SUPRAMOLECULAR CHEMISTRY
7
solid became flocculent. The suspension was then filtered
and the filtrate evaporated to dryness under reduced
pressure at 40 °C to yield methyl 2-pyrazinecarboxylate
as colourless oil which rapidly crystallised into an off-white
solid at room temperature (37.0 g, 94%). Found: C, 51.94;
H, 4.55; N, 20.55. Calc. for C H N O : C, 52.17; H, 4.38; N,
further purification (0.05 g, ca. 74%). Found: C, 52.70; H,
6.60; N, 36.43. Calculated for C H N O·⅓H2O: C, 52.43; H,
5
7
3
1
6.69; N, 36.69. H NMR (300 MHz, CDCl ): δ (ppm) 8.54 (d,
3
J = 1.5 Hz, 1H, H-3), 8.46 (dd, J = 1.5, 2.7 Hz, 1H, H-2), 8.40
(d, J1,2 = 2.7 Hz, 1H, H-1), 3.96 (s, 2H, CH2).
3,5-Bis{[(2-pyrazylmethyl)amino]methyl}-4-amino-4H-
6
6
2
2
2
0.28. 1H NMR (300 MHz, CDCl ): δ (ppm) 9.33 (d, J = 1.0
1,2,4-triazole (P MAT): 2-(aminomethyl)pyrazine (0.5 g,
3
Z
Hz, 1H, H-3), 8.79 (d, J = 2 Hz, 1H, H-1), 8.74–8.73 (m, 1H,
H-2), 4.06 (s, 3H, OCH3).
4.58 mmol) and 3,5-bis(chloromethyl)-4-amino-1,2,4-tri-
azole (0.331 g, 1.53 mmol) were dissolved in acetonitrile
(40 mL). To this was added K CO (1.05 g, 7.64 mmol) and
2-Pyrazinemethanol: A stirred solution of methyl 2-pyra-
2
3
zinecarboxylate (4.94 g, 35.8 mmol) in methanol (350 mL)
was slowly added sodium borohydride (5.410 g, 143 mmol)
in 1 g portions over 10 min. Caution: The solution became
yellow and evolved heat and gas, add the sodium boro-
hydride cautiously. The solution was stirred overnight
the resulting suspension heated at reflux for four hours.
At this point the suspension was filtered and the filtrate
taken to dryness. The residue was dissolved in dichlo-
romethane (10 mL) and the white solid (residual Na CO )
filtered off. The filtrate was taken to dryness, yielding crude
3,5-bis{[(2-pyrazylmethyl)amino]methyl}-4-amino-4H-
2
3
at room temperature. H O (20 mL) was added and the
2
reaction was shaken vigorously. The suspension was then
evaporated to dryness under reduced pressure to an oily
yellow powder. Ethyl acetate (350 mL) was then added and
the resulting suspension was stirred vigorously overnight.
The suspension was filtered and evaporated to dryness
under vacuum to give the crude product as a yellow oil
1,2,4-triazole (P MAT) as a red oil. The ligand was used as
is, without further purification.
Z
3,5-Bis{[(2-pyrazylmethyl)amino]methyl}-4-pyrrole-4H-
1,2,4-triazole (P MPT): Prepared in an analogous fashion to
Z
PZMAT, except using 3,5-bis(chloromethyl)-4-pyrrole-1,2,4-
triazole (0.293 g, 1.53 mmol), with the same quantities of
other reagents and solvents, yielding red oil. The ligand
which was used without further purification (2.80 g, ca.
1
7
1%). H NMR (300 MHz, CDCl ): δ (ppm) 8.64 (br, 1H, H-3),
was used as is, without further purification.
3
II
8.53 (m, 1H, H-2), 8.50 (m, 1H, H-1), 4.84 (s, 2H, CH2).
[Fe (P MAT) ](BF ) ∙MeOH∙2H O
(1∙MeOH∙2H O):
2
Z
2
4 4
2
2
2
-Pyrazinemethylphthalimide:
Triphenylphosphine
3,5-bis{[(2-pyrazylmethyl)amino]methyl}-4-amino-4H-
1,2,4-triazole (0.216 g, 0.69 mmol) was dissolved in
MeOH (5 mL) and the solution thoroughly degassed
by consecutive vacuum/argon purges. To MeOH (5 mL)
degassed by consecutive vacuum/argon purges was
(
7.80 g, 29.7 mmol) and phthalimide (4.50 g, 30.6 mmol)
were added to a solution of crude 2-(hydroxylmethyl)pyra-
zine (2.80 g, 25.5 mmol) in dry tetrahydrofuran (200 mL).
The stirred solution was then cooled in an ice bath before
diisopropyl azodicarboxylate (5.90 g, 30.4 mmol) was
slowly added over 5 min. The solution was stirred for two
days at room temperature and taken to dryness under
reduced pressure and the resulting yellow oil was sus-
pended in ethanol (20 mL) before again being taken to
dryness under reduced pressure, producing a thick yellow
slurry. The slurry was dissolved in hot ethanol (~200 mL)
and left to cool and evaporate to ~50 mL overnight at
room temperature. The resulting solid was filtered off to
give the desired product as an analytically pure slightly
yellow solid (3.82 g, 75%). Found: C, 65.14; H, 3.89; N, 17.52.
II
added Fe (BF ) ∙6H O (0.222 g, 0.69 mmol) and the solu-
4
2
2
tion transferred via cannula to the P MAT solution. The
Z
resulting brown suspension was stirred for a further
five minutes before being filtered under argon yield-
II
ing [Fe (P MAT) ](BF ) ·2H O·MeOH as brown powder
2
z
2
4 4
2
(0.190 g, 49%). Found: C, 29.29; H, 3.36; N, 23.76. Calc.
for Fe C H N B F ·2H O·MeOH: C, 29.53; H, 3.76; N,
2
28 36 20
4
16
2
23.75. ESI-MS (MeCN): found = 327.1789, calculated for
+
[(C H N )H] = 327.1794.
1
4
18 10
II
[Fe (P MPT) ](BF ) ∙3H O (2∙3H O): Prepared in analo-
gous fashion to [Fe (P MAT) ](BF ) ∙MeOH∙2H O, except
2
Z
2
4 4
2
2
II
2
Z
2
4 4
2
1
Calc. for C H N O : C, 65.27; H, 3.79; N, 17.56. H NMR (300
using P MPT (0.240 g, 0.71 mmol), with the same quan-
13
9
3
2
Z
MHz, CDCl ): δ (ppm) 8.66 (s, 1H, H-3), 8.48 (s, 2H, H-2 +
H-1), 7.89–7.92 (m, 2H, phth-H), 7.77–7.74 (m, 2H, phth-H),
tities of other reagents and solvents, yielding orange
powder (0.292 g, 83%). Found: C, 33.90; H, 3.56; N, 21.75.
Calc. for Fe C H N B F ·3H O: C, 34.16; H, 3.66; N,
3
5
.06 (s, 2H, CH2).
-(Aminomethyl)pyrazine: 2-Pyrazinemethylphthalimide
0.15 g, 0.63 mmol) was suspended in ethanol (10 mL) and
2
36 40 20
4
16
2
2
22.13. ESI-MS (MeCN): found = 377.1996, calculated for
+
(
[(C H N )H] = 377.1951.
1
8
20 10
hydrazine hydrate (80% w/w%, 1.5 mL, 3.1 mmol) added
before the suspension was heated to reflux for two hours.
The suspension was then cooled to room temperature
then further cooled in the fridge. The suspension was
filtered and the filtrate taken to dryness yielding 2-(ami-
nomethyl)pyrazine as a yellow oil that was used without
Acknowledgements
We thank Dr. Shen Chong and Dr. Simon Granville (Robinson
Research Institute) for their assistance with the SQUID mag-
netometer and PPMS susceptometer.
Feltham, Humphrey L. C.
