Chemistry of Heterocyclic Compounds, Vol. 48, No. 8, November, 2012 (Russian Original Vol. 48, No. 8, August, 2012)
A NOVEL METHOD FOR THE SYNTHESIS OF
1,8-DIHYDROPYRIDO[2,3,4-gh]PERIMIDIN-7(6H)-ONES
A. V. Aksenov1*, N. A. Aksenov1, A. B. Kumshaeva1,
A. N. Smirnov1, and S. N. Ovcharov1
Keywords: 1,8-dihydropyrido[2,3,4-gh]perimidin-7(6H)-ones, -nitrostyrene, perimidines, polyphosphoric
acid, 1,3,6-triazapyrenes, amination, peri-annelation.
Many organic luminphores and dyes are polynuclear aromatic and heteroaromatic compounds,
including pyrene and its heterocyclic analogs. Effective medicines, (e.g., the antitumor compound AG 311) and
luminescent intercalators have been discovered on the basis of 4,9-diazapyrenes [1-3].
At this time the majority of azapyrenes are unavailable. Primarily this is due to the absence of efficient
methods for the peri-annelation of heterocyclic rings. In this study, we propose a method for the peri-annelation
of an [ab]pyridine ring to perimidines, which is based on a previously unknown intramolecular variant of our
recently discovered acetamidation of aromatic compounds using nitroalkanes in polyphosphoric acid (PPA)
[4, 5].
We have shown that the reaction of the perimidines 1a-c with 1.05-fold molar excess of β-nitrostyrene
(2) in PPA for 5 h at 65-70ºC led to previously unknown 8-phenyl-1,8-dihydropyrido[2,3,4-gh]perimidin-
7(6H)-ones 6a-c in 76-84% yields.
The reaction mechanism probably includes formation from perimidines 1a-c and -nitrostyrene (2) of
the nitro compounds 3a-c, which take part in an intramolecular acetamidation of aromatic compounds (as noted
above) via formation of oximes 5a-c and a Beckmann rearrangement of the latter.
13
IR spectra were recorded on a Specord 75 IR instrument in KBr pellets. 1H and C NMR spectra were
recorded on a Bruker DRX-500 instrument (500 and 125 MHz, respectively) using DMSO-d6 with TMS as
internal standard. Elemental analysis was carried out on a KOVO CHN-1 CHN analyzer. Melting points were
determined on a PTP-M apparatus (Khimlaborpribor). Monitoring of the reaction course and the purity of the
synthesized compounds was carried out on Silufol UV-254 plates with EtOAc as eluent. Commercial PPA was
used with an 80% P2O5 content.
8-Phenyl-1,8-dihydropyrido[2,3,4-gh]perimidin-7(6H)-ones 6a-c (General Method). A mixture of
perimidine 1a-c (1.00 mmol) and -nitrostyrene (2) (0.157 g ,1.05 mmol) in 80% PPA (2-3 g) was heated for 5
h at 65-70ºCwith vigorous stirring. The reaction mixture was then poured into water (30 ml) and neutralized
with ammonia solution. The precipitate formed was filtered off and washed with water (350 ml) and EtOAc
(350 ml). The residue was a practically pure substance, which could be recrystallized from EtOAc if needed.
_______
*To whom correspondence should be addressed, e-mail: alexaks05@rambler.ru.
1North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russia.
_________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1361-1363, August, 2012.
Original article submitted March 20, 2012.
0009-3122/12/4808-1269©2012 Springer Science+Business Media New York
1269
Aksenov
