Month 2014
A New Method of Dimroth Rearrangement in Fused Triazolo[1,5-d]-1,2,4-triazine
Scheme 3
(2.86 g), mp 104° (from benzene-light petroleum); uv spec-
trum λ max. 210 (4.44), 228 (4.30), 281 (4.12), 3.41
(3.57); max, 1730 cmÀ1 1H NMR (CDCI3) 8.29 (2H,d,
Scheme 4
;
Ar-H), 7.66–7.56 (3H, m, Ar-H), 4.50 (2H, q, CH2), 4.39
(2H, q, CH2) 3.17 (2H, s, CH2), 1.48 (3H, t, CH3) and
1.28 (2H, t, CH3);. 13C-NMR (CDCI3) ppm: 178.102,
173.045 (2C═O), 140.046 (1C), 138.214 (1C), 136.516
(1C), 131.120 (2C), 129.104, 128.712, 127.086, 60.610,
60.504, 15.416 [M+, 355]. Anal. Found: C, 57.5; H, 4.8;
N, 20.7%, Calcd. for C17H17N5O4; C, 57,5; H, 4.8;
N. 19.7%.
5,6-Diethoxycarbonyl-l-phenyl-1,2,3-triazolo[1,5-d][1,5-
c]-1,2,3-triazine (14).
A solution of the methylene
triazolotriazine (8) 1.40 g, (0.04 mole) in 200 mL of absolute
ethanol was stirred at 0° (ice-salt bath) and treated in one
portion with triethylamine 0.81 g, (0.08 mole) and then
dropwise with a solution of p-toluenesulphonyl azide 0.80 g;
(0.0 4 mole) in 20 mL of absolute ethanol. The mixture was
stirred for 2 h and filtered to give 0.50 g of the unreacted diester
(8); mp 90°, which was identical (mp and IR spectrum) with an
authentic sample.
EXPERIMENTAL
Melting points (uncorrected) of all analytical samples were
determined on a Kofler block. U.V. spectra were recorded for
ethanol solutions on a Pye-Unicam S.P. 800 spectrophotometer
using matched 1 cm3 quartz cells. The absorption maxima were
always given in nanometers: the figures in parenthesis are loga
values. Infrared spectra were obtained for Nujol suspensions on
a Perkin-Elmer 157G Infrared spectrophotomer. 1H and 13C
NMR spectra were measured at 200 MHz using a Varian instru-
ment. Chemical shifts are reported on the δ scale relative to
TMS as an internal standard. The letters s, d, t, q, and m are used
to indicate singlet, doublet, triplet, quartet, and multiplet, respec-
tively. Elemental analysis was performed on CHN-O rapid ana-
lyzer. The mass spectra were measured at 800 kv on an A.E.I.
M.S 902 instrument.
The ethanol filtrate was evaporated and the resulting oil was
triturated with ethanol-water to give the tricyclic diester (14) as
yellow needles (0.41 g), mp 171° (dimethylformamide-ethanol),
λ max 211 (4.44), 221 (4.40) and 281 (4.34), υ max 1740 cmÀ1
,
(CDCI3) 8.32 (2H, d, Ar-H), 7.44–7.52 (3H, m, Ar-H), 4.52 (4H,
q, 2CH2), and 1.44 (6H, t, 3CH3), 13C-NMR (CDCI3) ppm:
176.012, 172.102 (2C═O), 164.046 (1C), 138.214 (1C), 136.016
(1C), 134.502 (1C), 132.120 (2C), 129.104 (2C), 128.712 (1C),
127.086 (2C), 58.214, 58.014 (2CH2), 15.312, 15.106 (2CH3)
[M+, 381]. Anal. Found: C, 53.3; H, 4.0; N, 26.0%, Calcd. for
C17H17N5O4; C, 53.5; H, 3.9; N, 25.8%.
l-Phenyl-1,2,3,-triazolo[1,5,-d][1,5-c]-1,2,4-triazin-5,6-dicarboxylic
acid (15). A solution of the tricyclic diester (14) 0.38 g (0.01
mole), in 25 mL of ethanol, was heated under reflux with
aqueous solution of 2 mL of 2 M sodium carbonate for 3 h. The
mixture on evaporation left a residue, which was dissolved in
water and extracted with chloroform. Evaporation of the
chloroform extract gave oil, which in contact with methanol-
light petroleum, gave the diacid (15) as a pale pink solid 0.70 g,
mp 121° (from benzene), λ max 213 (94.43), 271 (4.40), 275
Ethyl 7-(2-ethoxy-2-oxoethyl)-3-phenyl-[1,2,3]triazole[5,1-
c][1,2,4]triazine-6-carboxylate (8).
Solutions of 4-phenyl-
1H-1,2,3-triazole-5-diazonium chloride 4.90 g (0.012 mole) (7),
in 60 mL of water and 60 mL of ethanol, diethyl-2-oxopropane-
1,3-dicarboxylate 4.90 g (0.012 mole), and sodium acetate 3.20 g
in 16 mL of water and 940 mL of ethanol, were mixed, cooled in
an ice salt-bath and stirred for 2 h. The ethanol was removed
under reduced pressure, and the aqueous mother liquor was
extracted with chloroform to give an oil in which on trituration
with ethanol yielded Ethyl 7-(2-ethoxy-2-oxoethyl)-3-phenyl-
[1,2,3]triazolo[5,1-c][1,2,4]triazine-6-carboxylate (8) 0.6 g, mp
174° (from ethanol), identical (m.p and IR spectrum) with an
authentic sample.
(4.44) and 284 (4.41);
υ max 3520, 1940, 1740, and
1725 cmÀ1; (CDCI3) 9.40 (2H, br, 2COOH), 8.40 (5H,s, Ar-H);
13C-NMR (CDCI3) ppm: 178.102, 174.302 (2C═O), 164.046
(1C), 138.214 (1C), 136.016 (1C), 134.502 (1C), 132.120 (2C),
129.104 (2C), 128.712 (1C), 127.086 (2C) [M+325]. Anal.
Found: C. 48.1; H, 2.3; N, 29.9%, Calcd. for C13H7O4 C, 48.0;
H, 2.2; N, 30.1%.
The ethanol mother liquor was heated under reflux for 10 min
and concentrated to give the triazolotriazine (8) as orange needles
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet