Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In ...Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.展开更多
Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strateg...Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle.展开更多
N-substituted furfurylamines(FAs)are valuable precursors for producing pharmacologically active compounds and polymers.However,enzymatic synthesis of the type of chemicals is still in its infancy.Here we report an imi...N-substituted furfurylamines(FAs)are valuable precursors for producing pharmacologically active compounds and polymers.However,enzymatic synthesis of the type of chemicals is still in its infancy.Here we report an imine reductase from Streptomyces albidoflavus(SaIRED)for the reductive amination of biobased furans.A simple,fast and interference-resistant high-throughput screening(HTS)method was developed,based on the coloration reaction of carbonyl compounds with 2,4-dinitrophenylhydrazine.The reductive amination activity of IREDs can be directly indicated by a colorimetric assay.With the reductive amination of furfural with allylamine as the model reaction,SaIRED with the activity of 4.8 U mg^(-1) was subjected to three rounds of protein engineering and screening by this HTS method,affording a high-activity tri-variant I127V/D241A/A242T(named M3,20.2 U mg^(-1)).The variant M3 showed broad substrate scope,and enabled efficient reductive amination of biobased furans with a variety of amines including small aliphatic amines and sterically hindered amines,giving the target FAs in yields up to>99%.In addition,other variants were identified for preparative-scale synthesis of commercially interesting amines such as N-2-(methylsulfonyl)ethyl-FA by the screen method,with isolated yields up to 87%and turnover numbers up to 9700 for enzyme.Gram-scale synthesis of N-allyl-FA,a valuable building block and potential polymer monomer,was implemented at 0.25 mol L^(-1) substrate loading by a whole-cell catalyst incorporating variant M3,with 4.7 g L^(-1) h^(-1) space-time yield and 91%isolated yield.展开更多
We demonstrate a superficial method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines using β-cyclodextrin as a supramolecular,biodegradable,and reusable catalyst in aqueous medium.The reaction product ...We demonstrate a superficial method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines using β-cyclodextrin as a supramolecular,biodegradable,and reusable catalyst in aqueous medium.The reaction product is in excellent yield with moderate to excellent selectivity.The mechanistic transformation presumably proceeds via a one-pot,multicomponent cyclization of dimedone in the presence of aromatic aldehydes and aromatic amines/INH,undergoing a tandem Michael addition reaction.The proposed approach in this study provides a highly efficient and environmentally benign route to N-substituted 1,8-dioxo-decahydroacridines.展开更多
Polypeptoids have been explored as mimics of polypeptides,owing to polypeptoids'superior stability upon proteolysis.Polypeptoids can be synthesized from one-pot ring-opening polymerization of amino acid N-substitu...Polypeptoids have been explored as mimics of polypeptides,owing to polypeptoids'superior stability upon proteolysis.Polypeptoids can be synthesized from one-pot ring-opening polymerization of amino acid N-substituted N-carboxyanhydrides(NNCAs).However,the speed of polymerization of NNCAs can be very slow,especially for NNCAs bearing a bulky N-substitution group.This hindered the exploration on polypeptoids with more diverse structures and functions.Therefore,it is in great need to develop advanced strategies that can accelerate the polymerization on inactive NNCAs.Hereby,we report that lithium/sodium/potassium hexamethyldisilazide(Li/Na/KHMDS)initiates a substantially faster polymerization on NNCAs than do commonly used amine initiators,especially for NNCAs with bulky N-substitution group.This fast NNCA polymerization will increase the structure diversity and application of polypeptoids as synthetic mimics of polypeptides.展开更多
A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the pre...A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.展开更多
An unexpected reaction of 10-bromomethyl-12-oxocalanolide A（2） with primary amine was demonstrated and studied. Consequentially,a new method for the preparation of N-substituted pyrroles starting fromγ-halo-α,β-u...An unexpected reaction of 10-bromomethyl-12-oxocalanolide A（2） with primary amine was demonstrated and studied. Consequentially,a new method for the preparation of N-substituted pyrroles starting fromγ-halo-α,β-unsaturated ketone was presented.展开更多
An efficient regioselective Friedel-Crafts hydroxyalkylation of N-substituted glyoxylamide with various indoles catalyzed by Lewis acids was developed. The reactions proceeded smoothly at room temperature and the 2-hy...An efficient regioselective Friedel-Crafts hydroxyalkylation of N-substituted glyoxylamide with various indoles catalyzed by Lewis acids was developed. The reactions proceeded smoothly at room temperature and the 2-hydroxy-2-（1H-indol-3-yl）-N-substituted acetamide resulted from the reactions catalyzed by FeSO4 were synthesized in excellent yields （up to 93%）. While the bisindole compounds were obtained when FeCl3 was used as a catalyst in excellent yields （up to 92%）. A possible mechanism was proposed.展开更多
An efficient synthesis of 3,4-dihydropyrimidine 2 （1H）-ones and thiones （3,4-DHPMs） core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The...An efficient synthesis of 3,4-dihydropyrimidine 2 （1H）-ones and thiones （3,4-DHPMs） core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The classical BigneUi reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times. ？2009 M. Saranga Pard. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A series of N-substituted （Z）-3-（（2-benzyl）-4-oxopent-2-yl）pyrrole-2,5-diones were synthesized and characterized. The compounds were synthesized from dimethyl-2-（（Z）-2-（benzylamino）-4-oxopent-2-en-3-yl） fu...A series of N-substituted （Z）-3-（（2-benzyl）-4-oxopent-2-yl）pyrrole-2,5-diones were synthesized and characterized. The compounds were synthesized from dimethyl-2-（（Z）-2-（benzylamino）-4-oxopent-2-en-3-yl） fumarate （9） and dimethyl acetylenedi-carboxylate followed by reaction with some amines in refluxing ethanol. The identification of the compounds were based on spectroscopic analysis such as 1R （infrared）, UV （ultraviolet）, ^1H-NMR （nuclear magnetic resonance） and the microanalysis of the elements （CHN （microanalysis）） data.展开更多
An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under...An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.展开更多
Organophosphorus-heteropolytungstic acids of 1 : 12 of P/W ratio, with N-substituted 2-amminoethylphosphonic acids R2R'N+CH2CH2PO3H- (R = R' = H; R = Me, R' = H; R = R' = Me; R = H, R' = Me2CH; R =...Organophosphorus-heteropolytungstic acids of 1 : 12 of P/W ratio, with N-substituted 2-amminoethylphosphonic acids R2R'N+CH2CH2PO3H- (R = R' = H; R = Me, R' = H; R = R' = Me; R = H, R' = Me2CH; R = H , R' = CH3(CH2)2CH2) as coordinate centers were prepared, and characterized by means of elemental analysis, IR, UV spectroscopy, TG and DSC thermal analysis. The results indicate that these organophosphorous-HPAs possess Keggin type structure, and their stoichiometric formulation is R2R'N+CH2CH2PO3H - ·W12O36 ·nH2O. The organic side chain with the ammino-group R2R'N+CH2CH2- and the phosphono-group-PO3H- participate altogether in the formation of the primary structure of the heteropoly anion. In other words, the entirety of each compound R2R'N+CH2CH2PO3H- is as the core or coordinate center of the heteropoly anions. The number of crystal water in the HPA was affected obviously by the N-substituents of the organo-phosphonic acids.展开更多
Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affordin...Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.展开更多
Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the init...Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the initiator,in non-polar n-hexane.Interestingly,the polymerization exhibited typical features of living polymerization though both monomer(liquid)and polymer(solid)have minimal solubility in n-hexane.The obtained polymer showed a stable helix structure independent of the temperatures screened,as evidenced by circular dichroism analysis.Also,the preliminary study demonstrated that the side chains can be post-functionalized through thiol-ene click chemistry with quantitative conversion.Together,this work provides guidance for the development of accelerated HROP of other liquid monomers bearing low reactivity.Besides,the helical and functionalizable poly(N-allyl alanine)could be a useful“clickable platform”for the design of variable biomaterials via efficient click chemistry.展开更多
Currently, industrial production of isocyanates, or diisocyanates in particular, has been exclusively based on phosgene processes. Phosgene is extremely toxic and large amounts of corrosive HC1 are produced as a side ...Currently, industrial production of isocyanates, or diisocyanates in particular, has been exclusively based on phosgene processes. Phosgene is extremely toxic and large amounts of corrosive HC1 are produced as a side product. In the view of environment protection and society safety, development of non-phosgene processes for isocyanates production will be highly desired, and this should be one of the most important missions for green chemistry and catalysis. In this review, efforts for development of non-phosgene method for syntheses of isocyanates, i.e., catalytic syntheses of N-substituted carbamates from nitro- or amino-compounds with CO, dimethyl carbonate （DMC）, urea and even CO2 etc. as carbonyl sources, then thermal cracking of N-substituted carbamates to afford corresponding i socyanates, are summarized, and a brief prospect for non-phosgene syntheses of isocyanates is also addressed.展开更多
The synthesis of anti-radiation active organic phosphorus compounds is an important field in search of radioprotectors.In order to develop new protectors of low toxicity and high potency, more than thirty phosphorus c...The synthesis of anti-radiation active organic phosphorus compounds is an important field in search of radioprotectors.In order to develop new protectors of low toxicity and high potency, more than thirty phosphorus compounds such as dialkylphosphorocyanidates(1), tetraalkylmonothiopyrophosphates(2), N-substituted dialkylphosphoramidates(3) and aminoalkylthiophosphates (4)have been designed and synthesized.展开更多
A mild and facile Wittig reaction between N-substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one-pot reaction in high yields （up t...A mild and facile Wittig reaction between N-substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one-pot reaction in high yields （up to 99%）. The product was obtained by simple filtration and no extra purification was necessary. Ethanol, an environment-benign solvent, was found to be a suitable reaction medium.展开更多
文摘Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.
基金2024 Special Talent Introduction Projects of Key R&D Program of Ningxia Hui Autonomous Region(2024BEH04049)the 2024 Guyuan City Innovation-Driven Achievement Transformation Project(2024BGTYF01-47)2025 Ningxia Natural Science Foundation Program(2025AAC030624).
文摘Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle.
文摘N-substituted furfurylamines(FAs)are valuable precursors for producing pharmacologically active compounds and polymers.However,enzymatic synthesis of the type of chemicals is still in its infancy.Here we report an imine reductase from Streptomyces albidoflavus(SaIRED)for the reductive amination of biobased furans.A simple,fast and interference-resistant high-throughput screening(HTS)method was developed,based on the coloration reaction of carbonyl compounds with 2,4-dinitrophenylhydrazine.The reductive amination activity of IREDs can be directly indicated by a colorimetric assay.With the reductive amination of furfural with allylamine as the model reaction,SaIRED with the activity of 4.8 U mg^(-1) was subjected to three rounds of protein engineering and screening by this HTS method,affording a high-activity tri-variant I127V/D241A/A242T(named M3,20.2 U mg^(-1)).The variant M3 showed broad substrate scope,and enabled efficient reductive amination of biobased furans with a variety of amines including small aliphatic amines and sterically hindered amines,giving the target FAs in yields up to>99%.In addition,other variants were identified for preparative-scale synthesis of commercially interesting amines such as N-2-(methylsulfonyl)ethyl-FA by the screen method,with isolated yields up to 87%and turnover numbers up to 9700 for enzyme.Gram-scale synthesis of N-allyl-FA,a valuable building block and potential polymer monomer,was implemented at 0.25 mol L^(-1) substrate loading by a whole-cell catalyst incorporating variant M3,with 4.7 g L^(-1) h^(-1) space-time yield and 91%isolated yield.
基金supported by Special Assistance Programme SAP,University Grants Commission,New Delhi,India
文摘We demonstrate a superficial method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines using β-cyclodextrin as a supramolecular,biodegradable,and reusable catalyst in aqueous medium.The reaction product is in excellent yield with moderate to excellent selectivity.The mechanistic transformation presumably proceeds via a one-pot,multicomponent cyclization of dimedone in the presence of aromatic aldehydes and aromatic amines/INH,undergoing a tandem Michael addition reaction.The proposed approach in this study provides a highly efficient and environmentally benign route to N-substituted 1,8-dioxo-decahydroacridines.
基金This research was supported by the National Natural Science Foundation of China(Nos.22075078,21774031,21861162010)the Natural Science Foundation of Shanghai(No.118ZR1410300)+3 种基金the National Key Research and Development Program of China(No.2016YFC1100401)the National Natural Science Foundation of China for Innovative Research Groups(No.51621002)Program of Shanghai Academic/Technology Research Leader(No.20XD1421400)Research program of State Key Laboratory of Bioreactor Engineering,the Fundamental Research Funds for the Central Universities(No.22221818014).
文摘Polypeptoids have been explored as mimics of polypeptides,owing to polypeptoids'superior stability upon proteolysis.Polypeptoids can be synthesized from one-pot ring-opening polymerization of amino acid N-substituted N-carboxyanhydrides(NNCAs).However,the speed of polymerization of NNCAs can be very slow,especially for NNCAs bearing a bulky N-substitution group.This hindered the exploration on polypeptoids with more diverse structures and functions.Therefore,it is in great need to develop advanced strategies that can accelerate the polymerization on inactive NNCAs.Hereby,we report that lithium/sodium/potassium hexamethyldisilazide(Li/Na/KHMDS)initiates a substantially faster polymerization on NNCAs than do commonly used amine initiators,especially for NNCAs with bulky N-substitution group.This fast NNCA polymerization will increase the structure diversity and application of polypeptoids as synthetic mimics of polypeptides.
基金the National Natural Science Foundation of China （No. 20072033）Specialized Research Fund for the Doctoral Program of Higher Education of China.
文摘A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.
基金supported financially by the National Natural Science Foundation of China(No.90713045)the National 863 Program of China(No.2006AA020501)Basic scientific research foundation of IMM,CAMS(No. 2007ZD03)
文摘An unexpected reaction of 10-bromomethyl-12-oxocalanolide A（2） with primary amine was demonstrated and studied. Consequentially,a new method for the preparation of N-substituted pyrroles starting fromγ-halo-α,β-unsaturated ketone was presented.
基金the National Natural Science Foundation of China (Nos. 21472130, 81373259) for financial support of this study
文摘An efficient regioselective Friedel-Crafts hydroxyalkylation of N-substituted glyoxylamide with various indoles catalyzed by Lewis acids was developed. The reactions proceeded smoothly at room temperature and the 2-hydroxy-2-（1H-indol-3-yl）-N-substituted acetamide resulted from the reactions catalyzed by FeSO4 were synthesized in excellent yields （up to 93%）. While the bisindole compounds were obtained when FeCl3 was used as a catalyst in excellent yields （up to 92%）. A possible mechanism was proposed.
文摘An efficient synthesis of 3,4-dihydropyrimidine 2 （1H）-ones and thiones （3,4-DHPMs） core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The classical BigneUi reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times. ？2009 M. Saranga Pard. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘A series of N-substituted （Z）-3-（（2-benzyl）-4-oxopent-2-yl）pyrrole-2,5-diones were synthesized and characterized. The compounds were synthesized from dimethyl-2-（（Z）-2-（benzylamino）-4-oxopent-2-en-3-yl） fumarate （9） and dimethyl acetylenedi-carboxylate followed by reaction with some amines in refluxing ethanol. The identification of the compounds were based on spectroscopic analysis such as 1R （infrared）, UV （ultraviolet）, ^1H-NMR （nuclear magnetic resonance） and the microanalysis of the elements （CHN （microanalysis）） data.
基金Project supported by the National Natural Science Foundation of China （No. 20672035） and Key Laboratory of 0rganofluorine Chemistry, Shanghai Institute of 0rganic Chemistry, Chinese Academy of Sciences.
文摘An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.
文摘Organophosphorus-heteropolytungstic acids of 1 : 12 of P/W ratio, with N-substituted 2-amminoethylphosphonic acids R2R'N+CH2CH2PO3H- (R = R' = H; R = Me, R' = H; R = R' = Me; R = H, R' = Me2CH; R = H , R' = CH3(CH2)2CH2) as coordinate centers were prepared, and characterized by means of elemental analysis, IR, UV spectroscopy, TG and DSC thermal analysis. The results indicate that these organophosphorous-HPAs possess Keggin type structure, and their stoichiometric formulation is R2R'N+CH2CH2PO3H - ·W12O36 ·nH2O. The organic side chain with the ammino-group R2R'N+CH2CH2- and the phosphono-group-PO3H- participate altogether in the formation of the primary structure of the heteropoly anion. In other words, the entirety of each compound R2R'N+CH2CH2PO3H- is as the core or coordinate center of the heteropoly anions. The number of crystal water in the HPA was affected obviously by the N-substituents of the organo-phosphonic acids.
基金the National Natural ScienceFoundation of China(No.20672012).
文摘Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.
基金supported by the National Natural Science Foundation of China(22201197,21925107)the Collaborative Innovation Center of Suzhou Nano Science and Technology,National Key R&D Program of China(2022YFB3704900)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20220507)the Natural Science Foundation of Jiangsu Higher Education Institutions(21KJB150035)。
文摘Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the initiator,in non-polar n-hexane.Interestingly,the polymerization exhibited typical features of living polymerization though both monomer(liquid)and polymer(solid)have minimal solubility in n-hexane.The obtained polymer showed a stable helix structure independent of the temperatures screened,as evidenced by circular dichroism analysis.Also,the preliminary study demonstrated that the side chains can be post-functionalized through thiol-ene click chemistry with quantitative conversion.Together,this work provides guidance for the development of accelerated HROP of other liquid monomers bearing low reactivity.Besides,the helical and functionalizable poly(N-allyl alanine)could be a useful“clickable platform”for the design of variable biomaterials via efficient click chemistry.
基金This work was supported by the National Natural Science Foundation of China （No. 21173240）.
文摘Currently, industrial production of isocyanates, or diisocyanates in particular, has been exclusively based on phosgene processes. Phosgene is extremely toxic and large amounts of corrosive HC1 are produced as a side product. In the view of environment protection and society safety, development of non-phosgene processes for isocyanates production will be highly desired, and this should be one of the most important missions for green chemistry and catalysis. In this review, efforts for development of non-phosgene method for syntheses of isocyanates, i.e., catalytic syntheses of N-substituted carbamates from nitro- or amino-compounds with CO, dimethyl carbonate （DMC）, urea and even CO2 etc. as carbonyl sources, then thermal cracking of N-substituted carbamates to afford corresponding i socyanates, are summarized, and a brief prospect for non-phosgene syntheses of isocyanates is also addressed.
文摘The synthesis of anti-radiation active organic phosphorus compounds is an important field in search of radioprotectors.In order to develop new protectors of low toxicity and high potency, more than thirty phosphorus compounds such as dialkylphosphorocyanidates(1), tetraalkylmonothiopyrophosphates(2), N-substituted dialkylphosphoramidates(3) and aminoalkylthiophosphates (4)have been designed and synthesized.
基金Project supported by the National Natural Science Foundation-of China （No. 21072044） and International Cooperation Foundation of Henan Province （No. 104300510062）.
文摘A mild and facile Wittig reaction between N-substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one-pot reaction in high yields （up to 99%）. The product was obtained by simple filtration and no extra purification was necessary. Ethanol, an environment-benign solvent, was found to be a suitable reaction medium.
