Pub Date : 2024-10-10DOI: 10.1016/j.tet.2024.134303
Truong Giang Luu , Hee-Kwon Kim
β-Keto sulfone is a useful structure in organic chemistry and pharmaceuticals. In the present study, we developed a highly efficient visible-light-promoted reaction to prepare β-keto sulfones under mild conditions. Synthesis was achieved via one-pot multi-component reaction of aryldiazo tetrafluoroborate salts, alkenes, and DABSO in the presence of air (O2) with rhodamine B serving as the photocatalyst. A variety of β-keto sulfones were obtained at high yields by this one-pot operation under aerobic atmosphere. This oxysulfonylation procedure has benefits such as mild reaction conditions, a wide tolerance of functional groups, and simplicity, making it a promising choice for preparing valuable β-keto sulfones.
β-酮砜是有机化学和制药中的一种有用结构。在本研究中，我们开发了一种在温和条件下制备 β-酮砜的高效可见光促进反应。在空气（O2）存在下，以罗丹明 B 为光催化剂，通过芳基重氮四氟硼酸盐、烯烃和 DABSO 的单锅多组分反应实现了合成。在有氧气氛下，通过这种一锅操作以较高的产率获得了多种 β-酮砜。这种氧化磺酰化过程具有反应条件温和、对官能团的耐受性广、操作简单等优点，是制备有价值的 β-酮砜的理想选择。
{"title":"Visible-light-promoted one-pot synthesis of β-keto sulfones from aryldiazo tetrafluoroborate salts via aerobic multicomponent reaction","authors":"Truong Giang Luu , Hee-Kwon Kim","doi":"10.1016/j.tet.2024.134303","DOIUrl":"10.1016/j.tet.2024.134303","url":null,"abstract":"<div><div>β-Keto sulfone is a useful structure in organic chemistry and pharmaceuticals. In the present study, we developed a highly efficient visible-light-promoted reaction to prepare β-keto sulfones under mild conditions. Synthesis was achieved via one-pot multi-component reaction of aryldiazo tetrafluoroborate salts, alkenes, and DABSO in the presence of air (O<sub>2</sub>) with rhodamine B serving as the photocatalyst. A variety of β-keto sulfones were obtained at high yields by this one-pot operation under aerobic atmosphere. This oxysulfonylation procedure has benefits such as mild reaction conditions, a wide tolerance of functional groups, and simplicity, making it a promising choice for preparing valuable β-keto sulfones.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134303"},"PeriodicalIF":2.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.tet.2024.134301
Swapnil V. Halnor, Chepuri V. Ramana
Herein, we describe an Au-catalyzed cycloisomerization process of a nitroalkyne that was projected to construct the central 2,2-disubstituted pseudoindoxyl core of the natural product Austamide. Our intended strategy for forging the pseudoindoxyl core is based on the nitroalkyne cycloisomerization followed by a subsequent intramolecular [3 + 2] cycloaddition. However, the [3 + 2] cycloaddition occurred in an undesired manner, ultimately leading to a complex hexacyclic scaffold.
{"title":"Attempted synthesis of the central 2,2-disubstituted pseudoindoxyl core of Austamide via a [Au]-catalyzed nitroalkyne cycloisomerization and intramolecular [3 + 2]-cycloaddition","authors":"Swapnil V. Halnor, Chepuri V. Ramana","doi":"10.1016/j.tet.2024.134301","DOIUrl":"10.1016/j.tet.2024.134301","url":null,"abstract":"<div><div>Herein, we describe an Au-catalyzed cycloisomerization process of a nitroalkyne that was projected to construct the central 2,2-disubstituted pseudoindoxyl core of the natural product Austamide. Our intended strategy for forging the pseudoindoxyl core is based on the nitroalkyne cycloisomerization followed by a subsequent intramolecular [3 + 2] cycloaddition. However, the [3 + 2] cycloaddition occurred in an undesired manner, ultimately leading to a complex hexacyclic scaffold.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134301"},"PeriodicalIF":2.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.tet.2024.134304
Qing Li , Kun Shang , Jin Wang , Chen-Sen Xu , Zhuoer Cai , Peng Yuan , Chun-Gu Wang , Min-Min Gu , Yu Zhang , Zhi-Xin Liao
Phyllocladane-type diterpenoids represent a rare group of tetracyclic diterpenes. Two diterpenoids (1 and 2) were extracted from Callicarpa longifolia var. floccosa, along with the Chemically synthesized derivatized compound 3. The crystal data for compound 1 were first reported in this study, and compound 2 was identified as a novel phyllocladane-type diterpenoid. In addition, calliterpenone monoacetate was previously erroneously reported as compound 2. We corrected the structure of calliterpenone monoacetate to 2a by X-ray diffraction, NMR calculations, and chemical synthesis, as well as the TDDFT-ECD method. At the same time, the antitumor activity of compounds 1 and 2 was studied.
{"title":"Identification, structural revision and biological evaluation of the phyllocladane-type diterpenoids from Callicarpa longifolia var. floccosa","authors":"Qing Li , Kun Shang , Jin Wang , Chen-Sen Xu , Zhuoer Cai , Peng Yuan , Chun-Gu Wang , Min-Min Gu , Yu Zhang , Zhi-Xin Liao","doi":"10.1016/j.tet.2024.134304","DOIUrl":"10.1016/j.tet.2024.134304","url":null,"abstract":"<div><div>Phyllocladane-type diterpenoids represent a rare group of tetracyclic diterpenes. Two diterpenoids (<strong>1</strong> and <strong>2</strong>) were extracted from <em>Callicarpa longifolia</em> var. <em>floccosa</em>, along with the Chemically synthesized derivatized compound <strong>3</strong>. The crystal data for compound <strong>1</strong> were first reported in this study, and compound <strong>2</strong> was identified as a novel phyllocladane-type diterpenoid. In addition, calliterpenone monoacetate was previously erroneously reported as compound <strong>2</strong>. We corrected the structure of calliterpenone monoacetate to <strong>2a</strong> by X-ray diffraction, NMR calculations, and chemical synthesis, as well as the TDDFT-ECD method. At the same time, the antitumor activity of compounds <strong>1</strong> and <strong>2</strong> was studied.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134304"},"PeriodicalIF":2.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.tet.2024.134295
Erick M.C. Pinheiro , Rafael P.R.F. Oliveira , Sandro J. Greco , Sergio Pinheiro
Azaflavanones are synthetic aza analogues of natural flavanones that have received attention in medicine. More recently, some alpha-ylidene azaflavanones have emerged as promising bioactive compounds. In the last decades, several approaches to synthesizing azaflavanones and alpha-ylidene azaflavanones have been described. These include intramolecular cyclizations of 2′-aminochalcones and analogues, coupling of 2-aminoacetophenones with aromatic aldehydes, metal-catalyzed coupling reactions of ortho-iodoanilines and the condensations of N-protected 2-aminoacetophenones and N-protected 2′-aminochalcones with aromatic aldehydes. This review discusses the different approaches in the racemic synthesis of azaflavanones and alpha-ylidene azaflavanones.
氮杂黄烷酮是天然黄烷酮的人工合成氮杂类似物，在医学领域备受关注。最近，一些α-亚基氮杂黄烷酮作为有前景的生物活性化合物出现。在过去的几十年中，人们已经描述了几种合成氮杂黄烷酮和α-亚基氮杂黄烷酮的方法。这些方法包括 2′-氨基查耳酮及其类似物的分子内环化反应、2-氨基苯乙酮与芳香醛的偶联反应、金属催化的邻碘苯胺偶联反应以及 N 保护的 2-氨基苯乙酮和 N 保护的 2′-氨基查耳酮与芳香醛的缩合反应。本综述讨论了外消旋合成氮杂黄烷酮和α-亚基氮杂黄烷酮的不同方法。
{"title":"Synthesis of azaflavanones and alpha-ylidene azaflavanones","authors":"Erick M.C. Pinheiro , Rafael P.R.F. Oliveira , Sandro J. Greco , Sergio Pinheiro","doi":"10.1016/j.tet.2024.134295","DOIUrl":"10.1016/j.tet.2024.134295","url":null,"abstract":"<div><div>Azaflavanones are synthetic aza analogues of natural flavanones that have received attention in medicine. More recently, some alpha-ylidene azaflavanones have emerged as promising bioactive compounds. In the last decades, several approaches to synthesizing azaflavanones and alpha-ylidene azaflavanones have been described. These include intramolecular cyclizations of 2′-aminochalcones and analogues, coupling of 2-aminoacetophenones with aromatic aldehydes, metal-catalyzed coupling reactions of <em>ortho</em>-iodoanilines and the condensations of N-protected 2-aminoacetophenones and N-protected 2′-aminochalcones with aromatic aldehydes. This review discusses the different approaches in the racemic synthesis of azaflavanones and alpha-ylidene azaflavanones.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134295"},"PeriodicalIF":2.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.tet.2024.134297
Adriana Galván , Guadalupe Flores-Gallegos , Orlando O. Hernández-Ramírez , Yolanda Alcaraz-Contreras , Selene Laguna-Rivera , Merced Martínez , Jorge Alberto Mendoza-Pérez , Eduardo Peña-Cabrera , Miguel A. Vázquez
Click chemistry reactions transformed organic synthesis by creating enormous compound libraries connecting almost any chemical entity. The copper-catalyzed alkyne-azide cycloaddition (CuAAC) was the most versatile and efficient and transcended diverse scientific fields such as biology and materials science. Thus, the development of new methodologies based on CuAAC keeps growing. A green approach was envisioned by stabilizing the air and water-sensitive CuI over an ordered mesoporous silica/ionic liquid matrix (MIM-SBA-15). The best catalyst performance was in the water as solvent under ultrasound irradiation, which reached quantitative transformation in a short time. Then, the scope was extended to 24 compounds primarily synthesized with high yields (75–99 %); the methodology tolerated different alkynes and azides with aromatic and alkyl groups. This methodology was also successfully tested in high yields in the multicomponent synthesis of 1,4-disubstituted 1,2,3-triazoles from organic bromides, alkynes, and KN3. The hybrid catalyst recovery and reuse were evaluated along ten reaction cycles; there was no significant loss in activity up to cycle number six (94 % yield).
{"title":"CuI@MIM-SBA-15 hybrid catalyst in the ultrasound-assisted synthesis of 1,4-disubstituted 1,2,3-triazoles in water","authors":"Adriana Galván , Guadalupe Flores-Gallegos , Orlando O. Hernández-Ramírez , Yolanda Alcaraz-Contreras , Selene Laguna-Rivera , Merced Martínez , Jorge Alberto Mendoza-Pérez , Eduardo Peña-Cabrera , Miguel A. Vázquez","doi":"10.1016/j.tet.2024.134297","DOIUrl":"10.1016/j.tet.2024.134297","url":null,"abstract":"<div><div>Click chemistry reactions transformed organic synthesis by creating enormous compound libraries connecting almost any chemical entity. The copper-catalyzed alkyne-azide cycloaddition (CuAAC) was the most versatile and efficient and transcended diverse scientific fields such as biology and materials science. Thus, the development of new methodologies based on CuAAC keeps growing. A green approach was envisioned by stabilizing the air and water-sensitive CuI over an ordered mesoporous silica/ionic liquid matrix (MIM-SBA-15). The best catalyst performance was in the water as solvent under ultrasound irradiation, which reached quantitative transformation in a short time. Then, the scope was extended to 24 compounds primarily synthesized with high yields (75–99 %); the methodology tolerated different alkynes and azides with aromatic and alkyl groups. This methodology was also successfully tested in high yields in the multicomponent synthesis of 1,4-disubstituted 1,2,3-triazoles from organic bromides, alkynes, and KN<sub>3</sub>. The hybrid catalyst recovery and reuse were evaluated along ten reaction cycles; there was no significant loss in activity up to cycle number six (94 % yield).</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134297"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.tet.2024.134292
Mark V. Sigalov , Bagrat A. Shainyan , Nina N. Chipanina , Larisa P. Oznobikhina
The Knoevenagel reaction of 2-acetyl-1,3-indandione, dehydroacetic acid, 3-acetyl-4-hydroxy-coumarin and acetyl-barbituric acid with pyrrol-2-carbaldehyde affords 2-(1-hydroxy-3-(1H-pyrrol-2-yl)allylidene)-1H-indene-1,3(2H)-dione 5, 3-(3-(1H-pyrrol-2-yl)acryloyl)-4-hydroxy-6-methyl-2H-pyran-2-one 6, 3-(3-(1H-pyrrol-2-yl)acryloyl)-4-hydroxy-2H-chromen-2-one 7 and 5-(1-hydroxy-3-(1H-pyrrol-2-yl)allylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione 8. The UV-induced E→Z isomerization, intra and intermolecular H-bonding is studied by NMR, IR, UV spectroscopy and theoretical calculations. The driving force for the E→Z isomerization is the formation of a bifurcate O–H⋯O⋯H–N hydrogen bond in the latter. The position of the E⇆Z equilibrium strongly depends on the solvent (CH2Cl2, acetone, EtOH, DMSO). According to QTAIM analysis, the formed OH⋯O bonds are strong or moderate in energy (from 7.6 to 10.2 kcal/mol), while the NH⋯O bonds are weak (from 4.8 to 6.4 kcal/mol).
{"title":"UV-induced E/Z isomerization of the electron-rich pyrrole ring containing diketoenols: Theoretical and experimental study","authors":"Mark V. Sigalov , Bagrat A. Shainyan , Nina N. Chipanina , Larisa P. Oznobikhina","doi":"10.1016/j.tet.2024.134292","DOIUrl":"10.1016/j.tet.2024.134292","url":null,"abstract":"<div><div>The Knoevenagel reaction of 2-acetyl-1,3-indandione, dehydroacetic acid, 3-acetyl-4-hydroxy-coumarin and acetyl-barbituric acid with pyrrol-2-carbaldehyde affords 2-(1-hydroxy-3-(1<em>H</em>-pyrrol-2-yl)allylidene)-1<em>H</em>-indene-1,3(2<em>H</em>)-dione <strong>5</strong>, 3-(3-(1<em>H</em>-pyrrol-2-yl)acryloyl)-4-hydroxy-6-methyl-2<em>H</em>-pyran-2-one <strong>6</strong>, 3-(3-(1<em>H</em>-pyrrol-2-yl)acryloyl)-4-hydroxy-2<em>H</em>-chromen-2-one <strong>7</strong> and 5-(1-hydroxy-3-(1<em>H</em>-pyrrol-2-yl)allylidene)-1,3-dimethylpyrimidine-2,4,6(1<em>H</em>,3<em>H</em>,5<em>H</em>)-trione <strong>8</strong>. The UV-induced <em>E</em>→<em>Z</em> isomerization, intra and intermolecular H-bonding is studied by NMR, IR, UV spectroscopy and theoretical calculations. The driving force for the <em>E</em>→<em>Z</em> isomerization is the formation of a bifurcate O–H⋯O⋯H–N hydrogen bond in the latter. The position of the <em>E</em>⇆<em>Z</em> equilibrium strongly depends on the solvent (CH<sub>2</sub>Cl<sub>2</sub>, acetone, EtOH, DMSO). According to QTAIM analysis, the formed OH⋯O bonds are strong or moderate in energy (from 7.6 to 10.2 kcal/mol), while the NH⋯O bonds are weak (from 4.8 to 6.4 kcal/mol).</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134292"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.tet.2024.134298
Sinuhé Galván-Gómez , Gabriela Rodríguez-García , Antonio J. Oliveros-Ortiz , Rosa E. del Río , Carlos M. Cerda-García-Rojas , Verónica Reyes-Olivares , Pedro Joseph-Nathan , Mario A. Gómez-Hurtado
<div><div>The exciton coupling (EC) phenomenon becomes a valuable tool for the absolute configuration (AC) determination of organic molecules when an interaction between two strategically located chromophores in a molecule is evidenced by circularly polarized radiation. Besides the widely used exciton chirality method in electronic circular dichroism, the technique has been also developed for vibrational circular dichroism (VCD). Notably, the information provided by C<img>O stretching vibrations (1680−1800 cm<sup>−1</sup>) in VCD have demonstrated high applicability. However, reported theoretical approaches have warned about the adequate interpretations of the EC phenomenon since analyzed bisignate bands could be associated with other vibrations. The current paper experimentally addresses the problem to expand the criteria for using EC data in AC determinations. Herein, the VCD exciton coupling (VCDEC) methodology is extended to the analysis of C–O stretching vibrations (1100–1300 cm<sup>−1</sup>) to uncover their possible use in AC determinations, as well as to reveal the specific contribution of the EC related to C–O vibrations when experimental parameters are considered. To this aim, naturally occurring <em>p</em>-menthene alcohols <strong>1</strong>–<strong>4</strong> isolated from <em>Ageratina glabrata</em> were previously used to prepare acetates <strong>5</strong> and <strong>6</strong>, and acetonides <strong>7</strong> and <strong>8</strong>, and now, to prepare carbonates <strong>9</strong>–<strong>11</strong>. Density functional theory (DFT) calculations, including the IR and VCD spectra of the seven derivatives (<strong>5</strong>–<strong>11</strong>), were carried out to reinforce the conformational and configurational analysis, while the experimental VCD spectra of <strong>5</strong>–<strong>7</strong>, <strong>9</strong>, and <strong>11</strong> demonstrated the presence of C–O couplets. A systematic analysis of these bands, including the Δ<em>ε</em> value at alpha and beta state (Δ<em>ε</em><sub><em>α</em></sub>, Δ<em>ε</em><sub><em>β</em></sub>, respectively), the amplitude of EC (A = <span><math><mrow><mo>∑</mo><mi>ǀ</mi><mo>Δ</mo><mi>ε</mi><mi>ǀ</mi></mrow></math></span>) value, the couplet period (<em>L =</em> <span><math><mrow><mover><mi>v</mi><mo>‾</mo></mover><mo>Δ</mo><msub><mi>ε</mi><mi>β</mi></msub></mrow></math></span> − <span><math><mrow><mover><mi>v</mi><mo>‾</mo></mover></mrow></math></span> <em>Δε</em><sub><em>α</em></sub>) value, the specific area of C–O at couplet (S = <em>Σf(x)</em>(u<sup>2</sup>)), and the percentage of area related to EC from C–O (S<sub>%</sub>) were considered. These experimental results were directly related to dihedral angles (<em>θ</em>) from simplistic models to establish the AC. The results suggested that A, Cp, S, and S<sub>%</sub> parameters are deeply related to the nature of the chromophores. Thereby, adequate molecular structural moieties should be chosen for AC determination when u
{"title":"The vibrational circular dichroism exciton coupling in single-bond C–O stretching vibrations of p-menthene derivatives","authors":"Sinuhé Galván-Gómez , Gabriela Rodríguez-García , Antonio J. Oliveros-Ortiz , Rosa E. del Río , Carlos M. Cerda-García-Rojas , Verónica Reyes-Olivares , Pedro Joseph-Nathan , Mario A. Gómez-Hurtado","doi":"10.1016/j.tet.2024.134298","DOIUrl":"10.1016/j.tet.2024.134298","url":null,"abstract":"<div><div>The exciton coupling (EC) phenomenon becomes a valuable tool for the absolute configuration (AC) determination of organic molecules when an interaction between two strategically located chromophores in a molecule is evidenced by circularly polarized radiation. Besides the widely used exciton chirality method in electronic circular dichroism, the technique has been also developed for vibrational circular dichroism (VCD). Notably, the information provided by C<img>O stretching vibrations (1680−1800 cm<sup>−1</sup>) in VCD have demonstrated high applicability. However, reported theoretical approaches have warned about the adequate interpretations of the EC phenomenon since analyzed bisignate bands could be associated with other vibrations. The current paper experimentally addresses the problem to expand the criteria for using EC data in AC determinations. Herein, the VCD exciton coupling (VCDEC) methodology is extended to the analysis of C–O stretching vibrations (1100–1300 cm<sup>−1</sup>) to uncover their possible use in AC determinations, as well as to reveal the specific contribution of the EC related to C–O vibrations when experimental parameters are considered. To this aim, naturally occurring <em>p</em>-menthene alcohols <strong>1</strong>–<strong>4</strong> isolated from <em>Ageratina glabrata</em> were previously used to prepare acetates <strong>5</strong> and <strong>6</strong>, and acetonides <strong>7</strong> and <strong>8</strong>, and now, to prepare carbonates <strong>9</strong>–<strong>11</strong>. Density functional theory (DFT) calculations, including the IR and VCD spectra of the seven derivatives (<strong>5</strong>–<strong>11</strong>), were carried out to reinforce the conformational and configurational analysis, while the experimental VCD spectra of <strong>5</strong>–<strong>7</strong>, <strong>9</strong>, and <strong>11</strong> demonstrated the presence of C–O couplets. A systematic analysis of these bands, including the Δ<em>ε</em> value at alpha and beta state (Δ<em>ε</em><sub><em>α</em></sub>, Δ<em>ε</em><sub><em>β</em></sub>, respectively), the amplitude of EC (A = <span><math><mrow><mo>∑</mo><mi>ǀ</mi><mo>Δ</mo><mi>ε</mi><mi>ǀ</mi></mrow></math></span>) value, the couplet period (<em>L =</em> <span><math><mrow><mover><mi>v</mi><mo>‾</mo></mover><mo>Δ</mo><msub><mi>ε</mi><mi>β</mi></msub></mrow></math></span> − <span><math><mrow><mover><mi>v</mi><mo>‾</mo></mover></mrow></math></span> <em>Δε</em><sub><em>α</em></sub>) value, the specific area of C–O at couplet (S = <em>Σf(x)</em>(u<sup>2</sup>)), and the percentage of area related to EC from C–O (S<sub>%</sub>) were considered. These experimental results were directly related to dihedral angles (<em>θ</em>) from simplistic models to establish the AC. The results suggested that A, Cp, S, and S<sub>%</sub> parameters are deeply related to the nature of the chromophores. Thereby, adequate molecular structural moieties should be chosen for AC determination when u","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134298"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mavintramycin A is a new aminohexopyranose nucleoside antibiotic with potent anti-Mycobacterium avium complex (MAC) activity against M. avium and M. intracellulare. Herein, we report the total syntheses of mavintramycin A and its structural analog cytosaminomycin C, which is a known anticoccidial antibiotic. Furthermore, the anti-MAC activities of mavintramycin A, cytosaminomycin C, and their corresponding p-methoxybenzyl-protected analogs were evaluated. Notably, the developed synthetic route enables ready access to various analogs of mavintramycin A for structure-activity relationship studies.
马文曲霉素 A 是一种新的氨基己吡喃糖核苷类抗生素，对阿维菌素分枝杆菌和细胞内分枝杆菌具有很强的抗分枝杆菌复合体（MAC）活性。在此，我们报告了马文曲霉素 A 及其结构类似物胞嘧啶霉素 C 的全合成，后者是一种已知的抗球菌抗生素。此外，我们还评估了马文曲霉素 A、胞氨霉素 C 及其相应的对甲氧基苄基保护类似物的抗 MAC 活性。值得注意的是，所开发的合成路线可随时获得各种马文霉素 A 类似物，用于结构-活性关系研究。
{"title":"Total syntheses of mavintramycin A and its structural analog, cytosaminomycin C, and evaluation of their antibacterial activities against Mycobacterium avium and Mycobacterium intracellulare","authors":"Hanaka Satoh , Daiki Lee , Shiho Arima , Kanji Hosoda , Satoru Shigeno , Hiroshi Tomoda , Taichi Ohshiro , Tohru Nagamitsu","doi":"10.1016/j.tet.2024.134299","DOIUrl":"10.1016/j.tet.2024.134299","url":null,"abstract":"<div><div>Mavintramycin A is a new aminohexopyranose nucleoside antibiotic with potent anti-<em>Mycobacterium avium</em> complex (MAC) activity against <em>M. avium</em> and <em>M. intracellulare</em>. Herein, we report the total syntheses of mavintramycin A and its structural analog cytosaminomycin C, which is a known anticoccidial antibiotic. Furthermore, the anti-MAC activities of mavintramycin A, cytosaminomycin C, and their corresponding <em>p</em>-methoxybenzyl-protected analogs were evaluated. Notably, the developed synthetic route enables ready access to various analogs of mavintramycin A for structure-activity relationship studies.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134299"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.tet.2024.134294
Guo-Zhen Wei, Xiao-Han Qiu, Lei Guo, Ming Bian, Hui-Yu Chen, Yu-Ning Gao, Zhen-Jiang Liu
An efficient decarboxylative difluoroalkylation method of cyclic N-sulfonyl ketimines with difluoroalkyl carboxylates has been developed through visible light-mediated photoredox catalysis process. This protocol provides a straightforward route for the synthesis of difluoroalkylated Cα-tetrasubstituted α-amino acid derivatives in moderate to good yields with excellent functional group tolerance under mild and simple conditions.
{"title":"Visible light mediated decarboxylative difluoroalkylations of cyclic N-sulfonyl ketimines: Efficient synthesis of difluoroalkylated Cα-tetrasubstituted α-amino acid derivatives","authors":"Guo-Zhen Wei, Xiao-Han Qiu, Lei Guo, Ming Bian, Hui-Yu Chen, Yu-Ning Gao, Zhen-Jiang Liu","doi":"10.1016/j.tet.2024.134294","DOIUrl":"10.1016/j.tet.2024.134294","url":null,"abstract":"<div><div>An efficient decarboxylative difluoroalkylation method of cyclic <em>N</em>-sulfonyl ketimines with difluoroalkyl carboxylates has been developed through visible light-mediated photoredox catalysis process. This protocol provides a straightforward route for the synthesis of difluoroalkylated C<sup>α</sup>-tetrasubstituted α-amino acid derivatives in moderate to good yields with excellent functional group tolerance under mild and simple conditions.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134294"},"PeriodicalIF":2.1,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.tet.2024.134293
Pushpa V. Malekar , Ganesh V. More , Chepuri V. Ramana
The enantioselective transfer hydrogenation of racemic β-keto γ-lactams via dynamic kinetic resolution using a chiral Ru(II) catalyst has been developed for the synthesis of optically active β-hydroxyl lactams with excellent conversion (up to 99 %), high diastereomeric ratio (dr 93:07) and enantiomeric selectivity (89 % ee). The reaction proceeded by using HCO2H/Et3N as hydrogen donor and features mild, additive free reaction conditions, fast crystallization, broad substrate scope, and an operationally simpler setup than that for molecular hydrogenation.
{"title":"Ru-catalyzed asymmetric transfer hydrogenation of racemic β-keto γ-lactams via dynamic kinetic resolution","authors":"Pushpa V. Malekar , Ganesh V. More , Chepuri V. Ramana","doi":"10.1016/j.tet.2024.134293","DOIUrl":"10.1016/j.tet.2024.134293","url":null,"abstract":"<div><div>The enantioselective transfer hydrogenation of racemic <em>β</em>-keto <em>γ</em>-lactams <em>via</em> dynamic kinetic resolution using a chiral Ru(II) catalyst has been developed for the synthesis of optically active <em>β</em>-hydroxyl lactams with excellent conversion (up to 99 %), high diastereomeric ratio (<em>dr</em> 93:07) and enantiomeric selectivity (89 % <em>ee</em>). The reaction proceeded by using HCO<sub>2</sub>H/Et<sub>3</sub>N as hydrogen donor and features mild, additive free reaction conditions, fast crystallization, broad substrate scope, and an operationally simpler setup than that for molecular hydrogenation.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"167 ","pages":"Article 134293"},"PeriodicalIF":2.1,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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