Tritylation of tetrazole and 5-substituted tetrazoles with triphenylmethanol

Full text of DOI:10.1023/A:1013849329273

Russian Journal of Organic Chemistry, Vol. 37, No. 11, 2001, pp. 1670 1671. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 11, 2001,
pp. 1740 1741.
Original Russian Text Copyright
2001 by Grigor’ev, Gaponik, Koldobskii.
SHORT
COMMUNICATIONS
Tritylation of Tetrazole and 5-Substituted Tetrazoles
with Triphenylmethanol
1
1
2
Yu. V. Grigor’ev , P. N. Gaponik , and G. I. Koldobskii
1
Research Institute of Physicochemical Problems, Belorussian State University, Minsk, Belarus
2
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 198013 Russia
e-mail: koldobsk@tu.spb.ru
Received May 30, 2001
In the recent years, protection of N H bonds in
nitrogen-containing heterocycles by introduction of
a triphenylmethyl (trityl) group has received increas-
ing application. For this purpose, chlorotriphenyl-
methane or its functional derivatives are generally
used, and the reaction is carried out in anhydrous
solvents and in an inert atmosphere or, as recently
proposed [1], under conditions of phase-transfer
catalysis.
tetrazoles appears in a weaker field than the respective
signal of the 2-substituted isomer [3]. Analysis of the
IR spectra of the isomer mixture and the major isomer
(which was isolated in the pure state) also indicates
2
that the tritylation of tetrazole occurs mainly at N .
The structure of 2-trityl-5-methyl- and 2-trityl-5-
phenyltetrazoles Ic and Id was confirmed by com-
paring their properties with those reported in [4, 5].
1- and 2-Trityltetrazoles Ia and Ib. A mixture of
In continuation of our studies on alkylation of
N-unsubstituted tetrazoles with alcohols [2] we now
demonstrate the possibility of using triphenylmethanol
as a more accessible and cheaper tritylating agent for
tetrazole, 5-methyltetrazole, and 5-phenyltetrazole.
3
.5 g (0.05 mol) of tetrazole, 13.8 g (0.053 mol) of
triphenylmethanol, and 2 drops of concentrated sul-
furic acid in 50 ml of benzene was refluxed for 3 h
with simultaneous distillation of water benzene azeo-
trope. The mixture was cooled, and the precipitate was
filtered off, thoroughly washed with ether and water,
and dried under reduced pressure at 80 C. We isolated
2
The reaction smoothly proceeds in benzene or CH Cl2
in the presence of an acid and with simultaneous
removal of water as an azeotropic mixture with the
corresponding solvent. From unsubstituted tetrazole,
a mixture of two regioisomeric trityl derivatives Ia
and Ib is formed. 5-Methyltetrazole and 5-phenyl-
tetrazole are converted into the corresponding 2-trityl-
tetrazoles Ic and Id. The ratio of isomers Ia and Ib
1
2 g of a colorless amorphous powder with mp 204
205 C (decomp.), which was a mixture of tetrazoles
Ia and Ib at a ratio of 1 : 6. From the filtrate,
an additional amount of isomer mixture Ia/Ib ( 1:1),
1 g, was isolated; mp 199 203 C. Overall yield
86%. IR spectrum, , cm : 638, 679, 702, 751, 767,
852, 866, 904, 967, 1000, 1022, 1034, 1095, 1130,
1170, 1188, 1263, 1323, 1374, 1444, 1491, 1595,
1
1
was estimated at 1:6 by H NMR spectroscopy,
taking into account that the 5-H signal of 1-substituted
R = Me, (c) Ph (d).
070-4280/01/3711-1670$25.00 2001 MAIK Nauka/Interperiodica
1

TRITYLATION OF TETRAZOLE AND 5-SUBSTITUTED TETRAZOLES
1671
1
1
3
7
030, 3063, 3156. H NMR spectrum, , ppm: 6.93
pelleted with KBr. The H NMR spectra were ob-
tained from solutions in CD Cl using a Tesla BS-
.48 m (15H, Harom), 8.48 s (0.85H, 5-H), 8.59 s
2
2
(0.15H, 5-H).
567A instrument (100 MHz).
2-Trityltetrazole. mp 206 207 C (from toluene);
published data [6]: mp 217 219 C. The IR spectrum
was identical to that given above. H NMR spectrum,
REFERENCES
1
,
ppm: 6.93 7.48 m (15H, Harom), 8.48 s (1H, 5-H).
Tetrazoles Ic and Id were synthesized in a similar
1.
Artamonova, T.V., Nordlander, E., and Koldob-
skii, G.I., Russ. J. Org. Chem., 2000, vol. 36, no. 5,
pp. 740 742.
way.
5
-Methyl-2-trityltetrazole (Ic). Yield 76%,
2. Gaponik, P.N., Khimicheskie problemy sozdaniya
novykh materialov i tekhnologii (Chemical Problems
in the Development of New Materials and Techno-
logies), Sviridov, V.V., Ed., Minsk: Belorus. Gos.
Univ., 1998, pp. 185 214.
mp 178 181 C (from toluene) [4]. IR spectrum, ,
1
cm : 639, 669, 698, 750, 764, 889, 903, 929, 1002,
1
1
025, 1085, 1155, 1184, 1285, 1323, 1356, 1386,
445, 1494, 1508, 1595, 3045, 3058. H NMR spec-
1
trum, , ppm: 2.52 s (3H, CH ), 6.98 7.42 m (15H,
Harom).
3. Konnecke, A., Behrendt, S., and Lippmann, E.,
3
J. Prakt. Chem., 1977, vol. 319, no. 3, pp. 408 418.
5
-Phenyl-2-trityltetrazole (Id). Yield 88%,
4. Huff, B.E., le Tourneau, M.E., Staszak, M.A., and
Ward, J.A., Tetrahedron Lett., 1996, vol. 37, no. 21,
pp. 3655 3658.
mp 157 159 C (from toluene) [5]. IR spectrum, ,
1
cm : 635, 673, 698, 730, 748, 764, 788, 876, 906,
9
1
24, 999, 1026, 1072, 1155, 1189, 1279, 1325, 1371,
449, 1467, 1492, 1528, 1597, 3047, 3061. H NMR
5. PCT Int. Appl. WO 9526188, 1995; Chem. Abstr.,
1
1996, vol. 124, no. 76527b.
spectrum, , ppm: 7.03 8.20 m (Harom).
The IR spectra were measured on a Perkin Elmer
Spectrum 1000 Fourier spectrometer from samples
6.
Bodanszky, M., Bodanszky, A., Casaretto, M., and
Zahn, H., Int. J. Peptide Protein Res., 1985, vol. 26,
pp. 550 556.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001