New method for the acetamination of perimidines

Full text of DOI:10.1007/s10593-010-0621-z

Chemistry of Heterocyclic Compounds, Vol. 46, No. 8, 2010
NEW METHOD FOR THE ACETAMINATION
OF PERIMIDINES
A. V. Aksenov1**, N. A. Aksenov1, O. N. Nadein1, and A. E. Tsys'1
Keywords: acetaminoperimidines, nitroethane, perimidines, polyphosphoric acid, acetamination.
In previous work, we have developed a number of methods for the synthesis of acetaminoperimidines
3a-c from perimidines 1a-c. The first method involved consecutive acylation and the Schmidt reaction, while the
second involved amination by sodium azide in PPA with subsequent acylation [1, 2]. In the present work, we
report a one-step method for the synthesis of these compounds using a new reagent system containing
nitroethane and PPA. Heating perimidines 1a-c (1 mmol) and nitroethane (0.08 g, 1.07 mmol) in PPA* (2-3 g)
at 95-105°C for 3 h with monitoring by thin-layer chromatography gave 6(7)-acetaminoperimidines 3a-c in
68-74% yield.
R
R
R
N
NH
O
N
NH
N
NH
EtNO2
PPA
PPA
HN
1a–c
N
Me
HO
Me
2a–c
1–3 a R = H, b R = Me, c R = Ph
3a–c
The reaction probably entails the intermediate formation of oximes 2a-c, which undergo the Beckmann
rearrangement to give amides 3a-c.
1
The H NMR spectra were taken on a Bruker WP-200 spectrometer at 200 MHz with TMS as the
internal standard. The reaction course and purity of the products were monitored by thin-layer chromatography
on Silufol UV-254 plates with 1:1 ethyl acetate–ethanol as the eluent.
The reaction mixture was treated with 50 ml water and brought to pH 8-9 by adding ammonium hydroxide.
The precipitate formed was filtered off. The mother liquor was extracted with three 50-ml portions of hot benzene.
The solvent was evaporated off and the residue was combined with the precipitate. The product was purified by
recrystallization. The 1H NMR spectra of 3a-c were similar to those given in our previous work [1].
_______
* The PPA sample used contained 86% P2O5 and was prepared according to Uhlig [3].
** To whom correspondence should be addressed, e-mail: k-biochem-org@stavsu.ru.
1Stavropol State University, Stavropol 355009, Russia.
__________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1265-1266, August, 2010.
Original article submitted June 3, 2010.
0009-3122/10/4608-1025©2010 Springer Science+Business Media, Inc.
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6(7)-Acetaminoperimidine (3a) was obtained in 68% yield; mp 225-226°C (ethyl acetate)
(mp 225-226°C [1]).
6(7)-Acetamino-2-methylperimidine (3b) was obtained in 44% yield (0.091 g); mp 247-248°C (ethyl
acetate) (mp 247-248°C [1]).
6(7)-Acetamino-2-phenylperimidine (3c) was obtained in 48% yield (0.106 g); mp 302-303°C (ethyl
acetate) (mp 302-303°C [1]).
REFERENCES
1.
2.
3.
A. V. Aksenov, A. S. Lyakhovnenko, N. Ts. Karaivanov, and I. I. Levina, Khim. Geterotsikl. Soedin.,
591 (2010). [Chem. Heterocycl. Comp., 46, 468 (2010)].
A. V. Aksenov, A. S. Lyakhovnenko, A. V. Andrienko, and I. I. Levina, Tetrahedron Lett., 51, 2406
(2010).
F. Uhlig, Angew. Chem., 66, 435 (1954).
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