Chemistry of acyl(imidoyl)ketenes: IX. Synthesis and thermolysis of 3-aroyl-8-chloro-1,2-dihydro-4H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones

Article abstract of DOI:10.1007/s11178-005-0321-9

Reactions of 3-Z-aroylmethylene-6-chloro-3,4-dihydro-2H-1,4-benzoxazine-2- ones with oxalyl chloride afford 3-aroyl-8-chloro-1,2-dihydro-4H-pyrrolo[2,1-c] [1,4]benzoxazine-1,2,4-triones and Z-3-(2-aryl-2-chlorovinyl)-6-chloro-2H-1,4- benzoxazine-2-ones. A

Full text of DOI:10.1007/s11178-005-0321-9

Russian Journal of Organic Chemistry, Vol. 41, No. 8, 2005, pp. 1222−1227. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 8, 2005,
pp. 1245−1250.
Original Russian Text Copyright © 2005 by Semenova, Krasnykh.
Chemistry ofAcyl(imidoyl)ketenes: IX.* Synthesis
and Thermolysis of 3-Aroyl-8-chloro-1,2-dihydro-4H-
pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones
T.D. Semenova2 and O.P. Krasnykh1
1Research and Education Center of Perm State Pharmaceutical Academy, Perm, 614990 Russia
e-mail: olkrasnykh@permonline.ru
2Perm State University, Perm, Russia
Received September14, 2004
Abstract—Reactions of 3-Z-aroylmethylene-6-chloro-3,4-dihydro-2H-1,4-benzoxazine-2-ones with oxalyl
chloride afford 3-aroyl-8-chloro-1,2-dihydro-4H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones and
Z-3-(2-aryl-2-chlorovinyl)-6-chloro-2H-1,4-benzoxazine-2-ones. Aroyl(imidoyl)ketenes generated by
decarbonylation of pyrrolobenzoxazinetriones undergo dimerization through [4+2]-cycloaddition to form
4-aroyl-3-aroyloxy-2-(2-oxo-2H-1,4-benzoxazin-3-yl)-1H,5H-pyrido[2,1-c][1,4]benzoxazine-1,5-diones.
The evolution of chemistry of acyl(imidoyl)ketenes is
hampered by insufficient development of convenient
methods for generation thereof from available initial
compounds (unlike the chemistry of monosubstituted
analogs, acyl ketenes and imidoyl ketenes) [2–5]. One
of the simplest and the most available procedure for
generating acyl(imidoyl)ketenes is thermal decarbonyla-
tion of 4-acyl-2,3(1H)-purrolediones. The main advantage
of this method is the possibility of wide variation of
substituents in initial pyrrolediones and consequently of
generating versatile acyl(imidoyl)ketenes.
the features of these reactions compared to those of
unsubstituted analogs.
The reaction of methyl 4-aryl-2-hydroxy-4-oxo-2-
butenoates Ia–Id with 2-amino-4-chlorophenol and 2-
aminophenol afforded 3-aroylmethylene-3,4-dihydro-2H-
1,4-benzoxazin-2-ones IIa–IIf (Scheme 1). The physico-
chemical characteristics of compounds IIa–IIf are
consistent with the published data on compounds of this
class and evidence their existence as Z-isomers stabilized
by an intramolecular hydrogen bond [9, 11–13].
The reaction of Z-3-aroylmethylene-3,4-dihydro-2H-
1,4-benzoxazin-2-ones IIa, IIb, IIe, and IIf with oxalyl
chloride in chloroform or dichloroethane solution furnished
substituted 3-aroyl-1,2-dihydro-4H-pyrrolo[2,1-c][1,4]-
benzoxazine-1,2,4-triones IIIa, IIIb, IIIe, and IIIf.
The thermolysis of 4-aroyl-2,3(1H)-pyrrolediones
fused by the [a] side to 1,4-benzoxazin-2-ones results in
generating aroyl(imidoyl)ketenes whose imidoyl fragment
is a part of a heterocycle [6–8]. The synthesis of initial
3-aroyl-1,2-dihydro-4H-pyrrolo[2,1-C][1,4]benzoxazine-
1,2,4-triones is performed by diacylation with oxalyl
chloride of Z-3-aroylmethylene-3,4-dihydro-2H-1,4-
benzoxazin-2-ones [9]. At the introduction of an NO2
group into the position 6 of the initial 1,4-benzoxazin-2-
one the reaction with oxalyl chloride yields instead of the
expected 8-nitropyrrolobenzoxazinetrione the 6-nitro-Z-
3-(2-phenyl-2-chlorovinyl)-2H-1,4-benzoxazin-2-one [10].
Pyrrolobenzoxazinetriones IIIa, IIIb, IIIe, and IIIf
are dark-violet crystalline substances soluble in
dichloroethane, acetonitrile, insoluble in carbon
tetrachloride and alkanes. The physicochemical
characteristics of compound IIIe are in agreement with
the previously published [9], the characteristics of
pyrrolediones IIIa, IIIb, and IIIf are consistent with these
data. Only the shift by 20 cm–1 to higher frequencies of
the lactone carbonyl absorption band in the IR spectra of
compounds IIIa and IIIb should be noted as compared
with analogous pyrrolobenzoxazinetriones lacking
a chlorine atom in position 8 [9].
Our target was the synthesis of pyrrolobenzoxazine-
triones with a chlorine atom in position 8, their thermolysis
for generation of acyl(imidoyl)ketenes, and evaluation of
*For communication VIII, see [1].
1070-4280/05/4108-1222©2005 Pleiades Publishing, Inc.

CHEMISTRY OF ACYL(IMIDOYL)KETENES: IX.
1223
Scheme 1.
R
COOCH3
O
O
OH
+
O
OH
H
R
R'
N
H
R'
NH2
O
_
_
Iа Id
IIа IIе
(COCl)2
O
N
O
O
O
O
N
O
OH
H2O
H
R
COR
O
COR
+
R'
R'
N
R'
Cl
Vc, Vd
OH
O
_
O
_
IVа, IVc IVf
IIIа IIIе
R' = Cl, R = C6H5 (a), p-ClC6H4 (b), p-CH3CH2OC6H4 (c), 3,4-(CH3O)2C6H3 (d); R' = H, R = p-ClC6H4 (e), 3,4-(CH3O)2C6H3 (f).
chlorostyrene derivative Vc (65%) as shown by spectral
data and TLC.
The solutions of pyrrolobenzoxazinetriones in inert
solvents in contact with air lose the dark-violet color due
to addition of water resulting in formation of 3-aroyl-2,3a-
dihydroxy-1,3a-dihydro-4H-pyrrolo[2,1-C][1,4]-benzoxa-
zine-1,4-diones IV. The latter are as a rule isolated from
the mother liquor in the synthesis of pyrrolobenzoxa-
zinetriones [9].
The adducts of pyrrolobenzoxazinetriones with water
IVa, IVc–IVf are crystalline substances of light-yellow
color giving a positive test (cherry-brown color) for enol
hydroxy group with an alcoholic solution of iron(III)
chloride. Their IR spectra contain characteristic absorp-
tion bands: a narrow band of nonassociated hydroxy group
in the region 3370–3415 cm–1 and a wide band of OH
group involved in hydrogen bonds in the region 3100–
3210 cm–1 in keeping with the known published data for
this kind compounds [9, 14].
The reaction of oxalyl chloride with 8-chloro-1,4-
benzoxazinones IIc and IId with electron-donor sub-
stituents in the aroyl moiety takes another route.
Benzoxazinone IId in contrast to its nonchlorinated analog
IIf under the same reaction conditions formed a product
of oxygen substituion in aroyl fragment by chlorine, Z-3-
[2-(3,4-dimethoxyphenyl)-2-chlorovinyl]-6-chloro-2H-1,4-
benzoxazin-2-one (Vd). Although the reaction mixture
during the process did not get black-violet, some pyrrolo-
benzoxazinetrione IIId still formed as evidenced by the
isolation of its hydration product IVd.
The thermolysis of pyrrolobenzoxazinetriones IIIa,
IIIb, IIIe, and IIIf in inert aprotic solvents at 168–190°C
resulted in formation of 4-aroyl-3-aroyloxy-2-(2-oxo-2H-
1,4-benzoxazin-3-yl)-1H,5H-pyrido-[2,1-c][1,4]benzoxa-
zine-1,5-diones VIa, VIb, VIe, and VIf (Scheme 2) due
to [4+2]-cyclodimerization involving the imidoylketene
moiety of generated aroyl(2-oxo-2H-1,4-benzoxazin-3-
yl)ketenes A for diene and the ketene C=C bond as
dienophile. The intermediately formed unstable dimers
B are stabilized by 1,3-acylotropic rearrangement into
pyridobenzoxazinetriones VI as was formerly shown by
an example of acyl(imidoyl)ketene A possessing similar
structure [R = 2,4,6-(CH3)3C6H2, R' = H] [8].
Compound Vd is an orange crystalline substance. Its
IR spectrum unlike that of the initial benzoxazinone IId
lacks the absorption band of the aroyl group, and the band
of the stretching vibrations of OCO group is displaced
by 20 cm–1 to lower frequencies. The same pattern is
observed in the IR spectrum of its analog with an NO2
group in position 6 [10].
The reaction of benzoxazinone IIc with oxalyl chloride
gave rise to a mixture of products. The violet color of the
reaction mixture indicated the presence of the target
pyrrolobenzoxazinetrione IIIc that was identified by its
adduct with water IVc. Apart from compound IVc was
isolated a mixture of benzoxazinone IIc (35%) and
Compounds VIa, VIb, VIe, and VIf are yellow
crystalline high-melting substances, sparingly soluble in
the common organic solvents. The IR spectra of the
thermolysis products contain a strong absorption band in
the region 1735–1750 cm–1 originating from the
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 8 2005

SEMENOVA, KRASNYKH
1224
Scheme 2.
O
N
O
O
O
H2O
COR
R'
COR
COOH
IIIа, IIIb, IIIe, IIIf
II
_CO2
_ CO
R'
N
H
C
O
А
C
_
_
N=C C=C
O=C C=C
+
+
C=C
C=C
O
N
O
N
O
N
O
O
R
O
N
O
COR
COR
O
R'
R'
O
R'
1,3~RCO
O
O
OCO
R
O
N
O
O
O
O
COR
O
COR
N
O
R'
R'
R'
B
D
VIа, VIb, VIe, VIf
superimposed bands of stretching vibrations of three OCO
bands belonging to aroyl and lactam carbonyl groups in
the region 1655–1685 cm–1, and stretching vibrations
bands of the C=C and C=N bonds in the region 1590–
(Scheme 2). The second path involving the very reactive
ketene A seems more probable for the former path
requires more water, and we tried to exclude the presence
of water during the experiment as much as possible.
1
1605 cm–1. In the H NMR spectra appears a char-
The study performed showed that the presence of
a chlorine atom in the position 6 of the substituted
3,4-dihydro-2H-1,4-benzoxazin-2-ones affected their
reaction with oxalyl chloride; the electron-donor sub-
stituents in the 3-arylmethylidene fragment favored the
formation of Z-3-(2-aryl-2-chlorovinyl)-2H-1,4-benzoxa-
zin-2-ones and significantly reduced the yield of the target
pyrrolobenzoxazinetriones. The introduction of chlorine
does not affect the thermal decarbonylation of the
pyrrolobenzoxazinetriones; the generated aroyl(2-oxo-2H-
1,4-benzoxazin-3-yl)ketenes same as their unsubstituted
analogs are stabilized by [4+2]-cyclodimerization where
one molecule plays the role of dienophile with its C=C
bond, and the second one acts as diene with the
imidoylketene and not the alternative acylketene fragment
(dimer D, Scheme 2).
acteristic downfield signal of the aromatic proton H10 in
the range 9.1–9.3 ppm in a good agreement with existence
of the interaction between the oxygen atom C1=O and
H10 hydrogen previously established by X-ray diffraction
study on a similar in structure pyridobenzoxazinedione
[8]. It should be mentioned that the integral intensity of
this signal in the spectra of compounds VIa, VIb, VIe,
and VIf is less than unity, although the overall intensity of
all aromatic protons, including the downfield one, cor-
responds to their number. Apparently since the oxazine
ring in the tricyclic system of compounds VI is not flat
[6–8], some spatial isomers arise where the bond
C1=O···H–C10 does not exist.
Alongside compounds VI the thermolysis yielded
benzoxazinones II as minor components of the reaction
mixture whose presence was revealed by TLC. The latter
may form by hydrolysis of the oxalyl fragment in the initial
pyrrolobenzoxazinetriones, or via reaction of the generated
acyl(imidoyl)ketene A with traces of water giving unstable
acid C which decomposes in the course of thermolysis
EXPERIMENTAL
IR spectra of compounds obtained were recorded on
a spectrophotometer UR-20 from mulls in mineral oil.
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 8 2005

CHEMISTRY OF ACYL(IMIDOYL)KETENES: IX.
1225
1H NMR spectra were registered on spectrometers
Bruker AM-300 and Bruker DRX-400 (internal reference
TMS, solvent DMSO-d6).
NH). Found, %: Cl 9.94; N 3.81. C18H14ClNO5.
Calculated, %: Cl 9.85; N 3.89.
Z-3-(3,4-Dimethoxybenzoylmethylene)-3,4-
dihydro-2H-1,4-benzoxazin-2-one (IIf). In 100 ml of
dioxane were dissolved 5.95 g (22 mmol) of methyl
2-hydroxy-4-(3,4-dimethoxyphenyl)-4-oxo-2-butenoate
Id and 2.44 g (22 mmol) of 2-aminophenol, the solution
was boiled for 2 h 20 min, and half of the solvent was
distilled off. The separated precipitate was filtered off
and recrystallized from toluene. Yield 3.6 g (50%),
mp 208–210°C. IR spectrum, ν, cm–1: 1620 (RCO), 1735
(OCO). 1H NMR spectrum, δ, ppm: 3.86 s (6H, 2CH3),
6.88 s (1H, CH), 7.08–7.70 group of signals (7H, ArH),
12.82 s (1H, NH). Found, %: N 4.26. C18H15NO5.
Calculated, %: N 4.31.
The reaction progress was monitored and the purity
of compounds synthesized was checked by TLC on Silufol
UV-254 plates.
Compounds IIe–IVe were previously described [9,
12].
Z-3-Phenacylidene-6-chloro-3,4-dihydro-2H-1,4-
benzoxazin-2-one (IIa). In 40 ml of dioxane were
dissolved 2.32 g (10 mmol) of methyl benzoylpyruvate Ia
and 1.75 g (10 mmol) of 2-amino-4-chlorophenol, and
the mixture was boiled for 1 h 30 min. Then half of the
solvent was distilled off, the separated precipitate was
filtered off and recrystallized from toluene. Yield 2.2 g
(60%), mp 213–215°C (publ.: mp 212–213°C [13]). IR
spectrum, ν, cm–1: 1640 (RCO), 1765 (OCO). 1H NMR
spectrum, δ, ppm: 6.93 s (1H, CH), 7.03–8.09 group of
signals (7H, ArH), 7.80 s (1H, H5), 12.60 s (1H, NH).
Found, %: Cl 11.92; N 4.75. C16H10ClNO3. Calculated,
%: Cl 11.83; N 4.67.
3-Benzoyl-8-chloro-1,2-dihydro-4H-pyrrolo[2,1-
c]-[1,4]benzoxazine-1,2,4-trione (IIIa) and 3-
benzoyl-2,3a-dihydroxy-8-chloro-1,3a-dihydro-4H-
pyrrolo[2,1-c]-[1,4]benzoxazine-1,4-dione (IVa). In
a mixture of 25 ml of anhydrous dichloroethane and
17 ml of anhydrous chloroform was dissolved 2 g
(6.7 mmol) of benzoxazinone IIa. Then 0.6 ml (7.0 mmol)
of oxalyl chloride was added dropwise, and the mixture
was boiled for 2 h with protection from atmospheric
moisture. The solvent was distilled by half, the separated
precipitate of compound IIIa was filtered off, and washed
with chloroform. Yield 1.25 g (52%), mp 186–188°C. IR
spectrum, ν, cm–1: 1635 (RCO), 1670 (C2=O), 1750
(NCO), 1795 (OCO). Found, %: Cl 9.94; N 4.05.
C18H8ClNO5. Calculated, %: Cl 10.02; N 3.96. The
mother liquor was evaporated, and the residue was
recrystallized from a mixture chloroform–hexane, 4:1.
We obtained 0.08 g (3%) of compound IVa, mp 216–
219°C. IR spectrum, ν, cm–1: 1640 (PhCO), 1740–1760
(OCO, NCO), 3100–3200 br (OH ass.), 3380 (OH).
Found, %: Cl 9.57; N 3.71. C18H10ClNO6. Calculated,
%: Cl 9.54; N 3.77.
Z-3-Aroylmethylene-3,4-dihydro-2H-1,4-benzo-
xazin-2-ones IIb–IId were prepared similarly. Com-
pound IIb was obtained from 4.5 g (18.7 mmol) of
compound Ib. Yield 2.8 g (45%), mp 192–194°C. IR
spectrum, ν, cm–1: 1640 (RCO), 1765 (OCO). 1H NMR
spectrum, δ, ppm: 6.87 s (1H, CH), 7.13 d.d (1H, H7,
4
3
3J 8.8, J 2.4 Hz), 7.25 d (1H, H8, J 8.8 Hz), 7.58 d.d
(2H, H3', H5', J6.8 Hz), 7.83 d (1H, H5, J 2.4 Hz),
8.01 d.d (2H, H2', H6', J 6.8 Hz), 12.57 s (1H, NH).
3
4
3
Found, %: Cl 21.14; N 4.28. C16H9Cl2NO3. Calculated,
%: Cl 21.22; N 4.19.
Compound IIc was obtained from 3.0 g (12 mmol) of
compound Ic. Yield 2.15 g (52%), mp 185–186°C. IR
spectrum, ν, cm–1: 1620 (RCO), 1765 (OCO). 1H NMR
spectrum, δ, ppm: 1.35 t (3H, CH3, J 6.8 Hz), 4.12 q (2H,
CH2, J 6.8 Hz), 6.87 s (1H, CH), 7.05 d.d (2H, H3', H5',
3
4
3J 8.4 Hz), 7.11 d.d (1H, H7, J 8.4, J 2.4 Hz), 7.25 d
(1H, H8, 3J 8.4 Hz), 7.78 d (1H, H5, 4J 2.4 Hz), 7.98 d.d
(2H, H2', H6', 3J 8.4 Hz), 12.54 s (1H, NH). Found, %:
Cl 10.42; N 4.13. C20H18ClNO5. Calculated, %: Cl 10.31;
N 4.07.
3-(p-Chlorobenzoyl)-8-chloro-1,2-dihydro-4H-
pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-trione (IIIb).
In 20 ml of anhydrous dichloroethane was dissolved
0.95 g (2.8 mmol) of benzoxazinone IIb. Then 0.26 ml
(3.0 mmol) of oxalyl chloride was added dropwise, and
the mixture was boiled for 1 h 30 min with protection
from atmospheric moisture. The solvent was distilled by
half, the separated precipitate of compound IIIb was
filtered off, and washed with chloroform. Yield 0.77 g
(70%), mp 202–203°C. IR spectrum, ν, cm–1: 1640
(RCO), 1695 (C2=O), 1730 (NCO), 1775 (OCO). Found,
Compound IId was obtained from 3.0 g (11.3 mmol)
of compound Id. Yield 0.65 g (16%), mp 202–204°C. IR
spectrum, ν, cm–1: 1620 (RCO), 1750 (OCO). 1H NMR
spectrum, δ, ppm: 3.86 s (6H, OCH3), 6.91 s (1H, CH),
7.11 group of signals (2H, H2', H6'), 7.25 d (1H, H5',
J 8.4 Hz), 7.52 d (1H, H8, 3J8.8Hz), 7.69 d.d (1H, H7,
4
4
3J 8.8, J 2 Hz), 7.77 d (1H, H5, J 2 Hz), 12.60 s (1H,
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 8 2005

SEMENOVA, KRASNYKH
1226
0.023 g (2%), mp 202–203°C. IR spectrum, ν, cm–1: 1740
(C=O), 1590 (C=C, C=N). 1H NMR spectrum, δ, ppm:
3.68 s (3H, OCH3), 3.72 s (3H, OCH3), 7.03–7.59 group
of signals (6H,ArH), 7.77 d (1H, H5, 4J 2.7 Hz). Found,
%: Cl 18.67; N 3.81. C18H13Cl2NO4. Calculated, %:
Cl 18.75; N 3.70.
%: Cl 18.22; N 3.74. C18H7Cl2NO5. Calculated, %:
Cl 18.27; N 3.61.
3-(3,4-Dimethoxybenzoyl)-1,2-dihydro-4H-
pyrrolo[2,1-
and 3-(3,4-dimethoxybenzoyl)-2,3a-dihydroxy-1,3a-
dihydro-4H-pyrrolo[2,1- ][1,4]benzoxazine-1,4-
c][1,4]benzoxazine-1,2,4-trione (IIIf)
c
Yield of compound IVd 0.22 g (17%), mp 171–173°C.
IR spectrum, ν, cm–1: 1660 (RCO), 1730 (NCO), 1780
(OCO), 3210–3230 br (OH ass.), 3375 (OH). 1H NMR
spectrum, δ, ppm: 3.81 s (3H, CH3O), 3.86 s (3H, CH3O),
6.92–8.31 group of signals (6H, ArH), 9.87 s (1H, OH),
11.70–13.50 br (OH). Found, %: Cl 8.15; N 3.36.
C20H14ClNO8. Calculated, %: Cl 8.21; N 3.24.
dione (IVf) were synthesized by the same procedure.
Compounds IIIf and IVf were obtained from 3.4 g
(10.45 mmol) of compound IIf. Yield of compound IIIf
2.17 g (55%), mp 159–161°C. IR spectrum, ν, cm–1:
1635 (RCO), 1660 (C2=O), 1730 (NCO), 1765 (OCO).
Found, %: N 3.75. C20H13NO7. Calculated, %: N 3.69.
Yield of compound IVf 0.14 g (3%), decomp. at 138–
140°C. IR spectrum, ν, cm–1: 1660 (RCO), 1730 (NCO),
1770 (OCO), 3205–3260 br (OH ass.), 3370 (OH).
1H NMR spectrum, δ, ppm: 3.81 s (3H, CH3O), 3.86 s
(3H, CH3O), 6.81–7.55 group of signals (7H,ArH), 9.43,
11.70–13.50 br (OH). Found, %: N 3.51. C20H15NO8.
Calculated, %: N.53.
4-Benzoyl-3-benzoyloxy-2-(2-oxo-6-chloro-2H-
1,4-benzoxazin-3-yl)-9-chloro-1H,5H-pyrido[2,1-
C][1,4]benzoxazine-1,5-dione (VIa). A solution of
0.3 g (0.9 mmol) of compound IIIa in 4 ml of Dowtherm
A was heated for 5 min at 178–180°C. On cooling the
separated precipitate was filtered off and recrystallized
from toluene to obtain 0.12 g (40%) of compound VIa,
mp 268–271°C. IR spectrum, ν, cm–1: 1600, 1665, 1680,
1750, 1760. 1H NMR spectrum, δ, ppm: 7.10–8.00 group
of signals (ArH), 9.3 group of signals (H10). Found, %:
Cl 10.78; N 4.21. C34H16Cl2N2O8. Calculated, %:
Cl 10.88; N 4.30.
6-Chloro-Z-3-(2-chloro-2-p-ethoxyphenylvinyl)-
2H-1,4-benzoxazine-2-one (Vc) and 2,3a-dihydroxy-
8-chloro-3-(p-ethoxybenzoyl)-1,3a-dihydro-4H-
pyrrolo[2,1-c][1,4]benzoxazine-1,4-dione (IVc). In
40 ml of anhydrous chloroform was dissolved 1.9 g
(5.5 mmol) of benzoxazinone IIc. Then 0.5 ml (5.8 mmol)
of oxalyl chloride was added dropwise, and the mixture
was boiled for 2 h 40 min with protection from atmospheric
moisture. The solvent was distilled by 2/3, the separated
precipitate was filtered off and recrystallized from
anhydrous chloroform. We obtained 0.24 g (10%) of
compound IVc, mp 177–178°C. IR spectrum, ν, cm–1:
1660 (RCO), 1735 (NCO), 1780 (OCO), 3200–3230 br
4-(p-Chlorobenzoyl)-3-(p-chlorobenzoyloxy)-2-
(2-oxo-6-chloro-2H-1,4-benzoxazin-3-yl)-9-chloro-
1H,5H-pyrido[2,1-C][1,4]benzoxazine-1,5-dione
(VIb). A solution of 0.75 g (1.93 mmol) of compound
IIIb in 3 ml of a mixture Dowtherm A–pseudocumene,
1:2, was boiled for 1 h at 185–187°C. On cooling the
separated precipitate was filtered off and recrystallized
from ethyl acetate. We obtained 0.2 g (29%) of compound
VIb, mp 280–283°C (decomp.). IR spectrum, ν, cm–1:
1585, 1605, 1680, 1750. 1H NMR spectrum, δ, ppm: 7.42–
8.01 group of signals (ArH), 9.27, 9.33 group of signals
(H10). Found, %: Cl 16.59; N 3.78. C34H14Cl4N2O8.
Calculated, %: Cl 16.69; N 3.89.
1
(OH ass.), 3415 (OH). H NMR spectrum, δ, ppm:
1.30 t (3H, CH3, J7.0Hz), 4.06 q (2H, CH2, J 7.0 Hz),
6.83–7.95 group of signals (7H,ArH), 12.50 s (1H, OH).
Found, %: Cl 8.64; N 3.49. C20H14ClNO7. Calculated,
%: Cl 8.53; N 3.37. From the mother liquor was
additionally isolated 0.25 g of a mixture of compounds
IIc and Vc, mp 150–156°C. IR spectrum, ν, cm–1: 1765,
1730 sh, 1620 w. 1H NMR spectrum, δ, ppm: 1.30 group
of signals (CH3), 4.08 group of signals (CH2), 6.84 s (1H,
CH in compound IIc), 6.88–7.75 group of signals (ArH),
12.50 s (1H, NH in compound Vc).
4-(p-Chlorobenzoyl)-3-(p-chlorobenzoyloxy)-2-
(2-oxo-2H-1,4-benzoxazin-3-yl)-1H,5H-pyrido-
[2,1-c]-[1,4]benzoxazine-1,5-dione (VIe) and 4-(3,4-
dimethoxybenzoyl)-3-(3,4-dimethoxybenzoyloxy)-2-
(2-oxo-2H-1,4-benzoxazin-3-yl)-1H,5H-pyrido-
6-Chloro-Z-3-[2-(3,4-dimethoxyphenyl)-2-
chlorovinyl]-2H-1,4-benzoxazin-2-one (Vd) and 3-
(3,4-di-methoxybenzoyl)-2,3a-dihydroxy-8-chloro-
1,3a-dihydro-4H-pyrrolo[2,1-C][1,4]benzoxazin-4-
one (IVd) were obtained in the same way from 1.1 g
(3.06 mmol) of compound IId. Yield of compound Vd
[2,1-c]-[1,4]benzoxazine-1,5-dione (VIf) were
obtained in a similar way. Compound VIe was obtained
from 1.0 g (2.83 mmol) of compound IIIe. Yield 0.65 g
(35%), mp 296°C (decomp.). IR spectrum, ν, cm–1: 1750,
1685, 1590. 1H NMR spectrum, δ, ppm: 7.54 group of
signals (15H, ArH), 9.03 group of signals (H10). Found,
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 8 2005

CHEMISTRY OF ACYL(IMIDOYL)KETENES: IX.
1227
6. Aliev, Z.G., Andreichikov, Yu.S., Krasnykh, O.P., and
Atovmyan, L.O., Izv. Akad. Nauk, Ser. Khim., 1993,
p. 1633.
7. Aliev, Z.G., Krasnykh, O.P., Maslivets,A.N.,Andreichikov,
Yu.S., and Atovmyan, A.O., Izv. Akad. Nauk, Ser. Khim.,
1999, p. 614.
8. Aliev, Z.G., Krasnykh, O.P., Maslivets, A.N., Andreichi-
kov, Yu.S., amdAtovmyan, L.O., Izv. Akad. Nauk, Ser. Khim.,
1999, p. 2154.
9. Maslivets, A.N., Mabrevskaya, I.V., Krasnykh, O.P., Bu-
rov, S.N., Andreichikov, Yu.S., Zh. Org. Khim., 1992,
vol. 28, p. 2545.
10. Aliev, Z. G., Krasnykh, O.P., Maslivets, A.N., and Atov-
myan, L.O., Izv. Akad. Nauk, Ser. Khim., 2000, p. 2080.
11. Inagaki, T. and Iwanami, Y., Org. Mass. Spectrometry, 1977,
p. 222.
12. Andreichikov, Yu. S., Voronova, L.A., and Kozlov,A.P., Zh.
Org. Khim., 1979, vol. 15, p. 520.
13. Iwanami,Y. and Seki, T., Bull. Chem. Soc. Jpn, 1971, vol. 44,
p. 1316.
14. Aliev, Z.G., Krasnykh, O.P., Konyukhova, N.A., Masli-
vets, A.N., and Atovmyan, L.O., Zh. Strukt. Khim., 2001,
vol. 42, p. 1008.
%: Cl 10.83; N 4.30. C34H16Cl2N2O8. Calculated,
%: Cl 10.88; N 34.30.
Compound VIf was obtained from 0.9 g (2.37 mmol)
of compound IIIf. Yield 0.07 g (8%), mp 272–273°C. IR
spectrum, ν, cm–1: 1585, 1650, 1670, 1740 br. 1H NMR
spectrum, δ, ppm: 3.72 group of signals (12H, OCH3),
6.78–7.75 group of signals (ArH), 9.14 d (H10). Found,
%: N 4.01. C38H26N2O12. Calculated, %: N 3.99.
REFERENCES
1. Maslivets,A.N.,Aliev, Z.G., Krasnykh, O.P., Golovnina, O.V.,
and Atovmyan, L.O., Khim. Geterotsikl. Soed., 2004,
vol. 10, p. 1501.
2. Tidwell, T.T., Ketenes, NewYork: J. Wiley & Sons, Inc., 1995,
655 p.
3. Zhou, C. and Birney, D., J. Am. Chem. Soc., 2002, vol. 124,
p. 5231.
4. Shumway, W.W., Doctoral Sci. (Chem.) Dissertation, Texas,
Tech. University, 2001.
5. Wentrup, G., Heilmayer, W., and Kollenz, G., Synthesis, 1994,
p. 1219.
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 8 2005