Organics

14 pages, 2928 KiB

Open AccessCommunication

Neighboring Nitrogen Atom-Induced Reactions of Azidoacetyl Hydrazides, including Unexpected Nitrogen-Nitrogen Bond Cleavage of the Hydrazide

by Hiroki Tanimoto, Ryo Adachi, Aoi Otsuki and Takenori Tomohiro

Organics 2022, 3(4), 520-533; https://doi.org/10.3390/org3040035 - 19 Dec 2022

Viewed by 2296

Abstract

We studied the hydrazide compounds of the α-azidoacetyl group, which showed specific click reactivity by the intramolecular hydrogen bonding between the azido group and the N-H of the hydrazide moiety. In the competitive click reactions with a general alkyl azide, both traceless and [...] Read more.

We studied the hydrazide compounds of the α-azidoacetyl group, which showed specific click reactivity by the intramolecular hydrogen bonding between the azido group and the N-H of the hydrazide moiety. In the competitive click reactions with a general alkyl azide, both traceless and non-traceless Staudinger-Bertozzi ligation occurred azide-site-selectively by the acceleration effect of the hydrogen bonding. However, the product obtained from the traceless reaction was further transformed into heterocyclic compounds. In addition, in an attempt at a synthesis of naphthalimide-possessing azidoacetyl hydrazide, nitrogen-nitrogen bond cleavage of the azidoacetyl hydrazides occurred to give the reduced amine product. These unexpected results could help design molecules for the successful Staudinger-Bertozzi ligation of the hydrazide compounds and develop a new nitrogen-nitrogen bond cleavage method. Full article

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13 pages, 2377 KiB

Open AccessArticle

Bis(3-methylthio-1-azulenyl)phenylmethyl Cations and Dications Connected by a 1,4-Phenylene Spacer: Synthesis and Their Electrochemical Properties

by Taku Shoji, Naoko Sakata, Ryuta Sekiguchi and Shunji Ito

Organics 2022, 3(4), 507-519; https://doi.org/10.3390/org3040034 - 16 Dec 2022

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Abstract

The preparation of bis(3-methylthio-1-azulenyl)phenylmethyl cations and 1,4-phenylenebis[bis(3,6-di-tert-butyl-1-azulenyl)methyl] dications was accomplished by the hydride abstraction of the corresponding hydride derivatives, which were synthesized by the acid-catalyzed condensation of 1-azulenyl methyl sulfide with benzaldehyde and terephthalaldehyde with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The intramolecular charge transfer among [...] Read more.

The preparation of bis(3-methylthio-1-azulenyl)phenylmethyl cations and 1,4-phenylenebis[bis(3,6-di-tert-butyl-1-azulenyl)methyl] dications was accomplished by the hydride abstraction of the corresponding hydride derivatives, which were synthesized by the acid-catalyzed condensation of 1-azulenyl methyl sulfide with benzaldehyde and terephthalaldehyde with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The intramolecular charge transfer among the azulene ring and the methylium moieties of these cations and dications was investigated by UV–Vis spectroscopy and electrochemical analyses. The pK_R⁺ values of the cations were examined for their thermodynamic stability spectrophotometrically. The voltammetry experiments of these cations revealed their reversible reduction waves on their cyclic voltammograms. Moreover, a notable spectral change of cations was observed by spectroelectrochemistry during electrochemical reduction conditions. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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5 pages, 518 KiB

Open AccessCommunication

Efficient Synthesis of a 2-Decyl-tetradecyl Substituted 7-Bromophenothiazine-3-carbaldehyde Building Block for Functional Dyes

by Burak Kürsat Börüsah and Thomas J. J. Müller

Organics 2022, 3(4), 502-506; https://doi.org/10.3390/org3040033 - 07 Dec 2022

Cited by 3 | Viewed by 1287

Abstract

(1) Polyfunctional molecules are versatile building blocks for efficient syntheses of novel phenothiazine-based materials with promising electronic properties. A prerequisite is a facile, high yielding access to these building blocks that bear solubilizing moieties and functional groups for orthogonal transformation. (2) Here, an [...] Read more.

(1) Polyfunctional molecules are versatile building blocks for efficient syntheses of novel phenothiazine-based materials with promising electronic properties. A prerequisite is a facile, high yielding access to these building blocks that bear solubilizing moieties and functional groups for orthogonal transformation. (2) Here, an efficient, improved two-step protocol for accessing a solubilizing 2-decyl-tetradecyl functionalized phenothiazine, i.e., an N-alkylated 7-bromophenothiazine-3-carbaldehyde, by Vilsmeier–Haack formylation and NBS (N-bromo succinimide) bromination is reported. (3) The sequence proceeds with higher yields and in shorter reaction times than the standard access employing bromination with elementary bromine. In addition, the work-up procedure essentially uses absorptive filtration on a plug of silica with the eluent. Full article

(This article belongs to the Special Issue Aromatic Heterocycles: A Wonderful Pool of Organic Materials)

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11 pages, 2242 KiB

Open AccessArticle

Phosphonated Polyethylenimine Maghemite Nanoparticles: A Convenient Support of Palladium for Cross-Coupling Reactions

by Clément Monteil, Etienne Jean, Nathalie Bar and Didier Villemin

Organics 2022, 3(4), 491-501; https://doi.org/10.3390/org3040032 - 21 Nov 2022

Cited by 1 | Viewed by 1372

Abstract

Phosphonated polyethylenimine grafted on iron oxide nanoparticles was used as a magnetic support for loading palladium. This cheap and accessible heterogeneous catalyst demonstrated good efficiency in Suzuki-Miyaura, Mizoroki-Heck, and Tsuji-Trost couplings. The nanocomposite is resistant to harsh conditions and can therefore be recycled [...] Read more.

Phosphonated polyethylenimine grafted on iron oxide nanoparticles was used as a magnetic support for loading palladium. This cheap and accessible heterogeneous catalyst demonstrated good efficiency in Suzuki-Miyaura, Mizoroki-Heck, and Tsuji-Trost couplings. The nanocomposite is resistant to harsh conditions and can therefore be recycled up to 10 cycles with high catalyst efficiency. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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10 pages, 1899 KiB

Open AccessArticle

Synthesis of 3-Hydroxy-9H-fluorene-2-carboxylates via Michael Reaction, Robinson Annulation, and Aromatization

by Yu-Min Wang, Yi-Hung Liu and Shiuh-Tzung Liu

Organics 2022, 3(4), 481-490; https://doi.org/10.3390/org3040031 - 10 Nov 2022

Viewed by 1796

Abstract

A series of 3-hydroxy-fluorene-2-carboxylate compounds were prepared from Michael addition of acetoacetate to 2-benzylideneindan-l-one followed by Robinson annulation and aromatization. In this reaction, we were able to isolate two Robinson annulation products and characterize them. This sequential reaction could proceed without the isolation [...] Read more.

A series of 3-hydroxy-fluorene-2-carboxylate compounds were prepared from Michael addition of acetoacetate to 2-benzylideneindan-l-one followed by Robinson annulation and aromatization. In this reaction, we were able to isolate two Robinson annulation products and characterize them. This sequential reaction could proceed without the isolation of intermediates to give the desired products directly in reasonable yields. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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11 pages, 1564 KiB

Open AccessArticle

How Do Positions of Phosphito Units on a Calix[4]Arene Platform Affect the Enantioselectivity of a Catalytic Reaction?

by Shaima Hkiri and David Sémeril

Organics 2022, 3(4), 470-480; https://doi.org/10.3390/org3040030 - 09 Nov 2022

Cited by 1 | Viewed by 1340

Abstract

Three chiral diphosphites, (S,S)-5,17-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)-25,26,27,28-tetrapropyloxycalix[4]arene (1), (S,S)-5,11,17,23-tetra-tert-butyl-25,27-dipropoxy-26,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)calix[4]arene (2) and (S,S)-5,11,17,23-tetra-tert-butyl-25,26-dipropoxy-27,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)calix[4]arene (3), based on conical calix[4]arene were investigated in the rhodium-catalyzed asymmetric hydrogenation [...] Read more.

Three chiral diphosphites, (S,S)-5,17-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)-25,26,27,28-tetrapropyloxycalix[4]arene (1), (S,S)-5,11,17,23-tetra-tert-butyl-25,27-dipropoxy-26,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)calix[4]arene (2) and (S,S)-5,11,17,23-tetra-tert-butyl-25,26-dipropoxy-27,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)calix[4]arene (3), based on conical calix[4]arene were investigated in the rhodium-catalyzed asymmetric hydrogenation of α-dehydroamino esters. High conversions were observed after 24 h under 5 bar of hydrogen whatever the employed diphosphite, and the chiral induction increases in the order 1 < 3 < 2. This may be due to the presence of the calix[4]arene moiety, which by its presence modifies the second coordination sphere of the catalytic center. The larger steric hindrance around the rhodium atom leads to the higher enantiomeric excess. Full article

(This article belongs to the Special Issue Progress in Synthesis and Applications of Phosphorus-Containing Compounds)

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24 pages, 5791 KiB

Open AccessReview

Thienothiophene Scaffolds as Building Blocks for (Opto)Electronics

by Jan Podlesný and Filip Bureš

Organics 2022, 3(4), 446-469; https://doi.org/10.3390/org3040029 - 03 Nov 2022

Cited by 3 | Viewed by 1804

Abstract

Thieno[3,2-b]thiophene and isomeric thieno[2,3-b]thiophene represent fused, bicyclic and electron rich heterocycles. These small planar organic compounds belong to the remarkable family of annulated building blocks for various organic materials. The first part of this review focuses on the synthesis [...] Read more.

Thieno[3,2-b]thiophene and isomeric thieno[2,3-b]thiophene represent fused, bicyclic and electron rich heterocycles. These small planar organic compounds belong to the remarkable family of annulated building blocks for various organic materials. The first part of this review focuses on the synthesis of the primary unsubstituted thienothiophene scaffolds. All synthetic pathways available in the literature, dating from the 19th century, are summarized. The second part is devoted to the applications of the thienothiophene-derived materials across (opto)electronics. Organic light emitting diodes, organic solar cells, organic field-effect transistors and nonlinear optics were identified as the most successful application areas of both thienothiophenes. The fundamental structure-property relationships were evaluated for each particular group of derivatives. Full article

(This article belongs to the Special Issue Aromatic Heterocycles: A Wonderful Pool of Organic Materials)

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16 pages, 6899 KiB

Open AccessReview

Synthetic Pathways to Pyrido[3,4-c]pyridazines and Their Polycyclic Derivatives

by Temitayo Omowumi Alegbejo Price, Flavio da Silva Emery and Wim Dehaen

Organics 2022, 3(4), 430-445; https://doi.org/10.3390/org3040028 - 18 Oct 2022

Viewed by 1866

Abstract

Pyrido[3,4-c]pyridazines are nitrogen-containing scaffolds that have been described as being promising in medicinal chemistry, but they are rather rare chemicals. In this review article, the literature on synthetic pathways towards pyrido[3,4-c]pyridazines is listed exhaustively, first with the bicyclic systems [...] Read more.

Pyrido[3,4-c]pyridazines are nitrogen-containing scaffolds that have been described as being promising in medicinal chemistry, but they are rather rare chemicals. In this review article, the literature on synthetic pathways towards pyrido[3,4-c]pyridazines is listed exhaustively, first with the bicyclic systems themselves that are obtained starting either from pyridines, pyridazines or other heterocycles. Then, the reports on the related tricyclic derivatives are discussed, again according to the source heterocycle, and finally we mention some examples on polycyclic systems. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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15 pages, 6430 KiB

Open AccessArticle

Design, Synthesis, and Photo-Responsive Properties of a Collagen Model Peptide Bearing an Azobenzene

by Daisuke Sato, Hitomi Goto, Yui Ishizaki, Tetsuya Narimatsu and Tamaki Kato

Organics 2022, 3(4), 415-429; https://doi.org/10.3390/org3040027 - 11 Oct 2022

Viewed by 1440

Abstract

Collagen is a vital component of the extracellular matrix in animals. Collagen forms a characteristic triple helical structure and plays a key role in supporting connective tissues and cell adhesion. The ability to control the collagen triple helix structure is useful for medical [...] Read more.

Collagen is a vital component of the extracellular matrix in animals. Collagen forms a characteristic triple helical structure and plays a key role in supporting connective tissues and cell adhesion. The ability to control the collagen triple helix structure is useful for medical and conformational studies because the physicochemical properties of the collagen rely on its conformation. Although some photo-controllable collagen model peptides (CMPs) have been reported, satisfactory photo-control has not yet been achieved. To achieve this objective, detailed investigation of the isomerization behavior of the azobenzene moiety in CMPs is required. Herein, two CMPs were attached via an azobenzene linker to control collagen triple helix formation by light irradiation. Azo-(PPG)₁₀ with two (Pro-Pro-Gly)₁₀ CMPs linked via a photo-responsive azobenzene moiety was designed and synthesized. Conformational changes were evaluated by circular dichroism and the cis-to-trans isomerization rate calculated from the absorption of the azobenzene moiety indicated that the collagen triple helix structure was partially disrupted by isomerization of the internal azobenzene. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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35 pages, 8646 KiB

Open AccessReview

Ten Years Milestones in Xanthine Oxidase Inhibitors Discovery: Febuxostat-Based Inhibitors Trends, Bifunctional Derivatives, and Automatized Screening Assays

by Miguel F. S. de Abreu, Camila A. Wegermann, Millena S. Ceroullo, Isabella G. M. Sant’Anna and Renato C. S. Lessa

Organics 2022, 3(4), 380-414; https://doi.org/10.3390/org3040026 - 10 Oct 2022

Cited by 2 | Viewed by 2327

Abstract

Xanthine oxidase (XO) is an enzyme involved in the oxidative process of hypoxanthine and xanthine to uric acid (UA). This process also produces reactive oxygen species (ROS) as byproducts. Both UA and ROS are dangerous for human health, and some health conditions trigger [...] Read more.

Xanthine oxidase (XO) is an enzyme involved in the oxidative process of hypoxanthine and xanthine to uric acid (UA). This process also produces reactive oxygen species (ROS) as byproducts. Both UA and ROS are dangerous for human health, and some health conditions trigger upregulation of XO activity, which results in many diseases (cancer, atherosclerosis, hepatitis, gout, and others) given the worsened scenario of ROS and UA overproduction. So, XO became an attractive target to produce and discover novel selective drugs based on febuxostat, the most recent XO inhibitor out of only two approved by FDA. Under this context, high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) have been successfully applied to rapidly and easily screen for bioactive compounds, isolated or in complex natural matrixes, that act as enzyme inhibitors through the use of an immobilized enzyme reactor (IMER). This article’s goal is to present advances comprising febuxostat-based XO inhibitors as a new trend, bifunctional moieties capable of inhibiting XO and modulating ROS activity, and in-flow techniques employing an IMER in HPLC and CE to screen for synthetic and natural compounds that act as XO inhibitors. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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16 pages, 2020 KiB

Open AccessArticle

Theoretical Study on the Diels–Alder Reaction of Fullerenes: Analysis of Isomerism, Aromaticity, and Solvation

by Diogo J. L. Rodrigues, Luís M. N. B. F. Santos, André Melo and Carlos F. R. A. C. Lima

Organics 2022, 3(4), 364-379; https://doi.org/10.3390/org3040025 - 22 Sep 2022

Cited by 2 | Viewed by 1963

Abstract

Fullerenes are reactive as dienophiles in Diels–Alder reactions. Their distinctive molecular shape and properties result in interesting and sometimes elusive reaction patterns. Herein, to contribute to the understanding of fullerene reactivity, we evaluate the energies of reactions for Diels–Alder cycloadditions of C₆₀ [...] Read more.

Fullerenes are reactive as dienophiles in Diels–Alder reactions. Their distinctive molecular shape and properties result in interesting and sometimes elusive reaction patterns. Herein, to contribute to the understanding of fullerene reactivity, we evaluate the energies of reactions for Diels–Alder cycloadditions of C₆₀, C₇₀, and IC₆₀MA with anthracene (Ant), by means of DFT computational analysis in vacuum and solution. The methods used showed little differentiation between the reactivity of the different fullerenes. The C₇₀-Ant adducts where addition takes place near the edge of the fullerene were found to be the most stable regioisomers. For the IC₆₀MA-Ant adducts, the calculated energies of reaction increase in the order: equatorial > trans-3 > trans-2 ≈ trans-4 ≈ trans-1 > cis-3 > cis-2. The change in the functional suggests the existence of stabilizing dispersive interactions between the surface of the fullerene and the addends. HOMA (harmonic oscillator model of aromaticity) analysis indicated an increase in aromaticity in the fullerene hexagons adjacent to the bonded addend. This increase is bigger in the rings of bisadduct isomers that are simultaneously adjacent to both addends, which helps explain the extra stability of the equatorial isomers. Solvation by m-xylene decreases the exothermicity of the reactions studied but has little distinguishing effect on the possible isomers. Thermal corrections reduce the exothermicity of the reactions by ~10 kJ∙mol⁻¹. Full article

(This article belongs to the Collection Advanced Research Papers in Organics)

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Organics, Volume 3, Issue 4 (December 2022) – 11 articles

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