A[3+2]/[2+1]cycloaddition reaction of gem–difluorocyclopropenes is presented,offering a mild and efficient approach to accessing tri-and tetra-substituted 4-fluoropyridines in moderate to good yields with excellent r...A[3+2]/[2+1]cycloaddition reaction of gem–difluorocyclopropenes is presented,offering a mild and efficient approach to accessing tri-and tetra-substituted 4-fluoropyridines in moderate to good yields with excellent regioselectivity.Multiple synthetic applications,including process-scale reactions,modification of bioactive molecules,derivatization reactions and synthesis of the analogue of the PKM2 modulator,are subsequently described.展开更多
A highly stereoselective asymmetric cascade cyclization reaction between o-hydroxycinnamaldehydes and diphenylphosphine oxide has been achieved with 84%-99% ee and 7：1-20：1 dr under the catalysis of L-diarylprolinol...A highly stereoselective asymmetric cascade cyclization reaction between o-hydroxycinnamaldehydes and diphenylphosphine oxide has been achieved with 84%-99% ee and 7：1-20：1 dr under the catalysis of L-diarylprolinol silyl ether. This reaction provides a facile access to highly enantioenriched 4- diphenylphosphinyl chroman-2-ols. It also represents a novel organocatalytic asymmetric phospha- Michael addition of α,β-unsaturated aldehydes with pentavalent P-nucleophiles.展开更多
The cyclization reaction of 2-ethynyl-N-sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K2CO3 under transition metal-free condition to give indoles in high yields.The recover...The cyclization reaction of 2-ethynyl-N-sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K2CO3 under transition metal-free condition to give indoles in high yields.The recovery and reusability of the present catalytic system were investigated.展开更多
The cyclization reaction of D-aspartic acid was studied, the carboxyl groups of D-aspartic acid were protected by benzyl alcohol to give compound D-dibenzyl aspartate. Then （4R）-benzyl azetidine-2-one-4-carboxylate ...The cyclization reaction of D-aspartic acid was studied, the carboxyl groups of D-aspartic acid were protected by benzyl alcohol to give compound D-dibenzyl aspartate. Then （4R）-benzyl azetidine-2-one-4-carboxylate and meso-3,6-disubstituted piperazine-2,5-diones were synthesized via intramolecular cyclization and intermolecular cycfization of D-dibenzyl aspartate, respectively, and their structures were confirmed by ^1 H NMR and MS. Both cyclization reaction conditions were also investigated in detail.展开更多
Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractiona...Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of H-1 NMR, P-31 NMR and x-ray diffraction analysis.展开更多
The cyclizaion reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups, has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-member...The cyclizaion reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups, has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-membered phosphorus heterocycles.The heterocyclizaional possibility of LR with bifunctional compounds was also discussed.展开更多
With high efficiency,mild conditions,and rapid reaction rate,click reactions have garnered much attention in the field of bioimaging since proposed by Sharpless et al.in 2001(Angew.Chem.,Int.Ed.2001,40,2004-2021).Insp...With high efficiency,mild conditions,and rapid reaction rate,click reactions have garnered much attention in the field of bioimaging since proposed by Sharpless et al.in 2001(Angew.Chem.,Int.Ed.2001,40,2004-2021).Inspired by the regenerative pathway of D-luciferin in fireflies,Liang et al.(Nat.Chem.2010,2,54-60)raised a 2-cyanobenzothiazole(CBT)-cysteine(Cys)click condensation reaction in 2010,which exhibits a higher secondorder reaction rate(9.19 M^(-1)s^(-1))and superior biocompatibility.As it has been developed in the past decade,remarkable progress has been made in the construction of enzyme-instructed CBT-Cys-based bioimaging probes.This review introduces the concept of the CBT-Cys click reaction,elucidates the mechanism of the CBT-Cys click reaction,and concerns the development progress of CBT-Cys reaction and its derived reactions[i.e.,2-cyano-6-hydroxyquinoline(CHQ)-Cys reaction and 2-pyrimidinecarbonitrile(PMN)-Cys reaction].Furthermore,we give a comprehensive and up-to-date review of enzyme-instructed CBT-Cyslike click reaction-based probes with significantly enhanced imaging signal and contrast for various bioimaging modes,including fluorescence imaging,photoacoustic imaging,magnetic resonance imaging,and positron emission tomography.In the end,we discuss the possible challenges and opportunities that may arise in the future.展开更多
Due to the significance of corresponding products,enantioselective borylative cyclization reactions have been studied intensively in recent years.Many groups have developed efficient methods to transform unsaturated s...Due to the significance of corresponding products,enantioselective borylative cyclization reactions have been studied intensively in recent years.Many groups have developed efficient methods to transform unsaturated system into asymmetric cyclic organoboron compounds with the ring-size range from three-membered to six-membered in general.Notably,in some cases,fused rings which contain more than two contiguous chiral centers could be obtained by this kind of strategies.This review summarized and reviewed the recent advances in this field and classified these work according to the species of metal catalysts.展开更多
An efficient method has been developed for the cascade synthesis of azo[1,2-a]indolones from azoles and2-fluoroaldehydes based on an iron-catalyzed SNAr and a direct acylation reaction.A number of azo[1,2-a]indolones ...An efficient method has been developed for the cascade synthesis of azo[1,2-a]indolones from azoles and2-fluoroaldehydes based on an iron-catalyzed SNAr and a direct acylation reaction.A number of azo[1,2-a]indolones containing different azole rings and substituents were obtained in good yields.展开更多
NTrifluoromethyl and cyclopropyl substituted 2-isoxazolines were synthesized via a DBU-promoted domino reaction of β-trifluoromethyl-/β-cyclopropyl-substituted enones with hydroxylamine. The domino reaction consists...NTrifluoromethyl and cyclopropyl substituted 2-isoxazolines were synthesized via a DBU-promoted domino reaction of β-trifluoromethyl-/β-cyclopropyl-substituted enones with hydroxylamine. The domino reaction consists of a Michael addition and the followed cyclization. A wide range of 3-substituted 5-cyclopropyl-5-trifluoromethyl-2-isoxazolines were obtained in good to excellent yields under mild reaction conditions. The method could also apply to other trifluoromethyl-substituted enones.展开更多
An efficient and straightforward synthetic method has been developed for the preparation of 4-cyanofuran-3-carboxylate derivatives via iodine/potassium carbonate-promoted ring-opening/cyclization/rearrangement domino ...An efficient and straightforward synthetic method has been developed for the preparation of 4-cyanofuran-3-carboxylate derivatives via iodine/potassium carbonate-promoted ring-opening/cyclization/rearrangement domino reaction of 1-cyanocyclopropane-1-carboxylates,which are a wide range of structurally interesting and pharmacologically significant compounds.展开更多
A series of quinolino[3,4-b]quinoxalin-6（5H）-ones have been synthesized using an Ugi/deprotection/cyclization（UDC） strategy, followed by a nucleophilic aromatic substitution reaction. This facile microwave-assiste...A series of quinolino[3,4-b]quinoxalin-6（5H）-ones have been synthesized using an Ugi/deprotection/cyclization（UDC） strategy, followed by a nucleophilic aromatic substitution reaction. This facile microwave-assisted method provided good yields and could potentially be used for the construction of a diverse library of quinolino[3,4-b]quinoxalin-6（5H）-ones for high-throughput screening in medicinal chemistry.展开更多
A fast and efficient method is described for the one-pot synthesis of 2,4（1H,3H）-quinazolinediones by cyclization reaction of anthranilic acid derivatives with potassium cyanate and acetic acid in PEG.Good to high y...A fast and efficient method is described for the one-pot synthesis of 2,4（1H,3H）-quinazolinediones by cyclization reaction of anthranilic acid derivatives with potassium cyanate and acetic acid in PEG.Good to high yields of the products obtain in short reaction times with simple work-up.展开更多
The YCl3-catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are im...The YCl3-catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are important units in many biologically active compounds.展开更多
Fluoroalkyl-containing organic compounds have exhibited wide applications in the field of pharmaceuticals,agrochemicals and materials science due to their outstanding properties such as biological activity,metabolic s...Fluoroalkyl-containing organic compounds have exhibited wide applications in the field of pharmaceuticals,agrochemicals and materials science due to their outstanding properties such as biological activity,metabolic stability,lipophilicity,excellent chemical and thermal stability.Therefore,various synthetic strategies have been developed for the construction of fluoroalkyl-containing compounds,using highly active fluorinating reagents and fluorinated building blocks.Recently,the use of easily available and inexpensive trifluoroacetic anhydride(TFAA)and its anhydride analogues has attracted great attention to access numerous fluoroalkyl-containing compounds through cyclization and coupling reactions.In this review,we summarized the recent advances in the synthesis of fluoroalkylated compounds using fluoroalkyl anhydrides as reagents.This review aims to provide a reference for researchers on how to develop new synthetic straregies of fluorine-containing organic compounds and achieve kilograms or even tons preparation of fluorine-containing organic compounds using fluoroalkyl anhydrides.展开更多
Suzuki coupling reactions between symmetrical monomers were conducted in various mesoporous silica nanoreactors grafted with palladium catalysts,enabling the selective formation of[12]cycloparaphenylene precursor with...Suzuki coupling reactions between symmetrical monomers were conducted in various mesoporous silica nanoreactors grafted with palladium catalysts,enabling the selective formation of[12]cycloparaphenylene precursor with separate yield up to 25%in one-pot reactions,much higher than that in homogeneous reaction.The spatial nanoconfinement of the nanoreactors promotes the macrocyclization while limits the concomitant linear oligomer formation,offering more possibilities for the synthesis of macrocycles from symmetrical monomers in one-pot reaction.展开更多
The crystals of the title compound C_(15)H_(17)N_2O_2PS were obtained by re crystallizing from ether-methanol solution. It belongs to the orthorhombic system, space group Pbca with a= 9. 255(1) , b= 17.189(8) , c =20....The crystals of the title compound C_(15)H_(17)N_2O_2PS were obtained by re crystallizing from ether-methanol solution. It belongs to the orthorhombic system, space group Pbca with a= 9. 255(1) , b= 17.189(8) , c =20. 446(4)A, V=3252.6 (7) A￣3, D_c=1. 31 g/cm￣3,Z= 8, μ(CuKa)=26. 87 cm-1, F(000)=1344. The structure was refined to R=0. 053, R_w=0. 055 for 1299 observed reflections (I≥3σ(I)). In the molecule P atom adopts distorted tetrahedral configuration.The bond (II)distances of P-O, P-N and P-C are 1.605(1) A, 1. 657(1) A 1. 801(1)A,(III)respectively. The X-ray crystallographic analysis demonstrates that there are intramolecular and intermolecular hydrogen bonds in the structure.展开更多
The crystal of title compound C18H16N2O was obtained by recrystal-lizing from ethanol solution. It belongs to orthorhombic system, space group Pbca witha=23. 229(2), b=11. 880(3), c=10. 733(3) A, V=2961 (0) A3, Mr=276...The crystal of title compound C18H16N2O was obtained by recrystal-lizing from ethanol solution. It belongs to orthorhombic system, space group Pbca witha=23. 229(2), b=11. 880(3), c=10. 733(3) A, V=2961 (0) A3, Mr=276. 34, Dc=1. 239 g/cm3, Z=8, A(MoKa)=0. 78 cm-1, F(000) =1168. 00. The structurewas refined to R=0. 049 and Rw=0. 046 for 1102 observed reflections (I＞2d(I) ).The bond lengths of C(3) -C(4) and C(3) -N(1) are 1. 349(5) A and 1. 340(6) A,respectively. The bond angles of N (1) -C(3) -C(2), AN (1) -C(3) -C(4), AC(2) -C(3) -C(4) and C(3) -C(4) -C(5) are 121. 1 (4), 128. 4(4), 110. 5(4)and 113. 1 (4), respectively. The dihedral angle between two phenyl rings is 29. 29.展开更多
The crystals of the title compound C19H16N2O3 were synthesized by thereaction of 4, 4-dicyano-1-phenyl-3-(3', 4'-methylenedioxyphenyl)-l-butan withlow-valent titanium reagent. It belongs to the orthorhombic sy...The crystals of the title compound C19H16N2O3 were synthesized by thereaction of 4, 4-dicyano-1-phenyl-3-(3', 4'-methylenedioxyphenyl)-l-butan withlow-valent titanium reagent. It belongs to the orthorhombic system, space group Pea21with a=11. 547(2), b=13. 168(4), c=10. 645(3) A, V=1618. 4(8) A3, Dc=1.315 g/cm3, Z=4, Mr=320.35. A=0. 71069 A, u(MoKa) =0. 90 cm-1, F(000)=672. The structure was refined to R=0. 036, Rw=0. 044 for 962 observed reflections(I＞3(I) ). X-ray analysis reveals that in the five membered ring the C(11) -C(12)bond is longer than normal double C=C bond while the C(11) -N (1) bond is shorterthan normal C(sp)2-N bond.展开更多
Visible-light photoredox catalysis is a powerful and attractive strategy for organic molecule activation and new reaction design owing to its environmental-friendly characteristics and unique catalytic mechanisms,and ...Visible-light photoredox catalysis is a powerful and attractive strategy for organic molecule activation and new reaction design owing to its environmental-friendly characteristics and unique catalytic mechanisms,and has found wide applications in organic synthesis.This catalytic strategy enables controllable generation of diverse nitrogen-centered radicals(NCRs)under mild conditions,providing access to construction of diverse nitrogencontaining compounds.In this review,we critically illustrate the recent advances in the field of visible-light photoredox-catalyzed cyclization of nitrogen-centered radicals,based on the different radical precursors and activation modes.Wherever possible,particular emphasis is also put on working models and synthetic applications.展开更多
基金the National Natural Science Foundation of China(Nos.21861007,21702034)Natural Science Foundation of Guangxi Province(No.2021GXNSFAA075024)+2 种基金“BAGUI Scholar”Program of Guangxi Province of ChinaHigh-Level Innovation Team and Distinguished Scholar Program in Guangxi Colleges and Universitiesthe Jiangxi Province Science and Technology Project(No.20212BAB213024)。
文摘A[3+2]/[2+1]cycloaddition reaction of gem–difluorocyclopropenes is presented,offering a mild and efficient approach to accessing tri-and tetra-substituted 4-fluoropyridines in moderate to good yields with excellent regioselectivity.Multiple synthetic applications,including process-scale reactions,modification of bioactive molecules,derivatization reactions and synthesis of the analogue of the PKM2 modulator,are subsequently described.
基金Financial support from the National Natural Science Foundation of China(Nos. 21472096, J1103306)
文摘A highly stereoselective asymmetric cascade cyclization reaction between o-hydroxycinnamaldehydes and diphenylphosphine oxide has been achieved with 84%-99% ee and 7：1-20：1 dr under the catalysis of L-diarylprolinol silyl ether. This reaction provides a facile access to highly enantioenriched 4- diphenylphosphinyl chroman-2-ols. It also represents a novel organocatalytic asymmetric phospha- Michael addition of α,β-unsaturated aldehydes with pentavalent P-nucleophiles.
基金supported by the National Natural Science Foundation of China (No. 21402137)Xinmiao Talents Program of Zhejiang Province (No. 2016R430021)
文摘The cyclization reaction of 2-ethynyl-N-sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K2CO3 under transition metal-free condition to give indoles in high yields.The recovery and reusability of the present catalytic system were investigated.
基金This work is supported by the National Natural Science Foundation of China （No. 20442004 10576002）.
文摘The cyclization reaction of D-aspartic acid was studied, the carboxyl groups of D-aspartic acid were protected by benzyl alcohol to give compound D-dibenzyl aspartate. Then （4R）-benzyl azetidine-2-one-4-carboxylate and meso-3,6-disubstituted piperazine-2,5-diones were synthesized via intramolecular cyclization and intermolecular cycfization of D-dibenzyl aspartate, respectively, and their structures were confirmed by ^1 H NMR and MS. Both cyclization reaction conditions were also investigated in detail.
文摘Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of H-1 NMR, P-31 NMR and x-ray diffraction analysis.
文摘The cyclizaion reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups, has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-membered phosphorus heterocycles.The heterocyclizaional possibility of LR with bifunctional compounds was also discussed.
基金supported by the National Natural Science Foundation of China(Grants 22234002 and 22074016)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_0245).
文摘With high efficiency,mild conditions,and rapid reaction rate,click reactions have garnered much attention in the field of bioimaging since proposed by Sharpless et al.in 2001(Angew.Chem.,Int.Ed.2001,40,2004-2021).Inspired by the regenerative pathway of D-luciferin in fireflies,Liang et al.(Nat.Chem.2010,2,54-60)raised a 2-cyanobenzothiazole(CBT)-cysteine(Cys)click condensation reaction in 2010,which exhibits a higher secondorder reaction rate(9.19 M^(-1)s^(-1))and superior biocompatibility.As it has been developed in the past decade,remarkable progress has been made in the construction of enzyme-instructed CBT-Cys-based bioimaging probes.This review introduces the concept of the CBT-Cys click reaction,elucidates the mechanism of the CBT-Cys click reaction,and concerns the development progress of CBT-Cys reaction and its derived reactions[i.e.,2-cyano-6-hydroxyquinoline(CHQ)-Cys reaction and 2-pyrimidinecarbonitrile(PMN)-Cys reaction].Furthermore,we give a comprehensive and up-to-date review of enzyme-instructed CBT-Cyslike click reaction-based probes with significantly enhanced imaging signal and contrast for various bioimaging modes,including fluorescence imaging,photoacoustic imaging,magnetic resonance imaging,and positron emission tomography.In the end,we discuss the possible challenges and opportunities that may arise in the future.
基金Financial support from Tianjin University and the National Natural Science Foundation of China(No.21801181)is acknowledged.
文摘Due to the significance of corresponding products,enantioselective borylative cyclization reactions have been studied intensively in recent years.Many groups have developed efficient methods to transform unsaturated system into asymmetric cyclic organoboron compounds with the ring-size range from three-membered to six-membered in general.Notably,in some cases,fused rings which contain more than two contiguous chiral centers could be obtained by this kind of strategies.This review summarized and reviewed the recent advances in this field and classified these work according to the species of metal catalysts.
基金financially supported by the Natural Science Foundation of China(Nos.21302135 and 21272169)Taizhou Science & Technology program(No.111ZD02)
文摘An efficient method has been developed for the cascade synthesis of azo[1,2-a]indolones from azoles and2-fluoroaldehydes based on an iron-catalyzed SNAr and a direct acylation reaction.A number of azo[1,2-a]indolones containing different azole rings and substituents were obtained in good yields.
基金Supports from the National Natural Science Foundation of China (Nos. 21272257, 21274041 and 21474028)
文摘NTrifluoromethyl and cyclopropyl substituted 2-isoxazolines were synthesized via a DBU-promoted domino reaction of β-trifluoromethyl-/β-cyclopropyl-substituted enones with hydroxylamine. The domino reaction consists of a Michael addition and the followed cyclization. A wide range of 3-substituted 5-cyclopropyl-5-trifluoromethyl-2-isoxazolines were obtained in good to excellent yields under mild reaction conditions. The method could also apply to other trifluoromethyl-substituted enones.
基金Financial support of this research by the National Natural Science Foundation of China (NSFC No. 21173181) is gratefully acknowledged by authorsfunded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘An efficient and straightforward synthetic method has been developed for the preparation of 4-cyanofuran-3-carboxylate derivatives via iodine/potassium carbonate-promoted ring-opening/cyclization/rearrangement domino reaction of 1-cyanocyclopropane-1-carboxylates,which are a wide range of structurally interesting and pharmacologically significant compounds.
基金the Chongqing Research Program of Basic Research and Frontier Technology(Nos.cstc2015jcyj A1328 and cstc2015zdcy-ztzx0191)the Scientific Research Foundation of Chongqing University of Arts and Sciences(Nos.R2013XY01 and R2013XY02)Sichuan Provincial Science Fund for Distinguished Young Scholars(No.2015JQO055)
文摘A series of quinolino[3,4-b]quinoxalin-6（5H）-ones have been synthesized using an Ugi/deprotection/cyclization（UDC） strategy, followed by a nucleophilic aromatic substitution reaction. This facile microwave-assisted method provided good yields and could potentially be used for the construction of a diverse library of quinolino[3,4-b]quinoxalin-6（5H）-ones for high-throughput screening in medicinal chemistry.
基金the University of Kurdistan Research Council for the partial support of this work
文摘A fast and efficient method is described for the one-pot synthesis of 2,4（1H,3H）-quinazolinediones by cyclization reaction of anthranilic acid derivatives with potassium cyanate and acetic acid in PEG.Good to high yields of the products obtain in short reaction times with simple work-up.
基金the National Natural Science Foundation of China(No.20802052)for financial support
文摘The YCl3-catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are important units in many biologically active compounds.
基金supported by the National Natural Science Foundation of China(Nos.21772022,and 22171124)Minjiang University(No.MJY21041)Fuzhou University.
文摘Fluoroalkyl-containing organic compounds have exhibited wide applications in the field of pharmaceuticals,agrochemicals and materials science due to their outstanding properties such as biological activity,metabolic stability,lipophilicity,excellent chemical and thermal stability.Therefore,various synthetic strategies have been developed for the construction of fluoroalkyl-containing compounds,using highly active fluorinating reagents and fluorinated building blocks.Recently,the use of easily available and inexpensive trifluoroacetic anhydride(TFAA)and its anhydride analogues has attracted great attention to access numerous fluoroalkyl-containing compounds through cyclization and coupling reactions.In this review,we summarized the recent advances in the synthesis of fluoroalkylated compounds using fluoroalkyl anhydrides as reagents.This review aims to provide a reference for researchers on how to develop new synthetic straregies of fluorine-containing organic compounds and achieve kilograms or even tons preparation of fluorine-containing organic compounds using fluoroalkyl anhydrides.
基金the financial support from the National Natural Science Foundation of China(Nos.22171083,21674035)the Fundamental Research Funds for the Central Universities(No.22221818014)+1 种基金the Shanghai Leading Academic Discipline Project(No.B502)the“Eastern Scholar Professorship”support from the Shanghai local government。
文摘Suzuki coupling reactions between symmetrical monomers were conducted in various mesoporous silica nanoreactors grafted with palladium catalysts,enabling the selective formation of[12]cycloparaphenylene precursor with separate yield up to 25%in one-pot reactions,much higher than that in homogeneous reaction.The spatial nanoconfinement of the nanoreactors promotes the macrocyclization while limits the concomitant linear oligomer formation,offering more possibilities for the synthesis of macrocycles from symmetrical monomers in one-pot reaction.
文摘The crystals of the title compound C_(15)H_(17)N_2O_2PS were obtained by re crystallizing from ether-methanol solution. It belongs to the orthorhombic system, space group Pbca with a= 9. 255(1) , b= 17.189(8) , c =20. 446(4)A, V=3252.6 (7) A￣3, D_c=1. 31 g/cm￣3,Z= 8, μ(CuKa)=26. 87 cm-1, F(000)=1344. The structure was refined to R=0. 053, R_w=0. 055 for 1299 observed reflections (I≥3σ(I)). In the molecule P atom adopts distorted tetrahedral configuration.The bond (II)distances of P-O, P-N and P-C are 1.605(1) A, 1. 657(1) A 1. 801(1)A,(III)respectively. The X-ray crystallographic analysis demonstrates that there are intramolecular and intermolecular hydrogen bonds in the structure.
文摘The crystal of title compound C18H16N2O was obtained by recrystal-lizing from ethanol solution. It belongs to orthorhombic system, space group Pbca witha=23. 229(2), b=11. 880(3), c=10. 733(3) A, V=2961 (0) A3, Mr=276. 34, Dc=1. 239 g/cm3, Z=8, A(MoKa)=0. 78 cm-1, F(000) =1168. 00. The structurewas refined to R=0. 049 and Rw=0. 046 for 1102 observed reflections (I＞2d(I) ).The bond lengths of C(3) -C(4) and C(3) -N(1) are 1. 349(5) A and 1. 340(6) A,respectively. The bond angles of N (1) -C(3) -C(2), AN (1) -C(3) -C(4), AC(2) -C(3) -C(4) and C(3) -C(4) -C(5) are 121. 1 (4), 128. 4(4), 110. 5(4)and 113. 1 (4), respectively. The dihedral angle between two phenyl rings is 29. 29.
文摘The crystals of the title compound C19H16N2O3 were synthesized by thereaction of 4, 4-dicyano-1-phenyl-3-(3', 4'-methylenedioxyphenyl)-l-butan withlow-valent titanium reagent. It belongs to the orthorhombic system, space group Pea21with a=11. 547(2), b=13. 168(4), c=10. 645(3) A, V=1618. 4(8) A3, Dc=1.315 g/cm3, Z=4, Mr=320.35. A=0. 71069 A, u(MoKa) =0. 90 cm-1, F(000)=672. The structure was refined to R=0. 036, Rw=0. 044 for 962 observed reflections(I＞3(I) ). X-ray analysis reveals that in the five membered ring the C(11) -C(12)bond is longer than normal double C=C bond while the C(11) -N (1) bond is shorterthan normal C(sp)2-N bond.
基金The authors’works in this area have been sponsored by the National Natural Science Foundation of China(Nos.91856119,21971081,21622201,21820102003,91956201 and 21772053)the Program of Introducing Talents of Discipline to Universities of China(111 Program,No.B17019).
文摘Visible-light photoredox catalysis is a powerful and attractive strategy for organic molecule activation and new reaction design owing to its environmental-friendly characteristics and unique catalytic mechanisms,and has found wide applications in organic synthesis.This catalytic strategy enables controllable generation of diverse nitrogen-centered radicals(NCRs)under mild conditions,providing access to construction of diverse nitrogencontaining compounds.In this review,we critically illustrate the recent advances in the field of visible-light photoredox-catalyzed cyclization of nitrogen-centered radicals,based on the different radical precursors and activation modes.Wherever possible,particular emphasis is also put on working models and synthetic applications.
