The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Yasushi Morita - One of the best experts on this subject based on the ideXlab platform.
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Intermolecular Hydrogen-Bond Networks and Physical Properties of BF4– and TCNQ•– Salts of Three-Fold Symmetric Tris(Alkylamino)phenalenyliums
2012Co-Authors: Tsuyoshi Murata, Eigo Miyazaki, Takuji Yokoyama, Kazuhiro Nakasuji, Yasushi MoritaAbstract:Synthesis, redox properties, and crystal structures of tris(Alkylamino)phenalenyliums (TAP) having alkyl Groups (n-Pr, i-Pr, t-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ•–) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an Alkylamino Group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino Groups and the extension of the π-electronic system. In the crystal structures of the BF4– salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP formed π-dimer or columnar structures, which were connected through intermolecular N–H···F hydrogen bonds with BF4– to construct multidimensional network structures. The TCNQ•– salts prepared by the metathesis method were characterized as fully ionic salts with a 1:1 component ratio. In the crystal structures, both TAP and TCNQ•– molecules formed π-dimers, and the intermolecular hydrogen bonds between TAP and TCNQ•– constructed a two-dimensional sheet
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Intermolecular Hydrogen-Bond Networks and Physical Properties of BF4– and TCNQ•– Salts of Three-Fold Symmetric Tris(Alkylamino)phenalenyliums
Crystal Growth & Design, 2011Co-Authors: Tsuyoshi Murata, Eigo Miyazaki, Takuji Yokoyama, Kazuhiro Nakasuji, Yasushi MoritaAbstract:Synthesis, redox properties, and crystal structures of tris(Alkylamino)phenalenyliums (TAP) having alkyl Groups (n-Pr, i-Pr, t-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ•–) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an Alkylamino Group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino Groups and the extension of the π-electronic system. In the crystal structures of the BF4– salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP formed π-dimer or columnar structures, which were connected through intermolecular N–H···F hydrogen bonds with BF4– to construct multidimensional network structures. The TCNQ•– salts prepared...
Hideo Saji - One of the best experts on this subject based on the ideXlab platform.
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Structure–Activity Relationships of Radioiodinated Benzoimidazopyridine Derivatives for Detection of Tau Pathology
ACS medicinal chemistry letters, 2018Co-Authors: Sho Kaide, Masahiro Ono, Hiroyuki Watanabe, Ayane Kitada, Masashi Yoshimura, Yoichi Shimizu, Masafumi Ihara, Hideo SajiAbstract:It is generally accepted that neurofibrillary tangles consisting of tau proteins are involved in the pathogenesis of Alzheimer’s disease (AD). For selective detection of tau pathology, we synthesized and evaluated radioiodinated benzoimidazopyridine (BIP) derivatives with an Alkylamino Group as tau imaging probes. In vitro selectivity to tau aggregates and in vivo pharmacokinetics of BIP derivatives varied markedly, being strongly dependent on the Alkylamino Group. In in vitro autoradiography with AD brain sections, the BIP derivative with a dimethylamino Group (BIP-NMe2) showed the highest selectivity to tau aggregates. Regarding the biodistribution using normal mice, the BIP derivative with an ethylamino Group (BIP-NHEt) showed the highest uptake (6.04% ID/g at 2 min postinjection) into and rapid washout (0.12% ID/g at 60 min postinjection) from the brain. These results suggest that the introduction of an optimal Alkylamino Group into the BIP scaffold may lead to the development of more potential tau im...
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Structure–Activity Relationships of Radioiodinated Benzoimidazopyridine Derivatives for Detection of Tau Pathology
2018Co-Authors: Sho Kaide, Masahiro Ono, Hiroyuki Watanabe, Ayane Kitada, Masashi Yoshimura, Yoichi Shimizu, Masafumi Ihara, Hideo SajiAbstract:It is generally accepted that neurofibrillary tangles consisting of tau proteins are involved in the pathogenesis of Alzheimer’s disease (AD). For selective detection of tau pathology, we synthesized and evaluated radioiodinated benzoimidazopyridine (BIP) derivatives with an Alkylamino Group as tau imaging probes. In vitro selectivity to tau aggregates and in vivo pharmacokinetics of BIP derivatives varied markedly, being strongly dependent on the Alkylamino Group. In in vitro autoradiography with AD brain sections, the BIP derivative with a dimethylamino Group (BIP-NMe2) showed the highest selectivity to tau aggregates. Regarding the biodistribution using normal mice, the BIP derivative with an ethylamino Group (BIP-NHEt) showed the highest uptake (6.04% ID/g at 2 min postinjection) into and rapid washout (0.12% ID/g at 60 min postinjection) from the brain. These results suggest that the introduction of an optimal Alkylamino Group into the BIP scaffold may lead to the development of more potential tau imaging probes
Damian J. Krysan - One of the best experts on this subject based on the ideXlab platform.
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Structure-Activity Relationships for the Antifungal Activity of Selective Estrogen Receptor Antagonists Related to Tamoxifen
PloS one, 2015Co-Authors: Arielle Butts, Jennifer A. Martin, Louis Didone, Erin K. Bradley, Mitchell Mutz, Damian J. KrysanAbstract:Cryptococcosis is one of the most important invasive fungal infections and is a significant contributor to the mortality associated with HIV/AIDS. As part of our program to repurpose molecules related to the selective estrogen receptor modulator (SERM) tamoxifen as anti-cryptococcal agents, we have explored the structure-activity relationships of a set of structurally diverse SERMs and tamoxifen derivatives. Our data provide the first insights into the structural requirements for the antifungal activity of this scaffold. Three key molecular characteristics affecting anti-cryptococcal activity emerged from our studies: 1) the presence of an Alkylamino Group tethered to one of the aromatic rings of the triphenylethylene core; 2) an appropriately sized aliphatic substituent at the 2 position of the ethylene moiety; and 3) electronegative substituents on the aromatic rings modestly improved activity. Using a cell-based assay of calmodulin antagonism, we found that the anti-cryptococcal activity of the scaffold correlates with calmodulin inhibition. Finally, we developed a homology model of C. neoformans calmodulin and used it to rationalize the structural basis for the activity of these molecules. Taken together, these data and models provide a basis for the further optimization of this promising anti-cryptococcal scaffold.
Tsuyoshi Murata - One of the best experts on this subject based on the ideXlab platform.
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Intermolecular Hydrogen-Bond Networks and Physical Properties of BF4– and TCNQ•– Salts of Three-Fold Symmetric Tris(Alkylamino)phenalenyliums
2012Co-Authors: Tsuyoshi Murata, Eigo Miyazaki, Takuji Yokoyama, Kazuhiro Nakasuji, Yasushi MoritaAbstract:Synthesis, redox properties, and crystal structures of tris(Alkylamino)phenalenyliums (TAP) having alkyl Groups (n-Pr, i-Pr, t-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ•–) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an Alkylamino Group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino Groups and the extension of the π-electronic system. In the crystal structures of the BF4– salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP formed π-dimer or columnar structures, which were connected through intermolecular N–H···F hydrogen bonds with BF4– to construct multidimensional network structures. The TCNQ•– salts prepared by the metathesis method were characterized as fully ionic salts with a 1:1 component ratio. In the crystal structures, both TAP and TCNQ•– molecules formed π-dimers, and the intermolecular hydrogen bonds between TAP and TCNQ•– constructed a two-dimensional sheet
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Intermolecular Hydrogen-Bond Networks and Physical Properties of BF4– and TCNQ•– Salts of Three-Fold Symmetric Tris(Alkylamino)phenalenyliums
Crystal Growth & Design, 2011Co-Authors: Tsuyoshi Murata, Eigo Miyazaki, Takuji Yokoyama, Kazuhiro Nakasuji, Yasushi MoritaAbstract:Synthesis, redox properties, and crystal structures of tris(Alkylamino)phenalenyliums (TAP) having alkyl Groups (n-Pr, i-Pr, t-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ•–) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an Alkylamino Group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino Groups and the extension of the π-electronic system. In the crystal structures of the BF4– salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP formed π-dimer or columnar structures, which were connected through intermolecular N–H···F hydrogen bonds with BF4– to construct multidimensional network structures. The TCNQ•– salts prepared...
Arielle Butts - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Structure-Activity Relationships for the Antifungal Activity of Selective Estrogen Receptor Antagonists Related to Tamoxifen
2016Co-Authors: Arielle Butts, Jennifer A. Martin, Louis Didone, Erin K. Bradley, Mitchell Mutz, J. KrysanAbstract:Cryptococcosis is one of the most important invasive fungal infections and is a significant contributor to the mortality associated with HIV/AIDS. As part of our program to repurpose molecules related to the selective estrogen receptor modulator (SERM) tamoxifen as anti-cryptococcal agents, we have explored the structure-activity relationships of a set of struc-turally diverse SERMs and tamoxifen derivatives. Our data provide the first insights into the structural requirements for the antifungal activity of this scaffold. Three key molecular char-acteristics affecting anti-cryptococcal activity emerged from our studies: 1) the presence of an Alkylamino Group tethered to one of the aromatic rings of the triphenylethylene core; 2) an appropriately sized aliphatic substituent at the 2 position of the ethylene moiety; and 3) electronegative substituents on the aromatic rings modestly improved activity. Using a cell-based assay of calmodulin antagonism, we found that the anti-cryptococcal activity of the scaffold correlates with calmodulin inhibition. Finally, we developed a homology model of C. neoformans calmodulin and used it to rationalize the structural basis for the activity of these molecules. Taken together, these data and models provide a basis for the further optimiza-tion of this promising anti-cryptococcal scaffold
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Structure-Activity Relationships for the Antifungal Activity of Selective Estrogen Receptor Antagonists Related to Tamoxifen
PloS one, 2015Co-Authors: Arielle Butts, Jennifer A. Martin, Louis Didone, Erin K. Bradley, Mitchell Mutz, Damian J. KrysanAbstract:Cryptococcosis is one of the most important invasive fungal infections and is a significant contributor to the mortality associated with HIV/AIDS. As part of our program to repurpose molecules related to the selective estrogen receptor modulator (SERM) tamoxifen as anti-cryptococcal agents, we have explored the structure-activity relationships of a set of structurally diverse SERMs and tamoxifen derivatives. Our data provide the first insights into the structural requirements for the antifungal activity of this scaffold. Three key molecular characteristics affecting anti-cryptococcal activity emerged from our studies: 1) the presence of an Alkylamino Group tethered to one of the aromatic rings of the triphenylethylene core; 2) an appropriately sized aliphatic substituent at the 2 position of the ethylene moiety; and 3) electronegative substituents on the aromatic rings modestly improved activity. Using a cell-based assay of calmodulin antagonism, we found that the anti-cryptococcal activity of the scaffold correlates with calmodulin inhibition. Finally, we developed a homology model of C. neoformans calmodulin and used it to rationalize the structural basis for the activity of these molecules. Taken together, these data and models provide a basis for the further optimization of this promising anti-cryptococcal scaffold.
