Russian Journal of Organic Chemistry, Vol. 38, No. 12, 2002, pp. 1817 1818. Translated from Zhurnal Organicheskoi Khimii, Vol. 38, No. 12, 2002,
pp. 1875 1876.
Original Russian Text Copyright
2002 by Pyrko.
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Transformation of 9-Aryl-3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8,9,10-
decahydroacridine-1,8-diones in Mineral Acids
A. N. Pyrko
Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus,
ul. Kuprevicha 5/2, Minsk, 220141 Belarus
Received January 18, 2002
It is known [1] that heating of 9-(4-dimethylamino-
phenyl)decahydroacridinedione Ia in acetic acid leads
to elimination of N,N-dimethylaniline molecule and
formation of octahydroacridinedione II (Scheme 1).
We made an attempt to involve other derivatives of
the same series in an analogous transformation. In
particular, as substrates we selected compounds Ib Ie
having various substituents in the para-position of
the benzene ring. However, 9-arylacridinediones Ib Ie
turned out to be stable, and they did not change on
heating in boiling acetic acid for 6 h. Elimination of
the 9-aryl group with formation of octahydroacridine-
dione II occurred when compounds Ib Ie were heated
in polyphosphoric (PPA), phosphoric, and sulfuric
acids. By condensation of volatile products formed in
the reaction of Id with phosphoric acid we isolated
phenol. These data indicate that the mechanism of
this reaction is analogous to that reported in [1].
Heating of 9-(p-nitrophenyl)decahydroacridinedione
Ie in PPA resulted in aromatization of the heteroring
with formation of 9-(p-nitrophenyl)octahydroacridine-
dione III (Scheme 1).
position. No elimination occurs when the para-posi-
tion of the 9-aryl group is occupied by an electron-
acceptor substituent. We failed to effect an analogous
transformation of 9-isobutyl-3,3,6,6-tetramethyl-1,2,-
3,4,5,6,7,8,9,10-decahydroacridine-1,8-dione under
similar conditions: the compound remained intact on
heating in phosphoric acid for 4 h at 155 C.
3,3,6,6-Tetramethyl-1,2,3,4,5,6,7,8-octahydro-
acridine-1,8-dione (II) (see table). A mixture of
1.5 mmol of compound Ib Id and 20 g of sulfuric,
phosphoric, or polyphosphoric acid was stirred under
conditions specified in table. The mixture was cooled
to room temperature and was then either poured into
200 ml of water (in the reactions with H3PO4 and
H2SO4) or carefully diluted with water (200 ml; in
the reactions with PPA). The mixture was left to stand
for 15 h and filtered, and the filtrate was neutralized
to pH 7 8 by adding solid sodium hydroxide. The
precipitate was filtered off, washed with water, dried
in air, and recrystallized from ethyl acetate hexane
(1:1). The product was identical to a sample prepared
by the procedure described in [2].
Thus heating of compounds Ia Ie in mineral acids
is accompanied by elimination of the 9-aryl substit-
uent if the latter contains a donor group in the para-
3,3,6,6-Tetramethyl-9-(p-nitrophenyl)-1,2,3,4,5,-
6,7,8-octahydroacridine-1,8-dione (III). A mixture
of 0.59 g (1.5 mmol) of compound Ie and 20 g of
Scheme 1.
X = NMe2 (a), H (b), OMe (c), OH (d), NO2 (e).
1070-4280/02/3812-1817$27.00 2002 MAIK Nauka/Interperiodica