Aliphatic C-H groups are among the most abundant yet least reactive functional groups in organic molecules.Nature has evolved metalloenzymes such as those of the cytochrome P450 superfamily that efficiently activate i...Aliphatic C-H groups are among the most abundant yet least reactive functional groups in organic molecules.Nature has evolved metalloenzymes such as those of the cytochrome P450 superfamily that efficiently activate individual tertiary(3)and secondary(2)C(sp^(3))-H bonds in complex molecules with the highest level of regio-and stereoselectivity[1];thus encouraging studies aimed at engineering artificial metalloenzymes for synthetic applications[2].展开更多
Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors...Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors of type III secretion system in Chlamydia trachomatis.展开更多
Homogeneous and heterogeneous types of catalysis are frequently considered as separate disciplines or even opposed to each other.In the present work,a new type of mixed het-ero-/homogeneous catalysis was demonstrated ...Homogeneous and heterogeneous types of catalysis are frequently considered as separate disciplines or even opposed to each other.In the present work,a new type of mixed het-ero-/homogeneous catalysis was demonstrated for the case of selective alkylarene oxidation by molecular oxygen.The proposed catalytic system consists of two widely available components:N-hydroxyphthalimide(NHPI,a homogeneous organocatalyst for free-radical chain reactions)and nanosized TiO_(2)(heterogeneous UV-active photoredox catalyst).The interaction of NHPI with TiO_(2) allows for a shift from UV to visible light photoredox activity and generation of phthalimide-N-oxyl(PINO)radicals that diffuse into the solution where NHPI/PINO-catalyzed free-radical chain reaction can proceed without the additional light input providing a fundamental increase in energy efficiency.The NHPI/TiO_(2) ratio controls the selectivity of oxidation affording preferential formation of hydroperoxide or ketone from alkylarene.展开更多
Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of matu...Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of maturation. Tissues from Cnidaria are suitable examples for exploration of the effects in relation to the presence and the absence of sulfate groups, when studying characteristic fragments of the long proteoglycan carbohydrate chains in silico. It has been described that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra. On the other hand, sulfated glucosaminoglycans play an important role in various developmental processes of Cnidaria. In order to understand this biological phenomenon on a sub-molecular level we have analysed the structures of sulfated and non-sulfated proteoglycan carbohydrate chains as well as the structure of diverse collagen molecules with computational methods including quantum chemical calculations. The strong interactions between the sulfate groups of the carbohydrates moieties in proteoglycans and positively charged regions of collagen are essential in stabilizing various Cnidaria tissues but could hinder the nematocyst formation and its proper function. The results of our quantum chemical calculations show that the sulfation pattern has a significant effect on the conformation of chondroitin structures under study.展开更多
Phosphorus-containing organic compounds are important feedstock for the synthesis of value-added bioactive molecules.Therefore,the development of highly efficient synthetic methods for the construction of phosphorus-e...Phosphorus-containing organic compounds are important feedstock for the synthesis of value-added bioactive molecules.Therefore,the development of highly efficient synthetic methods for the construction of phosphorus-element bonds has drawn huge attention in the past decades[1].Particularly,the formation of P–C bonds from phosphoruscentered radicals has been demonstrated to be one of the most efficient and convenient strategies,which has been widely applied for the synthesis of organic phosphorus compounds in recent years.展开更多
We report the divergent synthesis of benzannulated 2,8-dioxabicyclo[3.2.1]octanes and 2,3-dihydrobenzofurans using the concept of extended Corey-Chaykovsky reactions.With this concept,2-hydroxychalcones were treated w...We report the divergent synthesis of benzannulated 2,8-dioxabicyclo[3.2.1]octanes and 2,3-dihydrobenzofurans using the concept of extended Corey-Chaykovsky reactions.With this concept,2-hydroxychalcones were treated with the Corey ylide providing highly reactive donor-acceptor cyclopropanes that were introduced in a one pot manner for further transformations.展开更多
文摘Aliphatic C-H groups are among the most abundant yet least reactive functional groups in organic molecules.Nature has evolved metalloenzymes such as those of the cytochrome P450 superfamily that efficiently activate individual tertiary(3)and secondary(2)C(sp^(3))-H bonds in complex molecules with the highest level of regio-and stereoselectivity[1];thus encouraging studies aimed at engineering artificial metalloenzymes for synthetic applications[2].
文摘Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors of type III secretion system in Chlamydia trachomatis.
文摘Homogeneous and heterogeneous types of catalysis are frequently considered as separate disciplines or even opposed to each other.In the present work,a new type of mixed het-ero-/homogeneous catalysis was demonstrated for the case of selective alkylarene oxidation by molecular oxygen.The proposed catalytic system consists of two widely available components:N-hydroxyphthalimide(NHPI,a homogeneous organocatalyst for free-radical chain reactions)and nanosized TiO_(2)(heterogeneous UV-active photoredox catalyst).The interaction of NHPI with TiO_(2) allows for a shift from UV to visible light photoredox activity and generation of phthalimide-N-oxyl(PINO)radicals that diffuse into the solution where NHPI/PINO-catalyzed free-radical chain reaction can proceed without the additional light input providing a fundamental increase in energy efficiency.The NHPI/TiO_(2) ratio controls the selectivity of oxidation affording preferential formation of hydroperoxide or ketone from alkylarene.
基金Elements of the project are financed by the European Commission’s Framework Program 7(BIO-NMR-00007)-Bio-NMR grant:Jellyfish protein NMR(BIO-NMR-00007)-IEP.
文摘Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of maturation. Tissues from Cnidaria are suitable examples for exploration of the effects in relation to the presence and the absence of sulfate groups, when studying characteristic fragments of the long proteoglycan carbohydrate chains in silico. It has been described that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra. On the other hand, sulfated glucosaminoglycans play an important role in various developmental processes of Cnidaria. In order to understand this biological phenomenon on a sub-molecular level we have analysed the structures of sulfated and non-sulfated proteoglycan carbohydrate chains as well as the structure of diverse collagen molecules with computational methods including quantum chemical calculations. The strong interactions between the sulfate groups of the carbohydrates moieties in proteoglycans and positively charged regions of collagen are essential in stabilizing various Cnidaria tissues but could hinder the nematocyst formation and its proper function. The results of our quantum chemical calculations show that the sulfation pattern has a significant effect on the conformation of chondroitin structures under study.
文摘Phosphorus-containing organic compounds are important feedstock for the synthesis of value-added bioactive molecules.Therefore,the development of highly efficient synthetic methods for the construction of phosphorus-element bonds has drawn huge attention in the past decades[1].Particularly,the formation of P–C bonds from phosphoruscentered radicals has been demonstrated to be one of the most efficient and convenient strategies,which has been widely applied for the synthesis of organic phosphorus compounds in recent years.
基金We thank the Russian Science Foundation(Grant 21-73-20095)for support of this work.
文摘We report the divergent synthesis of benzannulated 2,8-dioxabicyclo[3.2.1]octanes and 2,3-dihydrobenzofurans using the concept of extended Corey-Chaykovsky reactions.With this concept,2-hydroxychalcones were treated with the Corey ylide providing highly reactive donor-acceptor cyclopropanes that were introduced in a one pot manner for further transformations.
基金国家海洋公益性行业科研专项(201005024)国家自然科学基金中俄(NSFC-RFBR)国际合作交流项目(81311120092)the Russian Foundation for Basic Research(grant 13-03-91170 within the bilateral grant program between RFBR and NSFC)资助
