Russian Chemical Bulletin, International Edition, Vol. 50, No. 9, pp. 16631667, September, 2001 1663
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Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 15851589, September, 2001.
Transformations of 1-amino-2-(3-hydroxyalk-1-ynyl)-9,10-anthraquinones
in the presence of amines
I. I. Barabanov, L. G. Fedenok, N. E. Polyakov, and M. S. Shvartsberg
Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences,
3 ul. Institutskaya, 630090 Novosibirsk, Russian Federation.
Fax: +7 (383 2) 34 2350. E-mail: email@example.com
When heated in piperidine, 1-amino-2-(3-hydroxyalk-1-ynyl)-9,10-anthraquinones un-
dergo cyclization into 2-(1-hydroxyalkyl)naphtho[2,3-g]indole-6,11-diones. In contrast,
1-amino-2-(3-hydroxy-3-phenylpropynyl)-9,10-anthraquinone reacts with primary and sec-
ondary amines to give the corresponding 1-amino-2-(1-amino-2-benzoylvinyl)-9,10-an-
thraquinones, which undergo cyclization into 4-dialkylamino- or 4-alkylamino-2-phenyl-
naphtho[2,3-h]quinoline-7,12-diones. Heating of the starting phenylpropynol with Et
causes its dehydrogenation and isomerization.
Key words: 1-amino-2-(3-hydroxyalk-1-ynyl)-9,10-anthraquinones, addition of amines,
dehydrogenation, isomerization, cyclization, 2-(1-hydroxyalkyl)naphtho[2,3-g]indole-6,11-
Fused quinoid heterocycles are interesting as sub-
stances with potential biological activity.
approach to their synthesis is based on the use of
alkynyl derivatives of simple quinones (anthra-, naphtho-,
and benzoquinones) as key intermediates.
it was shown that the addition of amines to
alkynylquinones containing a functional group vicinal
to the alkynyl substituent changes the geometry of the
unsaturated fragment and, in most cases, allows easy
cyclization of the adducts obtained. Depending on the
structure and/or the reaction conditions, the resulting
heterocycle can either lose or retain the amino group.
We have developed methods for the synthesis of
naphthoquinoline- and naphthoindolediones from amino
adducts of different vicinal oxo-, alkoxycarbonyl-,
alkyl-, and arylacetylenic derivatives of aminoanthra-
In the present work, the possibility and specific
features of the formation of adducts and the hetero-
cyclization of 1-amino-2-(3-hydroxyalk-1-ynyl)-9,10-
anthraquinones (13) in their reactions with amines
Results and Discussion
It was found that, when heated in piperidine at
80106 °C, 1-amino-2-(3-hydroxyprop-1-ynyl)- (1) and
(2) undergo intramolecular cyclization into 2-(1-hydroxy-
alkyl)naphtho[2,3-g]indole-6,11-diones (4, 5) in 58 and
77% yields, respectively (Scheme 1).
Closure of the pyrrole ring in the heterocyclization
of alcohols 1 and 2 under these conditions is hardly
possible without prior addition of the amine to the triple
bond. At the same time, no intermediates were detected
chromatographically during the cyclization. This sug-
gests that the multistep reaction includes the addition of
the amine to compounds 1 and 2, cyclization proper of
the adduct, and elimination of the amine, the formation
of the adduct being the rate-limiting step.
Unlike alcohols 1 and 2, phenyl analog 3 reacts with
piperidine, as well as with diethylamine and butylamine,
at 4080 °C in dioxane or without a solvent to give
aminovinyl ketones 6ac rather than expected substi-
tuted aminoallyl alcohols.
Such an unusual outcome of the reaction of com-
pound 3 with amines prompted us to search for addi-
tional confirmation of the structures of adducts 6ac.
The cyclization of amino ketones 6ac in the presence
of small amounts of H
in benzene at 20 °C gave
7,12-diones (7ac). In addition, heating of alcohol 3 in
morpholine at 120 °C for 1 h yielded naphthoquinoline-
dione 7d. Adducts 6ac and cyclization products 7ac
and 7d were compared with authentic compounds syn-
thraquinone (8). The substances obtained by two inde-
pendent methods were identical, which unambiguously
proves the correctness of structures 6ac for the ad-
ducts of amines to alcohol 3.
While studying the way in which alcohol 3 is trans-
formed into amino ketones 6, we found that heating of
3 in Et
N (8 h, 80 °C) unlike secondary and primary
amines, it cannot add to the triple bondaffords two
products, namely, 1-amino-2-benzoylethynyl- (8) and
in virtually quantitative yield in the ratio 1 : 1 (Scheme 2).