone
as a light yellow solid (81%). 4-Bromo-2Ј-azachalcone (0.58 g,
2.0 mmol), 16 (0.62 g, 2.0 mmol), and ammonium acetate
(4.0 g, 51 mmol) were dissolved in 4 ml of glacial acetic acid and
the mixture was refluxed for 7 h. After cooling, the reaction
mixture was basified with 7 ml of aqueous sodium hydroxide
(10 mol dmϪ3), and then extracted with dichloromethane. The
combined organic phases were dried over sodium hydroxide.
The evaporated residue was applied to a flash chromatography
column (activated alumina) and eluted with hexane–
dichloromethane–ethyl acetate (8 : 2 : 1–3 : 6 : 2) to give 4Ј-(p-
bromophenyl)-2,2Ј:6Ј,2Љ-terpyridine 10 (86%). Mp 158–160 ЊC.
Found: C, 64.95; H, 3.52; N, 10.81; calc. for C21H14BrN3:
C, 64.96; H, 3.63; N, 10.82%. δH(500 MHz, CDCl3) 7.35
(2H, td, 5,5Љ-H), 7.62 (2H, d, phenyl 3,5-H), 7.76 (2H, d, phenyl
2,6-H), 7.87 (2H, td, 4,4Љ-H), 8.65 (2H, 3,3Љ-H), 8.67 (2H, s,
3Ј,5Ј-H), 8.71 (2H, d, 6,6Љ-H).
4-Phenyl-2,2Ј:6Ј,2Љ-terpyridine 2
2-(Trimethylstannyl)pyridine (6.0 g), prepared from 2-bromo-
pyridine analogously to (trimethylstannyl)benzene, 2-acetyl-6-
bromopyridine (555 mg), bis(triphenylphosphine)palladium()
dichloride (220 mg), and lithium chloride (413 mg) were dis-
solved in anhydrous toluene and refluxed for 16 h. After filtra-
tion, the filtrate was evaporated to give 6-acetyl-2,2Ј-bipyridine
(41%, crude). The subsequent procedure was the same as for
4, replacing 2,6-diacetylpyridine with 6-acetyl-2,2Ј-bipyridine.
Mp 176–176.5 ЊC. νmax(KBr)/cmϪ1 3107, 1543, 1482, 1410, 761
and 687; δH(400 MHz, CDCl3) 7.33 (1H, ddd, 5Љ-H), 7.43–7.55
(3H, m, phenyl 3,4,5-H), 7.60 (1H, dd, 5-H), 7.80 (2H, d, phenyl
2,6-H), 7.88 (1H, t, 4Љ-H), 7.98 (1H, t, 4Ј-H), 8.48 (1H, dd,
5Ј-H), 8.60 (1H, dd, 3Љ-H), 8.65 (1H, dd, 3Ј-H), 8.70–8.79
(2H, m, 6,6Љ-H), 8.90 (1H, sd, 3-H); HRMS(FAB): found
m/z 310.1308 ([M + H]+); calc. for C21H15N3 + H: 310.1344.
4Ј-(p-Nitrophenyl)-2,2Ј:6Ј,2Љ-terpyridine 9. Yield: 80%, mp
210–211 ЊC. IR (KBr) 1512, 1352 cmϪ1 (NO2). HRMS:
355.1189 (M+); calc. for C21H14N4O2: M, 355.1194. δH(500
MHz, CDCl3) 7.56 (2H, ddd, 5,5Љ-H), 8.07 (2H, td, 4,4Љ-H),
8.25 (2H, d, phenyl 3,5-H), 8.42 (2H, d, phenyl 2,6-H), 8.70
(2H, 3,3Љ-H), 8.78–8.80 (4H, m, 6,3Ј,5Ј,6Љ-H).
6,6Љ-Diphenyl-2,2Ј:6Ј,2Љ-terpyridine 6
A mixture of 18 (0.21 g, 0.6 mmol), 17 (0.39 g, 1.2 mmol), and
ammonium acetate (0.27 g, 3.5 mmol) in methanol was heated
to reflux for 8 h. After cooling, water was added dropwise to
the solution until a yellow solid precipitated. After filtration,
washing with water and drying in vacuo, the crude material was
purified by column chromatography on silica with chloroform.
The product was the first to elute from the column. Recrystal-
lization by slow evaporation from a dichloromethane–ethanol
mixture gave white needles (0.16 g, 71%). Mp 206–207 ЊC.
Found: C, 84.10; H, 5.05; N, 10.78; calc. for C27H19N3: C, 84.13;
H, 4.97; N, 10.90%. δH(500 MHz, CDCl3) 7.46 (2H, t, phenyl
4-H), 7.53 (4H, t, phenyl 3,5-H), 7.81 (2H, d, 5,5Љ-H), 7.95 (2H,
t, 4,4Љ-H), 8.03 (1H, t, 4Ј-H), 8.19 (4H, phenyl 2,6-H), 8.63–8.71
(4H, m, 3,3Ј,3Љ,5Ј-H).
4Ј-(p-Chlorophenyl)-2,2Ј:6Ј,2Љ-terpyridine 11. Yield: 85%,
mp 171–172 ЊC. Found: C, 73.08; H, 3.96; N, 12.05; calc. for
C21H14ClN3: C, 73.36; H, 4.10; N, 12.22%. δH(500 MHz, CDCl3)
7.34 (2H, ddd, 5,5Љ-H), 7.47 (2H, d, phenyl 3,5-H), 7.83 (2H, d,
phenyl 2,6-H), 7.87 (2H, d, 4,4Љ-H), 8.65 (2H, 3,3Љ-H), 8.69 (2H,
s, 3Ј,5Ј-H), 8.71 (2H, d, 6,6Љ-H).
4Ј-(p-Aminophenyl)-2,2Ј:6Ј,2Љ-terpyridine 14. 4Ј-(p-Bromo-
phenyl) tpy 10 (0.5 g) was treated with liquid ammonia (60 ml)
in an autoclave at 175 ЊC, 150 atm for 48 h. After removal of
ammonia, residual brown solid was applied on an alumina
column and eluted with ethyl acetate (56%). Mp 253–254 ЊC.
HRMS: 324.1378 (M+); calc. for C21H20N4: M, 324.1375. δH(500
MHz, CDCl3) 6.81 (2H, d, 3ЈЈЈ,5ЈЈЈ-H), 7.35 (2H, td, 5,5Љ-H),
7.79 (2H, d, 2ЈЈЈ,6Љ-H), 7.88 (2H, td, 4,4Љ-H), 8.66 (2H, 3,3Љ-H),
8.69 (2H, s, 3Ј,5Ј-H), 8.73 (2H, d, 6,6Љ-H).
4Ј-Amino-2,2Ј:6Ј,2Љ-terpyridine 8
Ammonia gas was bubbled into acetamide (5 g)–phenol (13.6 g)
solution and the mixture was kept at 100 ЊC for 30 min. After
chloro-tpy (7; 3.7 g, 14 mmol) was added, the reaction mixture
was heated up to 160 ЊC over 10 min and maintained for 5 h
with continuous bubbling of the ammonia gas. After cooling,
the reaction mixture was separated between aqueous sodium
hydroxide (6 mol dmϪ3, 30 ml) and chloroform (30 ml).
The aqueous layer was washed with further portions of chloro-
form (5 × 30 ml). The combined organic layer was dried over
magnesium sulfate, and then the solvent was evaporated. The
product was recrystallized from benzene. Yield 63%, mp 222–
226 ЊC. Found: C, 72.40; H, 4.87; N, 22.46; calc. for C15H12N4:
C, 72.56; H, 4.87; N, 22.57%. δH(400 MHz, CDCl3) 7.31 (2H,
ddd, 5,5Љ-H), 7.74 (2H, s, 3Ј,5Ј-H), 7.84 (2H, ddd, 4,4Љ-H), 8.60
(2H, d, 3,3Љ-H), 8.67 (2H, ddd, 6,6Љ-H).
Method B11
Compounds 12, 13 and 15 were prepared by the following
synthetic method represented by the preparation of 12.
A mixture of acetamide (26.6 g, 450 mmol), ammonium
acetate (17.3 g, 2.25 mmol), p-tolualdehyde (1.80 g, 15 mmol),
and 2-acetylpyridine (3.7 g, 30 mmoL) was refluxed for 2 h and
cooled to 120 ЊC, and aqueous sodium hydroxide (13.1 g in 30
ml of water) was added. After further standing at 120 ЊC for 2 h
without stirring, the solution was cooled to room temperature.
A brown solid was separated, washed with water, and dissolved
in acetic acid (9 ml). The hydrobromide salt was precipitated
with 47% hydrobromic acid (9 ml), filtered off, and dissolved
in water (30 ml). The solution was basified with aqueous
potassium hydroxide (4 mol dmϪ3), and the obtained suspen-
sion was extracted with dichloromethane. After evaporation
of the solvent, the residue was recrystallized from ethanol
to give yellow needles (1.34 g), which were dissolved in
an ethanol–dichloromethane mixture (60 ml). Addition of a
Mohr salt aqueous solution (0.73 g in 15 ml) immediately gave
a purple solution. After evaporation of dichloromethane,
aqueous potassium hexafluorophosphate (0.68 g in 10 ml)
was added, and the collected precipitate, [Fe(12)2][PF6]2, was
Method A10
Compounds 9, 10 and 11 were synthesized by the following
procedure represented by the preparation of 10. Starting
from an appropriate 4-substituted benzaldehyde gave the
corresponding compound.
To a solution of 4-bromobenzaldehyde (3.7 g, 20 mmol) in
methanol (45 ml) and aqueous sodium hydroxide (1 mol dmϪ3
,
J. Chem. Soc., Perkin Trans. 2, 2001, 1045–1050
1049