Recent Advances in the Synthesis of Perimidines and their Applications

Well-defined cobalt(II)-catalyzed synthesis of perimidine derivatives via acceptorless dehydrogenative annulation

The versatility of the perimidine moiety offers a rich playground for researchers in fields ranging from medical science to industrial chemistry. Herein, we describe the first Co-catalyzed synthesis of 2,3-dihydro-1H-perimidine via acceptorless dehydrogenative annulation (ADA). Apart from featuring benzyl alcohol having different functionalities, heteroaryl and aliphatic alcohols also provide good yields. Our catalytic protocol is also suitable for different fatty alcohols for furnishing perimidine derivatives, keeping distal unsaturation intact. Several kinetic and control tests were carried out in order to understand the reaction sequence.

Hsp Inhibitor is Affective Against Adenocarcinomic Human Alveolar Basal Epithelial Cells Through Modulating ERK/MAPK Signaling Pathway

The extracellular signal-regulated kinase (ERK) - mitogen-activated protein kinase (MAPK) pathway regulates cell proliferation, differentiation, and apoptosis. Heat Shock Protein 90 (HSP90) is required to activate proto-oncogenic protein kinases and promotes tumor growth through anti-apoptotic effects on A549-non-small cell lung cancer (NSCLC). Therefore, deregulation of the ERK-MAPK pathway and abnormal expression of HSP90 are reasonably frequent events in NSCLC. In this study, novel perimidine-pyrazole compounds employed to block ERK-MAPK deregulation through inhibiting HSP dependent cancer cell survival mechanisms. A set of perimidine-pyrazole derivatives effects was monitored on NSCLC cell line. Array experiments performed to understand the effect of the compounds on signaling pathways and results were analyzed by gene enrichment analysis. Further, senescence and apoptosis experiments were performed to support the enrichment results along with in silico methods to determine perimidine-pyrazole/HSP interactions. Treatment of NSCLC cells with perimidine-pyrazole derivatives displayed cancer-inhibitory, pro-senescent and pro-apoptotic effects on NSCLC cells through ERK/MAPK pathway and these compounds are promising templates for designing anticancer drugs.

Stable peri-Naphthoisatogens without C2 Protection: Synthesis via Aldrone Condensation, Optical Properties and 1,3-Dipolar Cycloaddition Reaction

peri-Annulation of naphthalane, an important tool for realization of wide range of functional materials, is presently accomplished with limited few functional groups like imide, amide and diamine-derivative (perimidine). To increase the diversity, we have incorporated α-keto aldonitrone as a new functional group, and herein report about five peri-naphthoisatogens (PNTIs) dyes. The synthesis were accomplished using an unusual reaction of aromatic nitro group, which is nucleophilic attack of a C-nucleophile (enol) to the N-atom of nitro group. In five different 5-alkylamino-8-nitro-1-acetylnaphthalenes, intramolecular acid-catalyzed nucleophilic attack of enol moiety to the N-atom of nitro group produced α-keto aldonitrone via addition-elimination mechanism. The PNTIs showed characteristics of 1,3-dipole and reacted with ethyl acrylate to produce isoxazolidine ring, which subsequently converted into aza phenalenone derivative via ring cleavage. Both the PNTI and the corresponding derivative strongly absorb in the visible region, displaying absorption maximum at 551 and 561 nm (in CHCl3 ) respectively. Compared to the popular analogous dye naphthalene monoimides, PNTIs showed bathochromic shift of absorption maximum by more than 100 nm. The emission maximum for the PNTI and its derivative in chloroform were observed at 594 and 635 nm respectively.

Exploration of NIR Squaraine Contrast Agents Containing Various Heterocycles: Synthesis, Optical Properties and Applications

Squaraine dye is a popular class of contrast near-infrared (NIR) dyes. Squaraine dyes have shown the ability to be modified with various heterocycles. The indole moiety is the most notable heterocycle incorporated in squaraine dyes. A tremendous amount of work has gone into developing indole-based squaraine dyes and determining their applications. The optical properties of squaraine dyes containing an indole moiety facilitate high quantum yields and molar absorptivity, but the absorbance maxima is capped near 700 nm. This is the major limitation of indole-based squaraine dyes. In comparison, other heterocycles with larger conjugated systems such as quinoline and perimidine have demonstrated promising optical properties and immense potential for modifications, albeit with limited development. Quinoline- and perimidine-based squaraine dyes have molar extinction coefficients over 100,000 M-1 cm-1 and absorbances over 800 nm. This report will look at indole-, quinoline-, and perimidine-based squaraine dyes. Due to the sheer number of reported dyes, the search for indole-based squaraine dyes has been limited to reports from the past five years (2018-2023). For quinoline- and perimidine-based squaraine dyes, a holistic search was performed to analyze the optical properties and applications, due to the abovementioned limitation. This report will evaluate the three different classes of squaraines: indole-, quinoline-, and perimidine-based, to evaluate their optical properties and applications, with the goal of encouraging the exploration of other heterocycles for use in squaraine dyes.

2-(1H-Imidazol-2-yl)-2,3-dihydro-1H-perimidine

The novel compound 2-(1H-imidazol-2-yl)-2,3-dihydro-1H-perimidine was obtained in very good yield via a known eco-friendly protocol. The product was isolated in pure form as a solvate by simple filtration from the crude mixture. Its structure was assigned by 1D and 2D NMR experiments and was confirmed by high resolution MS and single crystal XRD. The temperature of methanol release was determined by DSC and the energy of the process theoretically estimated.

2-[2-(Diphenylphosphoryl)phenyl]-1H-perimidine

In this paper, we report the crystal structure of 2-[2-(diphenylphosphoryl)phenyl]-1H-perimidine (L1) obtained from the ring closure reaction of 1,8-diaminonaphthalene and 2-(diphenylphosphino)benzaldehyde, followed by the dehydrogenation reaction with sodium metabisulfite (Na2S2O5). L1 was characterised using 1H, 13C & 31P NMR, FT-IR and X-ray single structure analyses.

Highly Active Cyclic Zinc(II) Thione Catalyst for C-C and C-N Bond Formation Reactions

The first discrete seven-membered cyclic zinc(II) complex catalyzed room temperature Knoevenagel condensation reactions, and the synthesis of perimidine derivatives has been reported under mild reaction conditions. The cyclic zinc(II) complex [( L) ZnBr 2 ] ( 1 ) was isolated from the reaction between 1-(2-hydroxyethyl)-3-isopropyl-benzimidazole-2-thione ( L ) and ZnBr 2 . Complex 1 was characterized by different analytic techniques such as FT-IR, CHNS, TGA, NMR, and SCXRD. The mononuclear zinc(II) complex 1 was utilized as a catalyst for Knoevenagel condensation reactions to isolate twenty different substituted methylene malononitriles with excellent yield. Besides, the zinc(II) thione complex 1 was utilized for the synthesis of 2,4-dihydroperimidine derivatives in a highly efficient manner. Catalyst 1 depicted wide substrate scopes. Overall, twenty different substituted methylene malononitriles and nine different perimidine derivatives were synthesized using catalyst 1 at room temperature. The present investigation features a mild and fast synthetic approach along with excellent functional group tolerance.

A Panchromatic Cyclometalated Iridium Dye Based on 2-Thienyl-Perimidine

Though 2-arylperimidines have never been used in iridium(III) chemistry, the present study on structural, electronic and optical properties of N-unsubstituted and N-methylated 2-(2-thienyl)perimidines, supported by DFT/TDDFT calculations, has shown that these ligands are promising candidates for construction of light-harvesting iridium(III) complexes. In contrast to N-H perimidine, the N-methylated ligand gave the expected cyclometalated μ-chloro-bridged iridium(III) dimer which was readily converted to a cationic heteroleptic complex with 4,4′-dicarboxy-2,2′-bipyridine. The resulting iridium(III) dye exhibited panchromatic absorption up to 1000 nm and was tested in a dye-sensitized solar cell.

Ultrasound-assisted transition-metal-free catalysis: a sustainable route towards the synthesis of bioactive heterocycles

Heterocycles of synthetic and natural origin are a well-established class of compounds representing a broad range of organic molecules that constitute over 60% of drugs and agrochemicals in the market or research pipeline. Considering the vast abundance of these structural motifs, the development of chemical processes providing easy access to novel complex target molecules by introducing environmentally benign conditions with the main focus on improving the cost-effectiveness of the chemical transformation is highly demanding and challenging. Accordingly, sonochemistry appears to be an excellent alternative and a highly feasible environmentally benign energy input that has recently received considerable and steadily increasing interest in organic synthesis. However, the involvement of transition-metal-catalyst(s) in a chemical process often triggers an unintended impact on the greenness or sustainability of the transformation. Consequently, enormous efforts have been devoted to developing metal-free routes for assembling various heterocycles of medicinal interest, particularly under ultrasound irradiation. The present review article aims to demonstrate a brief overview of the current progress accomplished in the ultrasound-assisted synthesis of pharmaceutically relevant diverse heterocycles using transition-metal-free catalysis.

A DFT study of the tautomerism of 1H-benzo[de]cinnolines and their protonated forms

1H-Benzo[de]cinnolines and 1H-indeno[6,7,1-def]cinnolines have been studied theoretically at the B3LYP/6-311++G(d,p) level in the gas-phase and in water solution (PCM model); gas-phase geometries were used to calculate absolute shieldings (GIAO) that were transformed into chemical shifts using empirical equations. The annular tautomerism of neutral species and of protonated cations have been determined, and the most stable cations coincide with those determined experimentally.

Syntheses and crystal structures of 2-(p-tol-yl)-1H-perimidine hemihydrate and 1-methyl-2-(p-tol-yl)-1H-perimidine

The title compounds, 2-(4-methylphenyl)-1H-perimidine hemihydrate (1, C18H14N2·0.5H2O) and 1-methyl-2-(4-methylphenyl)-1H-perimidine (2, C19H16N2), were prepared and characterized by 1H NMR and single-crystal X-ray diffraction. The organic mol-ecule of the hemihydrate lies on a twofold rotation axis while the water mol-ecule lies on the inter-section of three twofold rotation axes (point group symmetry 222). As a consequence, the hydrogen atoms that are part of the N-H group and the water mol-ecule as well as the CH3 group of the p-tolyl ring are disordered over two positions. In compound 1, the perimidine and the 2-aryl rings are slightly twisted while its N-methyl-ated derivative 2 has a more distorted conformation because of the steric repulsion between the N-methyl group and the 2-aryl ring. In the crystal structures, mol-ecules of perimidine 2 are held together only by C-H⋯π contacts while the parent perimidine 1 does not exhibit this type of inter-action. Its crystal packing is established by inter-molecular N-H⋯O hydrogen bonds with the solvent water mol-ecules and additionally stabilized by π-π stacking.

Microwave-Assisted Synthesis of Quinazolines and Quinazolinones: An Overview

Microwave irradiation (MWI), as a unique, effective, sustainable, more economic, and greener source of energy compared to conventional heating, is applied in different organic transformations to result in the rapid formation of desired compounds due to thermal/kinetic effects. In this review, we try to underscore the applications of microwave irradiation (MWI) in the synthesis of quinazoline and quinazolinone derivatives that have been achieved and reported on in the last two decades.