Synthesis and structural study on heterocyclic compounds 7-decanoyloxy-3-(4′-substitutedphenyl)-4H-1-benzopyran-4-ones: Crystal structure of 7-decanoyloxy-3-(4′-methylphenyl)-4H-1-benzopyran-4-one

Article abstract of DOI:10.1016/j.molstruc.2009.12.033

Six new isoflavone-based esters, 7-decanoyloxy-3-(4′-substitutedphenyl)-4H-1-benzopyran-4-ones, derived from 1,3-benzenediol (resorcinol) and different para substituted phenylacetic acids have been synthesized and characterized. The molecular structures of the title compounds were elucidated with the employment of physical measurements and spectroscopic techniques (FTIR, 1D and 2D NMR). The conformation of 7-decanoyloxy-3-(4′-methylphenyl)-4H-1-benzopyran-4-one was determined by single crystal X-ray diffraction analysis of which the title compound crystallized into triclinic lattice with P-1 space group. Crystal structure of the title compound also revealed that the two phenyl rings of the central moiety were planar whilst the heterocyclic ring was found to pucker slightly from the mean plane.

Full text of DOI:10.1016/j.molstruc.2009.12.033

Journal of Molecular Structure 967 (2010) 25–33
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Synthesis and structural study on heterocyclic compounds
7-decanoyloxy-3-(40-substitutedphenyl)-4H-1-benzopyran-4-ones: Crystal
structure of 7-decanoyloxy-3-(40-methylphenyl)-4H-1-benzopyran-4-one
a
b
c
Guan-Yeow Yeap a, , Wan-Sinn Yam , Paulina Dominiak , Masato M. Ito
*
a Liquid Crystal Research Laboraotry, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
b Department of Chemistry, Warsaw University, Al.Zwirki I Wigury, 101, 02-089, Warsaw, Poland
c Department of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan
a r t i c l e i n f o
a b s t r a c t
Six new isoflavone-based esters, 7-decanoyloxy-3-(40-substitutedphenyl)-4H-1-benzopyran-4-ones,
derived from 1,3-benzenediol (resorcinol) and different para substituted phenylacetic acids have been
synthesized and characterized. The molecular structures of the title compounds were elucidated with
the employment of physical measurements and spectroscopic techniques (FTIR, 1D and 2D NMR). The
conformation of 7-decanoyloxy-3-(40-methylphenyl)-4H-1-benzopyran-4-one was determined by single
crystal X-ray diffraction analysis of which the title compound crystallized into triclinic lattice with P-1
space group. Crystal structure of the title compound also revealed that the two phenyl rings of the central
moiety were planar whilst the heterocyclic ring was found to pucker slightly from the mean plane.
Ó 2010 Published by Elsevier B.V.
Article history:
Received 6 August 2009
Received in revised form 8 December 2009
Accepted 12 December 2009
Available online 23 December 2009
Keywords:
7-Decanoyloxy-3-(40-substitutedphenyl)-
4H-1-benzopyran-4-ones
Single crystal X-ray diffraction analysis
Triclinic
Mean plane
FTIR
1D and 2D NMR
1. Introduction
ies of the title compounds in respective liquid and solid states. The
molecular structures and characteristics of the title compounds
Isoflavones are water-soluble chemicals found in many plants.
They comprise a class of often naturally occurring organic com-
pounds related to the flavonoids [1]. Although isoflavones are not
essential nutrients, their therapeutic and medicinal values in
reducing the incidence of several diseases and improving other
measures linked to cardiovascular risk were well documented
[2,3]. Some isoflavones and isoflavone-rich foods possess anti-can-
cer properties, including certain types of breast and prostate cancer
[4]. Another interesting feature of isoflavone derivatives is their
ability to form rod-like, calamitic liquid crystals of which many
of the compounds were polymorphic, exhibiting wide thermomor-
phic ranges [5,6]. Hence, we are prompted to explore the new iso-
flavone derivatives which may possess significant use particularly
in materials science.
will also be discussed. The synthetic routes toward the formation
of the intermediates and title compounds are shown in Fig. 1.
The molecular structures of all title compounds were elucidated
by spectroscopic techniques: fourier transformed infrared (FTIR)
and high resolution nuclear magnetic resonance, NMR (1H and
13C, homonuclear 1H–1H COSY, heteronuclear 1H–13C HMQC and
1H and 13C HMBC correlation studies). A crystal structure of 7-
decanoyloxy-40-methyl-isoflavone is further confirmed by single
crystal X-ray diffraction analysis.
2. Experimental
Resorcinol (Aldrich), methanesulfonyl chloride, boron trifluor-
ide (Merck), decanoyl chloride (Acros), phenylacetic acid, and its
p-substituted analogues (p-fluoro-, p-chloro-, p-bromo-, p-nitro-,
p-tolyl-, and p-methoxyphenylacetic acids) (TCI, Japan) were used
without further purification.
In this paper, we report a new series of isoflavone derivatives, 7-
decanoyloxy-3-(40-substitutedphenyl)-4H-1-benzopyran-4-ones
wherein the decanoyloxy chain was attached to the central moiety
via an ester linkage. This paper focuses on the conformational stud-
2.1. Syntheses of 1-(2, 4-dihydroxyphenyl)-2-(40-substitutedphenyl)-
ethanones, 1–6
* Corresponding author. Fax: +60 4 6574854.
E-mail addresses: gyyeap@usm.my, gyyeap_liqcryst_usm@yahoo.com (G.-Y.
A mixture containing 5 g of the appropriate 4-substituted phen-
Yeap).
ylacetic acid and 1.2 equiv of resorcinol in 40 ml BF3ꢀEt2O was
0022-2860/$ - see front matter Ó 2010 Published by Elsevier B.V.
doi:10.1016/j.molstruc.2009.12.033

26
G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
COOH
HO
OH
O
HO
OH
(a)
+
R
R
(b)
18
H3C
1
14
16
12
10
8
5
HO
O
O
O
8a
9
7
2
3
13
11
17
15
(c)
2'
O
6
4
1'
6'
3'
4'
4a
O
O
R
R
5'
Compound
R
13
14
15
16
17
18
F
Cl
Br
CH3
OCH3
H
Fig. 1. The reaction scheme for compounds 13–18. Reagents and conditions: (i) BF3ꢀEt2O heated at 75 °C for 4 h; (ii) N2 atmosphere, DMF, BF3ꢀEt2O heated at 55 °C for 1.5 h;
MeSO2Cl heated at 80 °C for 2 h; (c)(i)Et3N, DCM/DMF (ii) C9H19COCl stirred for 6 h at room temperature.
Table 1
FTIR spectral data (cmꢁ1) of compounds 13–18 in solid state (embedded in KBr).
Compounds
v (C–H)aliphatic
v (C@O)ester
v (C@O)pyranone
v (@C)arom
v (C–O)
13
14
15
16
17
18
2959, 2916 and 2851
2952, 2928 and 2855
2953, 2925 and 2853
2959, 2925 and 2852
2952, 2924 and 2852
2953, 2922 and 2851
1754
1745
1742
1743
1763
1745
1637
1647
1648
1647
1638
1647
1609
1576
1570
1575
1572
1572
–
–
–
–
1235
–
Table 2
Acquisition parameters used in the NMR measurements.
Parametersa
Experiment
1H NMR
400.1
13C NMR
100.6
2D COSY
400.1
2D HMQC
2D HMBC
SF (MHz)
F1 = 100.6
F2 = 400.1
F1 = 100.6
F2 = 400.1
SW (ppm)
20
250
18
F
F
1 = 200
2 = 20
F1 = 200
F2 = 20
PW (
ls)
8.3 (30° flip ring)
20 (90° flip ring)
8.3 (30° flip ring)
8.3 (30° flip ring)
8.3 (30° flip ring)
AQ (s)
D1 (S)
NS
4.0
1.0
32
1.3
0.3
2.0
16
0.09
1.0
64
0.4
1.0
32
2.0
15 000
65 K
TD
66 K
F
1 = 256
F1 = 512
F1 = 512
F2 = 2048
F2 = 1024
F2 = 4096
a
Abbreviations: F1, 13C channel (except 2D COSY where F1 and F2 are 1H channels); SF, spectrometer frequency; SW, spectral width; AQ, acquisition time; D1, relaxation
delay; NS, number of scans; TD, number of data points.
heated for 4 h at 75 °C under nitrogen atmosphere [7,8]. The mix-
ture was cooled down to ambient temperature and poured into an
ice-water bath. The oil was separated, air-dried, and recrystallized
from chloroform.
1: Yield 65%. Melting point (m.p.) 140.0–141.0 °C. Analysis:
calculated for C14H11FO3. C 68.29, H 4.50%; found C 68.10%, H
4.48%. IR (KBr)/cmꢁ1: 3419 (OH), 2907 (CH2 aliphatic), 1636
(C@O), 1598 (C@C).

G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
27
Table 3
Table 4
1H–1H correlations as inferred from 2D COSY experiment for compound 14.
13C–1H correlations as inferred from the 2D HMQC and HMBC experiments for
compound 14.
Atoma
1H–1H COSY correlations
Atoma
HMQC 1J
HMBC[J(C,H)] 2J
3J
4J
H2
–
H5
H6
H8
H20 or H60
H30or H50
H10
H6
H2
H5
H6
H8
H20 or H60
H30 or H50
H10b
H11b
H18
C2
C5
C6
C8
C20 or C60
C30 or C50
C10
C11
C18
C3
–
–
C10, C4, C8a
C4, C7, C8a
C4a, C8
C4a, C6
C40, C3
C10
–
–
C16
C20 or C6
C8
–
C5
–
–
–
–
–
H5 and H8
H6
H30 or H50
H20 or H60
H11
H10, H12 to H17
H11 and H18
H12 to H17
C8a, C7
C10
C40
H11
C11
C10
C17
(H12 to H17)b
H18
a
a
Based on the atomic numbering scheme in Fig. 1.
The H12 to H17 atoms correlate with the methylene proton, H11 and methyl
Based on the atomic numbering scheme in Fig. 1.
The H10 and H11 atoms correlate with the methylene carbons (C12–C15) but
b
b
proton, H18 but their chemical shifts could not be determined due to indistin-
their J[(C, H)] values can not be determined due to indistinguishable chemical shifts
of C12–C15 atoms.
guishable 1H chemical shifts of H12 to H17.
2: Yield 63%. m.p. 150.0–150.5 °C. Analysis: calculated for
C14H11ClO3. C 64.01, H 4.22%; found C 64.02, H 4.23%. IR (KBr)/
cmꢁ1: 3358 (OH), 2920 (CH2 aliphatic), 1630 (C@O), 1596 (C@C).
3: Yield 68%. m.p. 170.0–170.5 °C. Analysis: calculated for
C14H11 BrO3. C 57.75, H 3.61%; found C 57.65, H 3.60%. IR (KBr)/
cmꢁ1: 3322 (OH), 2892 (CH2 aliphatic), 1626 (C@O), 1587 (C@C).
4: Yield 69%. m.p. 144.0–145.0 °C. Analysis: calculated for
C15H14O3. C 74.36%, H 5.82%; found C 74.16, H 5.80%. IR (KBr)/
cmꢁ1: 3145 (OH), 2922, 2870 (CH2 aliphatic), 1623 (C@O), 1584
(C@C).
2.2. Syntheses of 7-hydroxy-3-(40-substitutedphenyl)-4H-1-
benzopyran-4-ones, 7–12
Five grams of 1-(2,4-dihydroxyphenyl)-2-(4-substitutedphe-
nyl)ethanones in dry dimethylformamide (DMF) was carefully
treated with 4.0 equiv of BF3.Et2O under nitrogen atmosphere. To
this mixture, 3.0 equiv of MeSO2Cl was added at 55 °C and stirred
for 1 h. The mixture was then heated for 2 h at 80 °C [7,8] prior to
being poured with rapid stirring into an ice-water bath. The prod-
uct thus obtained was subsequently purified with chloroform via
recrystallization.
5: Yield 60%. m.p. 156.0–157.0 °C. Analysis: calculated for
C15H14O4. C 69.76, H 5.46%; found C 69.50, H 5.43%. IR (KBr)/
cmꢁ1: 3412 (OH), 2836 (CH2 aliphatic), 1631 (C@O), 1568 (C@C),
1244 (C–O).
6: Yield 63%. m.p. 138.0–139.0 °C. Analysis: calculated for
C14H12O3. C 73.07, H 5.30%; found C 73.20, H 5.32%. IR (KBr)/
cmꢁ1: 3212 (OH), 2900 (CH2 aliphatic), 1639 (C@O), 1549 (C@C).
7: Yield 59%. m.p. 202.0–203.0 °C. Analysis: calculated for
C15H9 FO3. C 70.31, H 3.54%; found C 70.42, H 3.55%. IR (KBr)/
cmꢁ1: 3193 (OH), 1641 (C@O), 1598 (C@C).
Fig. 2. 1H–1H COSY spectrum of compound 14.

28
G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
Fig. 3. 1H–13C HMBC spectrum of compound 14.
Table 5
1H NMR chemical shifts (ppm) of compounds 13–18 in CDCl3, where m = number of carbon atoms in both terminal chains. TMS was used as an internal standard.
Compounds
Chemical shifts (ppm)
H2
H5
H8
H20,60
H30,50
H6
H10
H11
H12-H17
H18
Ar-OCH3
Ar-CH3
13
14
15
16
17
18
7.99
8.01
8.00
8.01
7.98
8.01
8.32
8.32
8.31
8.35
8.32
8.33
7.12
7.31
7.30
7.31
7.29
7.30
7.31
7.56
7.50
7.48
7.50
7.56
7.11-
7.45
7.41
7.28
6.98
7.39-
7.18a
2.59–2.63
2.59–2.64
2.59–2.63
2.61–2.65
2.59–2.63
2.59–2.63
1.74–1.82
1.74–1.82
1.69–1.79
1.76–1.84
1.74–1.80
1.74–1.80
1.29–1.45
1.29–1.45
1.29–1.44
1.23–1.49
1.29–1.45
1.29–1.45
0.87–0.91
0.87–0.91
0.87–0.91
0.89–0.93
0.87–0.91
0.87–0.91
–
–
–
–
3.84
–
–
–
–
2.42
–
7.16–7.19
7.15–7.18
7.16–7.19
7.14–7.17
7.74a
–
a
Overlapped signals of H30,50 and H6.
Table 6
13
C NMR chemical shifts (ppm) of compounds 13–18 in CDCl3. TMS was used as an internal standard.
Compounds
Chemical shifts (ppm)
C2
C3
C4
C4a
C5
C6
C7
C8
C8a
C10
C20,60
C30,50
13
14
15
16
17
18
153.50
153.36
153.50
152.88
154.58
143.15
124.93
120.09
124.93
125.54
122.24
125.60
175.73
175.58
175.53
175.71
175.81
175.57
120.14
117.88
122.53
122.31
119.48
122.30
128.20
122.97
128.20
127.85
123.84
127.85
115.55
111.28
120.14
119.52
114.04
119.59
155.17
155.23
155.17
154.61
156.68
154.66
111.35
111.39
111.39
110.90
110.88
110.92
157.06
157.08
157.06
156.71
159.74
156.69
130.41
128.19
130.41
128.83
127.81
128.54
130.61
130.88
130.61
129.26
130.13
128.97
129.15
125.01
129.15
128.62
125.18
128.32
C40
C9
C10
C11
C12-C15
C16
C17
C18
Ar-CH3
Ar-OCH3
13
14
15
16
17
18
134.77
132.09
134.77
138.22
152.60
131.59
171.84
171.71
171.46
171.50
171.49
171.48
34.80
34.80
34.42
34.42
34.41
34.42
24.81
24.81
24.81
24.81
24.81
24.81
23.07–29.40
22.68–29.41
22.68–29.41
22.68–29.41
22.68–29.41
22.68–29.41
32.25
31.86
31.86
31.86
31.86
31.86
22.68
22.68
22.68
22.68
22.68
22.68
14.50
14.40
14.11
14.11
14.11
14.12
–
–
–
–
–
–
–
21.28
–
–
55.35
–
8: Yield 60%. m.p. 229.0–230.0 °C. Analysis: calculated for
C15H9 ClO3. C 66.07, H 3.33%; found C 66.00, H 3.33%. IR (KBr)/
cmꢁ1: 3197 (OH), 1642 (C@O), 1593 (C@C).
9: Yield 63%. m.p. 242.0–243.0 °C. Analysis: calculated for
C15H9BrO3. C 56.81, H 2.86%; found C 56.70, H 2.83%. IR (KBr)/
cmꢁ1: 3177 (OH), 1641 (C@O), 1588 (C@C).

G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
29
10: Yield 70%. m.p. 254.0–255.0 °C. Analysis: calculated for
C16H12O3. C 76.18, H 4.74%; found C 76.30, H 4.75%. IR (KBr)/
cmꢁ1: 3188 (OH), 1623 (C@O), 1574 (C@C).
11: Yield 55%. m.p. 217.0–218.0 °C. Analysis: calculated for
C16H12O4. C 71.64, H 4.51%; found C 71.68, H 4.52%. IR (KBr)/
cmꢁ1: 3137 (OH), 1638 (C@O), 1595 (C@C), 1246 (C–O).
12: Yield 61%. 199.5–200.0 °C. Analysis: calculated for
C15H10O3. C 75.62, H 4.23%; found C 75.80, H 4.30%. IR (KBr)/
cmꢁ1: 3200 (OH), 1622 (C@O), 1584 (C@C).
as internal standard. Reported chemicals shifts for isoflavone, the
1H and 13C correlation spectral data were used to assign the chem-
ical shifts of the synthesized compounds [10–12]. Complete 1H and
13C NMR assignments of compounds 13–18 were obtained and
substantiated with the aids of DEPT and two-dimentional 1H–1H
correlation spectroscopy (COSY), 13C–1H heteronuclear multiple
quantum correlation (HMQC) and 13C–1H heteronuclear multiple
bond correlation (HMBC).
2.6. X-ray data collection, structure solution and refinement for
compound 16
2.3. Syntheses of 7-decanoyloxy-3-(40-substitutedphenyl)-4H-1-
benzopyran-4-ones, 13–18
The measurement of diffractional data was performed on a
Decanoyl chloride (1.2 equiv) was added to a mixture of 0.3 g of
Kuma KM4CCD
j-axis diffractometer with graphite-monochro-
7-hydroxy-3-(4-substitutedphenyl)-4H-1benzopyran-4-ones
in
mated MoK radiation and equipped with an Oxford Cryosystems
a
DMF/CH2Cl2 and 0.2 ml triethylamine. The mixture was stirred at
room temperature for 6 h. The solvent was later removed and
diethylether was added to the residue. Triethylammonium chlo-
ride was filtered off and the product was purified through recrys-
tallisation from absolute ethanol.
nitrogen gas-flow apparatus. The crystal was positioned at
62 mm from the KM4CCD camera. 2400 frames were measured
at 0.5° intervals (x scan) with a counting time of 10 s. The data
were corrected for Lorentz and polarization effects. No absorption
correction was applied. Data reduction and analysis were carried
out with the Oxford Diffraction Ltd. suit of programs.
2.4. FTIR measurements
The structure was solved by direct methods [13] and refined
using SHELXL [14]. The refinement was based on F2 for all reflec-
tions except those with very negative F2 Weighted R factors wR
The FTIR data were recorded using a Perkin Elmer 2000-FTIR
spectrophotometer in the frequency range 4000–400 cmꢁ1 with
samples prepared in KBr discs (Table 1).
.
and all goodness-of-fit S values are based on F2. Conventional R fac-
tors are based on F with F set to zero for negative F2. The Fo2 > 2
r(-
Fo2) criterion was used only for calculating R factors and is not
relevant to the choice of reflections for the refinement. The R fac-
tors based on F2 are about twice as large as those based on F. Scat-
tering factors were taken from crystallographic Tables 6.1.1.4 and
4.2.4.2 [15]. All hydrogen atoms were located from a difference
Fourier maps. The CH3 hydrogens were treated as part of idealized
CH3 groups with Uiso = 1.5Ueq, while the remainder of the hydrogen
2.5. NMR measurements
NMR data were obtained using Bruker 300 MHz and 400 MHz
ultrashield spectrometer. Standard Bruker pulse programs [9] were
used throughout the entire experiment. The spectroscopic details
of NMR are summarized in Table 2. Deuterated chloroform (CDCl3)
and dimethylsulphoxide (DMSO-d6) were used as solvent and TMS
atoms were refined with the ‘‘riding” model with Uiso = 1.2Ueq
.
Fig. 4. 1H–13C HMBC spectrum of compound 14.

30
G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
protons, H18 of the terminal alkyl chain. The presence of the H10
3. Results and discussion
3.1. IR spectroscopy
protons can be substantiated by a triplet at d = 2.59–2.63 ppm.
The other methylene protons, H11 and H12 to H17 are confirmed
by the occurrence of two sets of multiplets at d = 1.69–1.79 ppm
and 1.29–1.44 ppm, respectively.
The FTIR spectra of compounds 1–6 show the absorption bands
assignable to the stretching of OH at 3137–3419 cmꢁ1. Bands
appearing within the frequency range of 2836–2922 cmꢁ1 can be
ascribed to the stretching of aliphatic C–H. Whilst the stretching
of C@O (ketone) appears at 1623–1639 cmꢁ1, the signal ascribed
to the C@C aromatic is observed at 1549–1598 cmꢁ1. An additional
band attributable to the stretching of C–O is observed for com-
pound 5 at 1244 cmꢁ1. Two of the earlier mentioned bands corre-
sponding with the stretching of C–H and C@O (ketone) are absent
in compounds 7–12. Instead, the stretching of C@O (benzopyran-
one) at 1630–1647 cmꢁ1 is recorded. Compounds 13–18, on the
other hand, show bands at 2851–2959, 1742–1763, 1637–1648,
and 1609–1570 cmꢁ1, which can be assigned to the stretching of
aliphatic C–H, C@O ester and C@O benzopyranone, respectively.
An absorption occurring at 1235 cmꢁ1 can be attributed to the
stretching of C–O in compound 17.
The correlations of 1H–1H from COSY experiment (Table 3) are
employed to assign the aromatic protons. According to Fig. 2, the
three sets of doublets observed at d = 8.31, 7.50 and 7.41 ppm
can be ascribed to H5 and H20 (or H60) and H30 (or H50) respectively.
A double doublet at d = 7.15–7.18 ppm is assigned to H6 based on
the homonuclear coupling with the nearest proton (H5). The chem-
ical shift of the H8 atom is observed as a doublet at d = 7.30 ppm.
The structure of compound 14 is further substantiated by the
13C NMR, HMQC and HMBC spectroscopic data (Table 4). According
to the HMQC spectrum (Fig. 3), the C2 atom at d = 153.50 ppm is
assigned based on its correlation with H2 atom. Other aromatic
carbons are assigned based on the correlations between C5 and
H5 at d = 128.20 ppm, C6 and H6 at d = 120.14 ppm, C8 and H8 at
d = 111.39 ppm, C20 (or C60) and H20 (or H60) at d = 130.61 ppm as
well as C30 (or 50) and H30 (or H50) at d = 129.15 ppm (Table 5).
The HMQC spectrum also reveals that methylene carbons, C10
atom at d = 34.42 correlates with H10 atom (d = 2.59–2.63) and
C11 atom at d = 24.81 correlates with H11 atom (d = 1.69–1.79).
A multiplet at d = 1.29–1.44 ppm attributable to H12 to H17 are
found to correlate to C12 to C17 atoms within d = 31.86–
22.68 ppm. The methyl carbon atom, C18 are unambiguously as-
signed at d = 14.11 ppm based on its correlations with H18 atom
(Table 6).
3.2. NMR spectroscopy
Based on a representative compound 14, a complete assignment
for the title compounds can be described. The 1H NMR spectrum of
compound 14 indicates a singlet which is attributable to H2 atom
at d = 8.00 ppm. This substantiates the occurrence of a cyclization
reaction. A triplet at d = 0.87–0.91 ppm can be assigned to methyl
Fig. 5. The molecular structure with atom-numbering scheme of compound 16 (diamond view).
Fig. 6. The molecular packing of compound 16 (diamond view).

G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
31
HMBC experiment is used to assign quaternary carbons of com-
pound 14 (Fig. 4). The C3 atom is assigned based on its long range
correlation with H2 atom at d = 124.93 ppm. The long range HMBC
cross peaks of C4 atom with H5 proton at d = 175.53 ppm, C4a
atom and H5 atom at d = 122.53 ppm, as well as C8a atom with
H8 atom at d = 157.06 ppm confirm the positions of these atoms.
The assignment of C6 atom at d = 120.14 ppm is based on its corre-
lation with H5 atom. The 13C signal of the C7 atom at
d = 155.17 ppm is confirmed via its correlation with H8 atom.
The spectrum reveals cross peaks of H30 (or H50) atom with C40
atom at d = 134.77 ppm and H30 (or H50) with C10 at
d = 130.41 ppm.
Compounds 13, 15 16, 17 and 18 show similar NMR spectra
characteristics as discussed for compound 14 The 1H NMR spectra
for both compounds 16 and 17 each show an additional singlet at
d = 2.42 and 3.84 ppm, respectively, confirmed the presence of
methyl protons, Ar–CH3 for compound 16 and methoxy protons,
Ar–OCH3 for compound 17. The cross peaks of both protons with
their respective carbons in 13C NMR spectra reveals the chemical
shifts of methyl carbon, Ar–CH3 at d = 21.28 ppm and methoxy car-
bon, Ar–OCH3 at d = 55.35 ppm.
in the central moiety with a decanoyloxy chain attached to C7
via an ester linkage. Rings A, (C4–C5–C6–C7–C8–C9) and C,
(O1–C1–C2–C3–C4–C9) are almost planar with a dihedral angle
of 3.67°. The heterocyclic ring B, (C10–C11–C12–C13–C14–C15),
on the other hand, is twisted from the mean plane of ring C by
Table 8
Atomic coordinates and Biso/Beq of compound 16.
Aom
x
y
z
U(eq)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
8299(1)
3078(1)
3747(1)
7233(2)
8537(2)
6916(2)
4648(2)
4392(2)
2340(2)
2176(2)
4107(2)
6136(2)
6226(2)
7493(2)
9626(2)
10214(2)
8719(2)
6580(2)
5959(2)
5416(2)
4575(2)
6297(2)
5439(2)
7175(2)
6361(2)
8065(2)
7250(2)
8918(2)
8083(3)
9371(2)
7091(1)
7467(1)
3458(1)
3720(1)
7993(1)
8175(1)
7372(1)
6410(1)
5559(1)
4614(1)
4503(1)
5347(1)
6285(1)
9189(1)
9402(1)
10391(1)
11194(1)
10964(1)
9979(1)
3098(1)
1823(1)
1355(1)
45(1)
4200(1)
5611(1)
2923(1)
2400(1)
4771(1)
5263(1)
5180(1)
4547(1)
4386(1)
3832(1)
3417(1)
3530(1)
4098(1)
5878(1)
6337(1)
6880(1)
6987(1)
6537(1)
5996(1)
2496(1)
2174(1)
1677(1)
1367(1)
880(1)
19(1)
21(1)
21(1)
43(1)
18(1)
15(1)
16(1)
16(1)
19(1)
20(1)
18(1)
19(1)
16(1)
15(1)
18(1)
21(1)
20(1)
18(1)
17(1)
22(1)
22(1)
22(1)
22(1)
23(1)
24(1)
24(1)
26(1)
30(1)
41(1)
28(1)
C(9)
The results as inferred from the IR and NMR spectral data of all
compounds are found to conform to those reported in the litera-
ture [6] and are consistent with the proposed structure as shown
in Fig. 1.
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
3.3. Crystal structure analysis for compound 16
The molecular structure with the atom-numbering scheme and
packing of compound are shown in Figs. 5 and 6, respectively. Crys-
tal data of compound are collated in Table 7. The atomic coordi-
nates, Biso/Beq and anisotropic displacement parameters are given
in Tables 8 and 9, respectively. Tables 10 and 11 show the selected
bond lengths and angles as well as the torsion angles, respectively,
for compound 16.
ꢁ442(1)
ꢁ1749(1)
ꢁ2205(1)
ꢁ3494(1)
ꢁ3896(1)
ꢁ5162(1)
12282(1)
567(1)
50(1)
ꢁ302(1)
ꢁ857(1)
ꢁ1236(1)
7564(1)
From Fig. 5, it is apparent that the discrete molecule of com-
pound 16 comprise of two phenyl rings and a heterocyclic ring
Table 9
Anistropic displacement parameters (Å2 ꢂ 103) of compound 16.
Table 7
Atom
U11
U22
U33
U23
U13
U12
Crystal data and refinement of compound 16.
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
18(1)
19(1)
22(1)
42(1)
18(1)
17(1)
18(1)
17(1)
17(1)
18(1)
24(1)
19(1)
17(1)
18(1)
18(1)
19(1)
27(1)
24(1)
19(1)
27(1)
29(1)
28(1)
28(1)
31(1)
30(1)
31(1)
33(1)
40(1)
63(1)
36(1)
17(1)
21(1)
17(1)
31(1)
14(1)
13(1)
15(1)
14(1)
18(1)
17(1)
15(1)
19(1)
15(1)
14(1)
18(1)
23(1)
17(1)
15(1)
18(1)
21(1)
17(1)
18(1)
17(1)
18(1)
19(1)
20(1)
19(1)
23(1)
26(1)
22(1)
22(1)
24(1)
24(1)
52(1)
20(1)
16(1)
17(1)
16(1)
23(1)
23(1)
15(1)
19(1)
17(1)
14(1)
20(1)
18(1)
16(1)
18(1)
16(1)
18(1)
20(1)
20(1)
20(1)
21(1)
22(1)
23(1)
26(1)
28(1)
36(1)
25(1)
ꢁ7(1)
ꢁ3(1)
ꢁ7(1)
ꢁ20(1)
ꢁ3(1)
0(1)
2(1)
1(1)
1(1)
ꢁ1(1)
ꢁ3(1)
ꢁ1(1)
0(1)
0(1)
0(1)
ꢁ2(1)
ꢁ1(1)
0(1)
6(1)
7(1)
2(1)
26(1)
1(1)
0(1)
3(1)
1(1)
5(1)
ꢁ1(1)
ꢁ1(1)
5(1)
1(1)
3(1)
4(1)
ꢁ1(1)
5(1)
6(1)
2(1)
5(1)
3(1)
4(1)
2(1)
5(1)
4(1)
5(1)
6(1)
7(1)
12(1)
3(1)
0(1)
5(1)
3(1)
ꢁ9(1)
2(1)
5(1)
7(1)
5(1)
5(1)
2(1)
7(1)
5(1)
3(1)
3(1)
5(1)
1(1)
2(1)
7(1)
5(1)
5(1)
2(1)
3(1)
4(1)
4(1)
4(1)
5(1)
6(1)
10(1)
13(1)
2(1)
Crystal data
Values
Empirical formula
Formula weight
Temperature
Wavelength
Crystal system, space group
Dimensions
C26H30O4
406.50
100(2) K
0.71073 Å
Triclinic, P-1
a = 5.8905(3)Å
b = 11.2662(5)Å
c = 16.7581(7)Å
a
= 91.909(3)°
b = 94.435(4)°
c
= 100.622(4)°
C(9)
Volume
Z
Calculated density
Absorption coefficient
F(0 0 0)
Crystal size
Theta range for data collection
Limiting indices
Reflections collected/unique
Completeness to theta = 27.50
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2sigma(I)]
R indices (all data)
Largest diff. peak and hole
1088.51(9) A3
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
2
1.240 mgmꢁ3
0.082 mmꢁ1
436
0.35 x 0.26 x 0.18 mm
2.99 to 27.50 deg.
ꢁ7 6 h 6 7, ꢁ14 6 k 6 14, ꢁ21 6 l 6 21
19900/4991 [R(int) = 0.0193]
99.4%
0.9853 and 0.9718
Full-matrix least-squares on F2
4991/0/273
2(1)
ꢁ4(1)
ꢁ4(1)
ꢁ3(1)
ꢁ4(1)
ꢁ3(1)
ꢁ5(1)
ꢁ4(1)
ꢁ4(1)
ꢁ4(1)
ꢁ8(1)
ꢁ7(1)
1.067
R1 = 0.0359, wR2 = 0.1020
R1 = 0.0493, wR2 = 0.1051
0.280 and ꢁ0.232 e/Åꢁ3

32
G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
Table 10
Table 11
Selected bond lengths (Å) and angles (°) of compound 16.
Torsion angles (°) of compound 16.
C(7)–(8)
C(8)–C(9)
1.3791(14)
1.3893(14)
118.18(8)
124.20(8)
125.74(9)
119.40(9)
118.77(9)
121.83(9)
123.55(9)
122.06(9)
114.38(8)
116.98(9)
120.91(9)
122.08(9)
121.56(9)
119.15(9)
125.72(9)
121.45(9)
112.80(9)
117.36(9)
121.30(9)
115.28(9)
123.41(9)
118.19(9)
120.54(9)
121.23(9)
120.45(10)
1.3979(14)
1.4000(14)
1.3899(14)
1.3902(15)
1.3943(15)
1.5080(14)
1.3849(14)
1.4981(14)
1.5164(15)
1.5287(14)
1.5217(15)
1.5236(14)
1.5230(14)
1.5254(15)
1.5217(16)
1.5204(16)
121.58(10)
117.64(9)
121.72(10)
120.64(10)
121.53(9)
120.57(10)
124.32(10)
126.42(10)
109.25(9)
112.95(9)
112.40(9)
112.82(9)
113.79(9)
113.23(9)
114.40(9)
113.18(9)
113.71(10)
C(9)–O(1)–C(1)–C(2)
O(1)–C(1)–C(2)–C(3)
O(1)–C(1)–C(2)–C(10)
C(1)–C(2)–C(3)–O(2)
C(10)–C(2)–C(3)–O(2)
C(1)–C(2)–C(3)–C(4)
C(10)–C(2)–C(3)–C(4)
O(2)–C(3)–C(4)–C(9)
C(2)–C(3)–C(4)–C(9)
O(2)–C(3)–C(4)–C(5)
C(2)–C(3)–C(4)–C(5)
C(9)–C(4)–C(5)–C(6)
C(3)–C(4)–C(5)–C(6)
C(4)–C(5)–C(6)–C(7)
C(16)–O(3)–C(7)–C(8)
C(16)–O(3)–C(7)–C(6)
C(5)–C(6)–C(7)–C(8)
C(5)–C(6)–C(7)–O(3)
O(3)–C(7)–C(8)–C(9)
C(6)–C(7)–C(8)–C(9)
C(1)–O(1)–C(9)–C(4)
C(1)–O(1)–C(9)–C(8)
C(5)–C(4)–C(9)–O(1)
C(3)–C(4)–C(9)–O(1)
C(5)–C(4)–C(9)–C(8)
C(3)–C(4)–C(9)–C(8)
C(7)–C(8)–C(9)–O(1)
0.59(15)
ꢁ.95(16)
C(1)–O(1)–C(9)
C(16)–O(3)–C(7)
C(2)–C(1)–O(1)
C(1)–C(2)––C(3)
C(1)–C(2)–C(10)
C(3)–C(2)–C(10)
O(2)–C(3)–C(2)
O(2)–C(3)–C(4)
C(2)–C(3)–C(4)
C(9)–C(4)–C(5)
C(9)–C(4)–C(3)
C(5)–C(4)–C(3)
C(6)–C(5)–C(4)
C(5)–C(6)–C(7)
C(8)–C(7)–O(3)
C(8)–C(7)–C(6)
O(3)–C(7)–C(6)
C(7)–C(8)–C(9)
O(1)–C(9)–C(4)
O(1)–C(9)–C(8)
C(4)–C(9)–C(8)
C(11)–C(10)–C(15)
C(11)–C(10)–C(2)
C(15)–C(10)–C(2)
C(12)–C(11)–C(10)
C(10)–C(11)
C(10)–C(15)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
C(13)–C(26)
C(14)–C(15)
C(16)–C(17)
C(17)–C(18)
C(18)–C(19)
C(19)–C(20)
C(20)–C(21)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
C(24)–C(25)
C(11)–C(12)–C(13)
C(12)–C(13)–C(14)
C(12)–C(13)–C(26)
C(14)–C(13)–C(26)
C(15)–C(14)–C(13)
C(14)–C(15)–C(10)
O(4)–C(16)–O(3)
O(4)–C(16)–C(17)
O(3)–C(16)–C(17)
C(16)–C(17)–C(18)
C(17)–C(18)–C(19)
C(20)–C(19)–C(18)
C(19)–C(20)–C(21)
C(22)–C(21)–C(20)
C(21)–C(22)–C(23)
C(24)–C(23)–C(22)
C(25)–C(24)–C(23)
177.98(9)
179.21(10)
ꢁ0.71(15)
0.56(14)
ꢁ179.37(9)
ꢁ176.63(9)
2.05(14)
1.10(15)
179.77(9)
2.49(15)
ꢁ175.32(9)
ꢁ0.15(16)
2.48(16)
ꢁ175.39(9)
ꢁ2.61(16)
175.36(9)
ꢁ174.90(9)
2.79(16)
2.20(14)
ꢁ176.93(9)
178.64(9)
ꢁ3.52(15)
ꢁ2.29(15)
175.55(9)
178.83(9)
ꢁ0.29(16)
ꢁ44.36(14)
135.57(10)
133.61(11)
ꢁ46.46(14)
ꢁ1.59(15)
176.45(9)
0.12(16)
C(7)–C(8)–C(9)–C(4)
C(1)–C(2)–C(10)–C(11)
C(3)–C(2)–C(10)–C(11)
C(1)–C(2)–C(10)–C(15)
C(3)–C(2)–C(10)–C(15)
C(15)–C(10)–C(11)–C(12)
C(2)–C(10)–C(11)–C(12)
C(10)–C(11)–C(12)–C(13)
C(11)–C(12)–C(13)–C(14)
C(11)–C(12)–C(13)–C(26)
C(12)–C(13)–C(14)–C(15)
C(26)–C(13)–C(14)–C(15)
C(13)–C(14)–C(15)–C(10)
C(11)–C(10)–C(15)–C(14)
C(2)–C(10)–C(15)–C(14)
C(7)–O(3)–C(16)–O(4)
C(7)–O(3)–C(16)–C(17)
O(4)–C(16)–C(17)–C(18)
O(3)–C(16)–C(17)–C(18)
C(16)–C(17)–C(18)–C(19)
C(17)–C(18)–C(19)–C(20)
C(18)–C(19)–C(20)–C(21)
C(19)–C(20)–C(21)–C(22)
C(20)–C(21)–C(22)–C(23)
C(21)–C(22)–C(23)–C(24)
C(22)–C(23)–C(24)–C(25)
O(3)–C(16)–C(17)–C(18)
C(16)–C(17)–C(18)–C(19)
C(17)–C(18)–C(19)–C(20)
C(18)–C(19)–C(20)–C(21)
C(19)–C(20)–C(21)–C(22)
C(20)–C(21)–C(22)–C(23)
C(21)–C(22)–C(23)–C(24)
C(22)–C(23)–C(24)–C(25)
0.93(16)
ꢁ178.76(10)
ꢁ0.49(15)
179.21(10)
ꢁ1.00(16)
2.02(15)
ꢁ176.00(9)
ꢁ12.19(17)
168.22(9)
ꢁ0.73(17)
178.84(9)
178.77(9)
ꢁ178.89(9)
179.82(9)
177.34(9)
ꢁ177.53(9)
176.39(10)
ꢁ177.89(10)
178.84(9)
178.77(9)
ꢁ178.89(9)
179.82(9)
177.34(9)
ꢁ177.53(9)
176.39(10)
ꢁ177.89(10)
41.07°. The methyl group, C26 and decanoyloxy chain, O3 are ori-
entated slightly out of plane of the rings to which they are at-
tached. The angle of O3–C6–C7 is 112.80° and that of C13–C14–
C26 is 120.64°.
This value is the lowest in hitherto reported isoflavone system
according to Shoja [18] in 1992. The then lowest value reported
was ꢁ42.80°.
The bond lengths of C13–C26 (1.5080(14) Å), C2–C10
(1.4854(14) Å), and O3–C7 (1.3904(11) Å) are characteristics of
single bonds. On the other hand, the C@O linkage of benzopyran-
one, O2–C3 (1.2337 (12) Å) and that of the ester, O4–C16
(1.1920(13) Å) are characteristics double bonds as observed in
other isoflavone derivatives [16,17]. Fig. 6 also shows that the
decanoyloxy chain attached to C7 via an ester linkage is linear with
no folding. The torsion angle between C3–C2–C10–C15 is ꢁ46.46°.
The packing of the molecules (Fig. 6) shows that they lie anti
parallel to each other. The molecules are arranged in layers and
stacked along the b axis with two molecules in one unit cell. There
are no anomalously short intermolecular contacts in the crystal of
compound 16. The crystal cohesion resulted from dipolar interac-
tions between anti parallel ester groups as well as van der Waals
interaction of neighbouring molecules stabilize the packing of the
molecules.

G.-Y. Yeap et al. / Journal of Molecular Structure 967 (2010) 25–33
33
The molecular structure of compound 16 based on crystallogra-
References
phy methods (Fig. 6) confirmed the structure inferred from FTIR
and NMR spectroscopic techniques.
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Acknowledgements
[15] A.J.C. Wilson (Ed.), International Tables for Crystallography, vol. C, Kluwer,
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The main author would like to thank Universiti Sains Malaysia
and the Malaysian Government especially the Ministry of Science,
Technology and Innovation (MOSTI) for the eScience Grant No.
305/PKIMIA/613328, USM Short-Term Grant No. 304/PKIMIA/
638006 and USM Incentive Grant No. 304/JPNP/600004.
[18] M. Shoja, Acta Cryst. C48 (1992) 2033.