Two new organic-inorganic compounds [(CH2)5NH2]3[PMo12O40]·3[(CH2)NH] 1 and [(CH2)5NH2]6[P2Mo18O62]·5H2O 2 have been synthesized using conventional and hydrothermal methods, respectively, and character...Two new organic-inorganic compounds [(CH2)5NH2]3[PMo12O40]·3[(CH2)NH] 1 and [(CH2)5NH2]6[P2Mo18O62]·5H2O 2 have been synthesized using conventional and hydrothermal methods, respectively, and characterized by elemental analyses, IR, TG and single-crystal X-ray diffraction. X-ray analyses show that in these compounds heteropolymolybdates [PMo12O40]^3- and [P2Mo18O62]^6- are reserved their Keggin or Dawson structures and linked to piperidine through electrostatic and hydrogen-bonding interactions.展开更多
Copolymerization of propylene and hindered piperidine monomers was carried out over a high activity supported Ziegler-Natta catalyst, using Al(C2H5)(3) as cocatalyst. Factors which affect the copolymerization were stu...Copolymerization of propylene and hindered piperidine monomers was carried out over a high activity supported Ziegler-Natta catalyst, using Al(C2H5)(3) as cocatalyst. Factors which affect the copolymerization were studied, The copolymers exhibited high light stability without adding extra light stabilizers. A self-stabilized polypropylene was prepared.展开更多
Piperidine absorbs CO2 and H2O in air to form a molecular complex: piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was...Piperidine absorbs CO2 and H2O in air to form a molecular complex: piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1^-with a=0.648 6(8) nm, b=0.809 200) nm, c= 1.357 1(16) nm, a=96.96706)°, β =102.506(15)°,γ=104.202 05)°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction (electron transfer) betweenl-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.展开更多
Direct Analysis in Real Time Mass Spectrometry(DART-MS)was applied to identify and study the distribution profile of piperidine alkaloids in different parts of Prosopis juliflora,without isolation and separation of th...Direct Analysis in Real Time Mass Spectrometry(DART-MS)was applied to identify and study the distribution profile of piperidine alkaloids in different parts of Prosopis juliflora,without isolation and separation of the compounds by standard chromatographic techniques.With the help of DART-MS,chemical fingerprint of raw plant parts were generated,which revealed the presence of piperidine alkaloids in leaf,pod and flower.A comparative study of the distribution pattern,showed variation in the presence and distribution of these alkaloids in various parts of P.juliflora.The leaves and pod displayed the largest alkaloid pattern with a total of 12 different alkaloids in each part,whereas only 4 alkaloids were present in flower.Alkaloids:julifloridine,prosopine,prosopinine and prosafrinine were ubiquitously distributed in all the alkaloid rich plant parts.Juliprosopine was pre-eminet alkaloid in leaf,whereas pod and flower displayed copious amounts of julifloridine.展开更多
A novel compound N-phenethyl-4-hydroxy-4-phenyl piperidine hydrochloride (C19H24ClNO·H2O) has been synthesized and structurally characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray ...A novel compound N-phenethyl-4-hydroxy-4-phenyl piperidine hydrochloride (C19H24ClNO·H2O) has been synthesized and structurally characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group P212121 with a = 8.6306(8), b = 11.0464(10), c = 19.3221(18)A^°, V = 1842.1(3)A^°^3, Z = 4, Dc =1.211 g/cm^3,μ = 0.217 mm^-1, Mr= 335.86, F(000) = 720, S = 0.973, R = 0.0420 and wR = 0.1009 for 3627 unique reflections with 3157 observed ones (I 〉 2σ(I)). In the crystal, the dihedral angles made by piperidine ring with two benzene rings are 84.8(6) and 62.5(7)°, respectively. Intermolecular O-H…O and O-H…Cl hydrogen bonds involving water molecules form chains along the b axis, which stabilizes the crystal structure. The preliminary bioactivity tests indicated that the title compound has good effect of cellular growth inhibition to K562 cells and potential bioactivity of anti-leukemia.展开更多
Piperidine absorbs CO2 and H2O contents in air to form a molecular complex: piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by FT-IR and NMR. The complex is stabilized via five ...Piperidine absorbs CO2 and H2O contents in air to form a molecular complex: piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by FT-IR and NMR. The complex is stabilized via five hydrogen bonds between the three components, N…O electrostatic interaction and O…O interaction (electron transfer) betweenl-piperidinecarboxylate and H2O. Through electron transfer from the carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of free water molecule. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.展开更多
Reactions of piperidine derivatives 4-(aminomethyl)piperidine(4-AMPD) and 1-methylpiperidin-4-amine(1-MPDA) with semi-conductive metal iodine SbI3 and PbI2 in concentrated HI aqueous solution afforded two one-dimensio...Reactions of piperidine derivatives 4-(aminomethyl)piperidine(4-AMPD) and 1-methylpiperidin-4-amine(1-MPDA) with semi-conductive metal iodine SbI3 and PbI2 in concentrated HI aqueous solution afforded two one-dimensional(1 D) chain compounds [(4-AMPD)SbI5]n(1), [(1-MPDA)SbI5]n(2) and a two-dimensional(2 D) single layered organicinorganic hybrid material [(1-MPDA)PbI4]n(3), which were confirmed by X-ray single-crystal diffraction, infrared(IR) spectroscopy and powder X-ray diffraction(PXRD). Simultaneously, compounds 1~3 exhibit strong emission peaks at 600 nm for 1 and 2 and 570 nm for 3, which were originated from their inorganic moieties.展开更多
The representative azo and anthraquinone dyes containing an insulated hindered piperidinegroup were synthesized.The effect of these pendent groups on lightfastness properties of the dyeswas studied,both in ethyl aceta...The representative azo and anthraquinone dyes containing an insulated hindered piperidinegroup were synthesized.The effect of these pendent groups on lightfastness properties of the dyeswas studied,both in ethyl acetate solution and on cellulose acetate and polyester films.The differ-ent trend of fading rates of azo dyes and anthraquinone dyes in solution and on substrates suggestsdifferent fading mechanisms operating in each case.展开更多
The monofunctional substitution reactions between trans-[PtCl(H2O)(NH3)(pip)]+,trans-[Pt(H2O)2(NH3)(pip)]2+,trans-[PtCl(H2O)(pip)2]+,trans-[Pt(H2O)2(pip)2]2+ (pip = piperidine) and adenine/gu...The monofunctional substitution reactions between trans-[PtCl(H2O)(NH3)(pip)]+,trans-[Pt(H2O)2(NH3)(pip)]2+,trans-[PtCl(H2O)(pip)2]+,trans-[Pt(H2O)2(pip)2]2+ (pip = piperidine) and adenine/guanine nucleotides are explored by using B3LYP hybrid functional and IEF-PCM salvation models. For the trans-[Pt(H2O)2(NH3)(pip)]2+ and trans-[PtCl(H2O)(NH3)(pip)]+ complexes,the computed barrier heights in aqueous solution are 13.5/13.5 and 11.6/11.6 kcal/mol from trans-Pt-chloroaqua complex to trans/cis-monoadduct for adenine and guanine,and the corresponding values are 20.7/20.7 and 18.8/18.8 kcal/mol from trans-Pt-diaqua complex to trans/cis-monoadduct for adenine and guanine,respectively. For trans-[PtCl(H2O)(pip)2]+ and trans-[Pt(H2O)2(pip)2]2+,the corresponding values are 21.5/21.3 and 19.4/19.4 kcal/mol,and 26.0/26.0 and 20.7/20.8 kal/mol for adenine and guanine,respectively. Our calculations demonstrate that the barrier heights of chloroaqua are lower than the corresponding values of diaqua for adenine and guanine. In addition,the free energies of activation for guanine in aqueous solution are all smaller than that for adenine,which predicts a preference of 1.9 kcal/mol when trans-[PtCl(H2O)(NH3)(pip)]+ and trans-[Pt(H2O)2(NH3)(pip)]2+ are the active agents and ~1.9 and ~ 5.3 kcal/mol when trans-[PtCl(H2O)(pip)2]+ and trans-[Pt(H2O)2(pip)2]2+ are the active agents,respectively. For the reaction of trans-Pt-chloroaqua (or diaqua) to cis-monoadduct,we obtain the same transition-state structure as from the reaction of trans-Pt-chloroaqua (or diaqua) to trans-monoadduct,which seems that the trans-Pt-chloroaqua (or diaqua) complex can generate trans-or cis-monoadduct via the same transition-state.展开更多
Aminonitriles were prepared efficiently from anodic cyanation of ?amino ester. The effect of different solvents and electrolytes was studied. The other byproducts were analyzed.
N-formylation of amines,a class of synthetically important reactions,is typically conducted using metal catalysts that are relatively expensive or not readily available and usually needs harsh conditions to increase t...N-formylation of amines,a class of synthetically important reactions,is typically conducted using metal catalysts that are relatively expensive or not readily available and usually needs harsh conditions to increase the reaction efficiency.Here,an efficient continuous microflow strategy was developed for the gas-liquid visible-light photocatalytic N-formylation of piperidine,which achieved a reaction yield of 82.97%and a selectivity of>99%at 12 min using cheap organic dye photocatalyst under mild reaction conditions.The influence of essential parameters,including light intensity,temperature and equivalents of the gas,additive and photocatalyst,on the reaction yield was systematically studied.Furthermore,kinetic investigations were conducted,exhibiting the dependence of reaction rate and equilibrium yield of N-formylpiperidine on light intensity,temperature and photocatalyst equivalent.The microflow photocatalytic approach established in this work,which realized a markedly higher space-time yield than the conventional batch method(37.9 vs.0.212 mmol h-1 L-1),paves the way for the continuous,green and efficient synthesis of N-formamides.展开更多
The rapid prevalence of antibiotic resistance has led to a significant global health problem. Although colistin is the last resort antibiotic, it is limited by dose dependent toxicity. A critical approach to solve thi...The rapid prevalence of antibiotic resistance has led to a significant global health problem. Although colistin is the last resort antibiotic, it is limited by dose dependent toxicity. A critical approach to solve this problem is to use an antibiotic adjuvant, which is able to potentiate the activity of antibiotic and reduce the dosage of antibiotic. Herein, we reported a novel 2-aminothiazoyl piperidine adjuvant, which enhanced the activity of colistin against Acinetobacter baumannii(A. baumannii). Two pilot libraries of 40compounds were prepared and their adjuvant activities were evaluated. The most potential compound11j enabled to cause16-fold reduction in the minimum inhibitory concentration(MIC) of colistin at 8μg/m L. Besides, time-kill curves exhibited that compound 11j had significant adjuvant activity to kill the bacteria. The predicted ADMET analysis showed that 2-aminothiazoyl piperidine derivatives had good drug-likeness and acceptable physicochemical properties. Furthermore, membrane permeability experiments demonstrated that compound 11j was beneficial for colistin to destroy the outer membrane of bacteria. Also, the comparative molecular similarity indices analysis(Co MSIA) and the density functional theory(DFT) calculations were conducted. The results drawn from these analyses indicated that the novel scaffold provided helpful information for the finding of new adjuvant lead.展开更多
A facile method for the title transformation is described. The reaction of 2,2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride (1b) and ketones bearing a-methylene group in acetonitrile proceeded smoothly to ...A facile method for the title transformation is described. The reaction of 2,2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride (1b) and ketones bearing a-methylene group in acetonitrile proceeded smoothly to give the a-oxyfunctionalized coupling products (6a-h). These coupling products decomposed upon heating in acidic medium to produce a-diketones (7a-h) in good to excellent yields.展开更多
The rhizome of giant taro(Alocasia macrorrhiza(L.)Schott),which is a highly adaptable wild plant,is a traditional Chinese herbal medicine.In the current study,the antiproliferative constituents of giant taro were inve...The rhizome of giant taro(Alocasia macrorrhiza(L.)Schott),which is a highly adaptable wild plant,is a traditional Chinese herbal medicine.In the current study,the antiproliferative constituents of giant taro were investigated and six new(1−6)and four known piperidine alkaloids(7−10)were isolated from its rhizomes.Their chemical structures and absolute configurations were elucidated using various spectroscopic methods and the Mosher ester method.The isolated alkaloids were screened for the antiproliferative activity through MTT assay.The results indicated that piperidine alkaloids exerted potential antiproliferative activity against HepG2,AGS and MCF-7 tumor cells.Further researches showed that compounds 3−5 dose-dependently decreased the colony formation rate and induced the apoptosis of AGS cells,while compound 4 induced AGS cell death via the proapoptotic pathway.This study demonstrates that the piperidine alkaloids isolated from giant taro exhibit significant antitumor activity,which provides phytochemical evidence for further development and utilization.展开更多
A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while hi...A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while highly efficient procedure for the intramolecular amidation of an isolated double bond. High diastereomeric excess was observed in this synthetic procedure.展开更多
Nitro and amino groups were introduced into piperidine skeleton to design derivatives of piperidine(labeled asα,β1,β2,β3,γandδ).Heats of formation(HOFs)are calculated in detail at the B3PW91/6-311+G(d,p)level fo...Nitro and amino groups were introduced into piperidine skeleton to design derivatives of piperidine(labeled asα,β1,β2,β3,γandδ).Heats of formation(HOFs)are calculated in detail at the B3PW91/6-311+G(d,p)level for these aminonitropiperidines.The results show that all derivatives have negative heats of formation,which were affected by the positions of substituted groups.The molecular stability is estimated and analyzed based on bond dissociation energies(BDE)and characteristic heights(H50).All derivatives designed in this paper are confirmed with lower impact sensitivity than 1,3,5-trinitro-1,3,5-triazinane(RDX)and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).Furthermore,the detonation velocities(D)and the detonation pressures(P)are predicted via the Kamlet-Jacobs equation.In all these molecules,δhas comparable detonation character with that of RDX and HMX and can be the candidate of high-energy-density compounds(HEDCs).展开更多
Three pairs of novel 2-aryl-3,4,5-trihydroxypiperidines (6-8 and their enantiomers), the piperidine analogues of the pyrrolidine alkaloids radicamine A and radicamine B, were prepared from six- membered cyclic nitro...Three pairs of novel 2-aryl-3,4,5-trihydroxypiperidines (6-8 and their enantiomers), the piperidine analogues of the pyrrolidine alkaloids radicamine A and radicamine B, were prepared from six- membered cyclic nitrones through a concise two-step procedure, i.e., Grignard reagent addition and deprotection. These novel polyhydroxylated piperidine iminosugars were assayed against 10 types of enzymes. Only compound 8 exhibited weak inhibition (IC50 1080 μmol/L) against β-galactosidase from rat intestinal lactases.展开更多
The light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10^(-4)M) pyrazine, pyridine and piperidine aqueous solutio...The light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10^(-4)M) pyrazine, pyridine and piperidine aqueous solutions containing KCl (0.1 M). The relaxation time is longer when the applied voltages are between-0.4 V and-0.8 V(vs. SCE) where the Raman effect also shows greater surface enhancement. Also observed was that for the piperidine case the relaxation time reaches its maximum at the more negative applied voltage. The origin of the relaxation is attributed mainly to the desorp- tion process of the pyrazine. pyridine and piperidine molecules off the roughened Ag electrode. An. electrostatic model was also proposed for the interpretation of these experimental observations.展开更多
A genistein derivative, 5-hydroxy-3-(4-hydroxyphenyl)-7-(2-(piperidin- 1-yl)ethoxy)- 4H-chromen-4-one 3, was designed, prepared and structurally characterized by single-crystal X-ray diffraction. X-ray structure...A genistein derivative, 5-hydroxy-3-(4-hydroxyphenyl)-7-(2-(piperidin- 1-yl)ethoxy)- 4H-chromen-4-one 3, was designed, prepared and structurally characterized by single-crystal X-ray diffraction. X-ray structure analysis reveals that 3 crystallizes in the orthorhombic system, space group Pbca, with a = 16.238(3), b = 10.308(2), c = 22.987(5)A, V = 3847.6(13)A3, Z = 8,μ= 0.093 mm^-1, Dc = 1.317 g/cm^3, F(000) = 1616, R = 0.0789 and wR = 0.1554 for 1463 observed reflections with I 〉 2σ(I).展开更多
基金This project was financially supported by the National Science Foundation of China (No. 20371012)
文摘Two new organic-inorganic compounds [(CH2)5NH2]3[PMo12O40]·3[(CH2)NH] 1 and [(CH2)5NH2]6[P2Mo18O62]·5H2O 2 have been synthesized using conventional and hydrothermal methods, respectively, and characterized by elemental analyses, IR, TG and single-crystal X-ray diffraction. X-ray analyses show that in these compounds heteropolymolybdates [PMo12O40]^3- and [P2Mo18O62]^6- are reserved their Keggin or Dawson structures and linked to piperidine through electrostatic and hydrogen-bonding interactions.
文摘Copolymerization of propylene and hindered piperidine monomers was carried out over a high activity supported Ziegler-Natta catalyst, using Al(C2H5)(3) as cocatalyst. Factors which affect the copolymerization were studied, The copolymers exhibited high light stability without adding extra light stabilizers. A self-stabilized polypropylene was prepared.
基金Supported by Project of Education Department of Liaoning Province(20040084)
文摘Piperidine absorbs CO2 and H2O in air to form a molecular complex: piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1^-with a=0.648 6(8) nm, b=0.809 200) nm, c= 1.357 1(16) nm, a=96.96706)°, β =102.506(15)°,γ=104.202 05)°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction (electron transfer) betweenl-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.
文摘Direct Analysis in Real Time Mass Spectrometry(DART-MS)was applied to identify and study the distribution profile of piperidine alkaloids in different parts of Prosopis juliflora,without isolation and separation of the compounds by standard chromatographic techniques.With the help of DART-MS,chemical fingerprint of raw plant parts were generated,which revealed the presence of piperidine alkaloids in leaf,pod and flower.A comparative study of the distribution pattern,showed variation in the presence and distribution of these alkaloids in various parts of P.juliflora.The leaves and pod displayed the largest alkaloid pattern with a total of 12 different alkaloids in each part,whereas only 4 alkaloids were present in flower.Alkaloids:julifloridine,prosopine,prosopinine and prosafrinine were ubiquitously distributed in all the alkaloid rich plant parts.Juliprosopine was pre-eminet alkaloid in leaf,whereas pod and flower displayed copious amounts of julifloridine.
基金supported by the NNFSC (No. 20672073)Shanghai Leading Academic Discipline (No. T0402)
文摘A novel compound N-phenethyl-4-hydroxy-4-phenyl piperidine hydrochloride (C19H24ClNO·H2O) has been synthesized and structurally characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group P212121 with a = 8.6306(8), b = 11.0464(10), c = 19.3221(18)A^°, V = 1842.1(3)A^°^3, Z = 4, Dc =1.211 g/cm^3,μ = 0.217 mm^-1, Mr= 335.86, F(000) = 720, S = 0.973, R = 0.0420 and wR = 0.1009 for 3627 unique reflections with 3157 observed ones (I 〉 2σ(I)). In the crystal, the dihedral angles made by piperidine ring with two benzene rings are 84.8(6) and 62.5(7)°, respectively. Intermolecular O-H…O and O-H…Cl hydrogen bonds involving water molecules form chains along the b axis, which stabilizes the crystal structure. The preliminary bioactivity tests indicated that the title compound has good effect of cellular growth inhibition to K562 cells and potential bioactivity of anti-leukemia.
基金Supported by Project of Education Department of Liaoning Province (20040084)
文摘Piperidine absorbs CO2 and H2O contents in air to form a molecular complex: piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by FT-IR and NMR. The complex is stabilized via five hydrogen bonds between the three components, N…O electrostatic interaction and O…O interaction (electron transfer) betweenl-piperidinecarboxylate and H2O. Through electron transfer from the carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of free water molecule. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.
基金Financially supported by the National Natural Science Foundation of China(No.21571094,21661021,21865015)the Graduate Student Creativity Funding of Jiangxi Province(No.YC2015-S008)
文摘Reactions of piperidine derivatives 4-(aminomethyl)piperidine(4-AMPD) and 1-methylpiperidin-4-amine(1-MPDA) with semi-conductive metal iodine SbI3 and PbI2 in concentrated HI aqueous solution afforded two one-dimensional(1 D) chain compounds [(4-AMPD)SbI5]n(1), [(1-MPDA)SbI5]n(2) and a two-dimensional(2 D) single layered organicinorganic hybrid material [(1-MPDA)PbI4]n(3), which were confirmed by X-ray single-crystal diffraction, infrared(IR) spectroscopy and powder X-ray diffraction(PXRD). Simultaneously, compounds 1~3 exhibit strong emission peaks at 600 nm for 1 and 2 and 570 nm for 3, which were originated from their inorganic moieties.
文摘The representative azo and anthraquinone dyes containing an insulated hindered piperidinegroup were synthesized.The effect of these pendent groups on lightfastness properties of the dyeswas studied,both in ethyl acetate solution and on cellulose acetate and polyester films.The differ-ent trend of fading rates of azo dyes and anthraquinone dyes in solution and on substrates suggestsdifferent fading mechanisms operating in each case.
基金supported from the National Natural Science Foundation of China (No. 20971056)
文摘The monofunctional substitution reactions between trans-[PtCl(H2O)(NH3)(pip)]+,trans-[Pt(H2O)2(NH3)(pip)]2+,trans-[PtCl(H2O)(pip)2]+,trans-[Pt(H2O)2(pip)2]2+ (pip = piperidine) and adenine/guanine nucleotides are explored by using B3LYP hybrid functional and IEF-PCM salvation models. For the trans-[Pt(H2O)2(NH3)(pip)]2+ and trans-[PtCl(H2O)(NH3)(pip)]+ complexes,the computed barrier heights in aqueous solution are 13.5/13.5 and 11.6/11.6 kcal/mol from trans-Pt-chloroaqua complex to trans/cis-monoadduct for adenine and guanine,and the corresponding values are 20.7/20.7 and 18.8/18.8 kcal/mol from trans-Pt-diaqua complex to trans/cis-monoadduct for adenine and guanine,respectively. For trans-[PtCl(H2O)(pip)2]+ and trans-[Pt(H2O)2(pip)2]2+,the corresponding values are 21.5/21.3 and 19.4/19.4 kcal/mol,and 26.0/26.0 and 20.7/20.8 kal/mol for adenine and guanine,respectively. Our calculations demonstrate that the barrier heights of chloroaqua are lower than the corresponding values of diaqua for adenine and guanine. In addition,the free energies of activation for guanine in aqueous solution are all smaller than that for adenine,which predicts a preference of 1.9 kcal/mol when trans-[PtCl(H2O)(NH3)(pip)]+ and trans-[Pt(H2O)2(NH3)(pip)]2+ are the active agents and ~1.9 and ~ 5.3 kcal/mol when trans-[PtCl(H2O)(pip)2]+ and trans-[Pt(H2O)2(pip)2]2+ are the active agents,respectively. For the reaction of trans-Pt-chloroaqua (or diaqua) to cis-monoadduct,we obtain the same transition-state structure as from the reaction of trans-Pt-chloroaqua (or diaqua) to trans-monoadduct,which seems that the trans-Pt-chloroaqua (or diaqua) complex can generate trans-or cis-monoadduct via the same transition-state.
文摘Aminonitriles were prepared efficiently from anodic cyanation of ?amino ester. The effect of different solvents and electrolytes was studied. The other byproducts were analyzed.
基金the financial support from the National Natural Science Foundation of China(No.21808059)the Fundamental Research Funds for the Central Universities(No.JKA01221712).
文摘N-formylation of amines,a class of synthetically important reactions,is typically conducted using metal catalysts that are relatively expensive or not readily available and usually needs harsh conditions to increase the reaction efficiency.Here,an efficient continuous microflow strategy was developed for the gas-liquid visible-light photocatalytic N-formylation of piperidine,which achieved a reaction yield of 82.97%and a selectivity of>99%at 12 min using cheap organic dye photocatalyst under mild reaction conditions.The influence of essential parameters,including light intensity,temperature and equivalents of the gas,additive and photocatalyst,on the reaction yield was systematically studied.Furthermore,kinetic investigations were conducted,exhibiting the dependence of reaction rate and equilibrium yield of N-formylpiperidine on light intensity,temperature and photocatalyst equivalent.The microflow photocatalytic approach established in this work,which realized a markedly higher space-time yield than the conventional batch method(37.9 vs.0.212 mmol h-1 L-1),paves the way for the continuous,green and efficient synthesis of N-formamides.
基金financially supported by the National Natural Science Foundation of China (No. 81872775)。
文摘The rapid prevalence of antibiotic resistance has led to a significant global health problem. Although colistin is the last resort antibiotic, it is limited by dose dependent toxicity. A critical approach to solve this problem is to use an antibiotic adjuvant, which is able to potentiate the activity of antibiotic and reduce the dosage of antibiotic. Herein, we reported a novel 2-aminothiazoyl piperidine adjuvant, which enhanced the activity of colistin against Acinetobacter baumannii(A. baumannii). Two pilot libraries of 40compounds were prepared and their adjuvant activities were evaluated. The most potential compound11j enabled to cause16-fold reduction in the minimum inhibitory concentration(MIC) of colistin at 8μg/m L. Besides, time-kill curves exhibited that compound 11j had significant adjuvant activity to kill the bacteria. The predicted ADMET analysis showed that 2-aminothiazoyl piperidine derivatives had good drug-likeness and acceptable physicochemical properties. Furthermore, membrane permeability experiments demonstrated that compound 11j was beneficial for colistin to destroy the outer membrane of bacteria. Also, the comparative molecular similarity indices analysis(Co MSIA) and the density functional theory(DFT) calculations were conducted. The results drawn from these analyses indicated that the novel scaffold provided helpful information for the finding of new adjuvant lead.
基金Project supported by the National Natural Science Foundation of China.
文摘A facile method for the title transformation is described. The reaction of 2,2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride (1b) and ketones bearing a-methylene group in acetonitrile proceeded smoothly to give the a-oxyfunctionalized coupling products (6a-h). These coupling products decomposed upon heating in acidic medium to produce a-diketones (7a-h) in good to excellent yields.
基金supported by the National Natural Science Foundation of China(No.82173698)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2017)the Pearl River S&T Nova Program of Guangzhou(No.201806010169).
文摘The rhizome of giant taro(Alocasia macrorrhiza(L.)Schott),which is a highly adaptable wild plant,is a traditional Chinese herbal medicine.In the current study,the antiproliferative constituents of giant taro were investigated and six new(1−6)and four known piperidine alkaloids(7−10)were isolated from its rhizomes.Their chemical structures and absolute configurations were elucidated using various spectroscopic methods and the Mosher ester method.The isolated alkaloids were screened for the antiproliferative activity through MTT assay.The results indicated that piperidine alkaloids exerted potential antiproliferative activity against HepG2,AGS and MCF-7 tumor cells.Further researches showed that compounds 3−5 dose-dependently decreased the colony formation rate and induced the apoptosis of AGS cells,while compound 4 induced AGS cell death via the proapoptotic pathway.This study demonstrates that the piperidine alkaloids isolated from giant taro exhibit significant antitumor activity,which provides phytochemical evidence for further development and utilization.
基金Project supported by the National Natural Science Foundation of China (No. 20272049).
文摘A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while highly efficient procedure for the intramolecular amidation of an isolated double bond. High diastereomeric excess was observed in this synthetic procedure.
基金supported by the Natural Science Foundation of Guizhou Education University(Nos.14BS017 and 2019ZD001)the Natural Science Foundation of Guizhou Province(No.QKHPTRC20185778-09)。
文摘Nitro and amino groups were introduced into piperidine skeleton to design derivatives of piperidine(labeled asα,β1,β2,β3,γandδ).Heats of formation(HOFs)are calculated in detail at the B3PW91/6-311+G(d,p)level for these aminonitropiperidines.The results show that all derivatives have negative heats of formation,which were affected by the positions of substituted groups.The molecular stability is estimated and analyzed based on bond dissociation energies(BDE)and characteristic heights(H50).All derivatives designed in this paper are confirmed with lower impact sensitivity than 1,3,5-trinitro-1,3,5-triazinane(RDX)and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).Furthermore,the detonation velocities(D)and the detonation pressures(P)are predicted via the Kamlet-Jacobs equation.In all these molecules,δhas comparable detonation character with that of RDX and HMX and can be the candidate of high-energy-density compounds(HEDCs).
基金Financial support from National Basic Research Program of China (Nos. 2012CB822101 and 2011CB808603)the Natural Science Foundation of China (Nos. 21272240 and 21102149)
文摘Three pairs of novel 2-aryl-3,4,5-trihydroxypiperidines (6-8 and their enantiomers), the piperidine analogues of the pyrrolidine alkaloids radicamine A and radicamine B, were prepared from six- membered cyclic nitrones through a concise two-step procedure, i.e., Grignard reagent addition and deprotection. These novel polyhydroxylated piperidine iminosugars were assayed against 10 types of enzymes. Only compound 8 exhibited weak inhibition (IC50 1080 μmol/L) against β-galactosidase from rat intestinal lactases.
基金This work was supported by the National Natural Science Foundation of ChinaNational Laboratory for Structural Chemistry of Dynamical and Stable Species.
文摘The light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10^(-4)M) pyrazine, pyridine and piperidine aqueous solutions containing KCl (0.1 M). The relaxation time is longer when the applied voltages are between-0.4 V and-0.8 V(vs. SCE) where the Raman effect also shows greater surface enhancement. Also observed was that for the piperidine case the relaxation time reaches its maximum at the more negative applied voltage. The origin of the relaxation is attributed mainly to the desorp- tion process of the pyrazine. pyridine and piperidine molecules off the roughened Ag electrode. An. electrostatic model was also proposed for the interpretation of these experimental observations.
基金This work was supported by the National Natural Science Foundation of China (No. 30672516)
文摘A genistein derivative, 5-hydroxy-3-(4-hydroxyphenyl)-7-(2-(piperidin- 1-yl)ethoxy)- 4H-chromen-4-one 3, was designed, prepared and structurally characterized by single-crystal X-ray diffraction. X-ray structure analysis reveals that 3 crystallizes in the orthorhombic system, space group Pbca, with a = 16.238(3), b = 10.308(2), c = 22.987(5)A, V = 3847.6(13)A3, Z = 8,μ= 0.093 mm^-1, Dc = 1.317 g/cm^3, F(000) = 1616, R = 0.0789 and wR = 0.1554 for 1463 observed reflections with I 〉 2σ(I).