Melting points were determined on a Fischer-Johns apparatus and 1H and 13C-NMR spectra
were recorded in a Varian Unity Plus (300 MHz).
Amidine
2a: A DMSO (1 mL) solution of benzylamine (107 mg; 1 mmol) was added
to a DMSO (2 mL) solution of
5 (213 mg; 1.25 mmol) and CuCl (124 mg; 1.25 mmol). The
mixture was stirred under a nitrogen atmosphere, at 80oC for 20 h. AcOEt (2 mL) and 50%
aqueous NaOH (4 mL) were added. The mixture was vigorously stirred for 30 minutes. The
filtered and the solid was washed with AcOEt (10 mL). The organic layer was dried over
Na
2
SO
4
and the volatiles were removed in vacuum. The residue was purified by flash
chromatography on silica gel (10% AcOEt in hexane as the eluent) to give
2a as a white solid
(202 mg, 73% yield). Mp = 121-123oC. IR (KBr, cm-1): 3280, 3033, 2919, 1658, 1595,
1553, 1497, 1455, 1322, 1227, 1153, 970, 756, 697, 667; 1H-NMR (300 MHz, DMSO-
d6, δ)
9.33 (m, 1H), 8.58 (s, 1H), 8.38 (ddd, J=7.5 Hz, J=3.2 Hz, J=1.2 Hz, 2H), 7.73 (ddd, J=8.7
Hz, J=7.5 Hz, J=1.7 Hz, 2H), 7.60 (tt, J=8.7 Hz, J=1.2 Hz, 1H), 7.50-7.45 (m, 4H), 7.40-7.34
(m, 1H), 4.63 (d, J=6.3 Hz, 2H); 13C-NMR (75 MHz, DMSO-
d6, δ) 159.2 (s), 144.2 (s),
139.2 (s), 138.9 (s), 136.4 (s), 129.8 (s), 128.6 (s), 128.4 (s), 127.4 (s), 126.9 (s), 118.9 (s),
42.2 (s).
Amidine
2b: A suspension of 6 (152 mg; 1 mmol) in benzonitrile (1 mL) was added
to a benzonitrile (2 mL) solution of CuCl (124 mg; 1.25 mmol). The mixture was stirred,
under a nitrogen atmosphere, at 80oC for 20 h. AcOEt (2 mL) and 50% NaOH (4 mL) were
added. The mixture was vigorously stirred for 30 minutes. The organic layer was washed
consecutively with 3M NH
4
OH (until negative test for Cu(II) using 0.1M K
4
Fe(CN)
6
), with
5% NH
4
Cl (until neutralization), and then with water (15 mL). Subsequently it was dried over
Na
2
SO
4
and the volatiles were removed in vacuum. The residue was crystallized from ethyl
alcohol to give
2b as a yellow solid (191 mg, 75% yield). Mp = 151oC. IR (KBr, cm-1):
3346, 3203, 3061, 2920, 2851, 1645, 1578, 1530, 1510, 1466, 1447, 1216, 1181, 1145, 1034,
1008, 860, 771, 743, 697 cm-1; 1H-NMR (300 MHz, DMSO-
d6, δ) 9.07 (s, 1H), 8.90 (s,
1H), 8.22 (s, 1H), 8.17-8.13 (m, 3H), 7.70-7.64 (m, 2H); 13CNMR (75 MHz, DMSO-
d6, δ)
160.7 (s), 160.4 (s), 149.7 (q, J=37 Hz), 134.6 (s), 131.8 (s), 128.7 (s), 127.7 (s), 119.8 (q,
J=269 Hz).
4.3. Biological activity assays