Synthesis and studies of some ketosulfones, part II

Article abstract of DOI:10.1080/10426500500366186

Bromoketosulfones have been prepared. Their chemical composition and structure are proved by spectral methods. The addition of unsubstituted and substituted sulfinic acid to 2-bromo-1,3-diphenyl-2-propenone and 3-bromo-4-phenyl-3-butene-2-on has been stud

Full text of DOI:10.1080/10426500500366186

Phosphorus, Sulfur, and Silicon, 181:1609–1614, 2006
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500500366186
Synthesis and Studies of Some Ketosulfones, Part II
D. Aleksiev
S. Ivanona
G. Jekova
Department of Organic Chemistry, University Prof. A. Zlatarov,
Bourgas, Bulgaria
Bromoketosulfones have been prepared. Their chemical composition and structure
are proved by spectral methods. The addition of unsubstituted and substituted
sulfinic acid to 2-bromo-1,3-diphenyl-2-propenone and 3-bromo-4-phenyl-3-butene-
2-on has been studied kinetically by means of UV spectroscopy. Reactions follow the
second-order kinetics V = R [bromochalkone][sulfinic acid]. The dependence of rate
constants on the temperature and the influence of p-substitutents on the kinetic
parameters have been investigated. The activation energy and the enthalpy of acti-
vation are calculated in the temperature range 288–308 K.
Keywords Bromochalkones; nucleophilic addition; sulfinic acids
INTRODUCTION
Literature reviews show that the processes of isomerization of
chalkones, their physiological effect, and ways of extracting some of
them from natural resources have already been studied thoroughly.
A number of 2ꢀ-hydroxychalkones occur in nature. They constitute the
primary precursors of all important natural flavonoids1 and can be con-
verted in the laboratory into other flavonoids and dihydrochalkones.2
Chalkones have different physiological activities and act as
antibiotics.3 They find application in industries and as artificial
sweetners.4
The present work aims at studying the nucleophilic addition of
sulfinic acids to unsaturated bromochalkones. From a theoretical point
of view, it is interesting to study the change in the activity of the carbon–
carbon double bond regarding nucleophilic reagents depending simul-
taneously on a keto group and a halogen atom. On the other hand, the
Received May 25, 2005; accepted August 18, 2005.
Address correspondence to S. Ivanona, University of Prof. A. Zlatarov, Department of
Organic Chemistry, Bourgas, 8010 Bulgaria.
1609

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D. Aleksiev et al.
ketosulfones obtained are compounds having potential physiological
properties, and this fact determines the importance of this study.
RESULTS AND DISCUSSION
Synthesis
The reaction between bromochalkones and arenesulfinic acids takes
place by Scheme 1:
SCHEME 1 Ar = Ph (2a, 3a, 5a); Ar = 4-MeC6H4 (2b, 3b, 5b); Ar = 4-CIC6H4
(2c, 3c, 5c).
3-arylsulfonyl-2-bromo-1,3-diphenylpropanones (3a–c) and 4-aryls-
ulfonyl-3-bromo-4-phenyl-2-butanones (5a–c) were synthesized as a
result of the interaction of equimolar amounts of the corresponding
reagents (2a–c reacts with 1 and 4, respectively) in ethanol at r.t. for
24 h. The compounds obtained are colorless crystalline substances and
are stable at long storage (Table I).
Spectroscopic Analysis
In the IR spectra of 3-arylsulfonyl-2-bromo-1,3-diphenylpropanones
and 4-arylsulfonyl-3-bromo-4-phenyl-2-butanones, there are intensive
absorption bands corresponding to the asymmetric and symmetric va-
lence vibration of the sulfonyl group at 1313–1297 and 1140–1135 cm−1
.
An absorption band assigned to the carbonyl group can be seen at
1750–1663 cm−1. Skeleton vibrations of the aromatic nucleus are char-
acterized by an absorption band at 1640–1450 cm−1. C H Aryl off-
plane deformation vibrations at 830–790 cm−1 prove the presence of
p-substituted benzenes. The characteristic absorption maxima at 1360–
1340 and 1160–1150 cm−1 show that there are arylsulfonyl groups
present in the compounds under study.

Ketosulfones
1611
TABLE I Physical and Analytical Data for Compounds 3–5
Analysis (%) found (calcd.)
Compound
no.
Yield % M.P. ◦
C
Formula mol. wt.
C
H
S
3a
3b
3c
5a
5b
5c
80
91
93
87
86
95
212
206
204
147
131
140
C21H17O3SBr
429.29
58.76
3.96
4.81
(4.60)
7.23
(7.31)
6.91
(6.75)
8.73
(8.52)
8.41
(58.50) (3.45)
59.61 4.29
(59.45) (4.10)
54.39 3.45
(54.05) (3.12)
52.33 4.08
(51.90) (3.75)
53.56 4.46
(53.15) (4.08)
47.84 3.49
(47.60) (3.20)
C
22H19O3SBr
443.30
C21H16O3SClBr
463.75
C
16H15O3SBr
367.24
C
17H17O3SBr
381.25
(8.12)
7.98
(7.50)
C
16H14O3SClBr
401.69
The 1H NMR spectra contain chemical shifts for aromatic multi-
plets at 7.28–8.10 ppm. There are also two doublets centered at 5.15–
5.25 ppm and 6.20–6.30 ppm, and integrals show that each doublet
corresponds to one proton. The singlet assigned to the methyl protons
is at 2.42 ppm.
Kinetic Study
Reaction Order
The kinetic parameters of the interaction of arenesulfinic acids with
2-bromo-1,3-diphenyl-2-propenone and 3-bromo-4-phenyl-3-butene-2-
on were determined. The interactions are second order reactions, but
they are first order regarding each reagent. The overall reaction or-
der was determined by using the Van’t Hoff method and the half-time
method in the concentration interval 0.15–10 M. The overall reac-
tion order for the nucleophilic addition of benzensulfinic acids to 2-
bromo-1,3-diphenyl-2-propenone was calculated to be 1.71 (Table II),
TABLE II Experimental Proof of the Benzensulfinic Acids
Addition Order to 2-Bromo 1,3-Diphenyl-2-Propenone by the
Methods of Van’t Hoff and Half-Time in the Concentration
Range 0.01–10 M, T = 298 K
Concentration Range C, M
0.01–0.1
0.1–1
1–5
5–10
Order value by the Van’t Hoff Method
Order Value by the half-time method
1.67
1.74
1.65
1.76
1.69
1.77
1.67
1.75

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D. Aleksiev et al.
TABLE III Experimental Proof to the Benzenesulfinic Acids
Addition Order to 3-bromo-4-Phenyl-3-Butene-2-On by the
Methods of Van’t Hoff and Half-Time in the Concentration
Range 0.01–10 M, T = 298 K
Concentration Range C, M
0.01–0.1
0.1–1
1–5
5–10
Order value by the Van’t Hoff Method
Order Value by the half-time method
1.60
1.70
1.59
1.75
1.62
1.78
1.58
1.77
and the reaction order for the interaction between 3-bromo-4-phenyl-3-
butene-2-on and benzenesulfinic acid was found to be 1.67 (Table III).
These calculations can also be proved by the linear dependence 1/[bro-
mochalkone] = f(τ). Slopes of straight lines for these dependences were
used to calculate rate constants for five different temperatures. The ac-
tivation energy and the enthalpy of activation were determined using
the Arrhenius equation (Table IV).
Effect of the Substituents
Rate constants for the addition of arenesulfinic acids to bro-
mochalkones are presented in Table IV. These results and the
TABLE IV Substituent Effect on Rate Constants and Addition
Parameters at Different Temperatures
Nusleophile Subst. Rate Temp. K K · 104
m
−1.s−1 E kJ · mol−1 ꢀH = kJ · mol−1
1
1
4
4
2b
2c
2b
2c
288
293
298
303
308
288
293
298
303
308
288
293
298
303
308
288
293
298
303
308
1.17 0.3
1.93 0.5
2.73 0.4
4.29 0.6
7.10 0.3
6.67 0.2
0.87 0.6
0.96 0.4
1.23 0.5
1.50 0.3
2.06 0.8
3.65 0.6
5.28 0.7
9.14 0.9
14.58 1.1
1.00 0.2
1.13 0.4
1.41 0.3
1.62 0.2
2.06 0.6
49.01
52.81
46.09
50.66
48.76
52.56
45.85
50.42

Ketosulfones
1613
calculated Hammet’s constants show that the methyl group in the p-
position in the benzene ring of the sulfinic acid accelerates the reac-
tion, while the chlorine atom in the same position has the opposite
effect.
The addition of a bromine atom to an α´-carbon atom of the carbon–
carbon double bond decreases the activity of the bond regarding nu-
cleophilic reagents. A comparison of rate constants shows that ni-
trochlkones are more active toward these reagents in the nucleophilic
reactions than bromochakones.
EXPERIMENTAL
Methods
Melting points were determined on a Melt-Temp apparatus and are un-
corrected. Microanalyses were obtained using an elemental Analyzer-
1104 (Carlo-Erba). IR and UV spectra were obtained using a Bruker
1
and Specord UV-VIS. H NMR (chemical shifts measured in deuter-
ated solvents are given in ppm from TMS) spectra were recorded with
a Bruker 350 MHz spectrometer, using CDCl3 solution.
The Typical Procedure for the Preparation
of 3-Arylsulfonyl-2-bromo-1,3-diphenylpropanones 3
and 4-arylsulfonyl-3-bromo-4-phenyl-2-butanones (5)
To 1,3-diphenyl-2-bromopropenone (3-bromo-4-phenyl-3-butene-2-on)
(0.01 mol) in 95% ethanol was added sulfinic acid (0.01 mol). The re-
action mixture was kept standing at 20◦C for 10 h to yield the substi-
tuted ketosulfones. The crystals obtained were filtered and recrystal-
lized from toluene.
Selected Data for 3a
IR (ν, cm−1, KBr): 1663 (CO Ph); 1297 (νSaOs ); 1135 (νSsO ). UV (λ max.,
2
2
nm (EtOH); lg ε): 206 (2.85); 258 (3.06); 313 (3.10). 1H NMR (δ) CDCl3:
7.20–7.80 (m, 15 H); 5.12 (d, CH); 6.11 (d, CH).
Selected Data for 3b
IR (ν, cm−1, KBr): 1667 (CO Ph); 1300 (νSaOs ); 1135 (νSsO ); UV (λ max.,
2
2
nm (EtOH); lg ε): 207 (3.01); 258 (2.99); 317 (3.21). 1H NMR (δ) CDCl3:
7.23–7.82 (m, 14 H); 5.10 (d, CH); 6.13 (d, CH); 2, 40 (s, CH3).

1614
D. Aleksiev et al.
Selected Data for 3c
IR (ν, cm−1, KBr): 1667 (CO Ph); 1313 (νSaOs ); 1140 (νSsO ). UV (λ max.,
2
2
nm (EtOH); lg ε): 206 (2.94); 260 (3.09); 318 (3.19). 1H NMR (δ, CDCl3:
7.18–7.78 (m, 14 H); 5.13 (d, CH); 6.12 (d, CH).
Selected Data for 5a
IR (ν, cm−1, KBr): 1702 (CO); 1295 (νSaOs ); 1140 (νSsO ). UV (λ max., nm
2
2
1
(EtOH); lg ε): 224 (2.19); 254 (3.00); 297 (3.03). H NMR (δ, CDCl3,
7.24–7.82 (m, 10 H); 5.13 (d, CH); 6.11 (d, CH).
Selected Data for 5b
IR (ν, cm−1, KBr): 1705 (CO); 1295 (νSaOs ); 1140 (νSsO ). UV (λ max., nm
2
2
1
(EtOH); lg ε): 225 (3.27); 252 (3.11); 296 (3.24). H NMR (δ, CDCl3:
7.20–7.75 (m, 9 H); 5.10 (d, CH); 6.14 (d, CH); 2.41 (s, CH3).
Selected Data for 5c
IR (ν, cm−1, KBr): 1750 (CO); 1305 (νSaOs ) 1140 (νSsO ). UV (λ max., nm
2
1 2
(EtOH); lg ε): 225 (3.33); 253 (3.21); 296 (3.39). H-NMR (δ, CDCl3:
7.23–7.81 (m, 9H); 5.12 (d, CH); 6.13 (d, CH).
Rate Measurement
Purified benzenesulfinic acids (0.001 mol) were added to the correspond-
ing bromoketones (0.001 mol) in ethanol (50 mL). Aliquots were taken
out at regular intervals of time and diluted with ethanol. Flow concen-
trations of reagents during the reaction were determined by means of
UV spectrophotometry. The second-order constants, activation energy,
and enthalpy of activation were calculated according to the literature.
REFERENCES
[1] J. B. Harbone, The Flavonoids. Advances in Research, p. 348 (Chapman and Hall,
London and New York, 1988).
[2] A. C. Jain and A. Sharma, Tetrahedron, 41, 5933 (1985).
[3] D. N. Dhar, The Chemistry of Chalcones and Related Compounds, p. 241 (John Wiley
& Sons, New York, Chichester, Brisbane, Toronto 1981).
[4] Chem. Abstr., 73, 45798 q (1970).