Synthesis and mesomorphic properties of bis ester derivatives of coumarin containing chalcone linkage

Article abstract of DOI:10.1016/j.molliq.2021.116178

Bis ester derivatives of coumarin containing chalcone linkage with various terminal alkoxy groups were designed, synthesized and characterized. Compounds 11a-m were studied for their mesomorphic properties using polarizing optical microscope & differential scanning calorimetry and photophysical properties using UV-vis & fluorescence spectroscopy. In this particular homologous series, compounds having lower flexible alkoxy chains showed very good mesogenic property with nematic mesophase formation, while analogues with higher chains failed to show any liquid crystalline property. Compound 11a with methoxy group showed very good absorbance and fluorescence as compared to higher chain length analogues.

Full text of DOI:10.1016/j.molliq.2021.116178

Journal of Molecular Liquids 335 (2021) 116178
Contents lists available at ScienceDirect
Journal of Molecular Liquids
journal homepage: www.elsevier.com/locate/molliq
Synthesis and mesomorphic properties of bis ester derivatives of
coumarin containing chalcone linkage
1
1
⇑
Priyanka Shah , Rina Soni , Shubhangi S Soman
Department of Chemistry, Faculty of Science, The M. S. University of Baroda, Vadodara 390 002, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Bis ester derivatives of coumarin containing chalcone linkage with various terminal alkoxy groups were
designed, synthesized and characterized. Compounds 11a-m were studied for their mesomorphic prop-
erties using polarizing optical microscope & differential scanning calorimetry and photophysical proper-
ties using UV-vis & fluorescence spectroscopy. In this particular homologous series, compounds having
lower flexible alkoxy chains showed very good mesogenic property with nematic mesophase formation,
while analogues with higher chains failed to show any liquid crystalline property. Compound 11a with
methoxy group showed very good absorbance and fluorescence as compared to higher chain length
analogues.
Received 17 December 2020
Revised 27 March 2021
Accepted 13 April 2021
Available online 17 April 2021
Keywords:
Coumarin
Bis ester
Ó 2021 Elsevier B.V. All rights reserved.
Chalcone
Mesomorphic
Photophysical
1. Introduction
crystal compounds are reported for their mesomorphic properties
[18–21].
Thermotropic liquid crystalline compounds containing hetero-
cyclic ring is developing area of research in liquid crystalline mate-
rial [1–5]. Thermotropic liquid crystalline materials with nematic
mesophase are important due to their large temperature range
and they have been used in liquid crystal displays. The type of
mesophase and layer arrangement can be affected by small
changes in the molecular shape in thermotropic rod shape liquid
crystalline molecules. At the same time central linkage plays
important role not only in formation of mesophase but also in ther-
mal stability and temperature range of mesophase [6–10]
Coumarin is one of the interesting heterocyclic ring which can
enhance all required properties in liquid crystalline material
including photoluminescence due to its very good photophysical
nature. Coumarins absorption and emission wavelength and pho-
toluminescence properties strongly depend on the nature and the
position of substituents [11]. Coumarin derivatives are well
explored for optical data storage materials as they have good solu-
bility in organic solvents along with very good photostability and
high quantum yield [12–14]. Moreover, the relative ease of synthe-
sis and high solubility make them suitable materials for optoelec-
tronic devices [15–17]. Coumarin containing thermotropic liquid
Recently, Mohammad et al synthesized three new homologous
series of coumarin heterocycles-derived symmetric dimers 1 con-
taining two Schiff base moieties as connected by phenyl ring
(Fig. 1) [22]. These synthesised compounds with terminal alkyl
chain above ten carbon length exhibited liquid crystalline proper-
ties, while compounds with lower alkyl chains are hard to exhibit
mesophase. Same group has also reported coumarin substituted
symmetric diaminopyridine molecules 2 as thermotropic liquid
crystals [23]. In this particular series of compound 2 with short
chains were found to be not showing any mesophase whereas
compounds with long-chains exhibited nematic mesophase only.
Ngaini & Hegde et al have reported azobenzene substituted cou-
marin derivatives 3 bearing different alkoxy chains for their liquid
crystalline properties and photo switching properties (Fig. 1) [24].
Azo-coumarin compound 3 with alkyl chain C6 to C12 showed
nematic phase while with C14 alkyl chain exhibited Smectic–A
phase.
Our group had reported coumarin derivatives with chalcone 4
and imine 5 linkages and studied their mesomorphic properties
(Fig. 1). Coumarin derivatives with chalcone linkage showed meso-
morphic property with terminal alkyl chain hexyl and above [25].
Schiff base linkages containing coumarin derivatives 5 exhibited
mesomorphic behaviour from propyloxy chain onwards. As a part
of further modification in coumarin chalcone derivatives we have
replaced terminal alkoxy group by ester to study their mesomor-
phic property. Herein we report synthesis and mesomorphic
⇑
Corresponding author.
E-mail address: shubhangiss@rediffmail.com (S.S Soman).
Both the authors have contributed equally.
1
https://doi.org/10.1016/j.molliq.2021.116178
0167-7322/Ó 2021 Elsevier B.V. All rights reserved.

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
O
O
O
O
N
N
O
O
O
O
OR
RO
1
R = -C6H13 to -C14H29
O
N
N
O
N
O
O
O
O
O
O
O
O
2
H2n+1CnO
OCnH2n+1
O
O
N
N
3
OCnH2n+1
n = 6,8,10,12 & 14
H2n+1CnO
O
O
N
H2n+1CnO
O
O
OCnH2n+1
O
5
OCnH2n+1
4
Fig. 1. Coumarin derivatives with liquid crystalline properties.
properties of bis ester derivatives of coumarin containing chalcone
linkage. The mesomorphic behaviour of the homologous com-
pounds with chalcone linkage with varying length of the terminal
alkyl chains were studied along with their photophysical
properties.
with 4-hydroxy benzaldehyde in ethanol using catalytic amount
of piperidine and acetic acid to give compound 10. Compound 10
was esterified with 4-alkoxy benzoic acid 7a-m using EDC, HOBt
and TEA in DCM to give compound 11a-m (Scheme 1). All synthe-
sized compounds were analysed by different analytical techniques
such as 1H- NMR, 13C NMR and IR analysis to confirm their
structures.
IR spectrum of the compound 11d showed broad peaks in the
region of 2956–2870 cmÀ1 for alkyl chain C-H stretching, at
1727 cmÀ1 for carbonyl stretching of lactone ring along with ester
and at 1659 cmÀ1 for carbonyl stretching of chalcone. 1H NMR of
compound 11d showed peaks corresponding to methyl and methy-
2. Results and discussion
2.1. Chemistry
Compound 11a-m were prepared in two steps from 3-acetyl-7-
hydroxy-chromen-2-one 8 (Scheme 1). Compound 8 was reacted
COOH
(i) Alkyl bromide,
KOH , methanol
reflux, 7 h
COOH
(ii) KOH
OH
6
reflux, 2 h
OCnH2n+1
7a-m
CHO
O
O
O
HO
OH
O
O
+
HO
Piperidine,Acetic acid
Ethanol
reflux, 48 h.
COCH3
OH
9
8
10
COOH
(i)EDC,TEA,HOBt
DCM, 0-5 oC, 15 min
(ii)Addition of 10,
30 min at 0-5 oC,
rt , 20 h
OCnH2n+1
H2n+1CnO
OCnH2n+1
7a-k
11a
11b
11c
11d
11e
11f
n = 1
11h
11i
11j
11k
11l
n = 8
n = 10
n = 12
n =14
n = 16
n = 2
n = 3
n = 4
n = 5
n = 6
n = 7
O
O
O
O
O
O
11m
n = 18
O
11 a-k
11g
Scheme 1. Synthesis of coumarin bis ester derivatives with chalcone linkage.
2

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
Table 1
lene groups in the region of 1.02–1.87 ppm and methylene groups
in region of 1.02–1.87 ppm and methylene groups bearing oxygen
were observed in region of 4.06–4.10. Aromatic protons were
observed in region of 7.00–8.64 ppm along with chalcone protons
as doublet at 7.90 and 7.95 with coupling constant value of 16.0 Hz
indicated trans coupling. 13C NMR of the compound 11d showed
peaks for methyl and methylene carbons from 13.85 to
68.13 ppm, aromatic carbons appeared from 110.4 to
164.57 ppm along with carbonyl carbon of ester and lactone group
and carbonyl carbon of chalcone were appeared at 186.13 ppm.
Phase assignments, transition temperature oC of compounds 11a-m as determined by
POM and DSC.
Compd Chain
length (onset 10 °C/min) [oC]/[
KJmolÀ1
2nd heating processa
1st cooling processa
D
H
(onset 10 °C/min) [oC]/
]
[
D
H KJmolÀ1
]
b
11a
11b
11c
1
2
3
Cr 176.39(34.22) Iso
Cr 173.93(44.11) Iso
Iso Cr
Iso 144.52(21.90) Cr
Cr 180.21c N 184.61(29.38) Iso Nd 163.94(19.52) Cr
Iso
11d
11e
11f
11g
11h
11i
4
Cr 187.14c N 193.18(30.94) Iso Nd 164.73(14.68) Cr
Iso
Cr 181.73(35.81) N 196.58
(0.62) Iso
5
Iso Nd 141.63(11.18) Cr
2.2. Mesomorphic properties
6
Cr 179.34(36.63) N 198.19
(1.03) Iso
Iso 144.99(0.31) N 135.07
(5.74) Cr
2.2.1. Differential scanning calorimetry study (DSC)
7
Cr 176.32(38.03) N 193.70
(0.65) Iso
Iso 151.81(2.14) N 102.49
(4.89) Cr
Compounds 11a-m were studied for phase identification and
optical textures using polarizing optical microscope. Mesophase
transition temperatures were further confirmed by differential
scanning calorimetry (DSC). For phase identification using POM,
thin film of compound was placed on glass slide, covered with
cover slip and heated at the rate of 10 °C/min to give isotropic liq-
uid. Changes in textures were observed under microscope under
1st cooling cycle and 2nd heating cycle at the rate of 10 °C/min.
Thermograms were calculated by DSC (DSC-822, Mettler Toledo
having Stare software) in heating and cooling cycle at the rate of
10 °C/min. Clear-cut transition temperatures and textures could
be obtained from DSC curves and POM observations for all of the
compounds, and they were in good agreement with each other
for the multiple heating/cooling cycles (Table 1).
8
Cr 168.23(21.22) Cr1
180.33(1.21) Iso
Iso 145.90(3.15) Cr
10
12
14
16
18
Cr 156.98(23.80) Cr1
182.32(4.90) Iso
Cr 145.84(24.06) Cr1
189.97(2.38) Iso
Cr 95.65(34.18) Cr1 178.11 Iso 171.18(4.82) Cr
(3.96) Iso
Cr 98.03(17.81) Cr1 186.83 Iso 175.09(3.99) Cr
(6.81) Iso
Cr 98.23(23.80) Cr1 168.70 Iso 154.08 (1.97) Cr
(0.99) Iso
Iso 157.07(3.03) Cr
Iso 192.58(5.98) Cr
11j
11k
11l
11m
a
Cr: Crystalline state; N: Nematic phase; I: Isotropic state, Cr/Cr1: crystal to
crystal transition
b
Temperature for crystallization was not obtained in DSC thermogram.
Mesophase transition during heating cycle has merged with peak observed for
Bis ester derivative of coumarin compound 11a showed one
endotherm for crystalline to Isotopic phase (Cry-Iso), however
any exotherm was not observed during cooling cycle. Compound
11b showed one endotherm for crystalline to Isotropic phase (Cr-
Iso) in heating cycle and one exotherm during cooling cycle for iso-
tropic to crystallization (Iso-Cr). Compound 11c showed two
endotherms for crystalline to nematic phase (Cr-N) and nematic
to isotropic phase (N-Iso), however only one exotherm was
observed during cooling cycle. Compounds 11b and 11d with ethyl
and butyl side chains showed one endotherm for crystalline to iso-
tropic liquid phase on heating and one exotherm from isotropic liq-
uid phase to crystallization (Iso-Cr) on cooling. Compound 11e
exhibited two endotherms from crystalline solid to nematic phase
(Cr-N) and nematic phase to isotropic liquid phase (N-Iso) on heat-
ing, while on cooling only one exotherm was observed correspond-
ing to isotropic liquid phase to crystalline solid state (Iso-Cr).
Compounds 11f and 11g showed two endotherms for heating cycle
and two exotherms on cooling cycle, while heating first transition
was observed from crystalline solid to nematic mesophase (Cr-N),
second transition was observed for nematic phase to isotropic liq-
uid phase (N-Iso) (Fig. 2a-b). Isotropic liquid phase to nematic
phase (Iso-N), nematic to crystalline solid (N-Cr) for compounds
11f and 11g was observed in cooling cycle as shown in (Fig. 2a-b,
Table 1). Compounds 11h with octyloxy side chain showed only
two endotherms during heating cycle for crystalline to crystalline
1 transition (Cr-Cr1) at lower temperature and crystalline 1 to iso-
tropic liquid phase (Cr1-Iso) and one exotherm observed during
cooling cycle (Table 1). All higher analogues in this series with
decyloxy to octadecyloxy side chains, compounds 11i-m showed
two endotherms in heating cycle corresponding crystalline to crys-
talline 1 transition (Cr-Cr1) at lower temperature and crystalline 1
to isotropic liquid phase (Cr1-Iso). In cooling cycles, compounds
11i-m showed one exotherm corresponding to isotropic liquid
phase to crystalline solid (Iso-Cr) (Table 1).
c
isotropic phase transition in DSC thermogram.
Mesophase transition during cooling cycle has merged with peak observed for
crystallization phase transition DSC thermogram.
d
pound was prepared by heating small amount of compound sand-
wiched between glass slide and cover slip and heated at the rate of
10 °C/min. Changes in textures were observed under microscope
under 1st cooling cycle and 2nd heating cycle at the rate of
10 °C/min.
Liquid crystal phase transitions for compound 11c with propy-
loxy group are illustrated in Fig. 3. By bringing the temperature up
to 180.21 °C at the rate of 10 °C/min, crystalline to nematic droplet
transition was observed. On further heating up to 184.61 °C, the
nematic phase lost its birefringence and was transformed to an iso-
tropic phase. By cooling the isotropic phase at 10 °C/min, nematic
droplets began to appear (Fig. 3a) and coalesce forming a nematic
marble texture (Fig. 3b). The nematic marble texture was changed
to crystalline solid when temperature is reduced to 163.94 °C.
In heating scan at the rate of 10 °C/min, compound 11d with
butyloxy side chain showed nematic texture at 187.14 °C and
turned to isotropic liquid on heating up to 193.18 °C. In cooling
scan at the rate of 10 °C/min, compound 11d showed neamtic mar-
ble texture (Fig. 3c), which was changed to nematic schlieren tex-
ture (Fig. 3d) on cooling followed by nematic phase lost its
birefringence and was transformed into crystalline solid when
temperature is reduced to 164.73 °C.
On changing the chain length from butyloxy to pentyloxy group
in compounds 11e showed nematic transitions during heating
cycle at 181.73 °C (Fig. 4a). On changing the chain length from
pentyloxy to hexyloxy group in compounds 11f showed nematic
transitions during heating and cooling cycles (Fig. 4b). Similarly,
compound 11g showed nematic phase at 176.32 °C (Fig. 4c) which
on further heating up to 193.70 °C, the nematic phase lost its bire-
fringence and was transformed to an isotropic phase. In cooling
scan at 10 °C/min for compound 11g, nematic marble texture
appeared at 151.81 °C (Fig. 4d). On further cooling, this nematic
2.2.2. Polarising optical microscopy (POM) study
Liquid crystal phase transitions for compounds 11a-m were
studied using polarizing optical microscope. Thin film of com-
3

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
Fig. 2. a-d. DSC plots in both heating and cooling cycles along with transition temperatures (a) compound 11f with hexyloxy chain (b) compound 11g with heptyloxy chain.
texture was changed to crystalline solid at 102.49 °C. Compounds
11h-m with alkoxy chain of C8, C10, C12, C14, C16 and C18 respec-
tively, were crystallized without showing any mesophase transi-
tion during 1st cooling cycle (Fig. 5a-b). Similarly in 2nd heating
cycle, compounds 11h-m were converted directly to isotopic liquid
without showing any mesophase transition.
enantiotropy nature of the series. From compounds 11g to 11m
zig-zag trend was observed as alkyl chains are increased in both
the terminal and these may lead to the excessive Van der Waals
attractive forces between the long alkyl chains. Compounds 11c-
11g showed N-Iso transition, initially it has increased from propy-
loxy to butyloxy side chain and then falling tendency from buty-
loxy to heptyloxy side chain. In cooling cycle, the Iso-N transition
curve was obtained for only two compounds 11f and 11g which
showed increasing tendency, however lower members of these
series showed nematic mesophase in POM study but transition
phases were not observed in DSC thermograms. In literature, long
chain bis esters have shown mesomorphic properties [22,23], how-
ever higher members of this series with octyloxy chain onwards,
failed to show any mesophase. The low melting points and exces-
sive Van der Waals attractive forces of these higher members of
series may be partially responsible for the lack of mesophase
formation. The exotherms observed for these compounds during
2.3. Structure-mesomorphic property relationship
The graph of phase-transition temperatures against the number
of carbons in bis-ester derivatives of coumarin containing chalcone
linkage with various n-alkoxy chains enabled the effects of the ter-
minal chain on the mesomorphic properties. The relationship was
established from two different plots (Fig. 6). The Cr-N/Iso transition
curve exhibited sharp increase tendency with the melting temper-
atures increased from ethyloxy derivative 11b to hexyloxy deriva-
tive 11f and covers large area which may be responsible for the
4

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
Fig. 3. a-d. Liquid crystal phase transition for compound 11c (a) nematic droplet (b) nematic marble texture; for compound 11d (c) nematic marble texture (d) nematic
schlieren texture.
Fig. 4. a-d. Liquid crystal phase transition (a) compound 11e nematic schlieren texture (b) compound 11f nematic schlieren texture (c) compound 11g nematic marble
texture in heating (d) compound 11g nematic marble texture in cooling.
5

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
Fig. 5. a-b. Liquid crystal phase transition analysis giving direct crystallization (a) compound 11h (b) compound 11i.
Fig. 6. Mesomorphic behaviour as a function of the number of carbon atoms (n) in the terminal alkoxy chain (a) 2nd in heating cycle (b) in 1st cooling cycle.
cooling cycle in DSC analysis have shown similar trend and sup-
ported non-existence of mesomorphic properties. The odd-even
effect was not very much clear in this particular series in both
heating and cooling cycles may be due to sequential increase of
chain lengths at the both sides of molecule, which has resulted
in excessive Van der Waals attractive forces and compounds were
found to be greasy in nature.
2.4. Photophysical properties
A photophysical study of the coumarin derivatives 11a-m was
performed to evaluate their absorption and emission spectra in
solutions of chloroform at room temperature. Fig. 7 shows the
UV-vis absorption spectrum of the compounds 11a-m in chloro-
form solution at 3.3 Â 10À2 mM concentration.
Compounds 11a-m with chalcone linkages showed two broad
absorption bands at 264 and 358 nm. Absorption wavelengths
kmax are quite similar for all the compounds and no any signifi-
cant change is observed which may be due to similar molecular
structure. There is only change in length of terminal alkoxy chain
Fig. 7. UV–vis absorption spectra of compounds 11a-m in CHCl3 at 3.3 Â 10À2 mM
hence there is no major shift in absorption peak for compounds
11a-m. In absorption spectra of compounds 11a-m, the character-
concentration.
istic peak was observed at 264 nm and at 358 nm corresponding to
p
-
p
* transition of coumarin [26,27]. As mentioned in literature
[26] it seems the n- *transition has merged with * transition.
The absorbance maximum attributed to the * transition of pyr-
emission at 421 nm with Stoke shift of 61 nm. On changing alkyl
chain to ethoxy in compound 11b, kmax of emission was observed
at 437 nm with bathochromic shift, but intensity of fluorescence
was dropped. Similar increase in kmax of emission and drop in flu-
orescence intensity was observed for compounds 11c-e with pro-
pyl, butyl and pentyl side chains respectively (Fig. 8).
Interestingly, compounds 11f-m showed very poor fluorescence
intensity with slight shift in kmax of emission. This drastic drop
p
p-p
p-p
one ring of coumarin nucleus was chosen as excitation wavelength
for fluorescence measurements (Fig. 8).
Compounds 11a-k were excited at kmax of absorbance and
their emission spectra were recorded in chloroform at 2.0 Â 10À2
mM concentration (Fig. 8). Compound 11a with methoxy group
at terminal position showed good fluorescence having kmax of
6

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
NMR spectral data were recorded on Avance Bruker Neo 400/500
spectrometer (400/500 MHz) with CDCl3 or DMSO d6 as solvent
and J values are in Hz. Thermograms were calculated by DSC
(DSC-822, Mettler Toledo having Stare software) in heating and
cooling cycle at the rate of 10 °C/min. Liquid crystal properties
were studied using Polarizing Optical Microscope -LEICA DM
2500P, CAMERA- LEICA-DFC 295 and Heating Pod- LINKA 19. UV-
Vis spectra were recorded on PerkinElmer Lambda- 35 dual beam
UV-Vis spectrophotometer. Fluorescence spectra were recorded
on JASCO FP-6300 fluorescence spectrophotometer.
4.2. Synthesis
4.2.1. Synthesis of 4-n-alkyloxybenzoic acid (7b-m)
To a solution of 4-hydroxy benzoic acid (3.5 g, 0.03 mmol, 1 eq)
in methanol (25 mL) was added KOH (3.5 g, 0.06 mmol, 2.5 eq) and
stirred for 8–10 min. To this solition, alkyl bromide (0.03 mmol,
1.2 eq) was added and resulting mixture was refluxed at 64–
66 °C for 6–7 h. During this time, solid was separated out in reac-
tion mixture. To this reaction mixture, 20% aq solution of KOH
(5 mL) was added and refluxed for another 2 h to give clear solu-
tion. The reaction mixture was allowed to cool down to room tem-
perature and was acidified by 10% HCl solution (25 mL) followed
by addition of ice-cold water to give solid. The solid separated
out was filtered, dried and recrystallized from absolute ethanol
to give pure compound 7b-m.
Fig. 8. Fluorescence spectra of compounds 11a-k in CHCl3 at 2.0 Â 10À2 mM
concentration.
in fluorescence emission of compounds 11a-m may be due to non-
emissive decay caused by various competing processes such as
short lifetime of excited molecule, intramolecular or intermolecu-
lar relaxation [19,28].
4.2.2. Synthesis of 3-acetyl-7-hydroxy coumarin (8)
To a solution of resorcaldehyde (15.0 g, 0.108 mol, 1.0 eq) in
ethanol (50 mL) was added ethyl acetoacetate (13.62 mL,
0.108 mol, 1.0 eq) followed by catalytic amount of piperidine
(0.1 mL). The resulting mixture was refluxed for 18 h. The comple-
tion of reaction was checked by TLC. After completion of reaction,
reaction mixture was allowed to cool down to room temperature
and concentrated on a rotavapor. The viscous liquid obtained
was poured into ice cold water to give solid. The solid obtained
was filtered, washed with water, dried and recrystallized from
ethanol to give compound 8 as green crystals. Yield: 95%; M.P :
236–238 °C (Lit1 M.P. 240 °C).
3. Conclusion
Compounds 11a-m were studied for their mesomorphic proper-
ties using polarising optical microscope under both heating and
cooling scans at the rate of 10 °C/min. Mesophase transition tem-
peratures were confirmed by DSC thermograms. Compound 11c
showed nematic droplets which was changed to nematic marble
texture on cooling. Compound 11d-g showed nematic marble tex-
ture which was changed to nematic schlieren texture on cooling.
Interestingly higher chain analogues from C8 onwards did not
show any mesophase transitions during heating and cooling cycles.
Compound 11h-m showed direct crystallization during cooling
cycle without any mesophase. Thus, bis esters containing chalcone
moiety with coumarin heterocycle having lower flexible alkoxy
chains showed mesogenic properties, but its higher chain ana-
logues failed to show any liquid crystalline properties. Thus, meso-
morphic behaviour of bis ester coumarin derivatives containing
chalcone linkage has been widely affected on varying flexible ter-
minal alkyl chains on both ends. Compounds were also studied
for their photophysical properties. Compound 11a with methoxy
chain showed very good fluorescence as compared to higher chain
length analogues this may be due to the non-emissive decay in
molecule with higher chain lengths.
4.2.3. (E)-7-hydroxy-3-(3-(4-hydroxyphenyl)acryloyl)–2H-chromen-
2-one (10)
To a solution of compound 8 (1.02 g, 5.0 mmol) in ethanol
(50 mL) was added 4-hydroxy benzaldehyde 9 (0.61 g, 5.0 mmol)
and stirred for 10–15 min. To this mixture, catalytic amount of
pyrrolidine and acetic acid were added and resulting mixture
was refluxed at 78–80 °C for 36 h. The completion of reaction
was checked by TLC. After completion of reaction, the reaction
mixture was allowed to cool to room temperature, concentrated
on rotavapor and poured into ice cold water to give brown solid.
The crude product was filtered, washed with water, and dried.
The crude compound was purified by column chromatography
using pet ether:ethyl acetate (7:3) to give pure compound 10 as
bright orange solid. Yield: 48%; M.P: >260 °C; 1H NMR (400 MHz,
DMSO d6): d 6.7 (d, 1H), 6.82–6.86 (m, 3H), 7.58 (d, J = 8.4 Hz,
2H), 7.62 (d, J = 15.6 Hz, 1H), 7.62 (d, J = 15.6 Hz, 1H), 7.77 (d,
J = 8.4 Hz, 1H), 8.61 (s, 1H), 10.16 (s, 1H); 13C NMR (100 MHz,
DMSO d6): d ppm 102.28, 111.55, 114.60, 116.44, 120.81, 121.68,
126.13, 131.21, 132.79, 144.18, 148.37, 157.47, 159.56, 160.69,
164.35, 186.58.
4. Experimental
4.1. Methods and materials
Reagent grade chemicals and solvents were purchased from
commercial supplier and used after purification. Thin-layer chro-
matography was performed on silica gel F254 plates (Merck &
Co., Kenilworth, NJ, USA). Acme’s silica gel (60–120 mesh) was
used for column chromatographic purification. All reactions were
carried out in normal atmosphere. Melting points are uncorrected
and were measured in open capillary tubes. IR spectra were
recorded as KBr pellets on Bruker spectrometer.1H NMR and13C-
4.2.4. Synthesis of bis-ester coumarin chalcone derivatives 11a-m
To the solution of 4-alkoxy benzoic acid 8a-m (1.30 mmol,
2.0 eq) in DCM (25 mL) was added EDC (0.37 g, 1.95 mmol,
3.0 eq), HOBt (0.17 g, 1.30 mmol, 2.0 eq) followed by addition of
TEA (0.27 mL, 1.95 mmol, 3.0 eq). The resulting solution was stir-
7

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
red at 0–5 °C for 10–15 min. To this cold reaction mixture, com-
pound 10(0.20 g, 0.65 mmol, 1.0 eq) was added and stirred for
30 min at 0–5 °C and then at room temperature for 20 h. The com-
pletion of reaction was checked by TLC. After completion of reac-
tion, the reaction mixture was diluted with water (30 mL) and
extracted with DCM (3 Â 20 mL). The organic layer was separated,
washed with water (20 mL), brine solution (20 mL), dried over
anhydrous Na2SO4, filtered and concentrated on a rotavapor to give
residue. The residue was scratched in methanol, filtered and dried
to give compound 11a-m as yellow solid.
3H), 7.90 (d, J = 16.0 Hz, 1H), 7.97 (d, J = 16.0 Hz, 1H), 8.16 (d,
J = 8.8 Hz, 4H), 8.64 (s, 1H); 13C NMR (125 MHz, CDCl3): d ppm
13.85, 19.21, 31.11, 31.13, 68.05, 68.13, 110.38, 114.36, 114.52,
116.21, 119.44, 120.40, 121.16, 122.43, 123.87, 124.22, 130.15,
130.93, 132.38, 132.57, 144.09, 147.78, 153.06, 155.82, 156.09,
159.13, 163.71, 163.94, 164.07, 164.57, 186.13; Anal. Calc. for
C40H36O9; C, 72.71; H, 5.49; found: C, 72.87; H, 5.61%.
4.2.4.5. (E)-4-(3-(7-((4-(Pentyloxy)benzoyl)oxy)-2-oxo-2H-chromen-
3-yl)-3-oxoprop-1-en-1-yl)phenyl 4-(pentyloxy)benzoate (11e). Yel-
low solid, Yield: 91%; M.P: 168–170 °C; IR (KBr): 3077, 2934,
2867, 1727, 1662, 1607, 1579, 1508, 1468, 1419, 1320, 1257,
4.2.4.1. (E)-4-(3-(7-((4-Methoxybenzoyl)oxy)-2-oxo-2H-chromen-3-
yl)-3-oxoprop-1-en-1-yl)phenyl 4-methoxybenzoate (11a). Yellow
solid, Yield: 84%; M.P: 188–190 °C; IR (KBr): 2934, 2840, 1730,
1661, 1608, 1578, 1556, 1511, 1460, 1419, 1366, 1327, 1261,
1232, 1167, 1145, 1063, 1006, 988, 842, 759 cmÀ1 1H NMR
;
(400 MHz, CDCl3): d 0.97 (t, J = 6.8 Hz, 6H), 1.39–1.50 (m, 8H),
1.82–1.88 (m, 4H), 4.05–4.09 (m, 4H), 6.99 (d, J = 8.8 Hz, 2H),
7.01 (d, J = 8.8 Hz, 2H), 7.26–7.34 (m, 4H), 7.74–7.77 (m, 3H),
7.90 (d, J = 16.0 Hz, 1H), 7.97 (d, J = 16.0 Hz, 1H), 8.17 (d,
J = 8.4 Hz, 4H), 8.64 (s, 1H); 13C NMR (125 MHz, CDCl3): d ppm
14.03, 22.45, 28.13, 28.77, 28.79, 68.35, 68.43, 110.38, 114.36,
114.52, 116.20, 119.44, 120.39, 121.15, 122.43, 123.88, 124.22,
130.14, 130.93, 132.38, 132.57, 144.09, 147.78, 153.06, 155.82,
156.09, 159.13, 163.71, 163.95, 164.06, 164.59, 186.15; Anal. Calc.
for C42H40O9; C, 73.24; H, 5.85; found: C, 73.38; H, 5.98%.
1165, 1150, 1063, 1026, 863, 844, 758 cmÀ1 1H NMR (400 MHz,
;
CDCl3): d 3.92 (s, 3H), 3.93 (s, 3H), 7.01 (d, J = 8.8 Hz, 2H), 7.02
(d, J = 8.8 Hz, 2H), 7.26–7.34 (m, 4H), 7.73–7.77 (m, 3H), 7.90 (d,
J = 16.0 Hz, 1H), 7.96 (d, J = 16.0 Hz, 1H), 8.17 (d, J = 8.4 Hz, 4H),
8.63 (s, 1H); 13C NMR (100 MHz, CDCl3): d ppm 55.64, 55.68,
110.41, 113.92, 114.09, 116.24, 119.48, 120.67, 121.42, 122.45,
123.84, 124.23, 130.19, 130.97, 132.39, 132.42, 132.61, 144.16,
147.86, 153.00, 155.76, 156.08, 159.18, 163.95, 164.05, 164.41,
164.59, 186.20; Anal. Calc. for C34H24O9; C, 70.83; H, 4.20; found:
C, 70.86; H, 4.32%.
4.2.4.6. (E)-4-(3-(7-((4-(Hexyloxy)benzoyl)oxy)-2-oxo-2H-chromen-
3-yl)-3-oxoprop-1-en-1-yl)phenyl 4-(hexyloxy)benzoate (11f). Yel-
low solid, Yield: 89%; M.P: 166–168 °C; IR (KBr): 2932, 2866,
1727, 1660, 1606, 1578, 1508, 1468, 1420, 1319, 1255, 1231,
1167, 1147, 1063, 1001, 868, 758 cmÀ1; 1H NMR (400 MHz, CDCl3):
d 0.93 (t, J = 6.8 Hz, 6H), 1.37–1.38 (m, 8H), 1.48–1.52 (m, 4H),
1.82–1.86 (m, 4H), 4.04–4.08 (m, 4H), 6.99 (d, J = 8.8 Hz, 2H),
7.01 (d, J = 8.8 Hz, 2H), 7.26–7.34 (m, 4H), 7.73–7.77 (m, 3H),
7.90 (d, J = 15.6 Hz, 1H), 7.96 (d, J = 15.6 Hz, 1H), 8.15 (d,
J = 8.4 Hz, 4H), 8.64 (s,1H); 13C NMR (125 MHz, CDCl3): d ppm
14.05, 22.60, 25.66, 29.04, 29.06, 31.55, 68.37, 68.45, 110.38,
114.37, 114.52, 116.21, 119.44, 120.39, 121.15, 122.44, 123.88,
124.23, 130.15, 130.93, 132.38, 132.57, 144.10, 147.78, 153.06,
155.82, 156.09, 159.14, 163.71, 163.95, 164.07, 164.59, 186.15;
Anal. Calc. for C44H44O9; C, 73.73; H, 6.19; found: C, 73.88; H,
6.33%.
4.2.4.2.
(E)-4-(3-(7-((4-Ethoxybenzoyl)oxy)-2-oxo-2H-chromen-3-
yl)-3-oxoprop-1-en-1-yl)phenyl 4-ethoxybenzoate (11b). Yellow
solid, Yield: 80%; M.P: 182–184 °C; IR (KBr): 3086, 3062, 2980,
2931, 1728, 1659, 1604, 1577, 1551, 1508, 1421, 1351, 1252,
1164, 1125, 1061, 920, 870, 848, 760 cmÀ1 1H NMR (400 MHz,
;
CDCl3): d 1.46–1.50 (m, 6H), 4.12–4.18 (m, 4H), 6.98–7.01 (m,
4H), 7.26–7.34 (m, 4H), 7.73–7.77 (m, 3H), (t, J = 7.2 Hz, 4H),
7.28–7.34 (m, 4H), 7.74–7.78 (m, 3H), 7.99 (d, J = 15.6 Hz,1H),
7.96 (d, J = 15.6 Hz, 1H), 8.5 (d, J = 8.0 Hz, 4H), 8.63 (s,1H); 13C
NMR (100 MHz, CDCl3): d ppm 14.67, 14.69, 63.86, 63.95, 110.40,
114.33, 114.49, 116.21, 119.47, 120.43, 121.19, 122.44, 123.84,
124.22, 130.17, 130.95, 132.37, 132.41, 132.60, 144.14, 147.84,
153.03, 155.80, 156.09, 159.16, 163.49, 163.85, 163.96, 164.60,
186.18; Anal. Calc. for C36H28O9; C, 71.52; H, 4.67; found: C,
71.68; H, 4.87%.
4.2.4.7. (E)-4-(3-(7-((4-(Heptyloxy)benzoyl)oxy)-2-oxo-2H-chromen-
3-yl)-3-oxoprop-1-en-1-yl)phenyl 4-(heptyloxy)benzoate (11g). Yel-
low solid, Yield: 70%; M.P: 170–172 °C; IR (KBr): 2925, 2859,
1727, 1661, 1607, 1506, 1463, 1420, 1261, 1222, 1163, 1066,
4.2.4.3. (E)-4-(3-(7-((4-(Propoxy)benzoyl)oxy)-2-oxo-2H-chromen-3-
yl)-3-oxoprop-1-en-1-yl)phenyl 4-(propoxy)benzoate (11c). Yellow
solid, Yield: 72%; M.P: 174–176 °C; IR (KBr): 3075, 3059, 2965,
2937, 2877, 1728, 1659, 1603, 1577, 1549, 1508, 1421, 1352,
1324, 1316, 1255, 1227, 1163, 1123, 1061, 991, 868, 844,
1003, 840, 813, 761 cmÀ1 1H NMR (400 MHz, CDCl3): d 0.92 (t,
;
J = 6.8 Hz, 6H), 1.34–1.41 (m, 12H), 1.46–1.49 (m, 4H), 1.81–1.86
(m, 4H), 4.05–4.09 (m, 4H), 6.99 (d, J = 8.4 Hz, 2H), 7.01 (d,
J = 8.8 Hz, 2H), 7.24–7.34 (m, 4H), 7.69–7.80 (m, 3H), 7.91 (d, J =
15.6 Hz,1H), 7.96 (d, J = 15.6 Hz,1H), 8.16 (d, J = 8.4 Hz, 4H), 8.64
(s, 1H); 13C NMR (125 MHz, CDCl3): d ppm 14.12, 22.63, 25.96,
29.05, 29.09, 29.11, 31.77, 68.37, 68.45, 110.38, 114.37, 114.53,
116.20, 119.45, 120.37, 121.12, 122.44, 123.87, 124.19, 129.98,
130.16, 130.94, 132.39, 132.57, 144.11, 147.81, 153.05, 155.83,
156.08, 159.16, 163.73, 163.96, 164.08, 164.65, 186.15; Anal. Calc.
for C46H48O9; C, 74.17; H, 6.50; found: C, 74.21; H, 6.62%.
760 cmÀ1 1H NMR (400 MHz, CDCl3): d 1.09 (t, J = 7.2 Hz, 6H),
;
1.87–1.88 (m, 4H), 4.03–4.04 (m, 4H), 7.01 (t, J = 7.2 Hz, 4H),
7.28–7.34 (m, 4H), 7.74–7.78 (m, 3H), 7.91 (d, J = 15.6 Hz,1H),
7.97 (d, J = 15.6 Hz, 1H), 8.16 (d, J = 8.0 Hz, 4H), 8.65 (s,1H); 13C
NMR (100 MHz, CDCl3): d ppm10.50, 22.44, 22.45, 69.80, 69.87,
110.40, 114.35, 114.51, 116.20, 119.47, 120.36, 121.13, 122.44,
123.84, 124.20, 130.17, 130.95, 132.39, 132.58, 144.13, 147.84,
153.03, 155.80, 156.08, 159.16, 163.69, 163.97, 164.05, 164.61,
186.18; Anal. Calc. for C38H32O9; C, 72.14; H, 5.10; found: C,
72.328; H, 5.23%.
4.2.4.8. (E)-4-(3-(7-((4-(Octyloxy)benzoyl)oxy)-2-oxo-2H-chromen-
3-yl)-3-oxoprop-1-en-1-yl)phenyl 4-(octyloxy)benzoate (11h). Yel-
low solid, Yield: 76%; M.P: 164–166 °C; IR (KBr): 2924, 2853,
1726, 1660, 1605, 1578, 1551, 1407, 1419, 1256, 1230, 1167,
4.2.4.4. (E)-4-(3-(7-((4-(Butoxy)benzoyl)oxy)-2-oxo-2H-chromen-3-
yl)-3-oxoprop-1-en-1-yl)phenyl 4-(butoxy)benzoate (11d). Yellow
solid, Yield: 74%; M.P: 180–182 °C; IR (KBr): 3082, 3058, 2956,
2934, 2870, 1727, 1659, 1603, 1577, 1507, 1420, 1351, 1319,
1124, 1064, 866, 758, 649 cmÀ1 1H NMR (400 MHz, CDCl3): d
;
1257, 1226, 1166, 1148, 1060, 1003, 870, 846, 759, 712 cmÀ1
;
1H
0.91 (t, J = 6.4 Hz, 6H), 1.32–1.37 (m, 16H), 1.46–1.51 (m, 4H),
1.81–1.88 (m, 4H), 4.05–4.09 (m, 4H), 6.99 (d, J = 8.8 Hz, 2H),
7.01 (d, J = 8.8 Hz, 2H), 7.26–7.34 (m, 4H), 7.74–7.78 (m, 3H),
7.90 (d, J = 16.0 Hz, 1H), 7.97 (d, J = 16.0 Hz, 1H), 8.16 (d,
NMR (400 MHz, CDCl3): d1.02 (t, J = 7.2 Hz, 6H), 1.49–1.58 (m,
4H), 1.80–1.87 (m, 4H), 4.06–4.10 (m, 4H), 7.00 (d, J = 8.4 Hz,
2H), 7.01 (d, J = 8.4 Hz, 2H), 7.26–7.34 (m, 4H), 7.74–7.78 (m,
8

P. Shah, R. Soni and Shubhangi S Soman
Journal of Molecular Liquids 335 (2021) 116178
J = 8.0 Hz, 4H), 8.64 (s,1H); 13C NMR (125 MHz, CDCl3): d ppm
14.13, 22.68, 25.99, 29.08, 29.10, 29.24, 29.34, 31.82, 68.37,
68.45, 110.37, 114.36, 114.52, 116.20, 119.43, 120.39, 121.15,
122.43, 123.87, 124.21, 130.14, 130.93, 132.38, 132.57, 144.08,
147.78, 153.06, 155.82, 156.09, 159.13, 163.71, 163.94, 164.07,
164.58, 186.12; Anal. Calc. for C48H52O9; C, 74.59; H, 6.18; found:
C, 74.78; H, 6.32%.
J = 15.8 Hz, 1H), 7.97 (d, J = 15.8 Hz, 1H), 8.15 (d, J = 8.0 Hz, 4H),
8.64 (s, 1H); 13C NMR (125 MHz, CDCl3): d ppm14.18, 22.73,
25.99, 29.08, 29.10, 29.40, 29.59, 29.62, 29.69, 29.72, 31.95,
68.36, 68.44, 110.40, 114.35, 114.50, 116.21, 1119.48, 120.33,
121.09, 122.45, 128.83, 124.20, 130.18, 130.95, 132.39, 132.58,
144.15, 147.86, 153.04, 155.81, 156.08, 159.17, 163.70, 163.98,
164.06, 164.63, 186.19; Anal. Calc. for C64H84O9; C, 77.07; H,
8.49; found: C, 77.19; H, 8.63%.
4.2.4.9. (E)-4-(3-(7-((4-(Decyloxy)benzoyl)oxy)-2-oxo-2H-chromen-
3-yl)-3-oxoprop-1-en-1-yl)phenyl 4-(decyloxy)benzoate (11i). Yel-
low solid, Yield: 64%; M.P: 184–186 °C; IR (KBr): 2924, 2855,
1728, 1661, 1607, 1506, 1465, 1420, 1321, 1261, 1223, 1163,
4.2.4.13. (E)-4-(3-(7-((4-(Octadecyloxy)benzoyl)oxy)-2-oxo-2H-chro-
men-3-yl)-3-oxoprop-1-en-1-yl)phenyl
4-(octadecyloxy)benzoate
(11m). Yellow solid, Yield: 63%; M.P: 166–168 °C; IR (KBr): 3436,
1065, 1004, 841, 814, 761, 718, 691 cmÀ1 1H NMR (400 MHz,
;
2918, 2851, 1728, 1663, 1608, 1579, 1510, 1470, 1281, 1257,
1170, 1151, 1071, 844, 832, 759 cmÀ1 1H NMR (400 MHz, CDCl3):
;
CDCl3): d 0.91 (t, J = 6.8 Hz, 6H), 1.30–1.38 (m,24H), 1.46–1.51
(m, 4H), 1.81–1.88 (m, 4H), 4.05–4.09 (m, 4H), 6.98–7.02 (m,
4H), 7.27–7.35 (m,4H), 7.74–7.78 (m,3H), 7.90 (d, J = 15.6 Hz,
1H), 7.97 (d, J = 15.6 Hz, 1H), 8.16 (d, J = 8.4 Hz, 4H), 8.65 (s,
1H); 13C NMR (125 MHz, CDCl3): d ppm 14.15, 22.70, 25.99,
29.08, 29.10, 29.34, 29.38, 29.57, 31.91, 68.37, 68.45, 110.39,
114.37, 114.53, 116.21, 119.45, 120.38, 121.13, 122.44, 123.87,
124.22, 129.99, 130.16, 130.93, 132.39, 132.57, 144.12, 147.81,
153.06, 155.83, 156.09, 159.16, 163.72, 163.96, 164.08, 164.63,
186.16; Anal. Calc. for C52H60O9; C, 75.34; H, 7.30; found: C,
75.49; H, 7.44%.
d 0.90 (t, J = 7.2 Hz, 6H), 1.27 (brs, 56H), 1.46–1.50 (m, 4H), 1.83–
1.86 (m, 4H), 4.05–4.09 (m, 4H), 6.99 (d, J = 8.8 Hz, 2H), 7.01 (d,
J = 8.4 Hz, 2H), 7.25–7.35 (m, 4H), 7.75 (d, J = 8.4 Hz, 1H), 7.76
(d, J = 8.4 Hz, 1H), 7.89–8.01 (m, 2H), 8.16 (d, J = 8.4 Hz, 4H),
8.65 (s, 1H); 13C NMR (125 MHz, CDCl3): d ppm 14.17, 22.72,
25.99, 29.08, 29.39, 29.59, 29.62, 29.69, 29.73, 31.95, 68.35,
68.43, 110.39, 113.99, 114.34, 114.50, 116.20, 119.47, 120.33,
121.09, 122.44, 123.82, 124.18, 130.17, 132.38, 132.57, 144.15,
147.85, 153.03, 155.80, 156.07, 159.16, 163.69, 163.97, 164.05,
164.62, 186.17; Anal. Calc. for C68H92O9; C, 77.53; H, 8.80; found:
C, 77.78; H, 8.97%.
4.2.4.10. (E)-4-(3-(7-((4-(Dodecyloxy)benzoyl)oxy)-2-oxo-2H-chro-
men-3-yl)-3-oxoprop-1-en-1-yl)phenyl
4-(dodecyloxy)benzoate
Declaration of Competing Interest
(11j). Yellow solid, Yield: 79%; M.P: 182–184 °C; IR (KBr): 2920,
2850, 1729, 1660, 1605, 1577, 1507, 1469, 1419, 1350, 1317,
The authors declare that they have no known competing finan-
cial interests or personal relationships that could have appeared
to influence the work reported in this paper.
1257, 1214, 1169, 1148, 1066, 1003, 842, 759 cmÀ1 1H NMR
;
(400 MHz, CDCl3): d 0.90 (t, J = 6.8 Hz, 6H), 1.29 (brs, 32H), 1.46–
1.49 (m, 4H), 1.83–1.86 (m,4H), 4.05–4.09 (m, 4H), 6.99 (d,
J = 8.8 Hz,2H), 7.01 (d, J = 8.8 Hz, 2H), 7.27–7.35 (m, 4H), 7.74–
7.78 (m, 3H), 7.90 (d, J = 15.6 Hz, 1H), 7.97 (d, J = 15.6 Hz, 1H),
8.16 (d, J = 8.0 Hz, 4H), 8.64 (s, 1H); 13C NMR (125 MHz, CDCl3):
d ppm 14.15, 22.71, 25.99, 29.08, 29.10, 29.37, 29.57, 29.61,
29.65, 29.67, 31.94, 68.37, 68.45, 110.38, 114.37, 114.53, 116.21,
119.43, 120.40, 121.66, 122.43, 123.88, 124.24, 130.14, 130.97,
132.38, 132.57, 144.10, 147.76, 153.06, 155.83, 156.10, 159.13,
163.71, 163.94, 164.08, 164.58, 186.14; Anal. Calc. for C56H68O9;
C, 75.99; H, 7.74; found: C, 76.09; H, 7.85%.
Acknowledgements
One of the authors (RS) is thankful to Department of Science &
Technology, Government of India for financial support vide refer-
ence no. SR/WOS-A/CS-9/2018 under Women Scientist Scheme to
carry out this work. Authors are also thankful to The Head, Depart-
ment of Chemistry, Faculty of Science, The M. S. University of Bar-
oda for providing laboratory facilities, DST-FIST for providing NMR
and POM facilities.
4.2.4.11.
(E)-4-(3-(7-((4-(Tetradecyloxy)benzoyl)oxy)-2-oxo-2H-
4-(tetradecyloxy)ben-
Appendix A. Supplementary data
chromen-3-yl)-3-oxoprop-1-en-1-yl)phenyl
zoate (11k). Yellow solid, Yield: 75%; M.P: 156–158 °C; IR (KBr):
2920,2852,1728,1662,1609,1577,1509,1468,1332,1258,1165,1066,
835,769 cmÀ1; 1H NMR (400 MHz, CDCl3): d 0.90 (t, J = 6.8 Hz, 6H),
1.28 (brs, 40H), 1.46–1.51 (m, 4H), 1.81–1.86 (m, 4H), 4.05–4.09
(m, 4H), 6.99 (d, J = 8.8 Hz, 2H), 7.01 (d, J = 8.8 Hz, 2H), 7.27–
7.34 (m, 4H), 7.90 (d, J = 15.6 Hz, 1H), 7.97 (d, J = 15.6 Hz, 1H),
8.16 (d, J = 8.8 Hz, 4H), 8.65 (s,1H); 13C NMR (125 MHz, CDCl3): d
ppm 14.18, 22.72, 25.99, 29.07, 29.09, 29.33, 29.39, 29.58, 29.62,
29.68, 31.95, 68.36, 68.44, 110.40, 114.00, 114.34, 114.50, 116.20,
119.48, 120.33, 121.08, 122.45, 123.82, 124.19, 130.18, 130.95,
131.52, 132.39, 132.58, 144.16, 147.86, 153.03, 155.80, 156.07,
159.18, 163.98, 164.06, 164.64, 186.19; Anal. Calc. for C60H76O9;
C, 76.56; H, 8.14; found: C, 76.68; H, 8.26%.
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.molliq.2021.116178.
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men-3-yl)-3-oxoprop-1-en-1-yl)phenyl
(11l). Yellow solid, Yield: 65%; M.P: 154–156 °C; IR (KBr): 2918,
4-(hexadecyloxy)benzoate
2851, 1725, 1660, 1610, 1577, 1507, 1469, 1420, 1320, 1259,
1169, 1073, 835, 764 cmÀ1 1H NMR (400 MHz, CDCl3): d 0.89 (t,
;
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