The Experts below are selected from a list of 108504 Experts worldwide ranked by ideXlab platform
Jim-min Fang - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of polycyclic and 4 5 diacylthiophene 2 carboxylates via intramolecular friedel crafts alkylations and unusual autooxidative fragmentation of the derivatives obtained from the samarium diiodide promoted coupling reactions of thiophene 2 car
Tetrahedron, 2007Co-Authors: Shyh-ming Yang, Jim-min FangAbstract:Abstract Our present study provides an expedient method for the synthesis of novel polycyclic and multi-substituted thiophene derivatives. A series of 4,5-di(hydroxyalkyl)-4,5-dihydroThiophene-2-Carboxylates (e.g., 4a – c and 10 ) were prepared by the SmI 2 -promoted three-component coupling reactions of Thiophene-2-Carboxylate with aromatic aldehydes and 4-methoxyacetophenone. Diol 4a was oxidized by DDQ or pyridinium dichromate to give 5-acyl-4-hydroxyalkyl-4,5-dihydroThiophene-2-Carboxylate 6a , which was subjected to dehydration to give either alkene 7 with terminal C C double bond or alkene 15a having conjugation with the ester group, depending on the reaction conditions using different quantities of p -toluenesulfonic acid. Alkene 7 underwent an intramolecular Friedel–Crafts alkylation to give a tetralone-fused Thiophene-2-Carboxylate 9 . By the similar procedure, a carbazole-fused thiophene 14 was also prepared. Alkenes 15a – c underwent autooxidative fragmentation to give 4,5-diacylThiophene-2-Carboxylates 5a – c that were elaborated to pyridazine-fused thiophenes.
-
Synthesis of polycyclic and 4,5-diacylThiophene-2-Carboxylates via intramolecular Friedel–Crafts alkylations and unusual autooxidative fragmentation of the derivatives obtained from the samarium diiodide-promoted coupling reactions of thiophene-2-car
Tetrahedron, 2007Co-Authors: Shyh-ming Yang, Jim-min FangAbstract:Abstract Our present study provides an expedient method for the synthesis of novel polycyclic and multi-substituted thiophene derivatives. A series of 4,5-di(hydroxyalkyl)-4,5-dihydroThiophene-2-Carboxylates (e.g., 4a–c and 10) were prepared by the SmI2-promoted three-component coupling reactions of Thiophene-2-Carboxylate with aromatic aldehydes and 4-methoxyacetophenone. Diol 4a was oxidized by DDQ or pyridinium dichromate to give 5-acyl-4-hydroxyalkyl-4,5-dihydroThiophene-2-Carboxylate 6a, which was subjected to dehydration to give either alkene 7 with terminal C C double bond or alkene 15a having conjugation with the ester group, depending on the reaction conditions using different quantities of p-toluenesulfonic acid. Alkene 7 underwent an intramolecular Friedel–Crafts alkylation to give a tetralone-fused Thiophene-2-Carboxylate 9. By the similar procedure, a carbazole-fused thiophene 14 was also prepared. Alkenes 15a–c underwent autooxidative fragmentation to give 4,5-diacylThiophene-2-Carboxylates 5a–c that were elaborated to pyridazine-fused thiophenes.
-
Comparative study of TmI2, SmI2, and SmI2/HMPA in the cross-coupling reactions of 2-acetylthiophene and Thiophene-2-Carboxylate with carbonyl compounds
Tetrahedron Letters, 2004Co-Authors: Jiun-jie Shie, Penny S. Workman, William J Evans, Jim-min FangAbstract:Abstract The cross-coupling reactions of acetylthiophene or ethyl Thiophene-2-Carboxylate with aldehydes or ketones were achieved in a regioselective manner by using thulium diiodide in THF solution. Similar coupling reactions were also realized by using samarium diiodide together with excess amounts of hexamethylphosphoramide (HMPA). However, ethyl Thiophene-2-Carboxylate was inert in SmI 2 /THF solution, and acetylthiophene was simply reduced to thienylethanol by SmI 2 in the absence of HMPA.
-
Carbazolothiophene-2-carboxylic acid derivatives as endothelin receptor antagonists
Bioorganic & Medicinal Chemistry Letters, 2004Co-Authors: Govindarajulu Babu, Hui Ming Yu, Shyh-ming Yang, Jim-min FangAbstract:Abstract The SmI 2 -promoted three-component coupling reaction of Thiophene-2-Carboxylate, indole-2-carbaldehyde and acetophenone provides an expedient route to a series of tetracyclic carbazolothiophene compounds bearing the indole and thiophene rings. Among these samples, 9-benzyl-4-methyl-4-(4-hydroxyphenyl)-10-oxo-4,10-dihydrocarbazolo[2,3- b ]thiophene-2-carboxylic acid ( 18 ) shows the most potent inhibition against the endothelin-1 induced increase of intracellular calcium ion concentration.
-
Synthesis of Polysubstituted Benzothiophenes and Sulfur-Containing Polycyclic Aromatic Compounds via Samarium Diiodide Promoted Three-Component Coupling Reactions of Thiophene-2-Carboxylate
Journal of Organic Chemistry, 2002Co-Authors: Shyh-ming Yang, Jiun-jie Shie, Syn-hung Lu, Suman Kumar Nandy, Hung-yu Chang, Jim-min Fang, Gladys WangAbstract:By the promotion of samarium diiodide, Thiophene-2-Carboxylate reacted with 2 equiv of ketones at the C-4 and C-5 positions to give diols such as 2 and 9. Because the intermediary organosamarium species were oxophilic but not too basic, the double hydroxyalkylations with various ketone substrates, including alkyl aryl ketones, acetylthiophenes, cyclohexanone, α-tetralone, and α-phenylacetophenones, were realized without complication of side reactions. The diol products underwent an acid-catalyzed dehydration to give dienes such as 3 and 10, which were treated with DDQ to give either polysubstituted thiophenes (e.g., 4 and 11) or benzothiophenes (e.g., 5, 13, and 14) depending on the reaction conditions. Oxidative annulations of 4,5-diarylthiophenes 11 and 4,5,6,7-tetraphenylbenzothiophenes 14 were carried out by photochemical or chemical methods to give the sulfur-containing polycyclic aromatic compounds, such as phenanthro[9,10-b]Thiophene-2-Carboxylate, piceno[13,14-b]Thiophene-2-Carboxylate, and triben...
Shyh-ming Yang - One of the best experts on this subject based on the ideXlab platform.
-
Synthesis of polycyclic and 4,5-diacylThiophene-2-Carboxylates via intramolecular Friedel–Crafts alkylations and unusual autooxidative fragmentation of the derivatives obtained from the samarium diiodide-promoted coupling reactions of thiophene-2-car
Tetrahedron, 2007Co-Authors: Shyh-ming Yang, Jim-min FangAbstract:Abstract Our present study provides an expedient method for the synthesis of novel polycyclic and multi-substituted thiophene derivatives. A series of 4,5-di(hydroxyalkyl)-4,5-dihydroThiophene-2-Carboxylates (e.g., 4a–c and 10) were prepared by the SmI2-promoted three-component coupling reactions of Thiophene-2-Carboxylate with aromatic aldehydes and 4-methoxyacetophenone. Diol 4a was oxidized by DDQ or pyridinium dichromate to give 5-acyl-4-hydroxyalkyl-4,5-dihydroThiophene-2-Carboxylate 6a, which was subjected to dehydration to give either alkene 7 with terminal C C double bond or alkene 15a having conjugation with the ester group, depending on the reaction conditions using different quantities of p-toluenesulfonic acid. Alkene 7 underwent an intramolecular Friedel–Crafts alkylation to give a tetralone-fused Thiophene-2-Carboxylate 9. By the similar procedure, a carbazole-fused thiophene 14 was also prepared. Alkenes 15a–c underwent autooxidative fragmentation to give 4,5-diacylThiophene-2-Carboxylates 5a–c that were elaborated to pyridazine-fused thiophenes.
-
synthesis of polycyclic and 4 5 diacylthiophene 2 carboxylates via intramolecular friedel crafts alkylations and unusual autooxidative fragmentation of the derivatives obtained from the samarium diiodide promoted coupling reactions of thiophene 2 car
Tetrahedron, 2007Co-Authors: Shyh-ming Yang, Jim-min FangAbstract:Abstract Our present study provides an expedient method for the synthesis of novel polycyclic and multi-substituted thiophene derivatives. A series of 4,5-di(hydroxyalkyl)-4,5-dihydroThiophene-2-Carboxylates (e.g., 4a – c and 10 ) were prepared by the SmI 2 -promoted three-component coupling reactions of Thiophene-2-Carboxylate with aromatic aldehydes and 4-methoxyacetophenone. Diol 4a was oxidized by DDQ or pyridinium dichromate to give 5-acyl-4-hydroxyalkyl-4,5-dihydroThiophene-2-Carboxylate 6a , which was subjected to dehydration to give either alkene 7 with terminal C C double bond or alkene 15a having conjugation with the ester group, depending on the reaction conditions using different quantities of p -toluenesulfonic acid. Alkene 7 underwent an intramolecular Friedel–Crafts alkylation to give a tetralone-fused Thiophene-2-Carboxylate 9 . By the similar procedure, a carbazole-fused thiophene 14 was also prepared. Alkenes 15a – c underwent autooxidative fragmentation to give 4,5-diacylThiophene-2-Carboxylates 5a – c that were elaborated to pyridazine-fused thiophenes.
-
Carbazolothiophene-2-carboxylic acid derivatives as endothelin receptor antagonists
Bioorganic & Medicinal Chemistry Letters, 2004Co-Authors: Govindarajulu Babu, Hui Ming Yu, Shyh-ming Yang, Jim-min FangAbstract:Abstract The SmI 2 -promoted three-component coupling reaction of Thiophene-2-Carboxylate, indole-2-carbaldehyde and acetophenone provides an expedient route to a series of tetracyclic carbazolothiophene compounds bearing the indole and thiophene rings. Among these samples, 9-benzyl-4-methyl-4-(4-hydroxyphenyl)-10-oxo-4,10-dihydrocarbazolo[2,3- b ]thiophene-2-carboxylic acid ( 18 ) shows the most potent inhibition against the endothelin-1 induced increase of intracellular calcium ion concentration.
-
Synthesis of Polysubstituted Benzothiophenes and Sulfur-Containing Polycyclic Aromatic Compounds via Samarium Diiodide Promoted Three-Component Coupling Reactions of Thiophene-2-Carboxylate
Journal of Organic Chemistry, 2002Co-Authors: Shyh-ming Yang, Jiun-jie Shie, Syn-hung Lu, Suman Kumar Nandy, Hung-yu Chang, Jim-min Fang, Gladys WangAbstract:By the promotion of samarium diiodide, Thiophene-2-Carboxylate reacted with 2 equiv of ketones at the C-4 and C-5 positions to give diols such as 2 and 9. Because the intermediary organosamarium species were oxophilic but not too basic, the double hydroxyalkylations with various ketone substrates, including alkyl aryl ketones, acetylthiophenes, cyclohexanone, α-tetralone, and α-phenylacetophenones, were realized without complication of side reactions. The diol products underwent an acid-catalyzed dehydration to give dienes such as 3 and 10, which were treated with DDQ to give either polysubstituted thiophenes (e.g., 4 and 11) or benzothiophenes (e.g., 5, 13, and 14) depending on the reaction conditions. Oxidative annulations of 4,5-diarylthiophenes 11 and 4,5,6,7-tetraphenylbenzothiophenes 14 were carried out by photochemical or chemical methods to give the sulfur-containing polycyclic aromatic compounds, such as phenanthro[9,10-b]Thiophene-2-Carboxylate, piceno[13,14-b]Thiophene-2-Carboxylate, and triben...
-
A novel photochromic system of 4,5-dialkenylthiophenes constructed by the smarium diiodide promoted coupling reactions of Thiophene-2-Carboxylate with aryl ketones.
Organic Letters, 2002Co-Authors: Jiun-jie Shie, Shyh-ming Yang, Chao-tsen Chen, Jim-min FangAbstract:The SmI2-promoted coupling reaction of ethyl Thiophene-2-Carboxylate with aryl ketones (2 equiv), followed by acid-catalyzed dehydration and oxidative aromatization, gave dialkenylthiophenes 1b−d, which underwent electrocyclizations upon irradiation with 300-nm light in CH3CN solution to give the corresponding closed-ring species with absorption λmax ≈ 425 nm. The interconversion between dialkenylthiophenes and their corresponding closed-ring species constitutes a novel photochromic system bearing an ester group for potential uses in linkage and wavelength tuning.
Lanny S Liebeskind - One of the best experts on this subject based on the ideXlab platform.
-
Stereocontrolled Synthesis of α-Amino-α′-alkoxy Ketones by a Copper-Catalyzed Cross-Coupling of Peptidic Thiol Esters and α-Alkoxyalkylstannanes
Organic Letters, 2011Co-Authors: Hao Li, Anyu He, John R Falck, Lanny S LiebeskindAbstract:A stereocontrolled synthesis of α-amino-α′-alkoxy ketones is described. This pH-neutral copper(I) Thiophene-2-Carboxylate (CuTC)-catalyzed cross-coupling of amino acid thiol esters and chiral nonracemic α-alkoxyalkylstannanes gives α-amino-α′-alkoxy ketones in good to excellent yields with complete retention of configuration at the α-amino- and α-alkoxy-substituted stereocenters.
-
Palladium-Catalyzed, Copper(I)-Mediated Coupling of Boronic Acids and Benzylthiocyanate. A Cyanide-Free Cyanation of Boronic Acids
Organic Letters, 2006Co-Authors: Zhihui Zhang, Lanny S LiebeskindAbstract:A new method for the synthesis of nitriles is described. As a complement to the classic cyanation of aryl halides using cyanide sources and a transition metal catalyst, the palladium-catalyzed cross-coupling of thiocyanates with boronic acids in the presence of copper(I) Thiophene-2-Carboxylate (CuTC) affords nitriles in good to excellent yields.
-
Heteroaromatic Thioether−Boronic Acid Cross-Coupling under Neutral Reaction Conditions
Organic Letters, 2002Co-Authors: Lanny S Liebeskind, Jiri SroglAbstract:π-Deficient heteroaromatic thioethers undergo efficient palladium-catalyzed cross-coupling with boronic acids mediated by copper(I) Thiophene-2-Carboxylate.
Jiri Srogl - One of the best experts on this subject based on the ideXlab platform.
-
Heteroaromatic Thioether−Boronic Acid Cross-Coupling under Neutral Reaction Conditions
Organic Letters, 2002Co-Authors: Lanny S Liebeskind, Jiri SroglAbstract:π-Deficient heteroaromatic thioethers undergo efficient palladium-catalyzed cross-coupling with boronic acids mediated by copper(I) Thiophene-2-Carboxylate.
-
Heteroaromatic thioether-boronic acid cross-coupling under neutral reaction conditions.
Organic letters, 2002Co-Authors: Lanny S. Liebeskind And, Jiri SroglAbstract:π-Deficient heteroaromatic thioethers undergo efficient palladium-catalyzed cross-coupling with boronic acids mediated by copper(I) Thiophene-2-Carboxylate.
Do-hoon Hwang - One of the best experts on this subject based on the ideXlab platform.
-
Thieno[3,2-b]thiophene-Substituted Benzo[1,2-b:4,5-b ']dithiophene as a Promising Building Block for Low Bandgap Semiconducting Polymers for High-Performance Single and Tandem Organic Photovoltaic Cells
Chemistry of Materials, 2014Co-Authors: Chang Eun Song, Won Suk Shin, In-nam Kang, Do-hoon HwangAbstract:We designed and synthetized a new poly{4,8-bis((2-ethylhexyl)thieno[3,2-b]thiophene)-benzo[1,2-b:4,5-b′]dithiophene-alt-2-ethylhexyl-4,6-dibromo-3-fluorothieno[3,4-b]Thiophene-2-Carboxylate} (PTTBDT-FTT) comprising bis(2-ethylhexylthieno[3,2-b]thiophenylbenzo[1,2-b:4,5-b′]dithiophene (TTBDT) and 2-ethylhexyl 3-fluorothieno[3,4-b]Thiophene-2-Carboxylate (FTT). The optical bandgap of PTTBDT-FTT was 1.55 eV. The energy levels of the highest occupied and lowest unoccupied molecular orbitals of PTTBDT-FTT were −5.31 and −3.73 eV, respectively. Two-dimensional grazing-incidence X-ray scattering measurements showed that the film’s PTTBDT-FTT chains are predominantly arranged with a face-on orientation with respect to the substrate, with strong π–π stacking. An organic thin-film transistor fabricated using PTTBDT-FTT as the active semiconductor showed high hole mobility of 2.1 × 10–2 cm2/(V·s). Single-junction bulk heterojunction photovoltaic cells with the configuration ITO/PEDOT:PSS/PTTBDT-FTT:PC71BM/Ca/Al were...
-
Thieno[3,2-b]thiophene-Substituted Benzo[1,2-b:4,5-b ']dithiophene as a Promising Building Block for Low Bandgap Semiconducting Polymers for High-Performance Single and Tandem Organic Photovoltaic Cells
Chemistry of Materials, 2014Co-Authors: Chang Eun Song, Won Suk Shin, In-nam Kang, Do-hoon HwangAbstract:We designed and synthetized a new poly{4,8-bis((2-ethylhexyl)thieno[3,2-b]thiophene)-benzo[1,2-b:4,5-b′]dithiophene-alt-2-ethylhexyl-4,6-dibromo-3-fluorothieno[3,4-b]Thiophene-2-Carboxylate} (PTTBDT-FTT) comprising bis(2-ethylhexylthieno[3,2-b]thiophenylbenzo[1,2-b:4,5-b′]dithiophene (TTBDT) and 2-ethylhexyl 3-fluorothieno[3,4-b]Thiophene-2-Carboxylate (FTT). The optical bandgap of PTTBDT-FTT was 1.55 eV. The energy levels of the highest occupied and lowest unoccupied molecular orbitals of PTTBDT-FTT were −5.31 and −3.73 eV, respectively. Two-dimensional grazing-incidence X-ray scattering measurements showed that the film’s PTTBDT-FTT chains are predominantly arranged with a face-on orientation with respect to the substrate, with strong π–π stacking. An organic thin-film transistor fabricated using PTTBDT-FTT as the active semiconductor showed high hole mobility of 2.1 × 10–2 cm2/(V·s). Single-junction bulk heterojunction photovoltaic cells with the configuration ITO/PEDOT:PSS/PTTBDT-FTT:PC71BM/Ca/Al were...
-
Thieno[3,2-b]thiophene-Substituted Benzo[1,2-b:4,5-b′]dithiophene as a Promising Building Block for Low Bandgap Semiconducting Polymers for High-Performance Single and Tandem Organic Photovoltaic Cells
Chemistry of Materials, 2014Co-Authors: Ji-hoon Kim, Chang Eun Song, Won Suk Shin, In-nam Kang, Bongsoo Kim, Do-hoon HwangAbstract:We designed and synthetized a new poly{4,8-bis((2-ethylhexyl)thieno[3,2-b]thiophene)-benzo[1,2-b:4,5-b′]dithiophene-alt-2-ethylhexyl-4,6-dibromo-3-fluorothieno[3,4-b]Thiophene-2-Carboxylate} (PTTBDT-FTT) comprising bis(2-ethylhexylthieno[3,2-b]thiophenylbenzo[1,2-b:4,5-b′]dithiophene (TTBDT) and 2-ethylhexyl 3-fluorothieno[3,4-b]Thiophene-2-Carboxylate (FTT). The optical bandgap of PTTBDT-FTT was 1.55 eV. The energy levels of the highest occupied and lowest unoccupied molecular orbitals of PTTBDT-FTT were −5.31 and −3.73 eV, respectively. Two-dimensional grazing-incidence X-ray scattering measurements showed that the film’s PTTBDT-FTT chains are predominantly arranged with a face-on orientation with respect to the substrate, with strong π–π stacking. An organic thin-film transistor fabricated using PTTBDT-FTT as the active semiconductor showed high hole mobility of 2.1 × 10–2 cm2/(V·s). Single-junction bulk heterojunction photovoltaic cells with the configuration ITO/PEDOT:PSS/PTTBDT-FTT:PC71BM/Ca/Al were...