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.

A series of Schiff’s bases have been synthesized by fly-ash:p-toluenesulfonic acid (fly-ash:PTS) catalyzed microwave assisted oxidative coupling of arylamines and substituted benzaldehydes under solvent-free condition. The synthesized Schiff’s bases are characterized by their physical constants, analytical and spectroscopic data. The group frequencies of imines such as IR (v, cm–1) and NMR (δ, ppm) spectral data was correlated with Hammett substituent constants, F and R parameters using single and multi-linear regression analysis. The antimicrobial activities of these Schiff’s bases have been studied using Bauer-Kirby method.

A series of diarylpropenones is synthesized under microwave‐assisted solvent‐free conditions using FeCl3/bentonite as a stable acid catalyst system which can be reused several times without iron leaching.

Abstract. Zeolite Y clay modified copper nitrate catalyst was prepared. The obtained catalyst was analyzed by SEM, EDS, and powder XRD techniques. The zeolite Y clay modified copper nitrate catalyst was used for the synthesis of various substituted mesalazine by sulfonylation. The synthesized sulfonamides have been characterized by GC-MS, IR, 1 H, 13C and HSQC NMR techniques. The yield percentages of sulfonamides are more than 85%.

Some 4-(substituted phenylsulfonamido)benzoic acids have been synthesized by fly-ash:H 3 PO 3 nano catalyst catalyzed condensation of substituted benzenesulfonyl chlorides and 4-aminobenzoic acid in ultrasound irradiation conditions. The yields of the sulfonamides are more than 90%. The synthesized 4-(substituted phenylsulfonamido) benzoic acid derivatives were characterized by their physical constants, analytical and spectroscopic data. Antimicrobial activities of all sulfonamides were measured by Bauer-Kirby disc diffusion method.