Supplementary material
A bench-top catalyst: BF3.SiO2-assisted synthesis, biological assay and
computational simulations of azacholestanes
Azhar U. Khan1, Mahboob Alam2 and Dong-Ung Lee2,*
1
Department of Chemistry, School of Physical and Molecular Sciences, Al-Falah University,
Dhauj, Faridabad-121004, Haryana, India
2
Division of Bioscience,Dongguk University, Gyeongju 780-714, Republic of Korea
1
Preparation of the catalyst BF3.SiO2
Silica-supported boron trifluoride catalyst can easily be prepared from silica gel and BF3·Et2O
using the reported method. The reaction must be carried out under a hood. Briefly, a mixture of
BF3.OEt2 (4.2 mmol) and silica gel (0.5 g) in MeOH (5 mL) was prepared and stirred for 1 h at
room temperature. The generated suspension was then filtered and dried at ambient temperature
for 6 h, after which it was stored in a dry and covered container at room temperature for future
experiments. The silica supported boron trifluoride catalyst is identified by using various
physicochemical techniques and found to have a superimposed characteristic(Mirjalilet al. 2013)
as mentioned in literature. In order to ascertain the attachment of borontrifluoride to the silica
support, FT-IR spectra were recorded in (4000-400 cm-1) regions. FT-IR spectrum of the
BF3.SiO2 is shown in Fig. 1. The low frequency peak near 635 cm−1 is assigned to Si–O–Si outof-plane bending. The band at 961 cm−1 is ascribed to Si–O–Si symmetric stretching vibrations,
respectively. The moisture in BF3 represents the peak that is linked to the presence of the OH
band in its IR spectrum. Other characteristic peaks at 1531, 874 and 1111 cm-1 are assigned to BO, Si-OH and Si-O-Si, respectively (Supplementary Fig. 1). Scanning electron micrograph was
recorded to scrutinize the morphological changes happening on the surface of the silica. A clear
change in the morphology of the silica, after the introduction of boron trifluoride, was observed
by Scanning electron micrograph. Inspection of image of a sample catalyst specifies the
involvement of boron trifluoride particles. The dimensions of nanoparticles were observed with
SEM. The particle sizes of the commercial silica gel and BF3.SiO2 were about 24 and 30-40 nm,
respectively (Supplementary Fig. 2).
2
Supplementary Fig. 1FT-IR spectrum of (A) BF3.OEt2 (B) BF3.SiO2, and (C) SiO2.
3
(A)
(B)
Supplementary Fig. 2 Surface plot of (A) SiO2 and (B) BF3.SiO2.
4
Supplementary Scheme 1. The suggested mechanism for the azacholestanes using silica
supported boron tri-fluoride.
5
Supplementary Fig. 3 Estimated binding affinities of compounds (4-6) based on docked poses
within the active site of target enzyme (PDB: 4BH5).
6
(A)
(B)
Supplementary Fig. 4 (A) Ligand map generated using MMV; green indicates hydrogen bonds
while sky blue indicates steric interactions,
and (B) receptor-ligand interaction surfaces
including lipophilicity, H-bonding and solvent accessibility properties.
7
Supplementary Table 1Computed molecular descriptors and heat of formation of 4–6.
Compd.
Energy
(kJ/mol )
HOMO
LUMO
(eV)
(eV)
HOMOLUMO
(eV)
𝜂
𝑆
𝜇
(eV)
(eV−1)
(eV)
𝜔
Heat of
formation
(Kcal/mole)
4
-3452093.5
-9.060
-0.141
-8.919
4.459
0.224
-4.600
2.37
-113.15776
5
-4039331.1
-9.113
-0.325
-8.788
4.394
0.227
-4.719
2.53
-186.19817
6
-4644041.9
-9.174
-0.407
-8.767
4.383
0.228
-4.790
2.61
-112.03892
Where 𝜂=global hardness, 𝑆= global softness, 𝜇= chemical potential and 𝜔=electrophilicity
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Supplementary Table 2Computed physicochemical properties of 4–6.
Compd.
Volume (Å3)
Log P
PSA
D (debye)
nviolations
4
471.671
7.07
40.537
5.348
1
5
516.227
6.389
66.842
4.880
2
6
485.233
6.923
40.537
3.121
1
References
Mirjalil
BBF,
Bamoniri
A,
and
Attar
SAF
(2013)One-pot
preparation
of
N,N′-
alkylidenebisamides promoted by BF3.SiO2. Iran JCatal3, 157; and references cited therein.
9