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ISSN 1070-4280, Russian Journal of Organic Chemistry, 2018, Vol. 54, No. 8, pp. 1166–1172. © Pleiades Publishing, Ltd., 2018.
Original Russian Text © A.R. Makhmutov, 2018, published in Zhurnal Organicheskoi Khimii, 2018, Vol. 54, No. 8, pp. 1156–1161.
One-Pot Oxidative Synthesis of Substituted Quinolines from
Alcohols and Arylamines Catalyzed by
Fe(CrO2)2 in Water Medium
A. R. Makhmutova*
a Bashkir State University, ul. Z. Validi 32, Ufa, Bashkortostan, 450076 Russia
*e-mail: ainurmax@mail.ru
Received November 22, 2017
Abstract—One-pot tandem synthesis was developed for substituted quinolines (in up to 97% yields) involving
a selective catalytic oxidation of primary amines to aldehydes and their condensation with arylamines under the
action of a dispersion of Fe(CrO2)2 and water solution of H2O2 at room temperature. The stage of catalytic
oxidation of alcohols was accelerated by photoactivation. A presumable mechanism of the photoactivated
tandem synthesis of 2-methylquinoline was suggested. Catalyst Fe(CrO2)2 was prepared by photochemical
synthesis.
DOI: 10.1134/S1070428018080080
Development of processes based on the catalytic
oxidation of alcohols into the corresponding aldehydes
or ketones followed by their use in the subsequent
synthesis of diverse classes of organic substances
attracts especial scientific and practical interest.
Application of alcohols as reagents is due to their
availability and stability. These processes as a rule
belong to tandem syntheses involving two or more
reactions with new bonds formation proceeding in a
one-pot mode under the same conditions without
additional charging of some reagents or catalysts and,
consequently, without isolation of intermediate
products. Therewith the subsequent reaction is caused
by the formation of an active intermediate in the
previous stage. Tandem approach was successfully
implemented in the synthesis of esters [1], amides [2],
alkenes [3], heterocycles [4], substrates with an
activated С–Н bond [5], and acetals [6]. Catalytic
systems in tandem syntheses bear two main functions.
The first function consists in the oxidation of the
alcohol to the corresponding oxo compound (mainly
owing to the hydrogen atoms transfer to acceptor
compounds). The second function consists in the
catalytic synthesis of target products by the
condensation of aldehydes or ketones with diverse
organic substrates. The most detailed descriptions
concern catalytic systems based on complex
compounds of ruthenium Ru(PPh3)3(CO)(H)2 [7] and
[Ru(p-cymene)Cl2]2 [8]. Crotononitrile is commonly
used as hydrogen acceptor. The existence of anhydrous
and anaerobic environment in the tandem syntheses
involving ruthenium catalyst is essential.
The tandem syntheses are known to be utilized in
the preparation of practically important nitrogen
heterocycles. For example, 2,3-dialkylindoles were
obtained by catalytic reaction of aniline with vicinal
diols in the presence of iridium and ruthenium
complexes at 170°С within 24 h [9]. A synthesis is
described of substituted quinolines from alcohols and
arylamines in CCl4 [10]. The reaction proceeds in a
pressure reactor at 140°С at fractional charging of the
reagents in the course of 4 h. Effective catalytic
activity was found in iron containing compounds.
Iron compounds are capable to act as mediators in
redox processes due to the existence of variable
valence: Fe3+ + е– ↔ Fe2+ [11]. As a rule compounds
of Fe(III) are oxidants for organic substances [12].
Oxidative qualities of Fe3+ ions are fairly well
activated both thermally and under UV irradiation. For
instance, the photooxidation of primary aliphatic
alcohols activated by FeCl3 is described. The reaction
comes to an end complete reduction of Fe3+ ions. The
composition of photooxidation products obtained from
alcohols depends on the conditions of the process (рН
of the medium, presence of water in the system, etc.).
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