Spectral studies and configurational assignments of some 2-propenone derivatives

Article abstract of DOI:10.1080/10426500210229

3-(4-Substitutedphenyl)-1-phenyl-2-phenylthio-2-propen-1-ones (1-5) (1, R = H; 2, R = 4-OCH₃; 3, R = 4-Cl; 4, R = 4-Br; 5, R = 4-NO₂) have been synthesized by the condensation of 4-substituted benzaldehyde and phenacyl sulfide in pre

Full text of DOI:10.1080/10426500210229

This article was downloaded by: [University of Otago]
On: 24 December 2014, At: 12:09
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Phosphorus, Sulfur, and Silicon and the Related
Elements
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/gpss20
Spectral Studies and Configurational Assignments of
Some 2-Propenone Derivatives
S. M. Batterjee a
a Chemistry Department, Faculty of Science , King Abdulaziz University , PO Box 10093,
Jeddah, 21433, Kingdom of Saudi Arabia
Published online: 27 Oct 2010.
To cite this article: S. M. Batterjee (2002) Spectral Studies and Configurational Assignments of Some 2-Propenone Derivatives,
Phosphorus, Sulfur, and Silicon and the Related Elements, 177:1, 33-44, DOI: 10.1080/10426500210229
To link to this article: http://dx.doi.org/10.1080/10426500210229
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur and Silicon, 2002, 177:33–44
C
Copyright 2002 Taylor & Francis
1042-6507/02 $12.00 + .00
SPECTRAL STUDIES AND
CONFIGURATIONAL ASSIGNMENTS
OF SOME 2-PROPENONE DERIVATIVES
S. M. Batterjee
Chemistry Department, Faculty of Science,
King Abdulaziz University, PO Box 10093, Jeddah 21433,
Kingdom of Saudi Arabia
(Received March 5 2001.)
3-(4-Substitutedphenyl)-1-phenyl-2-phenylthio-2-propen-1-ones (1–5)
(1, R = H; 2, R = 4-OCH3; 3, R = 4-Cl; 4, R = 4-Br; 5, R = 4-NO2) have
been synthesized by the condensation of 4-substituted benzaldehyde and
phenacyl sulfide in presence of base. The structure and configuration of
these compounds were determined by UV, IR and NMR spectroscopy.
3
The DEPT, 2DNMR, NOE and JCH in the coupled 13C-NMR spectra
indicated that compounds 1–5 belong to the E-configuration.
Keywords: Configuration; trisubstituted ethylene; UV; IR and NMR
spectra
INTRODUCTION
Structural proof and configurational assignments of trisubstitued
4
ethylenes were based on 1HNMR data1 and the theoretical shifts ob-
tained by applying the NMR rule of the additivity principle.5,6 It was
found that the vinylic carbon atom was shielded due to the electron-
withdrawing abilities of the attached groups and deshielded owing to
the electron-attracting group at the -position.7 A good evidence to as-
sign the configuration of trisubstituted ethylene is the long-range (3JCH
values which indicated E or Z isomers.8,9
)
This investigation forms a part of a study undertaken to establish
the configurational assignment of 3-(4-substituted phenyl)-1-phenyl-2-
phenylthio-2-propen-1-ones 1–5 utilizing their spectroscopic data. In
these compounds, the phenylthio and benzoyl groups are bulky and
cross-conjugated with the CH CHAr. It would be of interest to know
which of them is cis and which is trans to the aryl group.
Address correspondence to S. M. Batterjee, Chemistry Department, Faculty of Science,
King Abdulaziz University, PO Box 10093, Jeddah 21433, Kingdom of Saudi Arabia.
33

34
S. M. Batterjee
RESULTS AND DISCUSSION
The treatment of phenyl phenacyl sulfide10 with 4-substituted ben-
zaldehydes in the presence of a catalytic amount of piperidine afforded
condensation products11 1–5 according to a mechanism analogous to
that of Knoevenagel condensation (Eq. 1). The Knoevenagel reaction
SC6H5
|
C6H5COCH2SC6H5 + R C6H4 CHO → C 6 H 5 CO C CH C6H4
R
(1)
1, R = H; 2, R = 4-OCH3; 3, R = 4-Cl; 4, R = 4-Br; 5, R = 4-NO2
has been reported earlier for condensation of -cyano and -carboethoxy
sulfides with aromatic aldehydes.12
Elemental analyses, UV, IR and NMR spectroscopy indicated the
formation of 3-(4-substituted phenyl)-1-phenyl-2-phenylthio-2-propen-
1-ones 1–5 (Eq. 1). An initial determination of the structure of
compounds 1–5 could be suggested from the spectral data of 3-
(4-nitrophenyl)-1-phenyl-3-phenylthio-2-propen-1-one (6), which is dif-
ferent from that of compound 5 (R = 4-NO2). This indicates evidence for
the presence of a phenylthio moiety at the C-3 rather than at the 3-one
in compound 5. Compound 6 was obtained by the addition of sodium
thiophenoxide to 3-(4-nitrophenyl)-1-phenyl-2-propyn-1-one (Eq. 2).13
4-NO2 C6H4 C C CO C6H5 + Na+S C6H5
MeOH
> 4-NO2 C6H4 C CH CO C6H5
(2)
|
SC6H5
(6)
Furthermore, the acid hydrolysis14 of compound (1) (R = H) gave
benzyl phenyl diketone (7) which is expected to be the product if the
phenylthio is attached to C-2 ( -carbon with respect to the carbonyl
group) (Eq. 3).
C6H5 CH C CO C6H5
|
SC6H5
(1)
H2O, H+
>C6H5 CH2COCOC6H5 + C6H5SH
(7)
(3)
1

Spectral Studies
35
Structural Proof and Configurational Assignment
of Compounds (1--5)
Though compounds 1–5 can exist as E- and Z-configurational isomers,
only one form of compounds 1–5 was obtained. The more stable form,
whether the benzoyl should be trans or the phenylthio should be trans to
the aryl cannot be decided on steric grounds. This is because in either
case there are bulky groups in the cis position that gave rise to con-
siderable nonbonding interactions. The dipole moments revealed that
E-isomer was the likely structure of these compounds.15 However, a
study of their spectral data would be of a valuable aid in gaining fur-
ther information about their configuration.
Nuclear Magnetic Resonance
The configurational assignment of compounds 1–5 were based on NMR
analysis. Typical 1H and 13CNMR chemical shifts are given in Tables I
and II.
1
The two doublets in the H-NMR spectra at 8.28–7.43 (H-200,600)
and 7.91–6.95 ppm (H-300,500) strongly suggest the presence of para-
substituted aromatic ring. The two triplets at 7.39–7.37 (H-30,50) and
7.51–7.49 ppm (H-40) and a doublet at 8.29–7.72 ppm (H-20,60) with five
hydrogens suggest the presence of monosubstituted aromatic ring at-
tached to carbonyl group. Also, the doublet at 7.24–7.19 (H-2000,6000) and
a multiplet at 7.13 ppm (H-3000, 4000,5000) with five hydrogens indicate the
presence of monosubstituted aromatic ring bonded to sulfur atom. The
signal at 194.69–193.53 ppm in the 13C-NMR spectra and the peak
1
at frequency (¯) at 1662–1656 cm in the IR spectra is in the region

36
S. M. Batterjee
TABLE I 1H-NMR Spectral Data of 3-aryl-1-phenyl-2-phenylthio-2-propen-1-
ones (1–5) ( ppm, CDCl3)
Nucleus 1
H-20,60
H
1(R H)
2(R OCH3)a
3(R Cl)
4(R Br)
5(R NO2)
7.74 (d)
(J = 8.50 Hz)
7.71 (d)
7.65 (d)
(J = 8.72)
7.52 (d)
8.29 (d)
(J = 8.80)
7.72 (d)
7.80 (d)
(J = 7.45)
7.43 (d)
7.72 (d)
(J = 7.72)
8.28 (d)
H-200,600
H-40
(J = 7.94)
(J = 7.27)
(J = 7.29)
(J = 7.50)
(J = 8.78)
7.49 (t)
7.49 (t)
7.51 (t)
7.48 (t)
7.51 (t)
(J = 7.42)
7.39 (t)
(J = 7.36)
7.36 (m)+H-400
—
(J = 7.36)
7.37 (t)
(J = 7.43)
7.38 (t)
(J = 7.58)
7.37 (t)
(J = 7.40)
7.37 (t)
H-30,50
H-300,500
H-2000,6000
(J = 7.72)
(J = 7.69)
(J = 7.67)
(J = 7.79)
6.95 (d)
7.91 (d)
7.73 (d)
7.91 (d)
(J = 8.78)
7.24 (d)
(J = 8.53)
7.13 (m)
7.25 (s)
(J = 8.73)
7.23 (d)
(J = 7.60)
7.13 (m)
7.26 (s)
(J = 7.49)
7.22 (d)
(J = 7.34)
7.13 (m)
7.25 (s)
(J = 8.70)
7.19 (d)
(J = 7.25)
7.13 (m)
7.26 (s)
7.19 (m)
—
7.13 (m)
7.29(s)
H-3000,5000,4000
CH
a4-OCH3 protons appear at 3.85 ppm.
of carbonyl group of conjugated ketones.8 The 13C-NMR spectra of the
vinylic carbon that bears phenylthio group displays signal at 133.85–
133.05 ppm which agrees with the reported value for vinylic carbon
bearing an electron-withdrawing substituent.7,16,17 The low intensity
of such signal could be expected for carbon bearing no hydrogens.
TABLE II 13CNMR Spectral Data of 3-aryl-1-phenyl-2-phenylthio-2-propen-
1-ones (1–5) ( ppm, CDCl3)
Nucleus 13
C
1(R H)
2(R OCH3)a
3(R Cl)
4(R Br)
5(R NO2)
C-20,60
C-200600
C-400
131.55
129.29
132.55
128.67
128.09
128.09
131.41
127.54
127.54
137.11
136.28
135.16
137.82
133.05
194.14
132.54
128.89
132.12
129.29
113.89
160.76
130.32
128.02
126.89
137.79
165.64
127.64
142.00
133.85
194.69
132.55
129.29
133.05
128.24
130.64
147.24
129.11
123.68
128.31
141.36
144.33
136.51
133.32
133.29
193.55
130.37
128.42
132.44
128.06
129.39
133.04
131.24
128.91
127.33
135.53
137.33
134.59
139.41
133.49
194.38
129.29
130.64
132.54
128.25
123.79
147.22
129.29
132.71
131.64
141.07
140.94
136.51
134.31
133.31
193.33
C-300,50
C-300,500
C-4000
C-2000,6000
C-3 ,5000
C-40000
C-100
C-1
C-1000
C-3
C-2
C-1
a4-OCH3 carbon-13 appears at 55.35 ppm.

Spectral Studies
37
The DEPT technique8,9 shows the disappearance of quaternary car-
bons at
194.69–193.53 (C-1), 133.85–133.05 (C-2), 141.36–137.11
(C-10), 165.64–134.31 (C-100), and 136.51–135.16 (C-1000) (Tables I and II).
The CH COSY8,9 technique (2DNMR, HETCOR spectrum) is attractive
because it is efficient and indicates which carbons are bonded to which
hydrogens. The resulting counter plots (e.g., (R = H), Figure 1), confirm
the tentative 1H and 13C shift assignments (Tables I and II).
The configurational assignments of compounds 1–5 could be deter-
1
mined by applying the H-NMR additivity increment scheme.5,6,8 The
calculated chemical shifts of the vinylic protons in compounds 1–5 are
7.31 ppm for the E-configuration and 7.57 ppm for the correspond-
ing Z-isomer (Figure 2). These values indicate a small difference in the
chemical shift of the vinylic hydrogens for E- and Z-isomers.
FIGURE 1 The HETCOR spectrum of 1,3-diphenyl-2-propen-1-one 1 in CDCl3
at 400 MHz 1H and 100 MHz for 13C.

38
S. M. Batterjee
FIGURE 2 The calculated chemical shifts of the vinylic proton of E and Z of
1–5.
Therefore, the conclusion from the additivity calculation is unreli-
able. This may be due to the fact that the calculations are using a single
value for the aryl groups regardless of its substitution and the Ar-C C
dihedral angle.
Since the olefinic C C double bond in (1–5) is trisubstituted, the rel-
ative configuration cannot be obtained on the basis of the cis and trans
couplings of vicinal alkene proton in the 1H-NMR spectrum. However,
the relative configuration at the 2,3-double bond in compounds (1–5) can
be derived from NOE difference spectra of (3) (R = 4-Cl) (Figure 3a)
an enhancement of a signal when a nearby resonance is irradiated,
1
1H H through space interaction. The irradiation of H-20, 60 indicates
that H-30,50, H-300,500 and H-200,600 are definitely enhanced (Figure 3b).
Irradiation of H-300,500 with strongly enhances H-20,60, H-30,50 and
H-200,600 (Figure 3c). The results are supported by irradiation of
H-200,600 and H-300,500 strong effect on H-200,600 and H-30,50 (Figure 3d),
while irradiation of H-30,50 greatly enhances H-20,60, H-300,500 and
H-200,600 (Figure 3e). These observations indicate that the phenyl ring
attached to the carbonyl group and 4-chlorophenyl ring are on the
same side of the 2,3-double bond suggesting the E-configuration of
3
compound 3 (R = 4-Cl). This result is confirmed from JCH of the car-
bonyl carbon (C-1) 13C signal at 194.69–193.53 ppm in the coupled
13C-NMR spectrum. This technique gives conclusive information con-
cerning the relative configuration of C and H in tri-substituted
alkenes.8,9 As a result, a doublet (J = 16.9 Hz) and multiplet were
3
observed for compound 3 (R = 4-Cl). The JCH value = 16.9 Hz cou-
pling points to a trans configuration8,9 of carbonyl carbon (C-1) and
olefinic H-3. Consequently, the benzoyl and aryl groups are therefore
occupying cis-position. Similarly, compounds 1, 2, 4, and 5 belong to the
E-configuration.

Spectral Studies
39
FIGURE 3 (a) 1H NMR of 3 (R = 4-Cl); (b) Irradiation of H-20,60, (c) Irradiation
of H-300,500; (d) Irradiation of H-200,600 and H-300,500; (e) Irradiation of H-30,50.
Infrared Spectral Study
The infrared spectra of 1–5 can be used to confirm their E-configuration.
The C H stretching and deformation vibrations are not used to inves-
tigate the configuration. However, it may be determined by examining

40
S. M. Batterjee
TABLE III UV and IR Spectral Data of 3-aryl-1-phenyl-2-phenylthio-
2-propen-1-ones (1–5) and 1-phenyl 3-(4-nitrophenyl)-3-phenylthio-2-propen-
1-one (6)
1
¯ cm
Cpd.
R
nm (log ε)
C
O
C C
1
H
203
(4.06)
211
(4.29)
206
(4.20)
214
(4.32)
204
268
(3.91)
253
(4.27)
260
(4.11)
255
(4.39)
260
(3.93)
265
345
(3.49)
340
(4.15)
365
(3.93)
342
(3.95)
365
1661
1657
1659
1662
1656
1631
1582
1574
1599
1561
1513
1536
2
3
4
5
6
4-OCH3
4-Cl
285
(4.28)
4-Br
4-NO2
4-NO2
(4.11)
207
(3.74)
337
243
(4.21)
(4.06)
(4.09)
(4.10)
the characteristic vibrational frequencies of the C O and C C and the
influence of substitutent on them.
It was observed that the presence of a substituent in the 4-position
of the aryl group (at C-3) does not have any significant effect on
the frequency of the C O (C-1) stretching vibrations in compounds
1–5 (Table III). This is consistent with the deconjugation of the
carbonyl and aryl groups in the Z-isomer of -phenyl chalcone.18
In contrast, the frequency of C C is changed by varying the na-
ture of the 4-substituents. Table III shows that ¯C
(R = 4-NO2) is differing by ca 69 and 61 cm respectively than 1
in compound 5
C
1
FIGURE 4 Conjugative interaction between lone pair of sulfur atom and 4-
substituent.

Spectral Studies
41
(R = H) and 2 (R = 4-OCH3). Therefore, there is an appreciable conjuga-
tive interaction between the lone pair of electrons on the sulfur atom of
the phenylthio moiety and the 4-substituent on the aryl at C-3 through
the double bond (structure I; Figure 4). Consequently the configuration
of compounds 1–5 could exist in the E-configuration where the benzoyl
group is situated cis to the aryl ring.
Ultraviolet Spectral Studies
The electronic spectra of compounds 1–5 show three bands at
203–214, 253–268, and 345–365 nm except compound 2 (R = 4-OCH3)
which exhibited a fourth band at 285 nm. The bands at 345–365 nm
are presumably due to the stability of the quinoid resonance structure I
(Figure 4) via the electrostatic attraction between the electron density
on the oxygen atom of the carbonyl group and the developed positive
charge on the sulfur atom.
The high extinction coefficient and the lower wavelength of
compound 5 (R = 4-NO2; = 365 nm, log ε = 3.74) compared to
compound 6 3-(4-nitrophenyl)-3-phenylthio-1-phenyl-2-propene-1-one,
( = 337 nm), log ε = 4.10) (Table III) indicate a direct conjugation be-
tween the 4-NO2 substituent and the carbonyl group in the latter. How-
ever, the lower wavelength of 6 than that of 5 indicates that the former
subsist mainly in the Z-configuration (Figure 5). This is confirmed from
the difference in the frequency of C O and C C for compounds 6 (¯C
O
1631, ¯C 1536 cm 1) and 5 (¯C 1656, ¯C 1513 cm 1), which have
C
O
C
4-NO2 substituent. These electronic spectral data indicate the presence
of the phenylthio group at C-2 trans to the aryl group and compounds
1–5 belong to the E-configuration.

42
S. M. Batterjee
EXPERIMENTAL
Melting points were uncorrected. Microanalyses were performed by the
microanalysis unit, Faculty of Science, King Abdulaziz University, Jed-
dah. Infrared spectra (KBr pellets) were measured on Perkin-Elmer
1430 recording spectrophotometer and the electronic spectra were
recorded in absolute ethanol on UV VIS Shimadzu 160-A spec-
trometer. The 1H and 13C-NMR spectra were recorded at 400 and
100 MHz respectively (DRX 400 FTNMR Bruker). All the 1H-NMR spec-
tra were obtained for approximately 0.03 M solutions in CDCl3 with
TMS as internal reference and broadband and off-resonance decoupled
13CNMR spectra were obtained for approximately 0.5 M solutions in
CDCl3 with TMS as internal reference. 2D C/H shift correlated spec-
tra were obtained using the standard Bruker program. The 1H and 13
C
chemical shifts of the titled compounds are presented in Tables I and II.
Preparation of Phenacyl Aryl Sulfide11
Thiophenol (2.65 g, 0.024 mol) and 5.60 g (0.24 g atm) of finely di-
vided sodium metal were allowed to react in 300 ml of anhydrous di-
ethylether for 16 h. The suspension was cooled to 5 C and the mix-
ture was stirred while 4.80 g (0.024 mol) of phenacyl bromide was
added during 45 min. The temperature was held at 0 C throughout
the addition, then the mixture was allowed to warm to room tem-
perature during a further two and one half hour period. Dry ether
(250 ml) was then added, the sodium bromide filtered off, and the
product was crystallized from methanol after removal of ether, yield
4.31 g (77%) of phenyl phenacyl sulfide, m.p. 62 . Anal. Calcd. for
C14H12OS: C, 73.68; H, 5.26; S, 14.09. Found: C, 73.18; H, 5.53; S,
14.36.
Synthesis of 3-aryl-1-phenyl-1-phenylthio-2-propen-
1-ones11,19 (1 5) General Method
A mixture of phenacyl phenyl sulfide (0.05 mol), freshly distilled ben-
zaldehyde or pure substituted benzaldehyde (0.05 mol), glacial acetic
acid (30 ml), ammonium acetate (0.05 mol) and piperidine (2 ml) were
heated under reflux for 40 h. The solution was cooled, mixed with ether
(200 ml) as successively washed with dil HCI, aqueous sodium carbon-
ate (20%), a saturated aqueous solution of sodium bisulfite and water.
After drying and removal of ether, the residue was crystallized from
methanol-water. TLC (ethylacetate: petroleum ether 1:9) showed that
only one product was obtained.

Spectral Studies
43
1,3-diphenyl-2-phenylthio-2-propen-1-one (1). Pale yellow crystals,
yield 78%, m.p. 83 C. Anal. Calcd. for C21H16OS; C, 79.75; H, 5.06; S,
10.13. Found: C, 79.45; H, 5.26; S, 10.56.
1-phenyl-3-(4-methoxyphenyl)-2-phenylthio-2-propen-1-one (2). Pale
yellow crystals, yield 70%, m.p. 106 C. Anal. Calcd. for C22H18O2S: C,
76.30; H, 5.20; S, 9.25. Found: C, 76.42; H, 5.55; S, 8.94.
1-phenyl-3-(4-chlorophenyl)-2-phenylthio-2-propen-1-one (3). Deep
yellow crystals, yield 75%, m.p. 133 C. Anal. Calcd. for C21H15ClOS: C,
71.90; H, 4.28; S, 9.13. Found: C, 72.32; H, 4.61; S, 9.62.
1-phenyl-3-(4-bromophenyl)-2-phenylthio-2-propen-1-one (4). Beige
crystals, yield 75%, m.p. 132 C. Anal. Calcd. for C21H15BrOS: C, 63.80;
H, 3.80; S, 8.10. Found: C, 64.03; H, 4.03; S, 8.66.
1-phenyl-3-(4-nitrophenyl)-2-phenylthio-2-propen-1-one (5). Deep
yellow crystals, yield 82%, m.p. 133 C. Anal. Calcd. for C21H15NO3S: C,
69.81; H, 4.16; N, 3.88; S, 8.86. Found: C, 70.37; H, 4.53; N, 4.08; S, 8.71.
Synthesis of 1-phenyl-3-(4-nitrophenyl)-3-phenylthio-2-
propen-1-one (6)
The synthesis of 3-aryl-1-phenyl-2-propyn-1-ones has been reported
earlier.13 1-Phenyl-3-(4-nitrophenyl)-propynone (0.5 g, 0.01 mol) was
dissolved in absolute methanol and a solution of equivalent amounts
of sodium and thiophenol (0.5 g, 0.01 mol) in absolute methanol were
added. A precipitate was formed, filtered off, washed with 1% sodium
hydroxide, then crystallized from methanol as yellow needles, 0.68 g
(94%), m.p. 125 C. 1H-NMR ppm (CDCl3); 7.67 (d, H-20,60, J = 8.46),
8.04 (d, H-200,600, J = 8.54), 7.64 (t, H-40, J = 7.89), 7.57 (t, H-30,50, J =
7.72), 8.16 (d, H-300,500, J = 8.26), 7.31 (m, H-2000,6000), 7.15 (m, H-3000,4000,5000)
and 7.52 (s, Z CH). Anal. Calc. for C21H15NO3S: C, 69.81; H, 4.16; N,
3.88; S, 8.86. Found: C, 69.43; H, 4.33; N, 3.58; S, 9.04.
REFERENCES
[1] Y. Amiel, J. Org. Chem., 36, 3691 (1971).
[2] Y. Amiel, J. Org. Chem., 36, 3697 (1971).
[3] Y. Amiel, J. Org. Chem., 39, 3867 (1974).
[4] E. A. Hamed, Ind. J. Chem., 37, 1202 (1998).
[5] U. E. Matter, C. Pascual, E. Pretsch, A. Pross, W. Simon, and S. Sternhell, Tetrahe-
dron, 25, 691 (1969).
[6] S. W. Tobey, J. Org. Chem., 34, 1281 (1969).
[7] F. A. Battino, G. Musumara, and Z. Rappoport, Magn. Res. Chem., 24, 31 (1986).
[8] M. Silverstein, G. C. Bassler, and T. C. Morrill, Spectrometric Identification of Or-
ganic Compounds (Wiley, New York, 1991), 4th ed.

44
S. M. Batterjee
[9] E. Breitmaier, Structure Elucidation by NMR (Wiley, New York, 1993).
[10] E. A. Hamed, M. S. M. El-Saadi, and F. M. El-Hegazy, Synth. Commun., 25, 3471
(1995).
[11] V. Ballah and C. Natarajan, Ind. J. Chem., 8, 694 (1970).
[12] H. Dresseler and J. E. Graham, J. Org. Chem., 32, 985 (1967).
[13] E. A. Hamed, S. M. Sharaf, S. A. Abdel-Baky, M. F. Ibrahim, and A. A. Youssef,
J. Phys. Org. Chem., 3, 657 (1990).
[14] R. A. McClelland, Can. J. Chem., 55, 548 (1977).
[15] V. Ballah and C. Natarajan, Ind. J. Chem., 9, 435 (1971).
[16] M. Beit-Yannai, Z. Rappoport, B. A. Shainyan, and Y. S. Danilevich, J. Org. Chem.,
62, 8049 (1997).
[17] Z. Rappoport, Acc. Chem. Res., 25, 474 (1992).
[18] P. J. Duke and D.W. Baykin, Jr., J. Org. Chem., 37, 1436 (1972).
[19] T. Mukaiyama, T. Takashima, and S. Ono, Tetrahedron Lett., 3439 (1967).