A C/D ring synthon of vitamin D is readily obtained from cholesteryl acetate via oxidation, elimination of acetoxy group and Norrish type II photochemical reaction.
Carbon dioxide reduction, as a sustainable and versatile strategy for the access of chemical fuels, has attracted increasing attention and enormous efforts have been devoted to it in recent years. However, employing c...Carbon dioxide reduction, as a sustainable and versatile strategy for the access of chemical fuels, has attracted increasing attention and enormous efforts have been devoted to it in recent years. However, employing carbon dioxide as double synthons via bimolecular reduction remains challenging. Here, by leveraging the bimolecular reduction of carbon dioxide to carbonyl and methyl respectively, we describe a Pd-catalyzed trifunctionalization of alkynes with aryl iodide for the first time and showcase its advantages on the formation of various β-diketones and their application in the constructing of heterocyclic compounds with important biological activity, including pyrimidine, oxazole, pyrazole.展开更多
The first diastereodivergent formal[4+1]cycloaddition reactions of azoalkenes with p-quinone methides(pQMs)have been accomplished.The reported reaction occurred via a domino oxa-1,4-addition/1,6-addition process,allow...The first diastereodivergent formal[4+1]cycloaddition reactions of azoalkenes with p-quinone methides(pQMs)have been accomplished.The reported reaction occurred via a domino oxa-1,4-addition/1,6-addition process,allowing the use of common azoalkenes as C1 synthons.A broad range of 2,3-dihydrobenzofurans was smoothly prepared in good yields and with reversible diastereoselectivities.The steric hindrance and hydrogenbonding interaction were proposed to account for the two different modes of diastereo-control.The projected reaction features the employment of azoalkene as carbene-like C1 synthon,mild conditions,broad substrate scope and tunable diastereoselectivity.展开更多
A metal-free cross coupling between common CH2Cl2 and carboxylic acids has been achieved with K2CO3 as the sole additive. This simple protocol is a convenient and cost-effective route to synthesize methylene diesters ...A metal-free cross coupling between common CH2Cl2 and carboxylic acids has been achieved with K2CO3 as the sole additive. This simple protocol is a convenient and cost-effective route to synthesize methylene diesters from a wide scope of carboxylic acids substrates with good functional group tolerance. Several gram-scale reactions have been performed to evaluate the effectiveness and practicality of this protocol.展开更多
1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [（C5H14N2）^2＋-（C7H5O4）2^·H2O]（1） and [（C5H14N2...1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [（C5H14N2）^2＋-（C7H5O4）2^·H2O]（1） and [（C5H14N2）^2＋（C12H6O4）^2-.2H2O]（2）. These two forms of salts are both monoclinic systems with space group P21/c（14）. The lattice parameters of salts 1 and 2 are a=1.32666（10） nm, b=0.90527（7） nm, c=1.67107（13） nm, β=103.125（1）° and a=1.4950（2） nm, b=0.75242（15） nm, c=1.6563（3） nm, β=92.834（2）°, respectively. Expected classical hydrogen bonds N-H...O and O-H...O appear in the chargetransfer salts, and asymmetric units of these two forms both contain water molecules which play a significant role in building novel supramolecular architectures. Robust hydrogen-bond interactions between 1-methylpiperazine and aromatic acid provide sufficient driving force to direct the two crystals to three-dimensional structures. Weak interactions C-H-O emerging in salts 1 and 2 further enhance their crystal structures. As a consequence, hydrogen-bonding interactions in these compounds afford diverse 3D net supramolecular architectures. Thermal stability of these compounds was investigated by thermogravimetric analysis（TGA）.展开更多
This highlight summarizes a recent development of KF-promoted three-component fluorinationaminocarbonylation reaction of aldehydes,tertiary amines,and TMSCF_(2)Br for the synthesis of structurally importantα-fluoroam...This highlight summarizes a recent development of KF-promoted three-component fluorinationaminocarbonylation reaction of aldehydes,tertiary amines,and TMSCF_(2)Br for the synthesis of structurally importantα-fluoroamide derivatives.The key to the success of this method could be attributed to the multiple functions of difluorocarbene precursor(TMSCF_(2)Br)as both a C1 synthon and a F1 reagent through the process of C-F bond cleavage and C-F bond re-formation.展开更多
The two-component solid forms involving 4,4'-methylene-bis(benzenamine) included both salts and co-crystals,while 4,4'methylene-bis(benzenamine) crystallized exclusively as a salt,in agreement with the differe...The two-component solid forms involving 4,4'-methylene-bis(benzenamine) included both salts and co-crystals,while 4,4'methylene-bis(benzenamine) crystallized exclusively as a salt,in agreement with the differences in the pK a values.Many of the crystal structures displayed either the neutral or the ionic form of the carboxylic acid-amino heterosynthon,and the similarity in crystal structures between the neutral and the ionized molecules makes the visual distinction between a salt and co-crystal dependent on the experimental location of the acidic proton.A variety of supramolecular hydrogen bonded motifs involving interactions between the aza molecules and carboxylic acid groups are observed rather than just the O-H···N/O-H···O motif.The motifs are identical in all the two compounds analyzed showing the robustness of these supramolecular synthons.In all adducts,recognition between the constituents is established through either N-H···O and/or O-H···O/O-H···N pairwise hydrogen bonds.In all adducts,COOH functional groups available on 1 and 2 interact with the N-donor compounds.The COOH moieties in 1 forms only single N-H···O hydrogen bonds,whereas in 2,it forms pairwise O-H···N/N-H···O hydrogen bonds.The supramolecular architectures are elegant and simple,with stacking of networks in 2,but a rather complex network with a threefold interpenetration pattern was found in 1.Thermal stability of these compounds has been investigated by thermogravimetric analysis(TGA) of mass loss.展开更多
Multifunctional molecules are capable of assembling via different supramolecular synthons,or hydrogen bond motifs,between the same or different functional groups,leading to the possibility of cocrystal.Utilization of ...Multifunctional molecules are capable of assembling via different supramolecular synthons,or hydrogen bond motifs,between the same or different functional groups,leading to the possibility of cocrystal.Utilization of the interplay of dimensionality(1-D,2-D and 3-D),orientation of functional groups of the building blocks,influence of rigid/flexible linking groups,and weak interactions provides an interesting route for the creation of novel supramolecular architectures in the crystal lattice.N-unsubstituted 1H-benzotriazole and carboxylic acid,being self-complementary molecules,offer a broad scope of study of binary compounds based on the complementary combination of H-bonding/donating sites.We report here the construction of three extended molecular networks in cocrystals of the carboxylic acid group of the acid and the 1H-benzotriazole triazole moiety.We have been able to identify four major supramolecualr synthons that would be helpful in the prediction of structural motifs for these kinds of studies.Interestingly,these heterosynthons are strikingly similar,to those of the homosynthons of the individual functional groups.The nature of the aza groups helps to enhance the overall volume of the crystal lattice thus leading to the formation of various supramolecular assemblies.Thermal stability of these compounds has been investigated by thermogravimetric analysis(TGA) of mass loss.展开更多
Imidazole base was crystallized with different aromatic carboxylic acids 2,4-dihydroxybenzoic acid, 5-chlorosalicylic acid, and 1,8-naphthalic acid, affording three new binary molecular organic salts of [(C 3 H 5 N 2 ...Imidazole base was crystallized with different aromatic carboxylic acids 2,4-dihydroxybenzoic acid, 5-chlorosalicylic acid, and 1,8-naphthalic acid, affording three new binary molecular organic salts of [(C 3 H 5 N 2 + )·(C 7 H 5 O 4 )] (1), [(C 3 H 5 N 2 + )·(C 7 H 4 O 3 Cl )] C 7 H 5 O 3 Cl (2), and [(C 3 H 5 N 2 + ) (C 12 H 7 O 4 )] (3). Proton transfer occurs from the COOH of carboxylic acid to nitrogen of imidazole in all complexes (1-3), leading to the hydrogen bond N-H…O in all structures. To our knowledge, the recognition pattern between the carboxylic acid group and imidazole (acid-imidazole synthon) is less well-studied so far. The cooperation among COOH, COO and imidazolium cation functional groups for the observed hydrogen bond synthons is examined in the three structures. Generally, the strong N-H…O and O-H…O hydrogen bonds define supramolecular architecture and connectivity within chains, while weaker C-H…O hydrogen bonds play the dominant role in controlling the interactions between layers in these novel organic salts. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss.展开更多
Four hydroxybenzoic acid building blocks,m-hydroxybenzoic acid,2,4-dihydroxybenzoic acid,2,5-dihydroxyterephthalic acid,and 5-hydroxyisophthalic acid,have been synthesized as robust cocrystallizing agents and employed...Four hydroxybenzoic acid building blocks,m-hydroxybenzoic acid,2,4-dihydroxybenzoic acid,2,5-dihydroxyterephthalic acid,and 5-hydroxyisophthalic acid,have been synthesized as robust cocrystallizing agents and employed in reactions with piperazine,including [(C4H12N22+).(C7H5O3)2 ](1),[(C4H12N22+).(C 7H5O4)2 ](2),[(C4H12N22+).(C8H5O62)](3),and [(C4H12N22+)1/2.(C8H5O5)].2H2O(4).Hydrogen-bonded directed assemblies of four salts were validated by single-crystal X-ray diffraction analysis.In compounds 1-4,hydroxybenzoic acids are all deprotonated and piperazine molecules are all protonated to form piperazine dications and keep the chair conformation.Thermal stability of these compounds has been investigated.展开更多
The results of crystallographic analyses on 1:1 and 1:4 well-defined co-crystals formed between glycine anhydride and each of 4-hydroxybenzoic acid and 3,5-dihydroxybenzoic acid are described. Neutral molecules are co...The results of crystallographic analyses on 1:1 and 1:4 well-defined co-crystals formed between glycine anhydride and each of 4-hydroxybenzoic acid and 3,5-dihydroxybenzoic acid are described. Neutral molecules are connected via heteromeric O-H···O and N-H···O contacts leading to different packing arrangements of supramolecular chains. On the basis of the molecular structures of glycine anhydride and carboxylic acid guests, the hydrogen bonds are arranged to give centrosymmetric synthons V and VII which are noteworthy for their robustness. Hydrogen-bond interactions between glycine anhydride and aromatic acid provide sufficient driving force to direct molecular recognition and crystal packing. Utilization of the orientation of functional groups of the building blocks, the acidity, and weak interactions provides a route for the creation of novel supra- molecular architectures in the crystal lattice. Both two co-crystals contain the expected hydrogen-bonded motifs, and there has been no proton transfer from either of the two carboxylic acids to the aza compound moiety. This demonstrates that glycine anhydride is very capable of affecting the construction of binary co-crystals in a predictable and rationale manner. It is noted that synthons VⅢ and IX are fairly large, but the real challenge in crystal engineering is to find a big enough synthon that occurs often enough. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss.展开更多
文摘A C/D ring synthon of vitamin D is readily obtained from cholesteryl acetate via oxidation, elimination of acetoxy group and Norrish type II photochemical reaction.
基金supported by the National Natural Science Foundation of China(21971073,22001075,22231002)the Natural Science Foundation of Guangdong Province(2019A1515011468)+2 种基金the Discipline Construction Project of Guangdong Medical University(4SG23231G,4SG23249G)the Ordinary University Characteristic Innovation Project of Guangdong Province(2022KTSCX047)the Key-Area Research and Development Program of Guangdong Province(2020B010188001)。
文摘Carbon dioxide reduction, as a sustainable and versatile strategy for the access of chemical fuels, has attracted increasing attention and enormous efforts have been devoted to it in recent years. However, employing carbon dioxide as double synthons via bimolecular reduction remains challenging. Here, by leveraging the bimolecular reduction of carbon dioxide to carbonyl and methyl respectively, we describe a Pd-catalyzed trifunctionalization of alkynes with aryl iodide for the first time and showcase its advantages on the formation of various β-diketones and their application in the constructing of heterocyclic compounds with important biological activity, including pyrimidine, oxazole, pyrazole.
基金support from the Natural Science Foundation of Henan Province(No.222300420084)the Application Research Plan of Key Scientific Research Projects in Colleges and Universities of Henan Province(No.22A150056)is gratefully acknowledged.
文摘The first diastereodivergent formal[4+1]cycloaddition reactions of azoalkenes with p-quinone methides(pQMs)have been accomplished.The reported reaction occurred via a domino oxa-1,4-addition/1,6-addition process,allowing the use of common azoalkenes as C1 synthons.A broad range of 2,3-dihydrobenzofurans was smoothly prepared in good yields and with reversible diastereoselectivities.The steric hindrance and hydrogenbonding interaction were proposed to account for the two different modes of diastereo-control.The projected reaction features the employment of azoalkene as carbene-like C1 synthon,mild conditions,broad substrate scope and tunable diastereoselectivity.
基金Financial support from the National Natural Science Foundation of China(NSFC, Nos. 21761021 and 21571094)Natural Science Foundation of Jiangxi Province(No. 20171BAB203002)Sci & Tech Project of Education Department of Jiangxi Province(No. 60007)
文摘A metal-free cross coupling between common CH2Cl2 and carboxylic acids has been achieved with K2CO3 as the sole additive. This simple protocol is a convenient and cost-effective route to synthesize methylene diesters from a wide scope of carboxylic acids substrates with good functional group tolerance. Several gram-scale reactions have been performed to evaluate the effectiveness and practicality of this protocol.
基金Supported by the National Natural Science Foundation of China（Nos.51372125, 21203106）, the Fund of the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, China（No.2013-34）, and the Scientific and Technical Development Project of Qingdao City, China（No. 13-1-4-184-jch）.
文摘1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [（C5H14N2）^2＋-（C7H5O4）2^·H2O]（1） and [（C5H14N2）^2＋（C12H6O4）^2-.2H2O]（2）. These two forms of salts are both monoclinic systems with space group P21/c（14）. The lattice parameters of salts 1 and 2 are a=1.32666（10） nm, b=0.90527（7） nm, c=1.67107（13） nm, β=103.125（1）° and a=1.4950（2） nm, b=0.75242（15） nm, c=1.6563（3） nm, β=92.834（2）°, respectively. Expected classical hydrogen bonds N-H...O and O-H...O appear in the chargetransfer salts, and asymmetric units of these two forms both contain water molecules which play a significant role in building novel supramolecular architectures. Robust hydrogen-bond interactions between 1-methylpiperazine and aromatic acid provide sufficient driving force to direct the two crystals to three-dimensional structures. Weak interactions C-H-O emerging in salts 1 and 2 further enhance their crystal structures. As a consequence, hydrogen-bonding interactions in these compounds afford diverse 3D net supramolecular architectures. Thermal stability of these compounds was investigated by thermogravimetric analysis（TGA）.
基金We gratefully acknowledge the financial support from the Start-up Grant in Nanjing Tech University(Nos.39837118,39837146)the National Natural Science Foundation of China(No.22001121).
文摘This highlight summarizes a recent development of KF-promoted three-component fluorinationaminocarbonylation reaction of aldehydes,tertiary amines,and TMSCF_(2)Br for the synthesis of structurally importantα-fluoroamide derivatives.The key to the success of this method could be attributed to the multiple functions of difluorocarbene precursor(TMSCF_(2)Br)as both a C1 synthon and a F1 reagent through the process of C-F bond cleavage and C-F bond re-formation.
基金supported by the National Natural Science Foundation of China(20701023 and 21172127)the Natural Science Foundation of Shandong Province,China(BS2010NJ004, 2009ZRB019KH)
文摘The two-component solid forms involving 4,4'-methylene-bis(benzenamine) included both salts and co-crystals,while 4,4'methylene-bis(benzenamine) crystallized exclusively as a salt,in agreement with the differences in the pK a values.Many of the crystal structures displayed either the neutral or the ionic form of the carboxylic acid-amino heterosynthon,and the similarity in crystal structures between the neutral and the ionized molecules makes the visual distinction between a salt and co-crystal dependent on the experimental location of the acidic proton.A variety of supramolecular hydrogen bonded motifs involving interactions between the aza molecules and carboxylic acid groups are observed rather than just the O-H···N/O-H···O motif.The motifs are identical in all the two compounds analyzed showing the robustness of these supramolecular synthons.In all adducts,recognition between the constituents is established through either N-H···O and/or O-H···O/O-H···N pairwise hydrogen bonds.In all adducts,COOH functional groups available on 1 and 2 interact with the N-donor compounds.The COOH moieties in 1 forms only single N-H···O hydrogen bonds,whereas in 2,it forms pairwise O-H···N/N-H···O hydrogen bonds.The supramolecular architectures are elegant and simple,with stacking of networks in 2,but a rather complex network with a threefold interpenetration pattern was found in 1.Thermal stability of these compounds has been investigated by thermogravimetric analysis(TGA) of mass loss.
基金supported by the National Natural Science Foundation of China (20701023 and 20971076)the Natural Science Foundation of Shandong Province,China (BS2010CL013 and2009ZRB019KH)
文摘Multifunctional molecules are capable of assembling via different supramolecular synthons,or hydrogen bond motifs,between the same or different functional groups,leading to the possibility of cocrystal.Utilization of the interplay of dimensionality(1-D,2-D and 3-D),orientation of functional groups of the building blocks,influence of rigid/flexible linking groups,and weak interactions provides an interesting route for the creation of novel supramolecular architectures in the crystal lattice.N-unsubstituted 1H-benzotriazole and carboxylic acid,being self-complementary molecules,offer a broad scope of study of binary compounds based on the complementary combination of H-bonding/donating sites.We report here the construction of three extended molecular networks in cocrystals of the carboxylic acid group of the acid and the 1H-benzotriazole triazole moiety.We have been able to identify four major supramolecualr synthons that would be helpful in the prediction of structural motifs for these kinds of studies.Interestingly,these heterosynthons are strikingly similar,to those of the homosynthons of the individual functional groups.The nature of the aza groups helps to enhance the overall volume of the crystal lattice thus leading to the formation of various supramolecular assemblies.Thermal stability of these compounds has been investigated by thermogravimetric analysis(TGA) of mass loss.
基金supported by the National Natural Science Foundation of China (20701023, 20971076)the Natural Science Foundation of Shandong Province, China (BS2010NJ004,2009ZRB019KH)
文摘Imidazole base was crystallized with different aromatic carboxylic acids 2,4-dihydroxybenzoic acid, 5-chlorosalicylic acid, and 1,8-naphthalic acid, affording three new binary molecular organic salts of [(C 3 H 5 N 2 + )·(C 7 H 5 O 4 )] (1), [(C 3 H 5 N 2 + )·(C 7 H 4 O 3 Cl )] C 7 H 5 O 3 Cl (2), and [(C 3 H 5 N 2 + ) (C 12 H 7 O 4 )] (3). Proton transfer occurs from the COOH of carboxylic acid to nitrogen of imidazole in all complexes (1-3), leading to the hydrogen bond N-H…O in all structures. To our knowledge, the recognition pattern between the carboxylic acid group and imidazole (acid-imidazole synthon) is less well-studied so far. The cooperation among COOH, COO and imidazolium cation functional groups for the observed hydrogen bond synthons is examined in the three structures. Generally, the strong N-H…O and O-H…O hydrogen bonds define supramolecular architecture and connectivity within chains, while weaker C-H…O hydrogen bonds play the dominant role in controlling the interactions between layers in these novel organic salts. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss.
基金supported by the National Natural Science Foundation of China (20701023,20971076)the Natural Science Foundation of Shandong Province,China (BS2010NJ004,2009ZRB019KH)
文摘Four hydroxybenzoic acid building blocks,m-hydroxybenzoic acid,2,4-dihydroxybenzoic acid,2,5-dihydroxyterephthalic acid,and 5-hydroxyisophthalic acid,have been synthesized as robust cocrystallizing agents and employed in reactions with piperazine,including [(C4H12N22+).(C7H5O3)2 ](1),[(C4H12N22+).(C 7H5O4)2 ](2),[(C4H12N22+).(C8H5O62)](3),and [(C4H12N22+)1/2.(C8H5O5)].2H2O(4).Hydrogen-bonded directed assemblies of four salts were validated by single-crystal X-ray diffraction analysis.In compounds 1-4,hydroxybenzoic acids are all deprotonated and piperazine molecules are all protonated to form piperazine dications and keep the chair conformation.Thermal stability of these compounds has been investigated.
基金financially supported by the National Natural Science Foundation of China (20701023, 51102138)the Natural Science Foundation of Shandong Province, China (BS2010NJ004,2009ZRB019KH)
文摘The results of crystallographic analyses on 1:1 and 1:4 well-defined co-crystals formed between glycine anhydride and each of 4-hydroxybenzoic acid and 3,5-dihydroxybenzoic acid are described. Neutral molecules are connected via heteromeric O-H···O and N-H···O contacts leading to different packing arrangements of supramolecular chains. On the basis of the molecular structures of glycine anhydride and carboxylic acid guests, the hydrogen bonds are arranged to give centrosymmetric synthons V and VII which are noteworthy for their robustness. Hydrogen-bond interactions between glycine anhydride and aromatic acid provide sufficient driving force to direct molecular recognition and crystal packing. Utilization of the orientation of functional groups of the building blocks, the acidity, and weak interactions provides a route for the creation of novel supra- molecular architectures in the crystal lattice. Both two co-crystals contain the expected hydrogen-bonded motifs, and there has been no proton transfer from either of the two carboxylic acids to the aza compound moiety. This demonstrates that glycine anhydride is very capable of affecting the construction of binary co-crystals in a predictable and rationale manner. It is noted that synthons VⅢ and IX are fairly large, but the real challenge in crystal engineering is to find a big enough synthon that occurs often enough. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss.
