Catalyst-Free Visible-Light-Promoted Cyclization of Aldehydes: Access to 2,5-Disubstituted 1,3,4-Oxadiazole Derivatives
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ABSTRACT:
SUBMITTER: Li J
PROVIDER: S-EPMC8515816 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A series of novel 2,5-disubstituted-1,3,4-oxadiazole derivatives were synthesized and screened for their antimicrobial and antioxidant activities. The assay indicated that compounds 3c, 3d, and 3i exhibited comparable antibacterial and antioxidant activity with first-line drugs. The structure activity relationship and molecular docking study of the synthesized compounds are also reported.
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Project description:In the title compound, C(16)H(14)N(2)O(3), the essentially planar 1,3,4-oxadiazole ring [maximum deviation = 0.0021?(11)?Å] is inclined at dihedral angles of 8.06?(6) and 11.21?(6)° with respect to the two benzene rings; the dihedral angle between the latter rings is 11.66?(5)°. In the crystal, short inter-molecular C?O inter-actions [2.9968?(15)?Å] connect adjacent mol-ecules into chains propagating in [203]. The crystal structure is further stabilized by weak inter-molecular C-H?? inter-actions.
| S-EPMC3011497 | biostudies-literature
Project description:In the title mol-ecule, C(12)H(10)N(6)O, the dihedral angle between the two pyrazine rings [planar to within 0.009?(3) and 0.018?(3)?Å] is 5.62?(15)°. They deviate from the central oxadiazole ring [planar to within 0.005?(3)?Å] by 1.52?(16) and 5.55?(17)°, respectively. In the crystal, C-H?N inter-actions involving the pyrazine rings connect mol-ecules to form zigzag supramolecular chains propagating in [010].
| S-EPMC3120570 | biostudies-literature
Project description:In the title compound, C(20)H(22)N(2)O(5), the central 1,3,4-oxadiazole ring is essentially planar [r.m.s. deviation from the best plane of 0.0011?Å] and makes dihedral angles of 4.10?(3) and 13.32?(4)° with the two benzene rings. In the crystal structure, the packing is stabilized by weak non-classical inter-molecular C-H?N hydrogen bonds, which link the mol-ecules into an extended network.
| S-EPMC2977367 | biostudies-literature
Project description:In the title compound, C(12)H(10)N(4)O(+)·2Br(-)·H(2)O, the cation is approximately planar: the terminal rings make a dihedral angle of 7.91?(6)° with each other and dihedral angles of 6.02?(1) and 6.50?(8)° with the central ring. It is linked to the bromide anions and water mol-ecules by N-H?Br hydrogen bonds. In addition, O-H?Br and N-H?Br hydrogen bonds link these units into a three-dimensional network. C-H?N, C-H?Br and N-H?O inter-actions are also observed.
| S-EPMC3011558 | biostudies-literature
Project description:A series of chiral 10-heteroazatriquinanes were synthesized from enantiopure asymmetric cis-2,5-disubstituted pyrrolidines through a one-pot tandem cyclization procedure. The structures and configurations of these new chiral 10-heteroazatriquinanes are confirmed by X-ray single-crystal diffraction analysis.
| S-EPMC3596118 | biostudies-literature
Project description:The aim of our study was the two-stage synthesis of 1,3,4-oxadiazole derivatives. The first step was the synthesis of hydrazide-hydrazones from 3-methyl-4-nitrobenzhydrazide and the corresponding substituted aromatic aldehydes. Then, the synthesized hydrazide-hydrazones were cyclized with acetic anhydride to obtain new 3-acetyl-2,3-disubstituted-1,3,4-oxadiazolines. All of obtained compounds were tested in in vitro assays to establish their potential antimicrobial activity and cytotoxicity. Our results indicated that few of the newly synthesized compounds had some antimicrobial activity, mainly compounds 20 and 37 towards all used reference bacterial strains (except Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa) and fungi. These substances showed a strong or powerful bactericidal effect, especially against Staphylococcus spp. belonging to Gram-positive bacteria. Compound 37 was active against Staphylococcus epidermidis at minimal inhibitory concentration (MIC) = 0.48 µg/mL and was characterized by low cytotoxicity. This compound possessed quinolin-4-yl substituent in the second position of 1,3,4-oxadiazole ring and 3-methyl-4-nitrophenyl in position 5. High effectiveness and safety of these derivatives make them promising candidates as antimicrobial agents. Whereas the compound 20 with the 5-iodofurane substituent in position 2 of the 1,3,4-oxadiazole ring showed the greatest activity against S. epidermidis at MIC = 1.95 µg/mL.
| S-EPMC7763531 | biostudies-literature
Project description:In the title compound, [CuCl(2)(C(6)H(7)N)(2)(C(12)H(8)N(4)O)](n), the Cu atom, located on an inversion center, is coordinated by four N atoms from two aniline ligands and two 2,5-bis-(4-pyrid-yl)-1,3,4-oxadiazole ligands. Two Cl atoms lying above and below the plane formed by these four N atoms inter-act weakly with the Cu atom [Cu-Cl = 2.7870?(7)?Å]. The trans 2,5-bis-(4-pyrid-yl)-1,3,4-oxadiazole ligands act as bridging ligands, linking adjacent Cu atoms and forming a one-dimensional coordination polymer. Two anilines coordinate with each Cu atom as terminal groups. The structure contains two classical N-H?Cl and two non-classical C-H?Cl hydrogen bonds.
| S-EPMC2980127 | biostudies-literature
Project description:Antibiotic resistance is now a global problem, and the lack of effective antimicrobial agents for the treatment of diseases caused by resistant microbes is increasing. The 3-acetyl-2,5-disubstituted-1,3,4-oxadiazolines presented in this article may provide a good starting point for the development of potential new effective antimicrobial agents useful in the treatment of bacterial and fungal infections. Particular attention is drawn to the 1,3,4-oxadiazole derivative marked with the number 29 with 5-nitrofuran-2-yl substituent in its chemical structure. This substance showed a strong bactericidal effect, especially against Staphylococcus spp., and no cytotoxicity to the L929 normal cell line.
| S-EPMC8704594 | biostudies-literature
Project description:We observed fluorescence emission from 2,5-diphenyl-1,3,4-oxadiazole (PPD) resulting from two-photon excitation with two different wavelengths near 380 and 760 nm. For this two-color two-photon (2C2P) excitation the emission spectra and intensity decays were the same as observed with single-photon excitation with an equivalent energy at 250 nm. The two-color two-photon-induced emission was observed when the PPD sample was illuminated with both wavelengths, but only when the picosecond laser pulses were spatially and temporally overlapped. The signal was about 70-fold and 1000-fold less for illumination at 380 or 760 nm alone, respectively. When illuminated with both wavelengths, the emission intensity of PPD depended quadratically on the total illumination power, when both beams were simultaneously attenuated to the same extent, indicating two-photon excitation. When the intensity at one wavelength was attenuated, the signal depended linearly on the power at each wavelength, indicating the participation of one-photon at each wavelength to the excitation process. For 2C2P excitation the time-zero anisotropy was larger than possible for single-photon excitation and was consistent with collinear electronic transitions for both wavelengths. The intensity depended on the polarization of each beam in a manner consistent with collinear transitions. These results demonstrate that two-color two-photon excitation can be readily observed with modern laser sources. This phenomenon can have numerous applications in the chemical and biomedical sciences, as a method for spatial localization of the measured volume.
| S-EPMC6917482 | biostudies-literature