Cyclization of o-carboxyanilides of aroylacetic acids: A route to a novel class of heterocyclic enamino ketones [3]

Full text of DOI:10.1023/B:COHC.0000027902.24144.e0

Chemistry of Heterocyclic Compounds, Vol. 40, No. 2, 2004
CYCLIZATION OF o-CARBOXYANILIDES
OF AROYLACETIC ACIDS: A ROUTE TO A NOVEL
CLASS OF HETEROCYCLIC ENAMINO KETONES
E. S. Vostrov, N. N. Mokhnatkina, O. M. Popova, M. V. Andrakovskiy, and A. N. Maslivets
Keywords: 2-aroylmethylene-3,1-benzoxazin-4-ones, o-carboxyanilides of aroylacetic acids.
A convenient method for obtaining amides of aroylacetic acids is aroylacylation of amines [1] and
amides [2] by aroylketenes, generated in thermolysis of 6-aryl-2,2-dimethyl-4H-1,3-dioxin-4-ones. Use of
anthranilic acid as the amine is of interest because of the possibility of using the carboxyl functional group in
further conversions.
In thermolysis of 6-aryl-2,2-dimethyl-4H-1,3-dioxin-4-ones 1a,b in the presence of anthranilic acid, we
obtained o-carboxyanilides of aroyl acetic acids 2a,b, which undergo ring closure when treated with
dicyclohexylcarbodiimide to form E-2-aroylmethylene-2,4-dihydro-1H-3,1-benzoxazin-4-ones 3a,b.
O
O
O
O
O
Me
Me
Ar
O
Ar
1
a,b
N
H
COOH
NH2
∆
4
a,b
–
Me CO
2
O
COOH
O
H
N
Ar
(
C H N) C
6 11 2
N
O
O
–(C H NH) CO
H
6
11
2
.
.
.
Ar
O
2
a,b
3
a,b
1
6 4
–4 a Ar = Ph, b Ar = p-MeOC H
Based on spectral data, we can eliminate the structure of the isomeric 3-aroyl-1,2,3,4-
tetrahydroquinoline-2,4-diones 4a,b for the products of intramolecular cyclization, but the described reaction is a
preparative method for obtaining representatives of a novel class of heterocyclic enamino ketones.
o-Carboxyanilide of Benzoylacetic Acid (2a). A solution of dioxinone 1a (1.00 g, 4.9 mmol) and
anthranilic acid (0.67 g, 4.9 mmol) in m-xylene (2 ml) was boiled for 10-15 min and then cooled down, and the
-
1
precipitate was filtered out. Yield 1.10 g (79%); mp 177-178°C (ethanol). IR spectrum (vaseline oil), ν, cm :
_
_________________________________________________________________________________________
Perm State University, Perm 614990, Russia; e-mail: koh2@psu.ru. Translated from Khimiya
Geterotsiklicheskikh Soedinenii, No. 2, pp. 290-291, February, 2004. Original article submitted January 19,
004.
2
0
009-3122/04/4002-0249©2004 Plenum Publishing Corporation
249

1
3
160 broad (NH, COOH), 1698 (COOH), 1685 broad (CONH, COPh), 1540 ("amide II"). H NMR spectrum
(
400 MHz, DMSO-d ), δ, ppm: 4.31 (2H, s, CH ); 7.18-8.44 (9H, m, C H +C H ); 11.26 (1H, s, NH); 13.60 (1H,
6
2
6
4
6
5
br. s, COOH). Found, %: C 67.76; H 4.60; N 5.00. C H NO . Calculated, %: C 67.84; H 4.63; N 4.94.
1
6
13
4
o-Carboxyanilide of 4-Methoxybenzoylacetic Acid (2b). Synthesized analogously. Yield 1.07 g
-
1
(
1
3
70%); mp 175-176°C (ethanol). IR spectrum (vaseline oil), ν, cm : 3145 broad (NH, COOH), 1703 (COOH),
1
670 broad (CONH, COC H ), 1533 ("amide II"). H NMR spectrum (400 MHz, DMSO-d ), δ, ppm: form (A):
.86 (3H, s, MeO); 4.22 (2H, s, CH ); 7.05-8.44 (8H, m, 2C H ); 11.26 (1H, s, NH), 13.58 (1H, br. s, COOH).
6
4
6
2
6
4
Found, %: C 65.25; H 4.80; N 4.45. C H NO . Calculated, %: C 65.17; H 4.83; N 4.47.
1
7
15
5
E-2-Phenacylidene-2,4-dihydro-1H-3,1-benzoxazin-4-one (3a). A solution of anilide 2a (0.95 g,
3
.35 mmol) and dicyclohexylcarbodiimide (0.69 g, 3.35 mmol) in 1,2-dichloroethane (20 ml) was boiled for 1 h
and then cooled down, and the precipitate of dicyclohexylurea was filtered out. The mother liquor was
evaporated and the residue was crystallized from 2-propanol. Yield 0.89 g (100%); mp 141-142°C (2-propanol).
-
1
IR spectrum (vaseline oil), ν, cm : 3050 broad (NH in the intramolecular hydrogen bond); 1762 (C =O); 1634
(
4)
1
broad (COPh in the intramolecular hydrogen bond). H NMR spectrum (400 MHz, CDCl ), δ, ppm: 5.95 (1H, s,
3
CH); 7.37-8.15 (9H, m, C H + C H ); 14.26 (1H, s, NH). Found, %: C 72.39; H 4.15; N 5.30. C H NO .
6
5
6
4
16 11
3
Calculated, %; C 72.45; H 4.18; N 5.28.
E-2-(4-Methoxybenzoylmethylene)-2,4-dihydro-1H-3,1-benzoxazin-4-one
(3b).
Synthesized
-
1
analogously. Yield 0.99 g (100%); mp 164-165°C (2-propanol). IR spectrum (vaseline oil), ν, cm : 3040 broad
NH in the intramolecular hydrogen bond); 1750 (C =O), 1630 broad (COC H in the intramolecular hydrogen
(
(
4)
6
4
1
bond). H NMR spectrum (400 MHz, CDCl ), δ, ppm: 3.88 (3H, s, MeO); 5.88 (1H, s, CH); 6.95-8.13 (8H, m,
3
1
3
2
C H ); 14.27 (1H, s, NH). C NMR spectrum (100 MHz, CDCl ), δ, ppm: 55.48 (MeO); 83.93 (C =CH);
6
4
3
(2)
1
14.10 (C(4a)); 121.25-129.35 (ArH); 137.00 (C(8a)); 162.12 (C ); 162.56 (C ); 177.30 (COC H ). Found, %:
(4)
(2)
6
4
C 69.17; H 4.48; N 4.75. C H NO . Calculated, %: C 69.15; H 4.44; N 4.74.
1
7
13
4
The research was done with the financial support of the Russian Foundation for Basic Research (grants
Nos. 04-03-33024, 04-03-96033) and the Ministry of Education of the Russian Federation (grant A03-2.11-55);
the NMR spectra were taken at the Ural Regional NMR Spectroscopy Center (URAL-NMR) (Russian
Foundation for Basic Research grant No. 00-03-40139).
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