Halogenation of some alkyl-substituted 4-aroyloxyimino-and 4-arylsulfonyloxyimino-2,5-cyclohexadienones

Article abstract of DOI:10.1023/A:1012403708255

The chlorination and bromination of 2,3-dimethyl-, 3-methyl-6-isopropyl-, and 2,6-diisopropyl-4-aroyl(or arylsulfonyl)oxyimino-2,5-cyclohexadienones follow the proposed rules of halogenation of 4-aroyl-(or arylsulfonyl)oxyimino-2,5-cyclohexadienones: the reaction occurs preferentially at the cis-C=C bond of the quinoid ring; simultaneous halogenation at both double bonds is not observed; halogen adds mainly across unsubstituted C=C bond; no halogenation occurs at the double bond already substituted by a halogen; bromination of the C=C bond with an alkyl substituent is more difficult than chlorination; the second halogen molecule adds only after regioselective dehydrohalogenation.

Full text of DOI:10.1023/A:1012403708255

Russian Journal of Organic Chemistry, Vol. 37, No. 3, 2001, pp. 382 387. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 3, 2001,
pp. 408 413.
Original Russian Text Copyright
2001 by Avdeenko, Zhukova, Konovalova.
Halogenation of Some Alkyl-Substituted 4-Aroyloxyimino-
and 4-Arylsulfonyloxyimino-2,5-cyclohexadienones
A. P. Avdeenko, S. A. Zhukova, and S. A. Konovalova
Donbass State Machine-Building Academy, ul. Shkadinova 72, Kramatorsk, 343913 Ukraine
Received January 14, 1999
Abstract The chlorination and bromination of 2,3-dimethyl-, 3-methyl-6-isopropyl-, and 2,6-diisopropyl-
4-aroyl(or arylsulfonyl)oxyimino-2,5-cyclohexadienones follow the proposed rules of halogenation of 4-aroyl-
(or arylsulfonyl)oxyimino-2,5-cyclohexadienones: the reaction occurs preferentially at the cis-C C bond of
the quinoid ring; simultaneous halogenation at both double bonds is not observed; halogen adds mainly across
unsubstituted C C bond; no halogenation occurs at the double bond already substituted by a halogen;
bromination of the C C bond with an alkyl substituent is more difficult than chlorination; the second halogen
molecule adds only after regioselective dehydrohalogenation.
In the preceding communications we reported on
the chlorination and bromination of 4-aroyloxyimino-
and 4-arylsulfonyloxyimino-2,5-cyclohexadienones
[1 4]. Analysis of the results allowed us to postulate
the following rules which govern halogenation of
these compounds:
(1) The halogenation involves only one C C bond
of the quinoid ring. In no cases simultaneous addition
of halogen at both C C bonds was observed [1 4];
(2) The halogenation occurs preferentially at the
cis-C C bond relative to the RO substituent on the
nitrogen atom (cis-stereoselectivity) [1];
(3) When an alkyl group is present at one double
bond, halogen adds preferentially at the unsubstituted
C C bond [2];
(4) Bromination of C C bond with an alkyl sub-
stituent is more difficult than chlorination, because of
greater size of bromine atom compared to chlorine [3];
(5) Halogen does not add at a double bond already
substituted by a halogen [1, 4];
(6) Addition of the second halogen molecule is
possible only after elimination of hydrogen halide;
the dehydrohalogenation is strictly regioselective:
hydrogen atom is abstracted from the -position with
respect to the carbonyl group, and halogen atom, from
the -position with respect to the imino group [1 4].
The goal of the present study was to obtain addi-
tional proofs for the above rules of halogenation of
4-aroyl(arylsulfonyl)oxyimino-2,5-cyclohexadienones.
For this purpose, we examined the chlorination and
bromination of 2,3-dimethyl-, 3-methyl-6-isopropyl-,
and 2,6-diisopropyl-substituted 4-aroyloxyimino- and
4-arylsulfonyloxyimino-2,5-cyclohexadienones.
The halogenation of 4-aroyloxyimino- and arylsul-
fonyloxyimino-2,3-dimethyl-2,5-cyclohexadienones
Ia Id was expected to occur at the unsubstituted
C5 C6 bond for the following reasons. First, the
C5 C6 bond is more reactive since it is located cis
with respect to the RO group on the nitrogen [2 6]
and second, two methyl groups in positions 2 and 3
should hinder halogen addition at the C2 C3 bond.
In fact, our experiments showed that the first halogen
molecule adds at the unsubstituted C5 C6 double
bond of compounds Ia Id to give 4-aroyl(arylsul-
fonyl)oxyimino-5,6-dihalo-2,3-dimethyl-2-cyclo-
hexenones IIa IId and IIIa IIId (Scheme 1). These
products are E isomers with respect to the methyl
groups. Treatment of compounds IIa IId and IIIa
IIId with triethylamine in chloroform gave the corre-
sponding 4-aroyl(arylsulfonyl)oxyimino-6-halo-2,3-di-
methyl-2,5-cyclohexadienones IVa IVd and Va Vd.
The dehydrohalogenation process is regioselective:
halogen atom is abstracted exclusively from position
5 of the quinoid ring to form only E isomer with
respect to the methyl groups (Scheme 1).
Addition of the second halogen molecule to com-
pounds IVa IVd and Va Vd should occur at the
C5 C6 bond located cis relative to the RO group.
However, there is a halogen atom in the ortho-posi-
tion with respect to the carbonyl group; in keeping
with numerous experimental data [1 4], such double
1070-4280/01/3703-0382$25.00 2001 MAIK Nauka/Interperiodica

HALOGENATION OF SOME ALKYL-SUBSTITUTED . . .
383
Scheme 1.
I VI, R = PhCO (a), 4-ClC6H4CO (b), PhSO2 (c), 3-NO2C6H4SO2 (d); II, IV, Hlg = Cl; III, V, Hlg = Br.
Scheme 2.
R = PhCO (a), 4-CH3C6H4SO2 (b), 3-NO2C6H4SO2 (c); VIII, X, Hlg = Cl; IX, XI, Hlg = Br.
bond becomes inactive and it does not take up halo-
gen. Therefore, the only possible is halogen addition
at the C2 C3 bond already containing two methyl
groups. Thus the chlorination of IVa IVd afforded
4-aroyl(arylsulfonyl)oxyimino-2,5,6-trichloro-5,6-di-
methyl-2-cyclohexenones VIa VId as E isomers
(Scheme 1). Bromination of compounds Va Vd does
not occur because of considerable steric hindrances to
addition of bulky bromine atoms.
The halogenation of 4-aroyl(arylsulfonyl)oxyimino-
6-isopropyl-3-methyl-2,5-cyclohexadienones VIIa
VIIc should occur at the C5 C6 bond in the cis posi-
tion with respect to the RON group. However, the
presence of a bulky isopropyl group hinders halogen
addition at that bond, and the reaction involves the
C2 C3 bond to give 4-aroyl(arylsulfonyl)oxyimino-
2,3-dihalo-6-isopropyl-3-methyl-2-cyclohexenones
VIIIa VIIIc and IXa IXc (E isomers with respect
to the methyl group; Scheme 2).
6-isopropyl-3-methyl-2-cyclohexenones XIIa XIIc
were obtained (E isomers with respect to the methyl
group). Compounds XIa XIc did not react with Br2
for the same reason as stated above for Va Vd.
4-Aroyl(arylsulfonyl)oxyimino-2,6-diisopropyl-2,5-
cyclohexadienones XIIIa XIIIc are capable of taking
up only one halogen molecule to afford 4-aroyl(aryl-
sulfonyl)oxyimino-5,6-dihalo-2,6-diisopropyl-2-cyclo-
hexenones XIVa XIVc and XVa XVc existing in
solution as a single E isomer (Scheme 3). This
indicates high cis-stereoselectivity of the halogenation
process. Regioselective dehydrohalogenation of com-
pounds XIVa XIVc, XVa, and XVc is impossible.
Scheme 3.
Regioselective dehydrohalogenation of compounds
VIIIa VIIIc and IXa IXc leads to formation of
(E)-4-aroyl(arylsulfonyl)oxyimino-2-halo-6-isopropyl-
3-methyl-2,5-cyclohexadienones Xa Xc and XIa XIc.
Taking into account that halogen does not add at
a double bond already containing a halogen atom,
further halogenation of Xa Xc and XIa XIc was
expected to occur at the C5 C6 bond. This was the
case in the reaction of Xa Xc with chlorine. As
XIII XV, R = 4-ClC6H4CO (a), 4-CH3C6H4CO (b),
4-CH3C6H4SO2 (c); XIV, Hlg = Cl; XV, Hlg = Br.
Compounds Ia Id, IVa IVd, VIIa VIIc, Xa Xc,
a result, 4-aroyl(arylsulfonyl)oxyimino-2,5,6-trichloro- and XIIIa XIIIc were chlorinated with gaseous
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

384
AVDEENKO et al.
Table 1. Chlorination of alkyl-substituted 4-aroyl(aryl-
sulfonyl)oxyimino-2,5-cyclohexadienones Ia Id, IVa IVd,
VIIa VIIc, Xa Xc, and XIIIa XIIIc
chlorine in dimethylformamide or in a mixture of
dimethylformamide with acetic acid. The conditions
are given in Table 1. The bromination of compounds
Ia Id, VIIa VIIc, XIIIa, and XIIIc was effected
with molecular bromine in CHCl3, AcOH, or DMF.
The conditions are summarized in Table 2.
Solvent (ratio)
Compounds VIIa, IXa, and XIa were identical
to those reported previously [3, 7]. The structure of
the newly synthesized compounds was proved by
1
Ia
Ib
Ic
DMF AcOH (1: 1)
DMF AcOH (1: 1)
DMF AcOH (1: 1)
0.39
0.35
0.35
70 75 IIa
50 60 IIb
elemental analyses (Table 3) and IR and H NMR
spectra. The IR spectra of quinoid compounds IV, V,
X, and XI contain characteristic carbonyl absorption
40
IIc
1
bands in the region 1644 1665 cm ; the carbonyl
Id
DMF AcOH (1: 1) 0.3
40 50 IId
60 70 VIa
60 70 VIb
50 60 VIc
60 75 VId
band in the spectra of semiquinoid derivatives II, III,
VI, VIII, IX, XII, XIV, and XV is observed at 1675
IVa
IVb
IVc
IVd
DMF AcOH (3: 1)
DMF AcOH (3: 1)
DMF AcOH (3: 1)
DMF AcOH (3: 1)
0.25
0.25
0.3
0.25
0.35
0.3
1
1721 cm . All the products show in the spectra
absorption bands from C C and C N bonds at 1453
1
1543 and 1582 1615 cm and SO2 group at 1335
1
VIIa DMF AcOH (1: 1)
VIIb DMF AcOH (3: 1)
VIIc DMF AcOH (3: 1)
Xa
Xb
Xc
40
VIIIa
1403 and 1195 1210 cm (or benzoyl carbonyl group
1
at 1748 1773 cm ). The 1H NMR spectra of the com-
50 60 VIIIb
60 70 VIIIc
80 90 XIIa, Xa
0.3
pounds prepared were consistent with the proposed
structures (Table 4).
DMF
DMF
DMF
0.25
0.2
0.2
90
90
XIIb
XIIc
EXPERIMENTAL
XIIIa DMF
XIIIb DMF
XIIIc DMF
0.25
0.2
0.2
70 80 XIVa
60 70 XIVb
60 70 XIVc
The IR spectra were measured on a UR-20 spectro-
photometer in KBr. The H NMR spectra were ob-
1
tained on a Varian VXR-300 instrument at 300 MHz;
The chemical shifts were measured relative to tetra-
methylsilane. The reaction mixtures were analyzed
by TLC on Silufol UV-254 plates using 10:1 ben-
zene hexane as eluent; spots were visualized by UV
irradiation.
Table 2. Bromination of alkyl-substituted 4-aroyl(aryl-
sulfonyl)oxyimino-2,5-cyclohexadienones Ia Id, VIIa
VIIc, XIIIa, and XIIIc
Compounds Ia Id, VIIa VIIc, and XIIIa XIIIc
were synthesized by acylation of the corresponding
p-benzoquinone monooximes with aroyl chlorides or
arenesulfonyl chlorides in diethyl ether in the presence
of triethylamine, following the procedure reported
in [7]. Table 3 contains yields, melting points, and
analytical data of the newly synthesized compounds.
Chlorination of 4-aroyloxyimino- and 4-aryl-
sulfonyloxyimino-2,5-cyclohexadienones Ia Id,
IVa IVd, VIIa VIIc, Xa Xc, and XIIIa XIIIc.
Dry gaseous chlorine was passed at a flow rate of
15 20 ml/min (at a temperature specified in Table 1)
through a solution of appropriate substrate in 10 ml of
DMF or DMF acetic acid (see Table 1) until complete
saturation. The mixture was diluted with 10 15 ml
of water, and the product was filtered off and recrys-
tallized from appropriate solvent. The yields, melting
points, and elemental analyses of compounds IIa IId,
VIa VId, VIIIa VIIIc, XIIb, XIIc, and XIVa XIVc
are given in Table 3.
Substrate
no.
Substrate Br2 Tempera-
Solvent
Product
molar ratio
ture,
C
Ia
Ib
Ic
Id
VIIa
VIIb
VIIc
XIIIa
XIIIc
CHCl3
CHCl3
CHCl3
CHCl3
AcOH
AcOH
AcOH
DMF
1: 3
1: 3
1: 3
1: 3
1: 5
1: 5
1: 5
1: 7
1: 3
25
IIIaa
IIIba
IIIca
IIIda
IXab
IXbb
IXcb
XVab
XVcc
25
25
25
40 50
50
40 50
40 50
50 60
DMF
a
Crystallizes after removal of the solvent by half.
b
Crystallizes after addition of 10 15 ml of water to the reaction
solution.
c
The oily substance formed after addition of 10 15 ml of water
was extracted with diethyl ether. The solvent was removed,
and the tarry residue was recrystallized.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

HALOGENATION OF SOME ALKYL-SUBSTITUTED . . .
385
Table 3. Yields, melting points, and elemental analyses of alkyl-substituted 4-aroyl(arylsulfonyl)oxyimino-2,5-cyclo-
hexadienones Ia Id, VIIb, VIIc, and XIIIa XIIIc and their halogenated derivatives II VI, VIIIa VIIIc, IXb, IXc,
Xa Xc, XIb, XIc, XIIa XIIc, XIVa XIVc, XVa, and XVc
Found, %
Calculated, %
Compound Yield,
mp, C (solvent)
Formula
no.
%
Hlg
N
Hlg
N
Ia
Ib
Ic
Id
IIa
IIb
IIc
IId
IIIa
IIIb
IIIc
IIId
IVa
IVb
IVc
IVd
Va
63
78
67
91
60
51
45
67
74
86
73
53
89
79
90
67
63
76
53
49
90
53
43
61
39
93
31
54
48
45
51
83
85
91
52
73
58
44
75
63
56
53
81
40
47
42
170 (i-PrOH)
158 (i-PrOH)
109 (i-PrOH)
134 (i-PrOH)
136 (i-PrOH)
118 (i-PrOH)
95 (i-PrOH)
127 (i-PrOH)
157 (i-PrOH)
137 (i-PrOH)
110 (i-PrOH)
125 (i-PrOH)
166 (AcOH)
193 (AcOH)
200 (AcOH)
112 (AcOH)
166 (AcOH)
192 (AcOH)
132 (AcOH)
208 (AcOH)
146 (AcOH)
157 (AcOH)
104 (AcOH)
124 (AcOH)
87 (i-PrOH)
130 (i-PrOH)
121 (i-PrOH)
114 (AcOH)
129 (AcOH)
141 (AcOH)
142 (i-PrOH)
127 (AcOH)
118 (AcOH)
156 (AcOH)
137 (AcOH)
148 (AcOH)
143 (AcOH)
88 (AcOH)
5.26, 5.33
4.79, 4.84
4.75, 4.81
8.27, 8.30
4.20, 4.27
3.75, 3.84
3.80, 3.85
6.80, 6.83
3.29, 3.34
3.05, 3.09
3.01, 3.07
C15H13NO3
C15H12ClNO3
C14H13NO4S
5.49
4.83
4.81
8.33
4.29
3.88
3.87
6.88
3.37
3.11
3.10
12.06, 12.19
12.25
C14H12N2O6S
C15H13Cl2NO3
C15H12Cl3NO3
C14H13Cl2NO4S
C14H12Cl2N2O6S
C15H13Br2NO3
C15H12ClBr2NO3
C14H13Br2NO4S
C14H12Br2N2O6S
C15H12ClNO3
C15H11Cl2NO3
C14H12ClNO4S
C14H11ClN2O6S
C15H12BrNO3
C15H11ClBrNO3
C14H12BrNO4S
C14H11BrN2O6S
C15H12Cl3NO3
C15H11Cl4NO3
C14H12Cl3NO4S
C14H12Cl3N2O6S
C17H19NO4S
C16H16N2O6S
C18H17Cl2NO3
C17H19Cl2NO4S
C16H16Cl2N2O6S
C17H19Br2NO4S
C16H16Br2N2O6S
C17H16ClNO3
C17H18ClNO4S
C16H15ClN2O6S
C17H18BrNO4S
C16H15BrN2O6S
C17H18Cl3NO4S
C16H15Cl3N2O6S
C19H20ClNO3
21.63, 21.71
29.50, 29.54
19.48, 19.57
17.40, 17.43
38.41, 38.47
43.37, 43.41
35.39, 35.43
32.17, 32.22
12.07, 12.21
21.80, 21.84
10.80, 10.87
9.47, 9.53
23.82, 23.89
31.32, 31.26
21.50, 21.56
32.17, 32.21
29.46, 29.50
35.79, 35.88
26.71, 26.78
23.97, 23.99
21.74
29.54
19.58
17.42
38.50
43.44
35.43
32.22
12.24
21.88
10.89
9.56
23.92
31.30
21.59
32.28
29.54
35.90
26.82
24.03
4.75, 4.80
4.30, 4.32
4.83
4.32
Vb
Vc
Vd
3.73, 3.75
3.74, 3.79
5.60, 5.67
3.85, 3.87
3.41, 3.49
3.50, 3.51
6.25, 6.31
4.12, 4.18
7.70, 7.35
3.79, 3.80
3.41, 3.44
6.37, 6.42
2.77, 2.81
3.80
3.78
5.66
3.88
3.54
3.53
6.33
4.20
7.78
3.83
3.47
6.44
2.84
VIa
VIb
VIc
VId
VIIb
VIIc
VIIIa
VIIIb
VIIIc
IXb
IXc
Xa
19.29, 19.33
17.47, 17.51
16.25, 16.27
32.25, 32.39
30.41, 30.47
11.12, 11.15
9.57, 9.61
19.37
17.55
16.30
32.41
30.50
11.17
9.64
Xb
Xc
3.73, 3.77
7.00, 7.02
3.32, 3.37
6.23, 6.29
3.13, 3.20
5.91, 5.94
3.97, 4.01
4.27, 4.30
3.80, 3.85
3.31, 3.37
3.39, 3.49
3.81
7.03
3.40
6.32
3.19
5.96
4.05
4.31
3.88
3.36
3.53
8.83, 8.85
8.90
XIb
XIc
XIIb
XIIc
XIIIa
XIIIb
XIIIc
XIVa
XIVb
XIVc
XVa
XVc
19.31, 19.37
18.01, 18.02
24.17, 24.20
22.49, 22.59
10.19, 10.23
19.39
18.04
24.25
22.65
10.26
117 (i-PrOH)
74 (i-PrOH)
91 (i-PrOH)
128 (AcOH)
112 (AcOH)
128 (i-PrOH)
138 (AcOH)
145 (AcOH)
C20H23NO3
C19H23NO4S
C19H20Cl3NO3
C20H23Cl2NO3
C19H23Cl2NO4S
C19H20ClBr2NO3
C19H23Br2NO4S
25.48, 25.51
17.75, 17.88
16.35, 16.40
38.59, 38.62
30.59, 30.67
25.54
17.90
16.41
38.63
30.67
2.70, 2.76
2.58, 2.67
2.77
2.69
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

386
AVDEENKO et al.
Table 4. 1H NMR spectra (CDCl3) of alkyl-substituted 4-aroyl(arylsulfonyl)oxyimino-2,5-cyclohexadienones Ia Ic,
VIIb, and XIIIa XIIIc and their halogenated derivatives IIa, IIc, IIIb, IIId, IVc, Vb, Vd, VIb, VIc, VIIIb XIIb,
XIVa XIVc, XVa, and XVc
Chemical shifts , ppm
5-H, 5-CH3 6-H, 6-CH
Coupling
constants
JH, H, Hz
Comp.
no.
2-H, 2-CH3, 2-CH 3-H, 3-CH3
R
Iaa
1.97 s, CH3
1.98 s, CH3
1.98 s, CH3
2.04 s, CH3
2.00 s, CH3
2.12 s, CH3
2.03 s, CH3
2.26 s, CH3 7.95 7.99 d, CH 6.59 6.61 d, CH 7.58 8.16 m, C6H5
2.26 s, CH3 7.98 8.02 d, CH 6.59 6.63 d, CH 7.66 8.19 d.d, C6H4
2.10 s, CH3 7.54 7.58 d, CH 6.46 6.49 d, CH 7.58 8.06 m, C6H5
10.5 (5 6)
10.2 (5 6)
10.2 (5 6)
2.1 (5 6)
2.7 (5 6)
2.1 (5 6)
2.4 (5 6)
Iba
Ic
IIaa
IIc
IIIb
IIId
2.29 s, CH3 6.29 d, CH
2.08 s, CH3 5.52 d, CH
2.36 s, CH3 5.77 d, CH
2.09 s, CH3 5.60 d, CH
4.87 d, CH
4.40 d, CH
4.70 d, CH
4.60 d, CH
7.64 8.19 m, C6H5
7.57 8.04 m, C6H5
7.51 8.08 d.d, C6H4
7.84 t, 5-H, 8.37 d, 6-H,
8.55 d, 4-H, 8.89 s, 2-H
7.58 8.06 m, C6H5
7.51 8.09 d.d, C6H4
7.85 t, 5-H, 8.37 d, 6-H,
8.56 d, 4-H, 8.91 s, 2-H
7.51 8.07 d.d, C6H4
7.57 8.03 m, C6H5
7.37 7.94 d.d, C6H4,
2.47 s, CH3
IVc
Vb
Vd
2.04 s, CH3
2.13 s, CH3
2.05 s, CH3
2.11 s, CH3 7.76 s, CH
2.36 s, CH3 8.17 s, CH
2.10 s, CH3 8.02 s, CH
VIb
VIc
VIIb
2.01 s, CH3
1.91 s, CH3
6.31 d.q, CH
2.22 s, CH3 7.80 s, CH
1.93 s, CH3 7.65 s, CH
2.09 s, CH3 7.29 s, CH
1.10 s, CH3,
1.12 s, CH3,
3.05 m, CH
1.10 d, CH3,
1.17 d, CH3,
3.00 m, CH
1.10 d, CH3
1.17 d, CH3
3.02 m, CH
1.27 s, CH3,
1.15 s, CH3
3.10 m, CH
1.13 s, CH3,
1.15 s, CH3,
3.11 m, CH
1.09 d, CH3,
1.21 d, CH3,
2.69 m, CH
1.87 s, CH3,
1.21 s, CH3,
3.15 m, CH
1.19 s, CH3,
1.21 s, CH3,
3.15 m, CH
1.12 s, CH3,
1.14 s, CH3,
3.08 m, CH
VIIIb
IXb
4.34 s, CH
4.67 s, CH
1.90 s, CH3 7.17 s, CH
2.10 s, CH3 7.13 s, CH
2.25 s, CH3 7.34 s, CH
2.30 s, CH3 7.33 s, CH
2.19 s, CH3 5.51 s, CH
7.18 d, CH 7.46 d, CH
7.19 q, CH 7.51 q, CH
6.79 q, CH 7.29 q, CH
7.36 7.91 d.d, C6H4,
2.47 s, CH3
7.36 7.91 d.d, C6H4,
2.47 s, CH3
Xb
7.36 7.95 d.d, C6H4,
2.47 s, CH3
XIb
7.38 7.95 d.d, C6H4,
2.48 s, CH3
XIIb
XIIIa
XIIIb
XIIIc
XIVa
7.37 7.91 d.d, C6H4,
2.47 s, CH3
1.14 s, CH3,
1.17 s, CH3,
3.15 m, CH
1.14 s, CH3,
1.16 s, CH3,
3.15 m, CH
1.07 s, CH3,
1.10 s, CH3,
3.08 m, CH
7.52 8.09 d.d, C6H4
2.4 (3 5)
1.5 (3 5)
2.7 (3 5)
1.5 (3 5)
7.34 8.04 d.d, C6H4,
2.47 s, CH3
7.38 7.95 d.d, C6H4,
2.47 s, CH3
1.09 d, 1.13 d, 6.91 q, CH 5.58 d, CH
1.19 d, 1.20 d, 7.51 8.04 d.d, C6H4
2CH3, 3.06 m,
CH
2CH3, 2.81 m,
CH
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

HALOGENATION OF SOME ALKYL-SUBSTITUTED . . .
Chemical shifts , ppm
387
Table 4. (Contd.)
Coupling
constants
JH, H, Hz
Comp.
no.
2-H, 2-CH3, 2-CH 3-H, 3-CH3
5-H, 5-CH3
5.62 d, CH
6-H, 6-CH
R
XIVb
XIVc
XVa
XVc
1.09 d, 1.13 d, 6.92 q, CH
1.19 d, 1.21 d, 7.32 8.00 d.d, C6H4,
1.2 (3 5)
1.5 (3 5)
2.1 (3 5)
1.5 (3 5)
2CH3, 3.05 m,
CH
2CH3, 2.81 m, 2.46 s, CH3
CH
1.02 d, 1.08 d, 6.54 q, CH
5.43 d, CH
5.73 d, CH
5.57 d, CH
1.12 d, 1.15 d, 7.36 7.91 d.d, C6H4,
2CH3, 2.70 m, 2.48 s, CH3
CH
1.10 s, 1.12 s, 7.51 8.06 d.d, C6H4
2CH3, 2.49 m,
CH
2CH3, 2.98 m,
CH
1.20 d, 1.24 d, 6.86 q, CH
2CH3, 3.05 m,
CH
1.12 d, 1.19 d, 6.49 q, CH
1.04 t, 2CH3,
2.38 m, CH
7.36 7.92 d.d, C6H4,
2.46 s, CH3
2CH3, 2.99 m,
CH
a
In DMSO-d6.
Bromination of 4-aroyloxyimino- and 4-arylsul-
REFERENCES
fonyloxyimino-2,5-cyclohexadienones Ia Id, VIIa
VIIc, XIIIa, and XIIIc. A 3 M solution of bromine
was added dropwise under vigorous stirring to 10 ml
of a 0.5 M solution of compound Ia Id, VIIa VIIc,
XIIIa, or XIIIc in the same solvent (Table 2). The
product was filtered off and recrystallized from
appropriate solvent. The yields, melting points, and
elemental analyses of compounds IIIa IIId, IXb,
IXc, XVa, and XVb are given in Table 3.
1. Avdeenko, A.P. and Glinyanaya, N.M., Russ. J. Org.
Chem., 1995, vol. 31, no. 11, pp. 1507 1513.
2. Avdeenko, A.P., Glinyanaya, N.M., and Pirozhen-
ko, V.V., Russ. J. Org. Chem., 1996, vol. 32, no. 1,
pp. 85 89.
3. Avdeenko, A.P., Glinyanaya, N.M., and Pirozhen-
ko, V.V., Russ. J. Org. Chem., 1995, vol. 31, no. 10,
pp. 1380 1385.
Dehydrohalogenation of 4-aroyloxyimino- and
4-arylsulfonyloxyimino-2-cyclohexenones IIa IId,
IIIa IIId, VIIIa VIIIc, and IXa IXc. Halogen
derivative IIa IId, IIIa IIId, VIIIa VIIIc, or
IXa IXc, 1 mmol, was dissolved in a minimal
amount of chloroform, and 0.1 0.15 ml of triethyl-
amine was added dropwise. After 3 5 min, the prod-
uct was filtered off, washed with small portions of
water and acetic acid, and recrystallized. The yields,
melting points, and elemental analyses of compounds
IVa IVd, Xa Xc, XIb, and XIc are given in Table 3.
4. Avdeenko, A.P., Glinyanaya, N.M., and Pirozhen-
ko, V.V., Zh. Org. Khim., 1993, vol. 29, no. 7,
pp. 1402 1411.
5. Baldwin, J.E. and Norris, R.K., J. Org. Chem., 1981,
vol. 46, no. 6, pp. 697 703.
6. Perrin, C.L. and Engler, R.E., J. Org. Chem., 1997,
vol. 62, no. 3, pp. 687 692.
7. Titov, E.A. and Burmistrov, S.I., Ukr. Khim. Zh.,
1960, vol. 26, no. 6, pp. 744 749.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001