dried under argon over CaH2. THF was dried under argon over
sodium wire with benzophenone as an indicator.
was dissolved in DCM (50 mL) and dried with MgSO4. After
concentration the oil began to crystallise. The solid sample was
then centrifuged to remove the acetic acid that still remained. This
◦
formed a white solid, mp 68–70 C; nmax(KBr)/cm-1 3275, 1648,
N-Methylpyridine-4-carboxaldehyde iodide 915
1599, 1367; dH(400 MHz; CDCl3) 1.98 (3H, s), 4.35 (2H, D, J 6.2),
6.59 (1H, s), 7.10 (2H, d, J 5.8), 8.44 (2H, d, J 5.8); dC(100 MHz;
CDCl3) 23.0, 42.3, 122.2, 147.6, 149.8, 170.3.
Pyridine-4-carboxaldehyde 19 (5 mL, 56.9 mmol) in dichloro-
methane (20 mL) was treated with methyl iodide (7 mL,
112.4 mmol) and stirred at ambient temperature for 48 h. This gave
the title compound (12.2 g, 81%) filtered off as yellow/orange cubic
crystals with identical spectroscopic properties to the literature
4-(Acetylaminomethyl)-N-methylpyridinium iodide 27
◦
material, mp 104–105 C (lit.15 105–106 ◦C); nmax (KBr)/cm-1
N-Pyridin-4-ylmethylacetamide 26 (5.0 g, 0.03 mol) and MeI
(5.3 g, 0.04 mol) in DCM (50 mL) were left for two days or until the
reaction had gone to completion as monitored by TLC. Crystals
were filtered off as green needles, mp 142–144 ◦C (Found: C,
36.8; H, 4.4; N, 9.4. C9H13IN2O requires C, 36.9; H 4.4; N,
9.5%); nmax(KBr)/cm-1 3240, 1664, 1633, 1366, 1180; dH(400 MHz;
CD3OD) 2.05 (3H, s), 4.34 (3H, s), 4.60 (2H, d, J 5.1), 7.92 (2H,
d, J 6.5), 8.78 (2H, d, J 6.5); dC(100 MHz; CD3OD) 21.3, 42.1,
47.3, 125.7, 145.2, 159.8, 172.8; m/z 165 (M+, 100%) Acc. mass
C9H13IN2O: calc. 165.1022, found 165.1023.
3250, 3020, 1701, 1642, 1465, 1223, 1042 and 833; (Found: C,
33.5; H, 3.4; N, 5.5. C7H8INO requires C, 33.7; H, 3.2; N, 5.6%);
dH(250 MHz; CD3OD) (deuterated methanol solvate) 4.43 (3H, s,
CH3), 5.75 (1H, s, CH(OH)(OCD3), 8.13 (2H, d, J 6.2, ArH), 8.92
(2H, d, J 6.2, ArH); dC(62.9 MHz; CD3OD) 53.0–55.0 (OCD3),
95.8, 126.9, 146.9, 161.1 (one resonance is missing); m/z C8H12NO2
(methanol solvate from methanol) 154 (M+, 70%) and 122 (M+ -
CH3OH).
N-Methylpyridine-2-carboxaldehyde iodide 2115
[4-Aminomethyl-N-methylpyridinium chloride] hydrochloride 13
Pyridine-2-carboxaldehyde 20 (1 mL, 10.5 mmol) in dichloro-
methane (10 mL) was treated with methyl iodide (2.5 mL,
40.2 mmol) and heated at 60 ◦C for 48 h. This gave the title
compound (12.2 g, 81%) filtered off as yellow/orange cubic crystals
with identica◦l spectroscopic properties to the literature material,
4-(Acetylaminomethyl)-N-methylpyridinium iodide 27 (4.0 g,
0.014 mol) was refluxed in 150 mL of dilute HCl for 3 h. Aqueous
HCl was then removed in vacuo to give a brown precipitate,
mp 206–208 ◦C; nmax(KBr)/cm-1 2863, 1639, 1547, 1391, 1175;
dH(400 MHz; CD3OD) 4.42 (3H, s), 4.52 (2H, s), 8.13 (2H, d, J
6.5) and 8.98 (2H, d, J 6.5); dC(100 MHz; CD3OD) 32.9, 41.5,
127.1, 146.0, 152.5; m/z 123 (M+, 100%) Acc. mass C7H11IN2
(M+ - HCl and I): calc. 123.0917, found 123.0916.
◦
mp 179–182 C (lit.15 180–183 C); nmax (KBr)/cm-1 3043 (CH),
=
=
1698 (ArC O) and 1614 ArC C); dH(250 MHz; CD3OD) (mixture
of deuterated methanol solvate and hydrate) 4.44 (1.8H, s, CH3),
4.47 (1.2H, s, CH3), 6.00 (0.6H, s, CH(OH)(OCD3)), 6.30 (0.4H, s,
CH(OH)2), 8.05 (1H, t, J 6.8, ArH), 8.35 (1H, d, J 7.9, ArH),
8.63 (1H, t, J 7.6, ArH), 8.92 (1H, d, J 6.1, ArH); dC(62.9 MHz;
CD3OD) 45.6, 45.7, 85.8, 92.2, 125.4, 125.9, 127.1, 127.4, 146.2,
146.3, 147.1, 147.4, 155.0 and 157.2; m/z C8H12NO2 (methanol
solvate from methanol) 154 (M+, 70%) and 122 (M+ - CH3OH).
1-Methyl-4-[(1-methyl-1H-pyridin-4-ylidenemethylimino)-
methyl]pyridinium iodide 16
Mixing [4-aminomethyl-N-methylpyridinium chloride] hydro-
chloride 13 and N-methylpyridine-4-carboxaldehyde iodide 9 in
water with K2CO3 gave a green solution, mp >250 ◦C (UV Fig. 6).
4-(1,1-Hydroxymethoxymethyl)-1-methylquinolinium iodide 23
1-Methyl-4-[(1-methyl-1H-pyridin-4-ylidenemethylimino)-
methyl]pyridinium iodide 16
Quinoline-4-carboxaldehyde 22 (1.565 g, 9.96 mmol) in dichloro-
methane (15 mL)was treated with methyl iodide (2 mL, 32.1 mmol)
and heated to 130 ◦C for 16 h in a PTFE lined pressure bomb.
This gave the title compound (2.4 g, 74%) as brown cubic crystals,
mp >200 ◦C (from methanol) (Found C, 43.4; H, 4.2; N, 4.3.
C12H14INO2 requires C, 43.5; H, 4.2; N, 4.2%); nmax(KBr)/cm-1
3255 (OH), 2822 (CH), 1601 (ArC C) and 1527 (ArC C);
dH(250 MHz; D6DMSO) 4.59 (3H, s, CH3), 6.30 (1H, s), 8.04
(1H, t, J 7.8, ArH), 8.14 (1H, d, J 6.1, ArH), 8.24 (1H, t, J 7.8,
ArH), 8.47 (1H, d, J 8.9, ArH), 8.59 (1H, d, J 8.2, ArH), 9.40
(1H, d, J 6.1, ArH); dC(62.9 MHz; CD3OD) 45.5, 93.4, 118.7,
119.0, 127.3, 127.4, 129.9, 135.3, 139.25, 149.8 and 157.6; m/z 204
(M+ - I, 100%), 172 (M+ - CH3OHI, 45) Acc. mass C12H14NO2:
calculated 204.1019, found 204.1020.
Pyridine-4-carboxaldyhyde 19 (1.0 g, 9.3 mmol) and 4-
aminomethylpyridine 25 (1.0 g, 9.3 mmol) were dissolved in DCM
(50 mL). The solution was then dried using magnesium sulfate and
the DCM was evaporated in vacuo leaving an orange oil. This was
then dissolved in MeOH with an excess of MeI and K2CO3. After
leaving overnight, a precipitate formed which was filtered off. The
precipitate was a mixture of green and brown solid which was
washed with MeOH. The brown solid disappeared and a bright
emerald green product was left; after a few days, the colour of this
product began to fade to an olive green colour, mp >250 ◦C (UV
Fig. 7).
=
=
N-Methyl-1H-imidazole-2-carboxaldehyde 3220
N-Pyridin-4-yl-methylacetamide 2616
n-Butyllithium (32 mmol) (20 mL of a 1.6 mol/dm-3 solution
in hexanes) was added dropwise to a stirred solution of N-
methylimidazole 315 (2 mL, 25.8 mmol) in dry THF (30 mL)
under argon at -78 ◦C. After 30 min at -78 ◦C dimethylformamide
(4.6 mL, 59.4 mmol) was added dropwise. The mixture was
4-Aminomethylpyridine 25 (5.0 g, 0.05 mol) and acetic anhydride
(6.12 g, 0.06 mol) in water (50 g), were stirred for two days or until
the reaction had gone to completion as monitored by TLC. Water
was removed under vacuum leaving a pale yellow oil. The oil
This journal is
The Royal Society of Chemistry 2009
Org. Biomol. Chem., 2009, 7, 1633–1641 | 1639
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