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14 pages, 3919 KiB

Open AccessArticle

α-Carbonyl Rh-Carbenoid Initiated Cascade Assembly of Diazobarbiturates with Alkylidene Pyrazolones for Synthesis of Spirofuropyrimidines

by Yue Zhang, Yu-Hang Mi, Kuo Wang and Hong-Wu Zhao

Molecules 2024, 29(13), 3178; https://doi.org/10.3390/molecules29133178 - 3 Jul 2024

Viewed by 1516

Abstract

Catalyzed by Rh₂(esp)₂ (10 mol%) and (±)-BINAP (20 mol%) in DCE at 80 °C, the cascade assembly between diazobarbiturates and alkylidene pyrazolones proceeded readily and produced spiro-furopyrimidines in 38–96% chemical yields. The chemical structure of the prepared spirofuro-pyrimidines was firmly [...] Read more.

Catalyzed by Rh₂(esp)₂ (10 mol%) and (±)-BINAP (20 mol%) in DCE at 80 °C, the cascade assembly between diazobarbiturates and alkylidene pyrazolones proceeded readily and produced spiro-furopyrimidines in 38–96% chemical yields. The chemical structure of the prepared spirofuro-pyrimidines was firmly confirmed by X-ray diffraction analysis. Full article

(This article belongs to the Special Issue Recent Advances in Transition Metal Catalysis)

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8 pages, 1244 KiB

Open AccessCommunication

Introducing Bis(5-(Trifluoromethyl)pyridin-2-yl)amine Chelating Unit via Pd-Catalyzed Amination

by Nikolay A. Korinskiy, Anton S. Abel, Violetta A. Ionova, Stanislav I. Bezzubov, Alexei D. Averin and Irina P. Beletskaya

Molbank 2024, 2024(2), M1831; https://doi.org/10.3390/M1831 - 4 Jun 2024

Viewed by 2482

Abstract

We report a one-step synthesis of trifluoromethyl-substituted di(pyridin-2-yl)amine-based ligands. N-(hetero)aryl-substituted bis(5-(trifluoromethyl)pyridin-2-yl)amines were obtained from 2-bromo-5-(trifluoromethyl)pyridine and corresponding aromatic amines via Pd-catalyzed amination reaction in the presence of a Pd(dba)₂/BINAP catalytic system. Four new ligands were prepared in good to high [...] Read more.

We report a one-step synthesis of trifluoromethyl-substituted di(pyridin-2-yl)amine-based ligands. N-(hetero)aryl-substituted bis(5-(trifluoromethyl)pyridin-2-yl)amines were obtained from 2-bromo-5-(trifluoromethyl)pyridine and corresponding aromatic amines via Pd-catalyzed amination reaction in the presence of a Pd(dba)₂/BINAP catalytic system. Four new ligands were prepared in good to high yields and characterized by NMR, IR spectroscopies and mass spectrometry. The structure of one of the products was additionally supported by X-ray analysis. Full article

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8 pages, 3510 KiB

Open AccessCommunication

Heteroleptic Copper(I)-Based Complexes Incorporating BINAP and π-Extended Diimines: Synthesis, Catalysis and Biological Applications

by Corentin Cruché, Sayak Gupta, Jeremy Kodanko and Shawn K. Collins

Molecules 2022, 27(12), 3745; https://doi.org/10.3390/molecules27123745 - 10 Jun 2022

Cited by 4 | Viewed by 2855

Abstract

A series of copper-based photocatalysts of the type Cu(NN)(BINAP)BF₄ were synthesized bearing π-extended diimine ligands. Their behavior in several photocatalytic processes were evaluated and revealed acceptable levels of activity in an SET process, but negligible activity in PCET [...] Read more.

A series of copper-based photocatalysts of the type Cu(NN)(BINAP)BF₄ were synthesized bearing π-extended diimine ligands. Their behavior in several photocatalytic processes were evaluated and revealed acceptable levels of activity in an SET process, but negligible activity in PCET or ET processes. Suitable activity in ET processes could be restored through modification of the ligand. The BINAP-derived complexes were then evaluated for activity against triple-negative breast cancer cell lines. Controls indicated that copper complexes, and not their ligands, were responsible for activity. Encouraging activity was displayed by a homoleptic complex Cu(dppz)₂BF₄. Full article

(This article belongs to the Special Issue A Tribute to Design and Strategy in Organic Synthesis in Honour of Stephen Hanessian)

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10 pages, 5320 KiB

Open AccessArticle

Modified Cellulose with BINAP-Supported Rh as an Efficient Heterogeneous Catalyst for Asymmetric Hydrogenation

by Cuiping Yu, Weilong Wu, Min Gao and Yu Liu

Catalysts 2022, 12(1), 83; https://doi.org/10.3390/catal12010083 - 12 Jan 2022

Cited by 13 | Viewed by 3077

Abstract

Asymmetric catalysis is the preferred method for the synthesis of pure chiral molecules in the fine chemical industry. Cellulose has long been sought as a support in enantioselective catalysis. Dialdehyde cellulose (DAC) is produced by the selective oxidation of cellulose and is used [...] Read more.

Asymmetric catalysis is the preferred method for the synthesis of pure chiral molecules in the fine chemical industry. Cellulose has long been sought as a support in enantioselective catalysis. Dialdehyde cellulose (DAC) is produced by the selective oxidation of cellulose and is used to bind 5,5′-diamino Binap by forming a Schiff base. Here, we report the synthesis of modified cellulose-supported Rh as a novel biomass-supported catalyst and the characterization of its morphology, composition, and thermal stability. DAC-BINAP-Rh was a very effective catalyst in the asymmetric hydrogenation of enamides and could be easily recycled. This work provides a novel supported catalyst that broadens the applications of cellulose in asymmetric catalysis. Full article

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16 pages, 3751 KiB

Open AccessArticle

Mononuclear Copper(I) 3-(2-pyridyl)pyrazole Complexes: The Crucial Role of Phosphine on Photoluminescence

by Kristina F. Baranova, Aleksei A. Titov, Alexander F. Smol’yakov, Andrey Yu. Chernyadyev, Oleg A. Filippov and Elena S. Shubina

Molecules 2021, 26(22), 6869; https://doi.org/10.3390/molecules26226869 - 14 Nov 2021

Cited by 12 | Viewed by 3710

Abstract

A series of emissive Cu(I) cationic complexes with 3-(2-pyridyl)-5-phenyl-pyrazole and various phosphines: dppbz (1), Xantphos (2), DPEPhos (3), PPh₃ (4), and BINAP (5) were designed and characterized. Complexes obtained exhibit bright yellow-green [...] Read more.

A series of emissive Cu(I) cationic complexes with 3-(2-pyridyl)-5-phenyl-pyrazole and various phosphines: dppbz (1), Xantphos (2), DPEPhos (3), PPh₃ (4), and BINAP (5) were designed and characterized. Complexes obtained exhibit bright yellow-green emission (ca. 520–650 nm) in the solid state with a wide range of QYs (1–78%) and lifetimes (19–119 µs) at 298 K. The photoluminescence efficiency dramatically depends on the phosphine ligand type. The theoretical calculations of buried volumes and excited states explained the emission behavior for 1–5 as well as their lifetimes. The bulky and rigid phosphines promote emission efficiency through the stabilization of singlet and triplet excited states. Full article

(This article belongs to the Section Inorganic Chemistry)

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17 pages, 2271 KiB

Open AccessFeature PaperArticle

Hydrogenation of α,β-Unsaturated Carbonyl Compounds over Covalently Heterogenized Ru(II) Diphosphine Complexes on AlPO₄-Sepiolite Supports

by Verónica Caballero, Rafael Estevez, Diego Luna, Felipa M. Bautista, Antonio A. Romero, Laura Aguado-Deblas, Jesús Hidalgo-Carrillo and Isabel Romero

Catalysts 2021, 11(2), 289; https://doi.org/10.3390/catal11020289 - 22 Feb 2021

Cited by 1 | Viewed by 3285

Abstract

In this work, the covalent immobilization of two ruthenium(II) complexes, i.e., [Ru^IICl (bpea){(S)(-)(BINAP)}](BF₄), 1, and [Ru^IICl(bpea)(DPPE)](BF₄), 2, where BINAP = 2,2’-bis(diphenylphosphino)-1,1’-binaphthyl and DPPE = 1,2-bis(diphenylphosphino)ethane, have been obtained (AlPO₄-Sepiolite@1 and AlPO [...] Read more.

In this work, the covalent immobilization of two ruthenium(II) complexes, i.e., [Ru^IICl (bpea){(S)(-)(BINAP)}](BF₄), 1, and [Ru^IICl(bpea)(DPPE)](BF₄), 2, where BINAP = 2,2’-bis(diphenylphosphino)-1,1’-binaphthyl and DPPE = 1,2-bis(diphenylphosphino)ethane, have been obtained (AlPO₄-Sepiolite@1 and AlPO₄-Sepiolite@2) by using a N-tridentate ligand N,N-bis-(2-pyridylmethyl)ethylamine (bpea), linked to an amorphous AlPO₄-Sepiolite (20/80) inorganic support. This AlPO₄-sepiolite support is able to immobilize the double amount of ruthenium complex (1.65%) than the amorphous AlPO₄ (0.89%). Both heterogenized complexes have been assessed as catalysts in the liquid phase hydrogenation of several substrates with carbonyl and/or olefinic double bonds using methanol as solvent, attaining good catalytic activity and high enantioselectivity (99%). The highest Turn Over Number (TON) value (748.6) was obtained over the [Ru^II Cl (bpea)(DPPE)](BF₄) 2 catalyst, although the [Ru^IICl(bpea){(S)(-)(BINAP)}](BF₄) 1 exhibits better reusability. In fact, the [Ru^IICl(bpea){(S)(-)(BINAP)}](BF₄) immobilized on AlPO₄-Sepiolite maintained the activity throughout 14 successive runs. Furthermore, some findings on hydrogenation mechanisms of the α,β-unsaturated carbonyl compounds over Ru catalysts have been also obtained. Full article

(This article belongs to the Special Issue Recent Advances in Organometallic Chemistry and Catalysis)

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23 pages, 7882 KiB

Open AccessArticle

Syntheses of 3,3-Disubstituted Dihydrobenzofurans, Indolines, Indolinones and Isochromanes by Palladium-Catalyzed Tandem Reaction Using Pd(PPh₃)₂Cl₂/(±)-BINAP as a Catalytic System

by Guizhou Yue, Sicheng Li, Dan Jiang, Gang Ding, Juhua Feng, Huabao Chen, Chunping Yang, Zhongqiong Yin, Xu Song, Xiaoxia Liang, Li Zhang, Xianxiang Wang and Cuifen Lu

Catalysts 2020, 10(9), 1084; https://doi.org/10.3390/catal10091084 - 18 Sep 2020

Cited by 4 | Viewed by 3602

Abstract

A general procedure for the tandem arylation reaction of arylbromide with heteroaryl compounds was developed by using Pd(PPh₃)₂Cl₂/(±)-BINAP (1,1′-Binaphthalene-2,2′-diylbis (diphenylphosphane)) as catalytic system. Both sulphur- and oxygen-containing heterocycles were also employed as an efficient reagent for arylation, [...] Read more.

A general procedure for the tandem arylation reaction of arylbromide with heteroaryl compounds was developed by using Pd(PPh₃)₂Cl₂/(±)-BINAP (1,1′-Binaphthalene-2,2′-diylbis (diphenylphosphane)) as catalytic system. Both sulphur- and oxygen-containing heterocycles were also employed as an efficient reagent for arylation, which gave moderate to excellent yields with moderate to good regioselectivities (5:1 to > 20:1 ir (isomer ratio)). Except for dihydrobenzofurans, indolines and indolinones, this type of tandem reaction was also expanded to synthesize isochromanes. The synthesized new compounds were well characterized through different spectroscopic techniques, such as ¹H and ¹³C NMR (nuclear magnetic resonance), and mass spectral analysis. Full article

(This article belongs to the Special Issue Transition-Metal Catalysts for C–H Bond Functionalization of Heteroarenes)

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15 pages, 1771 KiB

Open AccessArticle

A Replicating Single-Cycle Adenovirus Vaccine Effective against Clostridium difficile

by William E. Matchett, Stephanie Anguiano-Zarate, Goda Baddage Rakitha Malewana, Haley Mudrick, Melissa Weldy, Clayton Evert, Alexander Khoruts, Michael Sadowsky and Michael A. Barry

Vaccines 2020, 8(3), 470; https://doi.org/10.3390/vaccines8030470 - 22 Aug 2020

Cited by 7 | Viewed by 4682

Abstract

Clostridium difficile causes nearly 500,000 infections and nearly 30,000 deaths each year in the U.S., which is estimated to cost $4.8 billion. C. difficile infection (CDI) arises from bacteria colonizing the large intestine and releasing two toxins, toxin A (TcdA) and toxin B [...] Read more.

Clostridium difficile causes nearly 500,000 infections and nearly 30,000 deaths each year in the U.S., which is estimated to cost $4.8 billion. C. difficile infection (CDI) arises from bacteria colonizing the large intestine and releasing two toxins, toxin A (TcdA) and toxin B (TcdB). Generating humoral immunity against C. difficile’s toxins provides protection against primary infection and recurrence. Thus, a vaccine may offer the best opportunity for sustained, long-term protection. We developed a novel single-cycle adenovirus (SC-Ad) vaccine against C. difficile expressing the receptor-binding domains from TcdA and TcdB. The single immunization of mice generated sustained toxin-binding antibody responses and protected them from lethal toxin challenge for up to 38 weeks. Immunized Syrian hamsters produced significant toxin-neutralizing antibodies that increased over 36 weeks. Single intramuscular immunization provided complete protection against lethal BI/NAP1/027 spore challenge 45 weeks later. These data suggest that this replicating vaccine may prove useful against CDI in humans. Full article

(This article belongs to the Special Issue Vaccines and Other Antibody Therapies Against Bacterial Infection)

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10 pages, 885 KiB

Open AccessArticle

Rhodium(I)-Complexes Catalyzed 1,4-Conjugate Addition of Arylzinc Chlorides to N-Boc-4-pyridone

by Fenghai Guo, Matthew A. McGilvary, Malcolm C. Jeffries, Briana N. Graves, Shekinah A. Graham and Yuelin Wu

Molecules 2017, 22(5), 723; https://doi.org/10.3390/molecules22050723 - 1 May 2017

Cited by 1 | Viewed by 6351

Abstract

Rhodium(I)-complexes catalyzed the 1,4-conjugate addition of arylzinc chlorides to N-Boc-4-pyridone in the presence of chlorotrimethylsilane (TMSCl). A combination of [RhCl(C₂H₄)₂]₂ and BINAP was determined to be the most effective catalyst to promote the 1,4-conjugate addition [...] Read more.

Rhodium(I)-complexes catalyzed the 1,4-conjugate addition of arylzinc chlorides to N-Boc-4-pyridone in the presence of chlorotrimethylsilane (TMSCl). A combination of [RhCl(C₂H₄)₂]₂ and BINAP was determined to be the most effective catalyst to promote the 1,4-conjugate addition reactions of arylzinc chlorides to N-Boc-4-pyridone. A broad scope of arylzinc reagents with both electron-withdrawing and electron-donating substituents on the aromatic ring successfully underwent 1,4-conjugate addition to N-Boc-4-pyridone to afford versatile 1,4-adducts 2-substituted-2,3-dihydropyridones in good to excellent yields (up to 91%) and excellent ee (up to 96%) when (S)-BINAP was used as chiral ligand. Full article

(This article belongs to the Collection Heterocyclic Compounds)

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22 pages, 6880 KiB

Open AccessArticle

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabenzonorbornadienes with N-Substituted Piperazine Nucleophiles

by Wen Yang, Renshi Luo and Dingqiao Yang

Molecules 2015, 20(12), 21103-21124; https://doi.org/10.3390/molecules201219748 - 27 Nov 2015

Cited by 17 | Viewed by 6085

Abstract

Iridium-catalyzed asymmetric ring-opening of oxabenzonorbornadienes with N-substituted piperazines was described. The reaction afforded the corresponding ring-opening products in high yields and moderate enantioselectivities in the presence of 2.5 mol % [Ir(COD)Cl]₂ and 5.0 mol % (S)-p-Tol-BINAP. The [...] Read more.

Iridium-catalyzed asymmetric ring-opening of oxabenzonorbornadienes with N-substituted piperazines was described. The reaction afforded the corresponding ring-opening products in high yields and moderate enantioselectivities in the presence of 2.5 mol % [Ir(COD)Cl]₂ and 5.0 mol % (S)-p-Tol-BINAP. The effects of various chiral bidentate ligands, catalyst loading, solvent, and temperature on the yield and enantioselectivity were also investigated. A plausible mechanism was proposed to account for the formation of the corresponding trans-ring opened products based on the X-ray structure of product 2i. Full article

(This article belongs to the Section Organic Chemistry)

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15 pages, 341 KiB

Open AccessArticle

Synthesis of New BINAP-Based Aminophosphines and Their ³¹P-NMR Spectroscopy

by Christopher Anstiss, Peter Karuso, Mark Richardson and Fei Liu

Molecules 2013, 18(3), 2788-2802; https://doi.org/10.3390/molecules18032788 - 1 Mar 2013

Cited by 11 | Viewed by 7884

Abstract

BINAP aminophosphines are prevalent N,P-bidentate, chiral ligands for asymmetric catalysis. While modification via the BINAP-nitrogen linkage is well explored and has provided a diverse body of derivatives, modification of the other substituents of the phosphorous center is another avenue in generating new congeners [...] Read more.

BINAP aminophosphines are prevalent N,P-bidentate, chiral ligands for asymmetric catalysis. While modification via the BINAP-nitrogen linkage is well explored and has provided a diverse body of derivatives, modification of the other substituents of the phosphorous center is another avenue in generating new congeners of this important class of chiral ligands. Herein reported are new BINAP aryl aminophosphines with electron rich or deficient substituents on the aryl rings. This scalable synthesis converted readily available starting material, (S)-BINOL, to a key intermediate (S)-NOBIN, from which the final chiral aminophosphines were prepared via a palladium-catalyzed, phosphonylation reaction. The aryl substituents are able to modify the electronic properties of the phosphorous center as indicated by the range of ³¹P-NMR shifts of these new ligands. A computational analysis was performed to linearly quantitate contributions to the ³¹P-NMR shifts from both resonance and field effects of the substituents. This correlation may be useful for designing and preparing other related aminophosphines with varying ligand properties. Full article

(This article belongs to the Section Organic Chemistry)

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14 pages, 324 KiB

Open AccessArticle

Palladium-Catalyzed Amination of Dichloroquinolines with Adamantane-Containing Amines

by Anton S. Abel, Alexei D. Averin, Olga A. Maloshitskaya, Evgenii N. Savelyev, Boris S. Orlinson, Ivan A. Novakov and Irina P. Beletskaya

Molecules 2013, 18(2), 2096-2109; https://doi.org/10.3390/molecules18022096 - 6 Feb 2013

Cited by 10 | Viewed by 6190

Abstract

Pd-catalyzed amination of isomeric 2,6-, 2,8-, 4,8- and 4,7-dichloroquinolines was studied using adamantane-containing amines in which substituents at the nitrogen atom differ in bulkiness. The selectivity of the amination of 2,6-dichloroquinoline was very low, substantially better results were obtained with 2,8-dichloroquinoline, and 4,8- [...] Read more.

Pd-catalyzed amination of isomeric 2,6-, 2,8-, 4,8- and 4,7-dichloroquinolines was studied using adamantane-containing amines in which substituents at the nitrogen atom differ in bulkiness. The selectivity of the amination of 2,6-dichloroquinoline was very low, substantially better results were obtained with 2,8-dichloroquinoline, and 4,8- and 4,7-dichloroquinolines provided the best yields of the amination products. Diamination of 4,8- and 4,7-dichloroquinolines was carried out with two amines which differ strongly in the bulkiness of the alkyl group. In the majority of cases BINAP ligand was successfully applied, however, it had to be replaced with DavePhos in certain reactions when using the most sterically hindered amine as well as for the diamination reactions. Full article

(This article belongs to the Special Issue Advances in Heteroaromatic Chemistry)

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13 pages, 481 KiB

Open AccessArticle

Ruthenium-Catalyzed Selective Hydrogenation of bis-Arylidene Tetramic Acids. Application to the Synthesis of Novel Structurally Diverse Pyrrolidine-2,4-diones

by Christos S. Karaiskos, Dimitris Matiadis, John Markopoulos and Olga Igglessi-Markopoulou

Molecules 2011, 16(7), 6116-6128; https://doi.org/10.3390/molecules16076116 - 20 Jul 2011

Cited by 3 | Viewed by 6026

Abstract

Catalytic hydrogenation of 3,5-bis-arylidenetetramic acids, known for their biological activity, has been developed. The chemoselective ruthenium-catalyzed reduction of the exocyclic carbon-carbon double bonds on pyrrolidine-2,4-dione ring system, containing other reducible functions, has been investigated. Depending on the substrate the yield of the hydrogenation [...] Read more.

Catalytic hydrogenation of 3,5-bis-arylidenetetramic acids, known for their biological activity, has been developed. The chemoselective ruthenium-catalyzed reduction of the exocyclic carbon-carbon double bonds on pyrrolidine-2,4-dione ring system, containing other reducible functions, has been investigated. Depending on the substrate the yield of the hydrogenation process can reach up to 95%. The structural elucidation has been established using NMR and HRMS spectral data. Full article

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11 pages, 256 KiB

Open AccessArticle

Asymmetric Glyoxylate-Ene Reactions Catalyzed by Chiral Pd(II) Complexes in the Ionic Liquid [bmim][PF₆]

by Xi Jun He, Zhen Lu Shen, Wei Min Mo, Bao Xiang Hu and Nan Sun

Int. J. Mol. Sci. 2007, 8(6), 553-563; https://doi.org/10.3390/i8060553 - 22 Jun 2007

Cited by 6 | Viewed by 10264

Abstract

The room temperature ionic liquid [bmim][PF₆] was employed as the reactionmedium in the asymmetric glyoxylate-ene reaction of α-methyl styrene (4a) with ethylglyoxylate using chiral palladium(II) complexes as the catalysts. [Pd(S-BINAP)(3,5-CF₃-PhCN)₂](SbF₆)₂ (1b) showed the highest [...] Read more.

The room temperature ionic liquid [bmim][PF₆] was employed as the reactionmedium in the asymmetric glyoxylate-ene reaction of α-methyl styrene (4a) with ethylglyoxylate using chiral palladium(II) complexes as the catalysts. [Pd(S-BINAP)(3,5-CF₃-PhCN)₂](SbF₆)₂ (1b) showed the highest catalytic activity. Under the reaction conditionsof 40 oC, 0.5 h, and 1b/4a molar ratio of 0.05, ethyl α-hydroxy-4-phenyl-4-pentenoate wasobtained in excellent chemical yield (94 %) with high enantioselectivity (70 %). Otherα-hydroxy esters can also be obtained in high chemical yields and enantioselectitiesthrough the glyoxylate-ene reactions of alkenes with glyoxylates catalyzed by 1b in[bmim][PF₆]. Moreover, the ionic liquid [bmim][PF₆] which contained the palladium(II)complex could be recycled and reused several times without significant loss of the catalyticactivity. Full article

(This article belongs to the Special Issue Ionic Liquids)

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