The Experts below are selected from a list of 1443 Experts worldwide ranked by ideXlab platform
Victor N Odinokov - One of the best experts on this subject based on the ideXlab platform.
-
7α alkylation and 7 7 bis alkylation of 20 hydroxyecdysone with propargyl bromide in a lithium ammonia solution and catalytic reductive Spirocyclization of 7 7 bis 2 propyn 1 yl 14 deoxy δ8 14 20 hydroxyecdysone
Steroids, 2016Co-Authors: I V Galyautdinov, Zarema R Khairullina, Valery P Sametov, Z S Muslimov, L M Khalilov, Victor N OdinokovAbstract:Abstract 7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution resulted in the formation of 7α-(2-propyn-1-yl)- and 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ 8(14) -20-hydroxyecdysone in 92% and 75% yield respectively. Upon catalytic hydrogenation (10% Pd–C) of 7,7-bis(2-propyn-1-yl) derivative Spirocyclization occurs by geminal 2-propyn-1-yl groups.
-
7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution and catalytic reductive Spirocyclization of 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ8(14)-20-hydroxyecdysone
Steroids, 2016Co-Authors: I V Galyautdinov, Zarema R Khairullina, Valery P Sametov, Z S Muslimov, L M Khalilov, Victor N OdinokovAbstract:Abstract 7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution resulted in the formation of 7α-(2-propyn-1-yl)- and 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ 8(14) -20-hydroxyecdysone in 92% and 75% yield respectively. Upon catalytic hydrogenation (10% Pd–C) of 7,7-bis(2-propyn-1-yl) derivative Spirocyclization occurs by geminal 2-propyn-1-yl groups.
Yasuteru Urano - One of the best experts on this subject based on the ideXlab platform.
-
novel intramolecular Spirocyclization based fluorogenic probes from rapid intraoperative imaging of tiny tumors to super resolution imaging
Optical Molecular Probes Imaging and Drug Delivery, 2015Co-Authors: Yasuteru Urano, Mako Kamiya, Masayo SakabeAbstract:We have established versatile and flexible design strategies for novel organic fluorogenic probes based on intramolecular Spirocyclization. First-in-class probes for rapid detection of in vivo tiny tumors and for super-resolution imaging were successfully developed.
-
a spontaneously blinking fluorophore based on intramolecular Spirocyclization for live cell super resolution imaging
Nature Chemistry, 2014Co-Authors: Mako Kamiya, Toshitada Yoshihara, Ko Sugawara, Kohki Okabe, Mehmet C Tarhan, Hiroyuki Fujita, Takashi Funatsu, Yasushi Okada, Seiji Tobita, Yasuteru UranoAbstract:A self-blinking fluorophore suitable for super-resolution imaging has been developed. The blinking arises from a reversible intramolecular Spirocyclization in a rhodamine-based fluorophore that switches between a fluorescent open form and a non-fluorescent closed form. The advantages over existing methodologies are demonstrated using single-molecule localization microscopy imaging inside cells.
-
A spontaneously blinking fluorophore based on intramolecular Spirocyclization for live-cell super-resolution imaging
Nature Chemistry, 2014Co-Authors: Mako Kamiya, Toshitada Yoshihara, Ko Sugawara, Kohki Okabe, Mehmet C Tarhan, Hiroyuki Fujita, Takashi Funatsu, Yasushi Okada, Seiji Tobita, Yasuteru UranoAbstract:Single-molecule localization microscopy is used to construct super-resolution images, but generally requires prior intense laser irradiation and in some cases additives, such as thiols, to induce on–off switching of fluorophores. These requirements limit the potential applications of this methodology. Here, we report a first-in-class spontaneously blinking fluorophore based on an intramolecular Spirocyclization reaction. Optimization of the intramolecular nucleophile and rhodamine-based fluorophore (electrophile) provide a suitable lifetime for the fluorescent open form, and equilibrium between the open form and the non-fluorescent closed form. We show that this spontaneously blinking fluorophore is suitable for single-molecule localization microscopy imaging deep inside cells and for tracking the motion of structures in living cells. We further demonstrate the advantages of this fluorophore over existing methodologies by applying it to nuclear pore structures located far above the coverslip with a spinning-disk confocal microscope and for repetitive time-lapse super-resolution imaging of microtubules in live cells for up to 1 h. A self-blinking fluorophore suitable for super-resolution imaging has been developed. The blinking arises from a reversible intramolecular Spirocyclization in a rhodamine-based fluorophore that switches between a fluorescent open form and a non-fluorescent closed form. The advantages over existing methodologies are demonstrated using single-molecule localization microscopy imaging inside cells.
-
Development of a highly specific rhodamine-based fluorescence probe for hypochlorous acid and its application to real-time imaging of phagocytosis
Journal of the American Chemical Society, 2007Co-Authors: Suguru Kenmoku, Hirotatsu Kojima, Yasuteru Urano, Tetsuo NaganoAbstract:The tetramethylrhodamine (TMR) fluorophore is a useful platform for fluorescence probes, being applicable, for example, to biological investigations utilizing fluorescence microscopy, owing to its excellent photochemical properties in aqueous media. We have developed new TMR derivatives that show different dependences of their behavior upon the environment. Among them, HMTMR showed unique characteristics, and its putative spirocyclic structure was confirmed by X-ray crystallography. Utilizing this discovery, we have established a strategy to modulate the fluorescence of TMR by regulating the Spirocyclization, and we have obtained a new fluorescence probe that can detect hypochlorous acid specifically. This probe, HySOx, can work in 99.9% aqueous solution at pH 7.4 and was confirmed to be able to detect hypochlorous acid being generated inside phagosomes in real time. HySOx is tolerant to autoxidation and photobleaching under bioimaging conditions. Regulation of the Spirocyclization of rhodamines, as we describe here, provides a new approach to the rational development of novel fluorescence probes.
Hongbin Zhai - One of the best experts on this subject based on the ideXlab platform.
-
a 2 1 methylhydrazinyl pyridine directed c h functionalization Spirocyclization cascade facile access to spirosuccinimide derivatives
Chemical Communications, 2018Co-Authors: Hua Zhao, Xiaoru Shao, Taimin Wang, Shengxian Zhai, Huifei Wang, Hongbin ZhaiAbstract:A cobalt-catalyzed oxidative coupling of benzoic hydrazides with maleimides by utilizing 2-(1-methylhydrazinyl)pyridine as a bidentate directing group has been developed. This C–H functionalization/Spirocyclization cascade protocol shows high efficiency and remarkable functional group tolerance, and the ubiquitous spirosuccinimides were obtained in good to excellent yields with high regioselectivity. This strategy also provides a novel and efficient access to diverse symmetric and unsymmetrical bisspirosuccinimides.
-
A 2-(1-methylhydrazinyl)pyridine-directed C–H functionalization/Spirocyclization cascade: facile access to spirosuccinimide derivatives
Chemical Communications, 2018Co-Authors: Hua Zhao, Xiaoru Shao, Taimin Wang, Shengxian Zhai, Huifei Wang, Hongbin ZhaiAbstract:A cobalt-catalyzed oxidative coupling of benzoic hydrazides with maleimides by utilizing 2-(1-methylhydrazinyl)pyridine as a bidentate directing group has been developed. This C–H functionalization/Spirocyclization cascade protocol shows high efficiency and remarkable functional group tolerance, and the ubiquitous spirosuccinimides were obtained in good to excellent yields with high regioselectivity. This strategy also provides a novel and efficient access to diverse symmetric and unsymmetrical bisspirosuccinimides.
Yasumasa Hamada - One of the best experts on this subject based on the ideXlab platform.
-
formal meta specific intramolecular friedel crafts allylic alkylation of phenols through a Spirocyclization dienone phenol rearrangement cascade
Tetrahedron, 2013Co-Authors: Mariko Yoshida, Tomoyuki Nozaki, Tetsuhiro Nemoto, Yasumasa HamadaAbstract:Abstract Formal meta-specific intramolecular Friedel–Crafts allylic alkylation of phenols was achieved based on Spirocyclization–dienone–phenol rearrangement cascades. Systematic screening of acid catalysts revealed that Sc(OTf)3 was a highly effective catalyst for dienone–phenol rearrangement of spiro[4.5]cyclohexadienones. Using 5 mol % of Sc(OTf)3 as the promoter, various spirocyclic substrates were transformed into the corresponding phenol derivatives in good to excellent yield. Furthermore, the one-pot sequential Spirocyclization–dienone–phenol rearrangement proceeded using a palladium and scandium multi-catalytic system or a triphenylmethyl cation single-catalyst system, providing the corresponding meta-allylated phenol derivatives in excellent yield.
-
Formal meta-specific intramolecular Friedel–Crafts allylic alkylation of phenols through a Spirocyclization–dienone–phenol rearrangement cascade
Tetrahedron, 2013Co-Authors: Mariko Yoshida, Tomoyuki Nozaki, Tetsuhiro Nemoto, Yasumasa HamadaAbstract:Abstract Formal meta-specific intramolecular Friedel–Crafts allylic alkylation of phenols was achieved based on Spirocyclization–dienone–phenol rearrangement cascades. Systematic screening of acid catalysts revealed that Sc(OTf)3 was a highly effective catalyst for dienone–phenol rearrangement of spiro[4.5]cyclohexadienones. Using 5 mol % of Sc(OTf)3 as the promoter, various spirocyclic substrates were transformed into the corresponding phenol derivatives in good to excellent yield. Furthermore, the one-pot sequential Spirocyclization–dienone–phenol rearrangement proceeded using a palladium and scandium multi-catalytic system or a triphenylmethyl cation single-catalyst system, providing the corresponding meta-allylated phenol derivatives in excellent yield.
I V Galyautdinov - One of the best experts on this subject based on the ideXlab platform.
-
7α alkylation and 7 7 bis alkylation of 20 hydroxyecdysone with propargyl bromide in a lithium ammonia solution and catalytic reductive Spirocyclization of 7 7 bis 2 propyn 1 yl 14 deoxy δ8 14 20 hydroxyecdysone
Steroids, 2016Co-Authors: I V Galyautdinov, Zarema R Khairullina, Valery P Sametov, Z S Muslimov, L M Khalilov, Victor N OdinokovAbstract:Abstract 7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution resulted in the formation of 7α-(2-propyn-1-yl)- and 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ 8(14) -20-hydroxyecdysone in 92% and 75% yield respectively. Upon catalytic hydrogenation (10% Pd–C) of 7,7-bis(2-propyn-1-yl) derivative Spirocyclization occurs by geminal 2-propyn-1-yl groups.
-
7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution and catalytic reductive Spirocyclization of 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ8(14)-20-hydroxyecdysone
Steroids, 2016Co-Authors: I V Galyautdinov, Zarema R Khairullina, Valery P Sametov, Z S Muslimov, L M Khalilov, Victor N OdinokovAbstract:Abstract 7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution resulted in the formation of 7α-(2-propyn-1-yl)- and 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ 8(14) -20-hydroxyecdysone in 92% and 75% yield respectively. Upon catalytic hydrogenation (10% Pd–C) of 7,7-bis(2-propyn-1-yl) derivative Spirocyclization occurs by geminal 2-propyn-1-yl groups.
