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A. Csampai et al. / Journal of Molecular Structure 616 (2002) 73–78
77
3.3. 5-Methyl-7-phenyl-2,5-
dihydro[1,2,3]triazolo[4,5-d ]pyridazine-4-ylidene)-
pyridin-2-yl-amine (3)
and N1 or N3, two overlapping signals), 328.3 (N1 or
N3, interchangeable assignments); MS: 332 (Mþ),
791 [2M þ I]þ.
To a solution of (5-Methyl-2-(40-nitrophenyl)-7-
phenyl-2,5-dihydro[1,2,3]triazolo[4,5-d ]pyridazine-
4-ylidene)-pyridin-2-yl-amine (4b) [1] (500 mg) in
abs DMF (40 ml) was added methanolic (4 M) sodium
methoxide solution (1.5 equiv, 0.3 ml) and the
mixture was heated at 100 8C for 24 h. The DMF
was evaporated and the residue was suspended in
water and acidified with 10% HCl, extracted with
CH2Cl2 the organic phase was dried and evaporated.
Column chromatography of the residue (silica CHCl3:
MeOH 100:2) yielded 263 mg (70%) of product, mp
3.5. 5-Methyl-7-phenyl-2,5-
dihydro[1,2,3]triazolo[4,5-d]pyridazin-4-one (5)
To a solution of 2-(40-nitrophenyl)-5-methyl-7-
phenyl-2,5-dihydro[1,2,3]triazolo[4,5-d ]pyridazin-4-
one [1] (500 mg) in 40 ml abs DMF was added
methanolic a solution (4 M) of sodium methoxide
(1.5 equiv. 0.5 ml) and the mixture was heated at
100 8C for 6 h. The solvent was removed, the residue
was suspended in water, acidified with 10% HCl,
filtered off and the solid was crystallized from
acetonitrile to give 227 mg (70%) of product, mp
1
260 8C. H NMR d(DMSO-d6): 4.18 (3H, s, 5-Me),
1
7.15 (1H, m, Jo ¼ 7 Hz; Jo ¼ 5 Hz; Jm ¼ 1 Hz; H-50-
pyridyl), 7.4 (1H, m, Jo ¼ 8 Hz; Jm ¼ 1 Hz; Jp ¼ Hz;
H-30-pyridyl), 7.55–7.6 (3H, m, H-300, 400, 500-Ph), 7.99
(1H, m, Jo ¼ 8 Hz; Jo ¼ 7 Hz; Jp ¼ 2 Hz; H-40-
pyridyl), 8.21 (1H, m, Jo ¼ 5 Hz; Jm ¼ 2 Hz; Jp ¼
1 Hz; H-60-pyridyl), 8.65(2H, m, H-20, 60-Ph), 14.6 (1H,
b, 5-NH); 13C NMR d(DMSO-d6): 43.3, 115.9, 121.7,
128.7, 129.1, 130.4, 137.7, 136.9, 138.7, 141.3,
142.0, 142.1, 150.3, 156.5; 15N NMR d(CDCl3):
186.1 (N10); 190.0 (Na); 191.1 (N5); 317.8 (N6); MS,
245–246 8C; H NMR d(DMSO-d6): 3.82 (3H, s, 5-
Me), 7.5–7.6 (3H, m, H-30, 40, 50-Ph), 8.3 (2H, m, H-
20, 60-Ph); 13C NMR d(DMSO-d6): 39.0, 127.5, 128.8,
130.0, 133.1, 133.8, 137.6, 140.7, 153.8; 15N NMR
d(CDCl3): 194.3 (N5); 324.3 (N6); MS, Mcalcd
227.0807, Mfound: 227.0808 ^ 5 ppm.
:
3.6. Alkylation of 5
To a mixture of a solution of 5 (300 mg) in abs
DMF (10 ml) and potassium carbonate (500 mg) was
added methyl iodide (1 ml). The reaction mixture was
stirred at room temperature for 1 h, filtered and
evaporated. The residue was submitted to column
chromatography (silica, CHCl3: MeOH 100:2) to
yield two products: 6 (with a higher Rf value) and 7
(lower Rf).
M
calcd: 303.1232, Mfound: 303.1233 ^ 5 ppm.
3.4. (10,2,5-Trimethyl-7-phenyl-2,5-
dihydro[1,2,3]triazolo[4,5-d ]pyridazine-4-ylidene)-
pyridinium-2-yl-amine iodide (4)
A mixture of 3 (300 mg), abs DMF (10 ml)
potassium carbonate (500 mg) and MeI (1 ml) was
stirred at room temperature for 1 h. The mixture was
then was filtered and the filtrate evaporated. The
residue was crystallized from acetonitrile to yield
colourless crystals: yield 410 mg (90%), mp 263–
264 8C. 1H NMR d(CDCl3–CD3OD 1:1): 4.12 (3H, s,
N-10-Me), 4.22 (3H, s, 5-Me), 4.49 (3H, s, 2-Me), 7.33
(1H, t, Jo ¼ 7 Hz; Jo ¼ 6:2 Hz; H-50), 7.45 (1H, d,
Jo ¼ 7:5 Hz), 7.54 (3H, m, H-300, 400, 500-Ph), 8.07 (1H,
t, Jo ¼ 7:5 Hz; Jo ¼ 7 Hz; H-40), 8.36 (2H, m, H-200,
600-Ph), 8.46 (1H, d, Jo ¼ 6:2 Hz; H-60); 13C NMR
d(DMSO-d6): 42.4, 43.2, 44. 2, 118.2, 120.1, 127.6,
129.2, 9, 132.2, 136.7, 139.9, 140.4, 142.8, 143.5,
147.3, 156.4; 15N NMR d(CDCl3–CD3OD 1:1): 180.1
(N10), 188.4 (N5), 202.0 (Na), 268.8 (N2), 325.3 (N6
3.7. 3,5-Dimethyl-7-phenyl-3,5-
dihydro[1,2,3]triazolo[4,5-d]pyridazin-4-one (6)
Yield: 170 mg (53%); mp 184–186 8C, 1H
NMR d(CDCl3): 3.96 (3H, s, 3-Me), 4.55 (3H, s,
5-Me), 7.58–7.64 (3H, m, H-30, 40, 50-Ph), 8.32
(2H, m, H-20, 60-Ph); 13C NMR d(CDCl3): 39.2,
43.6, 127.5, 128.7, 129.9, 133.1, 138.4, 139.7,
142.4, 155.5; no NOE effect between 5-Me and
the phenyl protons; HMBC: enhancement of the C-3a
absorption (128.7 ppm) when irradiating the 3-Me
proton at 4.57 ppm; 15N NMR d(CDCl3): 195.7 (N5),
231.0 (N1), 323.6 (N6), 383.8 (N2); MS: Mcalcd
241.0964, Mfound: 241.0954 ^ 5 ppm.
: