X. Yu – H. Hartmann · Azolo[1,2,4]triazinium Salts
505
acid/propionic acid (25 mL) and phosphoric acid (5 mL) at
1-(1,3,4-Thiadiazol-2-ylazo)-naphthalen-2-ol (20a) from
0 ◦C, was added under vigorous stirring and cooling. Af- 2-naphthol and 1,3,4-thiadiazole-2-diazonium hydrogensul-
ter a few minutes, the mixture was diluted with a saturated fate in a yield of 1.78 g (70%); m. p. 194 – 199 ◦C. – 1H
aqueous sodium acetate solution until the azo compound NMR (500 MHz, [D6]DMSO): δ = 6.94 (d, J = 9.4 Hz, 1H),
formed a precipitate. The product was isolated by filtration, 7.53 (t, J = 7.6 Hz, 1H), 7.66 (t, J = 8.0 Hz, 1H), 7.81 (d, J =
washed repeatedly with water and dried in air. Finally, the 7.7 Hz, 1H), 8.06 (d, J = 9.5 Hz, 1H), 8.39 (d, J = 8.1 Hz,
products obtained were purified by recrystallization from 1H), 9.44 (s, 1H), 14.90 (s, 1H) ppm.
a toluene/acetic acid mixture.
The following 1-hetarylazonaphthalen-2-ols were pre- (20b) from 2-naphthol and 5-methyl-1,3,4-thiadiazole-2-
pared according to this procedure: diazonium hydrogensulfate in a yield of 1.54 g (69%); m. p.
1-(5-Methyl-1,3,4-thiadiazol-2-ylazo)-naphthalen-2-ol
1-(2-Benzthiazolylazo)-naphthalen-2-ol (12a) from 2- 192 – 194 ◦C (dec.). – 1H NMR (500 MHz, [D6]DMSO):
naphthol and benzthiazole-2-diazonium hydrogensulfate in δ = 2.76 (s, 3H), 7.07 (d, J = 9.2 Hz, 1H), 7.56 (t, J =
a yield of 2.05 g (67%); m. p. 173 – 174 ◦C. – 1H NMR 7.0 Hz, 1H), 7.69 (t, J = 6.9 Hz, 1H), 7.88 (d, J = 7.4 Hz,
(500 MHz, [D6]DMSO): δ = 6.82 (d, J = 9.6 Hz, 1H), 7.38 1H), 8.13 (d, J = 9.0 Hz, 1H), 8.39 (d, J = 8.0 Hz, 1H), 14.51
(t, J = 7.7 Hz, 1H), 7.48 (t, J = 7.5 Hz, 1H), 7.52 (t, J = (s, 1H) ppm.
7.5 Hz, 1H), 7.64 (t, J = 7.4 Hz, 1H), 7.76 (d, J = 7.7 Hz, 1
1-(1,2,4-Thiadiazol-5-ylazo)-naphthalen-2-ol (22a) from
H), 7.85 (d, J = 8.0 Hz, 1H), 8.00 (d, J = 9.6 Hz, 1H), 8.03 2-naphthol and 1,2,4-thiadiazole-5-diazonium hydrogensul-
(d, J = 7.8 Hz, 1H), 8.29 (d, J = 8.0 Hz, 1H), 15.44 (s, 1H) fate in a yield of 1.56 g (61%); m. p. 145 – 150 ◦C. – 1H
ppm.
NMR (500 MHz, [D6]DMSO): δ = 6.50 (d, J = 9.8 Hz,
1-(6-Methyl-2-benzthiazolylazo)-naphthalen-2-ol (12b) 1 H), 7.39 – 7.42 (m, 1 H), 7.47 – 7.50 (m, 2 H), 7.74 (d,
from 2-naphthol and 6-methyl-benzthiazole-2-diazonium J = 9.8 Hz, 1 H), 8.14 – 8.16 (m, 1 H), 8.51 (s, 1 H) ppm.
hydrogensulfate in a yield of 1.63 g (51%); m. p. 194 ◦C.
1-(3-Methyl-1,2,4-thiadiazol-5-ylazo)-naphthalen-2-ol
1H NMR (500 MHz, [D6]DMSO): δ = 2.44 (s, 3H), (22b) from 2-naphthol and 3-methyl-1,2,4-thiadiazole-5-
–
6.91 (d, J = 9.5 Hz, 1H), 7.33 (d, J = 7.5 Hz, 1H), 7.55 diazonium hydrogensulfate in a yield of 1.26 g (47%); m. p.
(t, J = 7.2 Hz, 1H), 7.68 (t, J = 6.9 Hz, 1H), 7.77 – 7.82 159 – 161 ◦C. – 1H NMR (500 MHz, [D6]DMSO): δ = 2.49
(m, 2H), 7.85 (s, 1H), 8.06 (d, J = 9.5 Hz, 1H), 8.37 (d, (s, 3H), 6.61 (d, J = 9.7 Hz, 1H), 7.50 (t, J = 7.4 Hz, 1H),
J = 8.0 Hz, 1H), 15.32 (s, 1H) ppm.
7.58 (t, J = 7.1 Hz, 1H), 7.67 (d, J = 7.5 Hz, 1H), 7.91 (d,
1-(6-Methoxy-2-benzthiazolylazo)-naphthalen-2-ol (12c) J = 9.6 Hz, 1H), 8.20 (broad, 1H), 15.38 (s, 1H) ppm.
from 2-naphthol and 6-methoxy-benzthiazole-2-diazonium
hydrogensulfate in a yield of 2.41 g (72%); m. p. 235 ◦C. Preparation of 17, 19 and 21 (general procedure)
–
1H NMR (500 MHz, CDCl3): δ = 3.90 (s, 3H), 6.88 (d,
J = 13.9 Hz, 1H), 7.09 (dd, J = 8.9 Hz, J = 2.2 Hz, 1H), 7.29
Method A: To a solution of the appropriate 1-hetarylazo-
(d, J = 2.2 Hz, 1H), 7.47 (t, J = 7.5 Hz, 1H), 7.58 – 7.61 (m, substituted naphthalen-2-ol (0.01 mol) in DMF (25 mL)
2H), 7.77 (d, J = 9.4 Hz, 1H), 7.85 (d, J = 8.9 Hz, 1H), 8.47 POCl3 (2 mL) was added with cooling and the resulting mix-
(d, J = 8.0 Hz, 1H), 15.31 (s, 1H) ppm.
ture warmed at 90 ◦C for 3 h. After cooling to room temper-
1-(Thiazol-2-ylazo)-naphthalen-2-ol (18a) from 2- ature, the mixture was carefully poured in methanol (50 mL)
naphthol and thiazole-2-diazonium hydrogensulfate in containing perchloric acid (2 mL, 70%), and the precipitate
a yield of 2.02 g (79%); m. p. 131 – 133 ◦C. – 1H NMR was isolated by filtration with suction.
(500 MHz, [D6]DMSO): δ = 7.07 (d, J = 9.3 Hz, 1H),
Method B: To a solution of the appropriate 1-hetarylazo-
7.51 (dt, J = 8.0 Hz, J = 1.0 Hz, 1H), 7.67 (dt, J = 8.2 Hz, substituted naphthalen-2-ol (0.025 mol) in acetic acid
J = 1.1 Hz, 1H), 7.76 (d, J = 3.3 Hz, 1H), 7.86 (d, (25 mL) a strong acid (2 mL) was added and the resulting
J = 7.8 Hz, 1H), 7.91 (d, J = 3.3 Hz, 1H), 8.08 (d, mixture refluxed for 3 h. After cooling and addition of di-
J = 9.3 Hz, 1H), 8.41 (d, J = 8.3 Hz, 1H), 14.64 (s, 1H) ethyl ether the precipitate was isolated by filtration with suc-
ppm.
tion and recrystallized, after drying in air, from acetic acid.
1-(4-Phenyl-thiazol-2-ylazo)-naphthalen-2-ol (18b) from
The following azolo[1,2,4]triazinium salts were prepared
2-naphthol and 4-phenyl-thiazole-2-diazonium hydrogensul- according to this procedure:
fate in a yield of 1.36 g (41%); m. p. 203 ◦C. – 1H NMR
Benzo[4,5]thiazolo[2,3-c]naphtho[2,1-e][1,2,4]triazin-
(500 MHz, [D6]DMSO): δ = 7.10 (d, J = 9.3 Hz, 1H), 7.40 12-ium perchlorate (17a) from 1-(2-benzthiazolylazo)-
(t, J = 7.4 Hz, 1H), 7.49 (t, J = 7.5 Hz, 2 H), 7.56 (t, J = naphthalen-2-ol (12a) and perchloric acid as a yellow solid in
7.8 Hz, 1H), 7.71 (t, J = 8.1 Hz, 1H), 7.89 (d, J = 7.8 Hz, a yield of 2.0 g (53%) according to method A and in a yield
1H), 8.03 (d, J = 7.2 Hz, 2H), 8.15 (d, J = 9.3 Hz, 1 H), 8.18 of 0.81 g (83%) according to method B; m. p. 332 – 334 ◦C. –
(s, 1H), 8.47 (d, J = 8.2 Hz, 1H), 14.82 (s, 1H) ppm.
1H NMR (500 MHz, CF3COOH): δ = 8.08 – 8.11 (m, 2H),
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