One Pot Synthesis, Photophysical and X-ray Studies of Novel Highly Fluorescent Isoquinoline Derivatives with Higher Antibacterial Efficacy Based on the In-vitro and Density Functional Theory

Abstract

Series of cyano substituted isoquinoline dyes were synthesized by one-pot multicomponent reactions (MCRs) of aldehydes, malononitrile, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one and ammonium acetate. Results obtained from spectroscopic (FT-IR, (1)H-NMR, (13)C-NMR, EI-MS) and elemental analysis of synthesized compounds was in agreement with their chemical structures. Structure of the compound was further conformed by X-ray crystallographic. UV-vis and fluorescence spectroscopy measurements provided that all compounds are good absorbent and fluorescent. Fluorescence polarity study demonstrated that these compounds were sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, extenction coefficient, Stokes shift, oscillator strength transition dipole moment and fluorescence quantum yield were investigated in order to explore the analytical potential of synthesized compounds. The anti-bacterial activity of these compounds were first studied in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria. The minimum inhibitory concentration was then determined with the reference of standard drug chloramphenicol. The results displayed that compound 3 was better inhibitors of both types of the bacteria (Gram-positive and Gram-negative) than chloramphenicol. Furthermore, quantum chemistry calculations using DFT/6-31-G* level of theory confirm the results. Dipole moment and frontier molecular orbitals were also investigated.

Efficient method for the synthesis of 3-arylbenzoquinoline, pyranoquinoline, and thiopyranoquinoline derivatives using PEG1000-based dicationic acidic ionic liquid as recyclable catalyst via a one-pot multicomponent reaction

“…[1,2] Quinoline and its derivatives represent an important class of nitrogen-containing heterocycles as they are widely occurring natural alkaloids known for a wide range of pharmacological and biological activities, such as antiplasmodial, antimicrobial, antituberculosis, antibacterial, antiproliferative, antimalarial and anticancer activities. [3][4][5][6][7][8] In view of the importance of quinoline and its derivatives, a number of synthetic strategies have been developed for the preparation of substituted quinolines. [9][10][11][12][13] However, many of these reported methods suffer from drawbacks such as harsh reaction conditions, unsatisfactory yields, prolonged reaction time, and cumbersome product isolation procedure.…”