Synthesis of perimidine and 1,5-benzodiazepine derivatives using tamed Brønsted acid, BF3–H2O

p-Toluenesulfonic acid-promoted organic transformations for the generation of molecular complexity

Since the beginning of this century, p-toluenesulfonic acid (p-TSA) catalysed organic transformations have been an active area of research for developing efficient synthetic methodologies. Often, catalysis using p-TSA is associated with many advantages, such as operational simplicity, high selectivity, excellent yields, and ease of product isolation, which make organic synthesis convenient and versatile. Notably, p-TSA is a non-toxic, commercially available, inexpensive solid organic compound that is soluble in water, alcohols, and other polar organic solvents. p-TSA is a strong acid compared to many protic or mineral acids and its high acidity helps activate different organic functional groups. p-TSA-promoted conversions are fast, have a high atom and pot economy, and feature a multiple bond-forming index. Therefore, the utilization of p-TSA enables the synthesis of many important structural scaffolds without any hazardous metals, making it desirable in numerous applications of sustainable and green chemistry. Recently, this emerging area of research has become one of the pillars of synthetic organic chemistry to synthesise biologically relevant, complex carbocycles and heterocycles. This study provides a comprehensive summary of methods, applications, and mechanistic insights into p-TSA-catalysed organic transformations, covering the literature reports that have appeared since 2012.

Recent Advances in the Synthesis of Perimidines and their Applications

Perimidines are versatile scaffolds and a fascinating class of N-heterocycles that have evolved significantly in recent years due to their immense applications in life sciences, medical sciences, and industrial chemistry. Their ability of molecular interaction with different proteins, complex formation with metals, and distinct behavior in various ranges of light makes them more appealing and challenging for future scientists. Various novel technologies have been developed for the selective synthesis of perimidines and their conjugated derivatives. These methods extend to the preparation of different bioactive and industrially applicable molecules. This review aims to present the most recent advancements in perimidine synthesis under varied conditions like MW radiation, ultrasound, and grinding using different catalysts such as ionic liquids, acid, metal, and nanocatalyst and also under green environments like catalyst and solvent-free synthesis. The applications of perimidine derivatives in drug discovery, polymer chemistry, photo sensors, dye industries, and catalytic activity in organic synthesis are discussed in this survey. This article is expected to be a systematic, authoritative, and critical review on the chemistry of perimidines that compiles most of the state-of-art innovation in this area.

Synthesis of some 1H-1,5-benzodiazepine Series Containing Chromene Ring from α,β-Unsaturated Ketones of 6-Acetyl-5-Hydroxy-4-Methylcoumarin

BACKGROUND

Reaction of α,β-unsaturated ketones with o-phenylenediamine afforded corresponding 2,3-dihydro-1H-1,5-benzodiazepines.

OBJECTIVE

α,β-Unsaturated ketones of 6-acetyl-5-hydroxy-4-methylcoumarin are precursors for synthesis of 2,3-dihydro-1H-1,5-benzodiazepines by a reaction with o-phenylenediamine.

METHODS

Enones of 6-acetyl-5-hydroxy-4-methylcoumarin were prepared from this ketone and (un)substituted benzaldehydes in the presence of piperidine, triethylamine, or pyridine as a catalyst in absolute ethanol with 1:1 molar ratios, respectively. 2',3'-Dihydro-1H-1',5'-benzodiazepines were synthesized by using the reaction of these enones with o-phenylenediamine in absolute ethanol in the presence of glacial acetic acid as a catalyst. Their biological activities were evaluated using the disk diffusion method.

RESULTS

Seven new 2',3'-dihydro-1H-1',5'-benzodiazepines were obtained and their structures were confirmed by thin-layer chromatography, IR, NMR and MS spectra. Some synthesized benzodiazepines showed antibacterial and antifungal activities against Escherichia coli (Gram-(-) bacterium), Staphylococus epidermidis (Gram-(+) bacterium). Candida albicans (fungus).

CONCLUSION

The formation of enones from 6-acetyl-5-hydroxy-4-methylcoumarin and (un)substituted benzaldehydes could be catalyzed by piperidine, triethylamine, pyridine to afford similar yields. 2',3'-dihydro-1H- 1',5'-benzodiazepines have been synthesized from the aforementioned enones and o-phenylenediamine.

Nano-γ-Al2O3/SbCl5: an efficient catalyst for the synthesis of 2,3-dihydroperimidines

Nano-γ-Al₂O₃/SbCl₅ as a new Lewis acid nano catalyst was synthesized and characterized by FTIR, XRD, FESEM, TEM, EDS, BET and TGA techniques. Nano-γ-Al₂O₃/SbCl₅ has been employed for synthesis of 2-substituted perimidines via reaction of naphthalene-1,8-diamine with various aldehydes at room temperature under solvent-free conditions. This protocol proffers several benefits including high yields, easy workup, short reaction times and simple reaction conditions.

Nano-γ-Al₂O₃/SbCl₅ as a new Lewis acid nano catalyst was synthesized and characterized by FTIR, XRD, FESEM, TEM, EDS, BET and TGA techniques.

Synthesis of 2-phenylazonaphtho[1,8-ef][1,4]diazepines and 9-(3-arylhydrazono)pyrrolo[1,2-a]perimidines as antitumor agents

Two series of naphtho[1,8-ef][1,4]diazepines and pyrrolo[1,2-a]perimidines were prepared starting from 1,8-diaminonaphthalene and hydrazonoyl chlorides. The structures of the products were determined on the basis of their spectral data and elemental analyses. The mechanism of formation of such products was also discussed. The prepared compounds were screened for their antitumor activity against three cell lines, namely, MCF-7, TK-10 and UACC-62, and some derivatives showed promising activity.