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Chemistry (Weinheim An Der Bergstrasse,... Sep 2022A systematic investigation to arrange the typical anti-aromatic porphyrinoids in sequence was performed. Based on density functional theory calculations, six rules are...
A systematic investigation to arrange the typical anti-aromatic porphyrinoids in sequence was performed. Based on density functional theory calculations, six rules are summarized to obtain the high-performance anti-aromatic porphyrinoids: (1) when two atoms are deleted/added on the 18π electron current ring flowing pipe, we will immediately obtain a 16π/20π electron anti-aromatic system; (2) it is a good idea to increase the number of pyrrole/thiophen/furan units on the π-electron current ring flowing pipe; (3) the heteroatom selecting order is -O- (optimal choice), -NH- (second choice), and -S- (last choice); (4) it is worth noting that the C-C=C-C unit is not beneficial for the anti-aromatic properties; (5) it is very significant to avoid the crowded environment in the core space of an anti-aromatic molecule. In this view, -O- is much better than -S- and -NH-; (6) the "circular" skeleton is much better than an "ellipse-like", "rectangular", or "parallelogram-like" one.
Topics: Electrons; Molecular Structure; Porphyrins; Pyrroles
PubMed: 35699688
DOI: 10.1002/chem.202201125 -
The Journal of Organic Chemistry Jul 2022A simple, efficient and highly regioselective method for the preparation of 3,4- and 4,5-disubstituted -methylpyrazoles in a one-pot procedure is reported. The...
A simple, efficient and highly regioselective method for the preparation of 3,4- and 4,5-disubstituted -methylpyrazoles in a one-pot procedure is reported. The methodology developed was based on the regiochemical control of the reaction of 4-acyl-1-pyrrole-2,3-diones and methylhydrazine with an influence of the addition or absence of acid and the substrate structure.
Topics: Monomethylhydrazine; Pyrroles
PubMed: 35687873
DOI: 10.1021/acs.joc.2c00657 -
Chemical Reviews Feb 2017Subporphyrinato boron (subporphyrin) was elusive until the syntheses of tribenzosubporphine in 2006 and meso-aryl-substituted subporphyrin in 2007. These novel... (Review)
Review
Subporphyrinato boron (subporphyrin) was elusive until the syntheses of tribenzosubporphine in 2006 and meso-aryl-substituted subporphyrin in 2007. These novel contracted analogues possess a 14π-electron conjugated system embedded in a bowl-shaped structure. They exhibit absorption and fluorescence in the UV/vis region and nonlinear optical properties due to their octupolar structures. The unique coordination geometry around the central boron atom in the structure of subporphyrin enabled investigation of rare boron species, such as borenium cations, boron hydrides, and boron peroxides. Along with the burgeoning development of the chemistry of subporphyrins, analogous triphyrin systems have also emerged. Their rich coordination chemistry as a result of their free-base structures, which are different from the boron-coordinating structure of subporphyrins, has been intensively investigated. On the basis of the unique structures and reactivities of subporphyrins and their related triphyrin analogues, supramolecular architectures and covalently linked multicomponent systems have also been actively pursued. This Review provides an overview of the development of subporphyrin and triphyrin chemistry in the past decade and future prospects in this field, which may inspire molecular design toward applications based on their unique properties.
Topics: Circular Dichroism; Crystallography, X-Ray; Magnetic Resonance Spectroscopy; Oxidation-Reduction; Porphyrins; Pyrroles; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet
PubMed: 27779851
DOI: 10.1021/acs.chemrev.6b00403 -
Physical Chemistry Chemical Physics :... Dec 2022Phytochromes are a superfamily of photoreceptors that harbor linear tetrapyrroles as chromophores. Upon light illumination, the linear tetrapyrrole chromophore undergoes...
Phytochromes are a superfamily of photoreceptors that harbor linear tetrapyrroles as chromophores. Upon light illumination, the linear tetrapyrrole chromophore undergoes a double bond isomerization which starts a photocycle. In this work, we studied the photoisomerization of chromophore models designed based on the C- and D-rings of the phycocyanobilin (PCB) chromophore. In total, five different models with varying substitutions were investigated. Firstly, the vertical excitation energies were benchmarked using different computational methods to establish the relative order of the excited states. Based on these calculations, we computed the photoisomerization profiles using the extended multi-state (XMS) version of the CASPT2 method. The profiles were obtained for both the clockwise and counterclockwise rotations of the CC bond in the and isomers using a linear interpolation of internal coordinates between the Franck-Condon and MECI geometries. In the minimal chromophore model that lacks the substitutions at the pyrrole rings, the isomerization involves both C-C and CC bonds of the methine bridge between the C- and D-rings, resembling the hula-twist motion. The MECIs are characterized by a partial charge transfer between the two pyrrole rings pointing towards a twisted intramolecular charge transfer. Systematic introduction of substituents leads to an increase in the steric repulsion between the two pyrrole rings causing a pretwist of the dihedral around the CC bond, which creates a preference for the counterclockwise isomerization. An introduction of the carbonyl group at the D-ring increases the extent of charge transfer which changes the isomerization mechanism from hula-twist to one-bond flip.
Topics: Phytochrome; Tetrapyrroles; Pyrroles
PubMed: 36468544
DOI: 10.1039/d2cp04249e -
The Journal of Organic Chemistry Mar 2018The binding interactions between the azide anion (N) and the strapped calix[4]pyrroles 2 and 3 bearing auxiliary hydrogen bonding donors on the bridging moieties, as...
The binding interactions between the azide anion (N) and the strapped calix[4]pyrroles 2 and 3 bearing auxiliary hydrogen bonding donors on the bridging moieties, as well as of normal calix[4]pyrrole 1, were investigated via H NMR spectroscopic and isothermal titration calorimetry analyses. The resulting data revealed that receptors 2 and 3 have significantly higher affinities for the azide anion in organic media as compared with the unfunctionalized calix[4]pyrrole 1 and other azide receptors reported to date. Single crystal X-ray diffraction analyses and calculations using density functional theory revealed that receptor 2 binds CsN in two distinct structural forms. As judged from the metric parameters, in the resulting complexes one limiting azide anion resonance contributor is favored over the other, with the specifics depending on the binding mode. In contrast to what is seen for 2, receptor 3 forms a CsN complex in 20% CDOD in CDCl, wherein the azide anion is bound only vertically to the NH protons of the calix[4]pyrrole and the cesium cation is complexed within the cone shaped-calix[4]pyrrole bowl. The bound cesium cation is also in close proximity to a naphthobipyrrole subunit present in a different molecule, forming an apparent cation-π complex.
Topics: Azides; Calixarenes; Hydrogen Bonding; Models, Molecular; Molecular Conformation; Pyrroles
PubMed: 29441791
DOI: 10.1021/acs.joc.7b03135 -
Gastroenterology Apr 2023
Topics: Humans; Clostridium Infections; Enterocolitis, Pseudomembranous; Pyrroles; Sulfonamides
PubMed: 36220458
DOI: 10.1053/j.gastro.2022.10.004 -
Nihon Rinsho. Japanese Journal of... Aug 2016Although the first-line medicine for the treatment of reflux esophagitis (RE) is proton. pomp inhibitor(PPI), the effectiveness is affected by the internal metabolism of...
Although the first-line medicine for the treatment of reflux esophagitis (RE) is proton. pomp inhibitor(PPI), the effectiveness is affected by the internal metabolism of PPI, the polymor- phism of metabolized enzyme for PPI, the presence of H. pyloi infection or esophageal hernia, and the grade of RE. Recent study indicates that about 30 % of severe RE is not healed after PPI treatment. Vonoprazan, potassium-competitive acid blocker(P-CAB), is effective for severe RE by the adequate control of gastric acidity including night-time and the day 1 after administration of Vonoprazan, comparing to current PPIs. On the other hand, Vono- prazan may cause hypergastrinemia, and the long-term follow-up is required to evaluate the adverse events for Vonoprazan.
Topics: Drug Resistance; Esophagitis, Peptic; Humans; Proton Pump Inhibitors; Pyrroles; Sulfonamides
PubMed: 30562434
DOI: No ID Found -
Molecules (Basel, Switzerland) Sep 2023Derivatives combining acridine, pyrrole, and thiazolidine rings have emerged as promising candidates in the field of antitumor drug discovery. This paper aims to...
Derivatives combining acridine, pyrrole, and thiazolidine rings have emerged as promising candidates in the field of antitumor drug discovery. This paper aims to highlight the importance of these three structural motifs in developing potent and selective anticancer agents. The integration of these rings within a single molecule offers the potential for synergistic effects, targeting multiple pathways involved in tumor growth and progression. Spiro derivatives were efficiently synthesized in a two-step process starting from isothiocyanates and 2-cyanoacetohydrazide. The thiourea side chain in spiro derivatives was utilized as a key component for the construction of the thiazolidine-4-one ring through regioselective reactions with bifunctional reagents, namely methyl-bromoacetate, dietyl-acetylenedicarboxylate, ethyl-2-bromopropionate, and ethyl-2-bromovalerate. These reactions resulted in the formation of a single regioisomeric product for each derivative. Advanced spectroscopic techniques, including 1D and 2D NMR, FT-IR, HRMS, and single-crystal analysis, were employed to meticulously characterize the chemical structures of the synthesized derivatives. Furthermore, the influence of these derivatives on the metabolic activity of various cancer cell lines was assessed, with IC values determined via MTT assays. Notably, derivatives containing ester functional groups exhibited exceptional activity against all tested cancer cell lines, boasting IC values below 10 μM. Particularly striking were the spiro derivatives with methoxy groups at position 3 and nitro groups at position 4 of the phenyl ring. These compounds displayed remarkable selectivity and exhibited heightened activity against HCT-116 and Jurkat cell lines. Additionally, 4-oxo-1,3-thiazolidin-2-ylidene derivatives demonstrated a significant activity against MCF-7 and HCT-116 cancer cell lines.
Topics: Humans; Acridines; Pyrroles; Thiazolidines; Spectroscopy, Fourier Transform Infrared; Antineoplastic Agents; HCT116 Cells
PubMed: 37764394
DOI: 10.3390/molecules28186616 -
European Journal of Medicinal Chemistry May 2018The present review lists the papers and patents dealing with the class of polycondensed heterocycles called benzopyrroloxazines published in the last decades. The survey... (Review)
Review
The present review lists the papers and patents dealing with the class of polycondensed heterocycles called benzopyrroloxazines published in the last decades. The survey is limited to substances characterized by the presence of a bridgehead N atom, which means that the present N atom serves to connect different rings within the same molecule. In the case of benzopyrroloxazines, the bridgehead N atom belongs at the same time to the pyrrole and oxazine rings. All other compounds not possessing this feature were kept out accordingly. Relevant synthetic methods to such compounds have been outlined. Many different biological properties have been attributed to several functionalized derivatives of these heterocycles and cited within the review.
Topics: Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Antineoplastic Agents; Bacterial Infections; Chemistry Techniques, Synthetic; Drug Discovery; Humans; Inflammation; Neoplasms; Nitrogen; Oxazines; Pyrroles; Virus Diseases
PubMed: 29609119
DOI: 10.1016/j.ejmech.2018.03.061 -
Chemistry (Weinheim An Der Bergstrasse,... Mar 2022The recent discovery of calix[3]pyrrole, a porphyrinogen-like tripyrrolic macrocycle, has provided an unprecedented strain-induced ring expansion reaction into...
The recent discovery of calix[3]pyrrole, a porphyrinogen-like tripyrrolic macrocycle, has provided an unprecedented strain-induced ring expansion reaction into calix[6]pyrrole. Here, we synthesized calix[n]furan[3-n]pyrrole (n=1∼3) macrocycles to investigate the reaction scope and mechanism of the ring expansion. Single crystal X-ray analysis and theoretical calculations revealed that macrocyclic ring strain increases as the number of inner NH sites increases. While calix[1]furan[2]pyrrole exhibited almost quantitative conversion into calix[2]furan[4]pyrrole within 5 minutes, less-strained calix[2]furan[1]pyrrole and calix[3]furan were inert. However, N-methylation of calix[2]furan[1]pyrrole induced a ring-expansion reaction that enabled the isolation of a linear reaction intermediate. The mechanism analysis revealed that the ring expansion consists of regioselective ring cleavage and subsequent cyclodimerization. This reaction was further utilized for synthesis of calix[6]-type macrocycles.
Topics: Calixarenes; Pyrroles
PubMed: 35137995
DOI: 10.1002/chem.202200056