Russian Journal of Organic Chemistry, Vol. 38, No. 9, 2002, pp. 1380 1381. Translated from Zhurnal Organicheskoi Khimii, Vol. 38, No. 9, 2002,
pp. 1431 1432.
Original Russian Text Copyright
2002 by Skuratova, Fedotova, Kharchenko.
SHORT
COMMUNICATIONS
Synthesis of Triketones from Meldrum’s Acid
M. I. Skuratova, O. V. Fedotova, and V. G. Kharchenko
Chernyshevskii Saratov State Universitety, Astrakhanskaya 83, Saratov, 410026 Russia
Received July 10, 2001
We were the first to synthesize triketones having
a Meldrum’s acid (2,2-dimethyl-1,3-dioxane-4,6-di-
one) fragment. Meldrum’s acid, like barbituric acid
and its analogs, exhibits a depressant effect on the
central nervous system and possesses a low toxicity
[1]. This makes it promising to search for new
pharmacologically active substances in the series of
5-substituted 2,2-dimethyl-1,3-dioxane-4,6-diones.
Triketones IIIa and IIIb were synthesized by
Michael addition of Meldrum’s acid (I) to , -un-
saturated ketones IIa and IIb, respectively, in basic
medium (Scheme 1). Meldrum’s acid is a CH acid
capable of forming the corresponding sodium salt.
The latter was generated in situ and was treated with
chalcone II. 5-Benzylidene-2,2-dimethyl-1,3-dioxane-
4,6-dione (IV) reacted with cyclohexanone to afford
unsymmetrical bicyclic oxo-1,5-diketone V which
exists in equilibrium with enol form VI (Scheme 1).
Functionalization of tricarbonyl compounds via intro-
duction of a Meldrum’s acid moiety considerably
extends their synthetic potential, thus stimulating
development of the chemistry of such specific oxo-
1,5-diketones.
5-(1,3-Diphenyl-3-oxopropyl)-2,2-dimethyl-1,3-
dioxane-4,6-dione (IIIa). To a solution of 1.44 g of
Meldrum’s acid [2] in 20 ml of anhydrous methanol
we added with stirring a solution of 0.7 g of sodium
in 10 ml of anhydrous methanol and, after 10 min,
a solution of 2.08 g of chalcone IIa in 20 ml of
anhydrous methanol. The mixture was stirred for
5 6 h at room temperature, 3 ml of concentrated
hydrochloric acid was added, and the precipitate of
NaCl was filtered off. The filtrate was diluted with
water and extracted with chloroform. The extract was
dried over magnesium sulfate and evaporated, and
the oily residue was ground with hexane. Yield 0.3 g
1
(41%), mp 97 98 C. IR spectrum, , cm : 1774,
1738, 1690 (C O). 1H NMR spectrum, , ppm: 1.34 s
(3H, CH3), 1.67 s (3H, CH3), 3.69 3.8 m (2H, CH2),
4.28 4.4 m (1H, PhCH), 4.52 4.76 m (1H, CH),
7.43 8.17 m (10H, Harom). Found, %: C 72.03;
H 5.95. C21H20O5. Calculated, %: C 71.59; H 5.68.
Scheme 1.
R = Ph (a), C6H4OCH3-4 (b).
1070-4280/02/3809-1380$27.00 2002 MAIK Nauka/Interperiodica
Skuratova
