Ring opening of 2,6-diaryl-3,5-diphenyl piperidine-4-one by acetic acid: Structural studies and Hirshfeld surface analysis of (E)-4-aryl-1,3-diphenylbut-3-en-2-ones

Article abstract of DOI:10.1002/jhet.4188

Six α,β-unsaturated carbonyl compounds have been obtained from 2,6-diaryl-3,5-diphenylpiperidine-4-one by the treatment with acetic acid. A plausible mechanism for the ring opening of 2,6-diaryl-3,5-diphenyl piperidin-4-ones is proposed. The resultant (E)

Full text of DOI:10.1002/jhet.4188

Received: 2 August 2020
DOI: 10.1002/jhet.4188
Revised: 26 October 2020
Accepted: 4 November 2020
A R T I C L E
Ring opening of 2,6-diaryl-3,5-diphenyl piperidine-4-one by
acetic acid: Structural studies and Hirshfeld surface
analysis of (E)-4-aryl-1,3-diphenylbut-3-en-2-ones
Gopal Vengatesh1 | Manthiram Sundaravadivelu1
Shanmugam Muthusubramanian2
|
1Department of Chemistry, The
Abstract
Gandhigram Rural Institute (Deemed to
be University), Gandhigram, India
Six α,β-unsaturated carbonyl compounds have been obtained from 2,6-diaryl-
3,5-diphenylpiperidine-4-one by the treatment with acetic acid. A plausible
mechanism for the ring opening of 2,6-diaryl-3,5-diphenyl piperidin-4-ones is
proposed. The resultant (E)-4-aryl-1,3-diphenylbut-3-en-2-ones have been
characterized by 1H and 13C nuclear magnetic resonance (NMR) spectral stud-
ies. One of the compounds was completely characterized by 2D NMR tech-
niques, and structure of the compound is further proved by single-crystal
X-ray diffraction (XRD) analysis. The crystal structure, three-dimensional
framework of crystal, and Hirshfeld surface analysis of two of the compounds
have been discussed. In the crystals, molecules are mainly linked by C HꢀꢀꢀO
hydrogen bonding interactions, and this interaction forms an inversion dimer
2Department of Organic Chemistry,
School of Chemistry, Madurai Kamaraj
University, Madurai, India
Correspondence
Manthiram Sundaravadivelu, Department
of Chemistry, The Gandhigram Rural
Institute (Deemed to be University),
Gandhigram 624302, Tamil Nadu, India.
Email: msundargri@gmail.com
Funding information
Ministry of Tribal Affairs, Government of
India for the award of NFST Scheme,
Grant/Award Number: 201718-NFST-
TAM-00803; UGC, New Delhi for Major
Research Project, Grant/Award Number:
42-358/2013 (SR)
1
1
with R2 (6) and R2 (10) ring motifs in one of the compounds. Hirshfeld surface
indicates the dominance of HꢀꢀꢀH contacts on the overall surface.
1 | INTRODUCTION
of interactions facilitates the design and emerging of new
materials with specified properties. The crystal packing
α,β-Unsaturated ketones are widely used in the field of
synthetic chemistry as valuable intermediates in building
complex organic molecules.1–6 They have also drawn
attention due to their broad applications in the field of
food, agriculture, and medicinal industries.7–10 A variety
of synthetic strategies such as aldol condensation,11 Heck
coupling,12 oxidation of allylic alcohols,13 Horner-
Wadsworth-Emmons reaction,14 and Saegusa-Ito oxida-
tion reaction15 have been developed toward the synthesis
of α,β-unsaturated carbonyl systems. Several transition
metals and acid catalyzed syntheses toward
α,β-unsaturated carbonyl compounds have been
reported.16–24 The analysis of intermolecular (strong and
weak) interaction plays a crucial role in the field of crys-
tal engineering and biological activity.25,26 The analysis
arrangements are predominantly controlled by the pres-
ence of strong hydrogen bonds such as O/N HꢀꢀꢀO/N.27
However, now researchers focus on the investigation of
weak intermolecular interactions such as C HꢀꢀꢀN/O/
halogens/π.28,29 The α,β-unsaturated aryl ketone consists
of π conjugation (C C C O)-based molecular systems.
These types of molecules have high nonlinear optical
properties.30 They mostly form weak intermolecular
interactions.31–33
We have already described the iodine/methanol-
mediated reaction of 2,6-diaryl-3,5-diphenylpiperidin-4-ones
leading to ring contraction.34 In continuation, attempts have
been made to aromatize 2,6-diaryl-3,5-diphenylpiperidin-
4-ones by several routes. During this investigation, it is
realized that 2,6-diaryl-3,5-diphenylpiperidin-4-ones are
J Heterocyclic Chem. 2020;1–13.
wileyonlinelibrary.com/journal/jhet
© 2020 Wiley Periodicals LLC.
1

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VENGATESH ET AL.
sensitive to acids undergoing ring cleavage yielding (E)-
4-aryl-1,3-diphenylbut-3-en-2-ones. The compounds obtained
were confirmed by 1D and 2D NMR spectral studies and
single-crystal XRD studies.
2f), Scheme 1. To optimize the reaction conditions, syn-
thesis of 2a under different conditions was studied that
include change of the solvent, volume of the acetic acid,
reaction time, and temperature (Table 1). The reaction in
ethanol (5 mL) and acetic acid (3 mL) at 70ꢁC affording
2a in 81% yield in 4 hours (Table 1, entry 3) was found to
be the optimized one. The reaction has been carried out
with substituted phenyl groups, such as methoxyphenyl,
chlorophenyl, fluorophenyl, and tolyl groups. Yield and
melting points of the resulting products (2a-2f) are pres-
ented in Table 2.
2 | RESULT AND DISCUSSION
The starting tetra substituted piperidones—2,6-diaryl-
3,5-diphenylpiperidin-4-ones (1a-1f)—were prepared by
a
one-pot process involving ammonium acetate
(1.0 mmol), dibenzyl ketone (1.0 mmol), and aryl alde-
hydes (2.0 mmol) in warm ethanol. This method is a
modified Mannich condensation developed by Noller and
Baliah.35 It was our original plan to aromatize this tetra
substituted piperidones to get symmetrical tetra
substituted pyridine derivatives. One such earlier attempt
with iodine and methanol has lead to an interesting ring
contraction yielding 5-aryl-2-methoxy-2,4-diphenyl-1H-
pyrrol-3-ones.34 In continuation of investigating different
routes for successful aromatization of 2,6-diaryl-
3,5-diphenyl piperidin-4-ones, the reaction was carried
out with iodine in the presence of different acids, both
Lewis and Bronsted. In all the cases, a single product was
obtained, and it has also been realized that even in the
absence of iodine, simple acid treatment would result in
the product formation. The product obtained has been
identified as (E)-4-aryl-1,3-diphenyl-but-3-en-2-ones (2a-
All the prepared enones have been fully character-
ized by IR and NMR spectral data. FT-IR and NMR
spectra of the compounds (2a-2f) are given in
supporting information. In the IR spectrum of 2a, C O
and C C stretching frequencies appear at 1677,
1603 cm−1. In the 1H NMR spectrum of 2a, the two
hydrogen singlet due to methylene hydrogens appears at
3.87 ppm, and the 15 aromatic protons resonate between
7.00 and 7.39 ppm. The olefinic hydrogen appears as a
sharp singlet at 7.68 ppm. 1H 1H COSY and NOESY
correlations are shown in Figure 1, and the NOESY cor-
relation between 3.87 and 7.68 ppm helps to identify the
ortho protons of 4-aryl ring. The DEPT-135 and HSQC
spectra are used for the assignment of 13C NMR signals.
In the DEPT-135 spectrum of 2a, the signal at 46.6 ppm
is confirmed as that due to benzylic carbon. The signals
at 126.7, 128.0, 128.2, 128.5, 129.1, 129.3, 129.4, 129.8,
SCHEME 1 Synthesis of
(E)-4-aryl-1,3-diphenyl-but-3-en-
2-one 2 [Color figure can be
viewed at
wileyonlinelibrary.com]
TABLE 1 Optimization of the
synthesis of compound 2a
Entry
Solvent:CH3COOH
CH3COOH
Temp. (ꢁC)
Time (h)
Product (yield [%])
1
2
3
4
5
6
7
60
60
70
70
70
68
62
12
4
55
EtOH (5 mL):2 mL
EtOH (5 mL):3 mL
EtOH (5 mL):3 mL
EtOH (5 mL):4 mL
MeOH (5 mL):3 mL
CHCl3 (5 mL):3 mL
69
81a
78
79
62
58
4
8
8
12
12
aOptimum conditions.

VENGATESH ET AL.
3
TABLE 2 Yield and melting point of the synthesized compounds 2a-2f
Entry
Substrates (1)
Products (2)
Yield (%)
mp (ꢁC)
1
81
84
1a
2a
2b
2
3
4
74
84
79
85
1b
1c
106
2c
88
2d
2e
2f
1d
1e
5
6
82
73
98
114
1f
FIGURE 1 Important COSY,
NOESY and HMBC correlations of
compound 2a [Color figure can be
viewed at wileyonlinelibrary.com]
130.9, and 139.1 ppm are due to the aromatic and ole-
finic CH as confirmed by the DEPT spectrum, the rest of
the carbons being quaternary. In the HSQC spectrum,
the benzylic and aliphatic CH protons observed at 3.87
and 7.68 ppm correlate with 13C signals at 46.6 and
139.0 ppm, respectively, confirming the assignment of

4
VENGATESH ET AL.
benzylic and olefinic carbons. HMBC spectrum of 2a
was also informative in assigning the quaternary car-
bons. Important HMBC correlation is presented in
Figure 1. In the HR-MS spectrum of compound 2a,
molecular ion peak appears at m/e 299.203, and the cal-
culated mass is 299.135. The [M-H2O]+ peak (281.206) is
also found in the HRMS spectrum of compound 2a. The
HRMS spectrum of 2a is provided in the SI section.
To the best of our knowledge, there is no successful
formation of monobenzylidene derivative from
dibenzylketone, and this method is thus a better option
benzaldehyde (singlet at 9.9 ppm) providing evidence to
the proposed mechanism.
2.1 | Single-crystal XRD analysis
2.1.1 | Structural commentary
The single-crystal X-ray diffraction study shows that com-
pound 2a (Figure 2) crystallizes in the monoclinic space
group P21/n, while compound 2c (Figure 3) crystallizes in
the triclinic space group P − 1 with one independent
molecule (Z0 = 1) in the asymmetric unit. In compound
2a, four molecules (Z = 4) are in the unit cell, while two
molecules (Z = 2) are in compound 2c. Experimental
details of the crystals are shown in Table 3. The com-
pounds 2a and 2c are composed of two phenyl rings (p-
chlorophenyl in compound 2c) and one benzyl group,
which are linked by a CO C(Ph) CH enone bridge.
The molecules are not planar. In 2a, the dihedral angle
between the two phenyl rings at C1 (C11 C16) and C2
(C17 C22) is 70.38ꢁ, while in 2c, this dihedral angle is
66.74ꢁ. In 2a, the benzyl ring (C5 C10) forms a dihedral
angle of 88.87ꢁ with the enone bridge (C1 C3), while in
2c, this seems to be 87.79ꢁ. This indicates that benzyl
toward
(E)-4-aryl-1,3-diphenylbut-3-en-2-ones.
Sim
et al.36 have reported the synthesis of 1,3,4-triphenylbut-
3-en-2-one as an intermediate for the synthesis of pyri-
dine derivative. In this reaction, aldehyde reacts with
acetylene derivative in the presence of RhCl (Ph3P)3,
2-amino-3-picoline and benzoic acid at 110ꢁC.
A plausible mechanism for the ring opening of
2,6-diaryl-3,5-diphenyl piperidine-4-one (1) to (E)-
4-aryl-1,3-diphenyl-but-3-en-2-ones (2) is presented in
Scheme 2. The protonated piperidone A undergoes
reverse Michael addition to give intermediate B. This
undergoes ene reaction to form intermediate C, which
1
tautomerizes to 2. The fact that the H NMR spectrum
of the crude reaction mixture shows the presence of
SCHEME 2 Tentative mechanism for the formation of α, β unsaturated ketone 2 [Color figure can be viewed at
wileyonlinelibrary.com]

VENGATESH ET AL.
5
group and enone bridge are nearly perpendicular to each
other.
supramolecular chains are further interconnected by
C Hꢀꢀꢀπ stacking interactions (Figure 4; Table 4) to form
a three-dimensional network structure (Figure 5). The
Cg3 interacts with two donor atoms (C10 H10 and
C16 H16) in two different molecules, where Cg3 is the
centroids of C17 C22 benzene ring. The centroid Cg1
has nearly T-shaped interaction with C21 H21 donor
atom, where Cg1 is the centroids of C5 C10
benzene ring.
The torsion angle of C17 C1 C2 C11 is −4.08ꢁ for
compound 2a. The same torsion angle is 4.18ꢁ for com-
pound 2c. The torsion angle for C1 C2 double bond as
indicated by O1 C3 C2 C1 is −9.47ꢁ for compound 2a,
which is 2.95ꢁ for compound 2c. The torsion angle of the
benzyl and carbonyl group, O1 C3 C4 C5, is 3.51ꢁ for
2a and it is 22.94ꢁ for compound 2c. The torsion angle of
the
carbonyl
group
and
C2
phenyl
ring,
In the crystal 2c, inversion dimers are linked by
pairwise C1 H1ꢀꢀꢀO hydrogen bonds (Table 5) generating
O1 C3 C2 C11, is 174.63ꢁ for compound 2a and
178.89ꢁ for compound 2c.
2
R2 (10) ring motif (Figure 6). The molecules are linked
by a pair of C1 H1ꢀꢀꢀO and C22 H22ꢀꢀꢀO1 hydrogen
1
bond interactions forming R2 (6) ring motif, oxygen
2.1.2 | Supramolecular features
(O1) atom acting as a bifurcated acceptor (Table 5;
Figure 6). These two ring loops form a chain along the c-
axis direction. Intramolecular C18 H18ꢀꢀꢀCg3 stacking
interaction is present in the crystal, and this interaction
may be due to hydrogen bonding, where Cg3 is the cen-
troids of C17 C22 benzene ring. Hydrogen-bonded
In the crystal 2a, molecules are connected by C HꢀꢀꢀO
hydrogen bonds (C13 H13ꢀꢀꢀO1i; symmetry code as in
Table 4) forming a supramolecular chain along the c-
axis direction (Figure 4). The formed one or more
FIGURE 2 ORTEP view of the
compound (E)-1,3,4-triphenylbut-3-en-
2-one (2a) [Color figure can be viewed at
wileyonlinelibrary.com]
FIGURE 3 ORTEP view of the
compound (E)-4-(4-chlorophenyl)-
1,3-diphenylbut-3-en-2-one (2c) [Color
figure can be viewed at
wileyonlinelibrary.com]

6
VENGATESH ET AL.
TABLE 3 Crystal data, data collection and refinement details
of the crystals 2a and 2c
TABLE 4 Hydrogen-bond geometry (Å, ꢁ) for compound 2a
D
HꢀꢀꢀA
D
H
HꢀꢀꢀA
2.56
2.98
2.75
2.96
DꢀꢀꢀA
D
HꢀꢀꢀA
Compound 2a
Compound 2c
C13 H13ꢀꢀꢀO1i
C10 H10ꢀꢀꢀCg3ii
C16 H16ꢀꢀꢀCg3iii
C21 H21ꢀꢀꢀCg1iv
0.93
0.93
0.93
0.93
3.44(2)
3.76(19)
3.61(16)
3.61(19)
160
142
155
128
Crystal data
Chemical formula
Mr
C22H18O
298.36
C22H17ClO
332.80
Crystal system, space
group
Monoclinic,
P21/n
Triclinic, P − 1
Notes: Cg1 and Cg3 are the centroids of the major and minor components of
the C5 C10 and C17 C22 rings, respectively. Symmetry codes: (i) 1−x,1
−y,2−z; (ii) 1 + x,y,z; (iii) 2−x,1−y,1−z; (iv) x,y,z.
Temperature (K)
296
296
a, b, c (Å)
5.9649 (5),
21.3686 (16),
13.2423 (10)
5.9042 (5),
12.2776 (6),
12.5148 (3)
Cg4 and Cg2 are the centroids of C17 C22 and C5 C10
benzene ring, respectively.
a, b, g (ꢁ)
90, 96.582 (4),
90
106.786 (1),
90.908 (5),
95.261 (3)
V (Å3)
1676.8 (2)
4
864.02 (9)
2
2.1.3 | Hirshfeld surface analysis
Z
Hirshfeld surfaces and fingerprint plots of the crystals 2a
and 2c were generated with the assistance of Crystal
Explorer37 and intermolecular interactions are visualized
based on established procedures.38 The Hirshfeld surface
mapped over dnorm in the standard surface range −0.1368
to 1.4608 a.u. is shown in Figures 8 and 9. In the dnorm
plotted, the red color spot indicates donor and acceptor
distance shorter than the sum of the van der Waals radii
or hydrogen-bonding interactions. The white and blue
color regions indicate distances equal to or longer than
the sum of the van der Waals radii, respectively.39 In the
crystal 2a, the red spots are appearing near the O1 atom,
while in crystal 2c near the O1, H1, H18, H22, H8, and
H4B atoms.
Radiation
type
Mo Ka
Mo Ka
m (mm−1
)
0.10
0.23
Crystal
size (mm)
0.42 ×
0.42 × 0.42
0.3 × 0.25 × 0.2
Data collection
Diffractometer
Bruker
APEX-II
CCD
Bruker APEX-
II
CCD
Absorption
correction
Multi-scan
Multi-scan
No. of measured,
independent and
observed [I >
17 671, 4436,
3133
9891, 3014,
1466
The two-dimensional fingerprint plots measure the
contributions of each type of intermolecular interac-
tion of the Hirshfeld surface.40 In crystal 2a
(Figure 10), the HꢀꢀꢀH contacts are the largest contribu-
tion to 58.2% of the surface, which represents van der
Waals interactions, followed by CꢀꢀꢀH/HꢀꢀꢀC contacts
involved in C Hꢀꢀꢀπ interactions (31.9%). The OꢀꢀꢀH/
HꢀꢀꢀO contacts contribute to 8.3% of the surface, and
the two sharp peaks correspond to strong hydrogen bond
interactions. In crystal 2c (Figure 11), the HꢀꢀꢀH contacts
make the most significant contribution to the Hirshfeld
surface (48.5%). Besides, CꢀꢀꢀH/HꢀꢀꢀC, ClꢀꢀꢀH/HꢀꢀꢀCl, OꢀꢀꢀH/
HꢀꢀꢀO and CꢀꢀꢀCl/ClꢀꢀꢀC contacts contribute 28.5%, 13.1%,
7.2% and 2.1%, respectively, to the surface.
2 s(I)] reflections
Rint
0.037
0.683
0.092
0.594
(sin q/l)max (Å−1
Refinement
R[F2 >
)
0.070, 0.190,
1.08
0.062, 0.186,
0.99
2 s(F2)], wR(F2), S
No. of reflections
4436
208
3014
273
No. of
parameters
No. of
restraints
0
72
H-atom treatment
H-atom
parameters
constrained
H-atom
parameters
constrained
Dρmax, Dρmin (e Å−3
)
0.33, −0.51
0.20, −0.20
2.1.4 | Electrostatic potential surface
chains are interconnected by C Hꢀꢀꢀπ stacking interac-
tions (Figure 7; Table 5). The Cg4 and Cg2 interact with
donor atoms C12 H12 and C14 H14, respectively. The
The Hirshfeld surface mapped over the calculated elec-
trostatic potential in compound 2a and 2c is shown in
Figure 12. The potential surface is mapped over blue and

VENGATESH ET AL.
7
FIGURE 4
be viewed at wileyonlinelibrary.com]
C
Hꢀꢀꢀπ and C HꢀꢀꢀO hydrogen bonding interaction of compound (E)-1,3,4-triphenylbut-3-en-2-one (2a) [Color figure can
FIGURE 5 A three-dimensional packing of the compound (E)-1,3,4-triphenylbut-3-en-2-one (2a) viewed along the a-axis [Color figure
can be viewed at wileyonlinelibrary.com]

8
VENGATESH ET AL.
red regions. The intense blue and red regions correspond
to positive and negative electrostatic potentials, respec-
tively. Moreover, the hydrogen-bond donors and acceptors
are shown as blue and red regions, respectively. In com-
pound 2a, blue regions present in the phenyl hydrogens,
intense red region present in carbonyl oxygen, and less
intense red region present in the center of the phenyl ring.
In compound 2c, the red region presents in carbonyl oxy-
gen, chlorine atom, and center of the aryl and phenyl ring.
The hydrogen bond donor blue region presents in one of
the phenyl hydrogens (Figure 12). It is further evidenced
by the donor and acceptor regions of the molecules.
3 | CONCLUSION
The unusual ring opening reaction of 2,6-diaryl-
3,5-diphenyl piperidin-4-ones to (E)-4-aryl-1,3-diphenyl-but-
3-en-2-ones in the presence of acetic acid is reported. A
tentative mechanism for the ring opening reaction is pro-
posed. The synthesized compounds are completely charac-
terized by NMR and single-crystal XRD techniques. Crystal
packing arrangement shows C HꢀꢀꢀO and C Hꢀꢀꢀπ weak
intermolecular interactions, and they play a crucial role in
the crystal packing arrangement. It is further evidenced by
Hirshfeld surface and fingerprint plot analysis.
TABLE 5 Hydrogen-bond geometry (Å, ꢁ) for compound 2c
D
HꢀꢀꢀA
D
H
HꢀꢀꢀA
2.60
2.56
2.72
2.86
2.93
DꢀꢀꢀA
D
HꢀꢀꢀA
C1 H1ꢀꢀꢀO1i
0.93
0.93
0.93
0.93
0.93
3.416(4)
3.412(4)
3.576(4)
3.735(14)
3.625(4)
147
153
154
156
133
C22 H22ꢀꢀꢀO1i
C12 H12ꢀꢀꢀCg4ii
C14 H14ꢀꢀꢀCg2iii
C18 H18ꢀꢀꢀCg3iv
4 | EXPERIMENTAL SECTION
4.1 | General method
Notes: Cg2, Cg3 and Cg4 are the centroids of the major and minor
components of the C5 C10, C11 C16 and C17 C22 rings respectively.
Symmetry codes: (i) 1/2 + x,1/2−y,−1/2 + z; (ii) −1/2 + x,1/2−y,−1/2 + z;
(iii) −1 + x,y,z; (iv) 3/2 + x,1/2−y,1/2 + z.
Melting points were determined by the open capillary
method. FT-IR spectra were recorded on a JASCO
FIGURE 6 Bifurcated C HꢀꢀꢀO
interaction and R21 (6), R21 (10) ring
motif of compound (E)-
4-(4-chlorophenyl)-1,3-diphenylbut-3-en-
2-one (2c) [Color figure can be viewed at
wileyonlinelibrary.com]

VENGATESH ET AL.
9
FIGURE 7 Inter and intra
molecular C Hꢀꢀꢀπ interaction of
compound (E)-
4-(4-chlorophenyl)-
1,3-diphenylbut-3-en-2-one (2c)
[Color figure can be viewed at
wileyonlinelibrary.com]
Single-crystal structural data of compounds 2a and
2c were collected by Bruker APEX-II CCD diffractome-
ter. The structural solution and refinement process
were done using ShelXS and ShelXL computational
program.41 The crystal packing diagrams, geometrical
calculations, and publication material were generated
using Mercury 3.10.1, PLATON, and Olex2 program,
respectively.42–44
4.1.1 | Typical experimental procedure
2,6-Diaryl-3,5-diphenyl piperidine-4-one (1 mmol) (1a-
1e) was dissolved in 5 mL of ethanol with 3 mL of acetic
acid and refluxed for 4 hours. Progress of the reaction
was monitored by TLC and after completion of the reac-
tion, the reaction mixture was neutralized with 10%
aqueous NaHCO3, and extracted with ethyl acetate. The
solvent was evaporated, and the crude product was puri-
fied by column chromatography. The final product was
recrystallized from hexane: ethyl acetate to obtain pure
compound.
FIGURE 8 Hirshfeld surface of the compound (E)-
1,3,4-triphenylbut-3-en-2-one (2a) plotted over dnorm [Color figure
can be viewed at wileyonlinelibrary.com]
FT/IR-4700 spectrophotometer using KBr pellet. 1D and
2D NMR spectra were recorded on a Bruker AVANCE
III HD 400 MHz spectrometer. NMR spectra were
recorded in CDCl3 using TMS as an internal standard.
Chemical shifts are described in ppm (δ). AR grade
chemicals purchased from local companies were used
without further purification. The compounds were puri-
fied by column chromatography using silica gel 60-120
mesh (hexane: ethyl acetate).
(E)-1,3,4-Triphenylbut-3-en-2-one (2a). Colorless pow-
der, yield 81%. Melting point (mp) 84ꢁC. (CAS
No. 128753-25-336) UV: 294 nm. FT-IR: 1677, 1603 cm−1
.
1H NMR (CDCl3/TMS, 400.22 MHz) 3.87 (2H, s), 7.01
(2H, d, J = 7.4 Hz), 7.11-7.15 (6H, m), 7.18-7.23 (2H, m),
7.25-7.28 (2H, m), 7.38-7.39 (3H, m), 7.68 (1H, s). 13C
NMR (CDCl3/TMS, 100.63 MHz) 46.6, 126.6, 127.9, 128.1,

10
VENGATESH ET AL.
FIGURE 9 Hirshfeld surface of the
compound (E)-4-(4-chlorophenyl)-
1,3-diphenylbut-3-en-2-one (2c) plotted
over dnorm [Color figure can be viewed at
wileyonlinelibrary.com]
FIGURE 10 Hirshfeld surface representations and 2D fingerprint plots of compound (E)-1,3,4-triphenylbut-3-en-2-one (2a) [Color
figure can be viewed at wileyonlinelibrary.com]
128.4, 129.0, 129.2, 129.3, 129.6, 130.8, 134.5, 134.6, 136.6,
139.0, 140.2, 198.8. HRMS (TOP MS ES) m/z: [M + 1]
calcd. for C22H18O 299.135; found 299.203.
s). 13C NMR (CDCl3/TMS, 100.63 MHz) 46.5, 55.2, 113.8,
126.6, 127.2, 127.8, 128.4, 128.9, 129.1, 129.4, 132.8, 134.9,
137.3, 138.1, 139.0, 160.5, 198.7.
(E)-4-(4-Methoxyphenyl)-1,3-diphenylbut-3-en-2-one
(2b). Colorless powder, yield 74%. Melting point
(E)-4-(4-Chlorophenyl)-1,3-diphenylbut-3-en-2-one
(2c). Colorless powder, yield 84%. Melting point
(mp) 106ꢁC. UV: 298 nm. FT-IR: 1686, 1603 cm−1.1H
NMR (CDCl3 / TMS, 400.22 MHz) 3.86 (2H, s), 6.92-6.95
(2H, m), 7.07-7.13 (6H, m), 7.26-7.28 (3H, m), 7.39-7.41
(mp) 85ꢁC. UV: 320 nm. FT-IR: 1678, 1602 cm−1 1H
.
NMR (CDCl3/TMS, 400.22 MHz) 3.77 (3H, s), 3.88 (2H,
s), 6.71 (2H, d, J = 6.9 Hz), 7.00-7.42 (12H, m), 7.71 (1H,

VENGATESH ET AL.
11
FIGURE 11 Hirshfeld surface representations and 2D fingerprint plots of compound (E)-4-(4-chlorophenyl)-1,3-diphenylbut-3-en-2-one
(2c) [Color figure can be viewed at wileyonlinelibrary.com]
FIGURE 12 The three-dimensional electrostatic potential surface of the compound (E)-1,3,4-triphenylbut-3-en-2-one (2a) and (E)-
4-(4-chlorophenyl)-1,3-diphenylbut-3-en-2-one (2c) [Color figure can be viewed at wileyonlinelibrary.com]

12
VENGATESH ET AL.
(3H, m), 7.26 (1H, s). 13C NMR (CDCl3/TMS,
100.63 MHz) 46.7, 126.7, 128.2, 128.4, 128.5, 129.2, 129.4,
129.6, 132.0, 133.0, 134.5, 135.1, 136.4, 137.5, 140.7, 198.7.
(E)-1,3-Diphenyl-4-(p-tolyl)but-3-en-2-one (2d). Color-
less powder, yield 79%. Melting point (mp) 88ꢁC. UV:
303 nm. FT-IR: 1686, 1598 cm−1.1H NMR (CDCl3/TMS,
400.22 MHz) 2.25 (3H, s), 3.86 (2H, s), 6.90-6.96 (4H, m),
7.08-7.13 (4H, m), 7.20-7.37 (6H, m), 7.38 (1H, s). 13C
NMR (CDCl3/TMS, 100.63 MHz) 21.3, 46.5, 126.6, 127.9,
128.4, 129.0, 129.2, 129.4, 129.8, 130.9, 131.8, 134.8, 137.1,
139.2, 139.4, 139.6, 198.8.
(E)-4-(4-Fluorophenyl)-1,3-diphenylbut-3-en-2-one
(2e). Colorless powder, yield 82%. Melting point
(mp) 98ꢁC. UV: 295 nm. FT-IR: 1682, 1591 cm−1.1H
NMR (CDCl3/TMS, 400.22 MHz) 3.88 (2H, s), 6.84-6.88
(2H, m), 7.02-7.03 (2H, m), 7.11-7.15 (4H, m), 7.27-7.29
(3H, m), 7.43 (3H, bs), 7.68 (1H, s). 13C NMR (CDCl3/
TMS, 100.63 MHz) 46.7, 115.3, 126.8, 128.1, 128.4, 129.2,
129.5, 130.0, 130.8, 132.7, 134.6, 136.6, 137.7, 140.0,
162.9, 198.7.
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DATA AVAILABILITY STATEMENT
The data that support the findings of this study are avail-
able in the supplementary material of this article.
ORCID
Manthiram Sundaravadivelu https://orcid.org/0000-
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SUPPORTING INFORMATION
Additional supporting information may be found online
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How to cite this article: Vengatesh G,
Sundaravadivelu M, Muthusubramanian S. Ring
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