Solvent-free synthesis, spectral studies, antimicrobial activities of some (E)-N-(substituted benzylidene)-9-ethyl-9H-carbazole-3-amine derivatives

Abstract

Background: This study aims to synthesis a series of (E)-N-(substituted benzylidene)-9-ethyl-9H-carbazole-3-amines, using solvent-free fly-ash:perchloric acid catalyst under microwave irradiation. To then characterize them using analytical, physical and spectroscopic data. Methods: Solvent-free microwave assisted (E)imines were adopted for the synthesis of (E)-N-(substituted benzylidene)-9-ethyl-9H-carbazole-3-amine, using fly-ash:perchloric acid as a catalyst. They were characterized by IR, NMR and mass spectroscopic data. The IR and NMR spectral data was correlated with substituent constants, F and R parameters using Hammett equation to study the effect of the substituents. Results: The yield of the synthesized imines were more than 75%. The spectral data of these (E)-N-(substituted benzylidene)-9-ethyl-9H-carbazole-3-amines had been correlated using single and multi-regression analysis. These gave a satisfactory or fair degree of correlation, with some parameters. Conclusion: Easy handling, non-hazardous and an environmentally safe method had been adopted for the synthesis of (E)-imines, using fly-ash:perchloric acid as catalyst, with better yields. Some of the Hammett spectral correlations were found to be satisfactory with the observed spectroscopic data.

Spectral QSAR and QPR Study of some (<i>E</i>)-4-(((2-Hydroxy-6-(Substituted Phenyl)-1,6 Dihydropyrimidin-4-yl)Methyl)Diazenyl)Benzoic Acid Derivatives

“…The results of statistical analysis [11][12][13][14][15][16][18][19][20][21] are shown in Table 2. From the table 2, the correlation of νCO stretches of all compounds gave satisfactory correlation for Hammett σ, σ + , and σ I constants.…”

“…36components or field and resonance components combined. The generated multi-regression equations are shown in (13)(14)(15)(16)(17)(18)(19)(20). …”

“…The CO, CH 2 , and CN carbon chemical shifts (δ, ppm) of pyrimidine derivatives have been assigned and correlated with Hammett substituent constants using single and multi-linear regression analysis [11][12][13][14][15][16][18][19][20][21].…”

“…From the proton NMR spectral chemical shift(ppm), the E and Z configuration was assigned in alkene [16], alkynes [17] and chalcones [18] derivatives. Recently, Mayavel et al have studied the effect of substituent on the (E)-N-(substituted benzylidene)-9-ethyl-9H-carbazole-3-amine derivatives [19] with IR and NMR spectral data through Hammett equation. Sathiyendiran et al, have studied the spectral correlations of some substituted styryl (E)-4-((2-oxopropyl) diazenyl) benzoic acids [20].…”

(<i>E</i>)-N-Substitutedbenzylidene-4-Methoxyanilines as Insect Antifeedants

“…This test was performed with a 4 th instar larva Achoea janata L against castor semilooper, were reared as described on the leaves of castor, Ricinus communis in the laboratory at the temperature range of 26 °C ±1 °C and a relative humidity of 75-85%. The leaf -disc bioassay method [24][25][26][27][28][29][30][31][32][33] was used against the 4 th instar larvae to measure the antifeedant activity. The 4 th instar larvae were selected for testing because the larvae at this stage feed very voraciously.…”