Supplementary material
A bench-topcatalyst: BF3.SiO2-assisted synthesis, biological assay and computational simulations of azacholestanes
Azhar U. Khan1, Mahboob Alam2 and Dong-Ung Lee2,*
1Department of Chemistry, School of Physical and Molecular Sciences, Al-Falah University, Dhauj, Faridabad-121004, Haryana, India
2Division of Bioscience,Dongguk University, Gyeongju 780-714, Republic of Korea
Preparation ofthe catalystBF3.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 out-of-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 B-O, 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).
Supplementary Fig.1FT-IR spectrum of (A) BF3.OEt2 (B) BF3.SiO2, and (C) SiO2.
(A) (B)
Supplementary Fig.2 Surface plot of (A) SiO2 and (B) BF3.SiO2.
Supplementary Scheme 1. The suggested mechanism for the azacholestanes using silica supported boron tri-fluoride.
Supplementary Fig.3 Estimated binding affinities of compounds (4-6) based on docked poses within the active site of target enzyme (PDB: 4BH5).
(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.
Supplementary Table 1Computed molecular descriptors and heat of formation of 4–6.
Compd. / Energy (kJ/mol ) / HOMO(eV) / LUMO
(eV) / HOMO-LUMO
(eV) / ?
(eV) / ?
(eV−1) / ?
(eV) / ? / 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 ?=global hardness, ?= global softness, ?= chemical potential and ?=electrophilicity
Supplementary Table 2Computed physicochemical properties of 4–6.
Compd. / Volume (Å3) / Log P / PSA / D (debye) / nviolations4 / 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.
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