Transformation of the adducts of acyl isothiocyanates with (cyanomethylene)triphenylphosphorane into 1,2,4-triazole derivatives

Full text of DOI:10.1023/A:1013146914057

Russian Journal of General Chemistry, Vol. 71, No. 7, 2001, pp. 1157 1158. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 7, 2001,
pp. 1227 1228.
Original Russian Text Copyright
2001 by Bezverkhnii, Smolii, Drach.
LETTERS
TO THE EDITOR
Transformation of the Adducts of Acyl Isothiocyanates
with (Cyanomethylene)triphenylphosphorane
into 1,2,4-Triazole Derivatives
V. D. Bezverkhnii, O. B. Smolii, and B. S. Drach
Institute of Bioorganic and Petroleum Chemistry,
National Academy of Sciences of the Ukraine, Kiev, Ukraine
Received September 12, 2000
Addition of easily available yilide I to acyl iso-
thiocyanates gives compounds II which were recently
used in the synthesis of phosphorus-containing pyri-
midine derivatives [1]. As shown in the scheme, we
have now succeeded in using reagents II for preparing
two new types of substituted 1,2,4-triazoles.
R = CH3 (a), 4-CH3C6H5 (b).
Methylation of compounds II leads to a mixture of
geometric isomers of substituted vinylphosphonic
salts III, but this has almost no effect on the subse-
[Cyano(5-methyl-1,2,4-triazol-3-yl)methylene]-
triphenylphosphorane (IV). To
a solution of
0.01 mol of compound II in 150 ml of methanol,
0.01 mol of methyl iodide was added. The mixture
was left to stand at 20 25 C for 12 h, and the me-
thanol was removed in vacuo. The residue was dis-
solved in 50 ml of acetonitrile, 0.03 mol of hydrazine
hydrate was added, and the mixture was refluxed for
5 h. The precipitate that formed was filtered off and
recrystallized from ethanol. Yield 60%. mp 261
quent cyclocondensation III
IV. The resulting
1,2,4-triazole ring formation is akin to the well-known
cyclization of amidrazones under the action of acylat-
ing agents [2]. That compounds IV contain an ylide
fragment is beyond question, since they readily enter
the Wittig reaction with aromatic aldehydes. Stereo-
chemical peculiarities of the transformations I
III
and IV V, as well as the implications of prototropy
for new 1,2,4-triazole derivatives IV and V will be
1
262 C. H NMR spectrum, , ppm: 1.92 br.s (3H,
discussed in more detail elsewhere.
CH3), 7.60 7.70 m (15H, 3C6H5), 12.55 br. s (1H,
1070-3632/01/7107-1157$25.00 2001 MAIK Nauka/Interperiodica

1158
BEZVERKHNII et al.
NH). Found, %: C 72.33; H 5.13; P 8.13. C23H19N4P.
Calculated, %: C 72.24; H 5.01; P 8.10.
C13H12N4O. Calculated, %: C 64.99; H 5.03; N 23.32.
3-[Cyano(p-methoxybenzylidene)methyl]-5-p-
tolyl-1,2,4-triazole (Vb) was prepared in a similar
way from compound IVb. Yield 65%. mp 231 233 C.
1H NMR spectrum, , ppm: 2.39 s (3H, CH3), 3.86 s
(3H, CH3O), 7.15 d (2Harom), 7.39 d (2Harom),
7.94 d.d (4Harom), 8.22 s (1H, CH=CCN), 14.5 br.s
(1H, NH). Found, %: C 72.08; H 5.05; N 17.65.
C19H16N4O. Calculated, %: C 72.14; H 5.10; N 17.71.
[Cyano(5-p-tolyl-1,2,4-triazol-3-yl)methylene]-
triphenylphosphorane (IVb) was prepared in a
similar way from compound IIb. Yield 87%. mp 246
1
248 C. IR spectrum, , cm : 2200 (C N), 3400 (NH).
1H NMR spectrum, , ppm: 2.45 s (3H, CH3), 7.08 d
(2Harom), 7.47 d (2Harom), 7.61 7.75 m (15H, 3C6H5),
13.06 br.s (1H, NH). Found, %: C 75.85; H 5.12;
P 6.80. C29H23N4P. Calculated, %: C 75.97; H 5.06;
P 6.76.
The IR spectra were obtained on a UR-20 spectro-
1
meter in KBr pellets. The H NMR spectra of com-
pounds IV and V were recorded on a Bruker-WP
(200 MHz) instrument in DMSO-d6 solutions with
TMS as internal reference.
3-[Cyano(p-methoxybenzylidene)methyl]-5-
methyl-1,2,4-triazole (Va).
A
suspension of
0.001 mol of compound IVa and 0.001 mol of
p-methoxybenzaldehyde in 10 ml of ethanol was ref-
luxed for 72 h. The precipitate that formed was fil-
tered off and purified by recrystallization from ethanol.
REFERENCES
1
1. Smolii, O.B., Panchishin, S.Ya., and Drach, B.S., Zh.
Obshch. Khim., 1993, vol. 63, no. 9, pp. 1990 1994.
Yield 45%. mp 188 190 C. IR spectrum, , cm :
1
2220 (C N), 3420 (NH). H NMR spectrum, , ppm:
2.41 s (3H, CH3), 3.85 s (3H, CH3O), 7.13 d (2Harom),
8.00 d (2Harom), 8.11 s (1H, CH=CCN), 13.87 br.s
(1H, NH). Found, %: C 64.80; H 5.12; N 23.40.
2. Nelson, D.G., Roger, R., Heatlie, J.W.M., and New-
lands, L.R., Chem. Rev., 1970, vol. 70, no. 1, pp. 151
170.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 7 2001