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1.
Luis G. Hernández‐Vázquez Marco A. Leyva Alejandro J. Metta‐Magaña Jaime Escalante 《Helvetica chimica acta》2012,95(11):2218-2230
Different cyclo‐β‐dipeptides were prepared from corresponding N‐substituted β‐alanine derivatives under mild conditions using PhPOCl2 as activating agent in benzene and Et3N as base. To evaluate β3‐substituent influence, the amino acids 7 – 26 were synthesized, and a β‐lactam formation reaction was carried out instead of cyclo‐β‐dipeptide formation. The crystal structures of three derivatives of cyclo‐β‐peptides and one β‐lactam are presented. 相似文献
2.
Deliang Kong Lihua Guo Meng Tian Shumiao Zhang Zhenzhen Tian Huayun Yang Ye Tian Zhe Liu 《应用有机金属化学》2019,33(1)
Fifteen organometallic Ir(III) half‐sandwich complexes ( 1A – 5C ) having the general formula [(η5‐Cpx)Ir(N^N)Cl]PF6 (Cpx = Cp*, tetramethyl(phenyl)cyclopentadienyl (Cpxph) or tetramethyl(biphenyl)cyclopentadienyl (Cpxbiph); N^N = diamine) have been synthesized and characterized. The molecular structure of 1A was determined using single‐crystal X‐ray diffraction analysis. The hydrolysis of 1A – 5C was monitored using UV–visible spectra. Complexes 3A – 3C showed catalytic activity for the oxidation of NADH to NAD+, where 3C showed the highest turnover number of 29.9 within 450 min. Cytotoxicity examination by MTT assay was carried out against two human cancer cell lines (HeLa and A549) after 24 or 48 h drug treatment. The complexes showed high potency, where the most potent complex ( 3C ; IC50 = 3.4 μM) was six times more active than cisplatin against A549 cells after 24 h drug exposure. Cytotoxic potency towards A549 cells increased with phenyl substitution on Cp ring: Cpxbiph > Cpxph > Cp*. In addition, the biological studies showed that 3C caused cell apoptosis and cell cycle arrest at G1 phase in A549 cancer cells. Moreover, 3C increased the level of reactive oxygen species markedly after 24 h, which may provide an important basis for killing cancer cells. Confocal laser scanning microscopy was used to track 3C in A549 cells. The cellular localization experiment showed that 3C targeted lysosomes and caused lysosomal damage. 相似文献
3.
Yizheng Geng Junyu Chen Haiwei Zhao Hongjian Sun Benjing Xue Xiaoyan Li Olaf Fuhr Dieter Fenske 《无机化学与普通化学杂志》2017,643(11):712-716
Three η4‐(C=C–C=O) coordination cobalt(I) complexes 1 – 3 were synthesized by the reactions of cinnamaldehyde, p‐fluorocinnamaldehyde, and p‐chlorocinnamaldehyde with CoMe(PMe3)4. Complex 4 as η2‐(C=C) coordination was prepared by the reaction of chalcone with Co(PMe3)4. The structures of complexes 1 – 4 were confirmed by single‐crystal X‐ray diffraction. Although the reactions didn't undergo C–H bond activation and decarbonylation, the formation of complexes 1 – 4 deepens our understanding of the reactions between α,β‐unsaturated aldehyde or ketone with low‐valent central cobalt atom. 相似文献
4.
Shinsuke Inagaki Sayuri Taniguchi Haruo Hirashima Tatsuya Higashi Jun Zhe Min Ruri Kikura‐Hanajiri Yukihiro Goda Toshimasa Toyo'oka 《Journal of separation science》2010,33(20):3137-3143
Enantioseparation of α,α‐diphenyl‐2‐pyrrolidinemethanol (D2PM) and methylphenidate (MPH; Ritalin®) using (R)‐(?)‐4‐(N,N‐dimethylaminosulfonyl)‐7‐(3‐isothiocyanatopyrrolidin‐1‐yl)‐2,1,3‐benzoxadiazole as the chiral derivatization reagent has been achieved for the first time, and a simple, reliable detection method using HPLC with fluorescence detection has been developed. D2PM and MPH have been derivatized with (R)‐(?)‐4‐(N,N‐dimethylaminosulfonyl)‐7‐(3‐isothiocyanatopyrrolidin‐1‐yl)‐2,1,3‐benzoxadiazole at 55°C for 15 min. The derivatives of D2PM and MPH have been separated, completely and rapidly, using a reversed‐phase system within 16 min (resolution factor (Rs)=1.60 and 2.53, respectively). The detection limits of (R)‐ and (S)‐D2PM were found to be 6.8 and 13 ng/mL, respectively, and those of D ‐ and L ‐threo‐MPH were 61 and 66 ng/mL, respectively (S/N=3). The proposed method was successfully applied to the analysis of rat plasma, where the rats were separately dosed with D2PM and MPH (Ritalin). 相似文献
5.
The synthesis, characterization and ε‐caprolactone polymerization behavior of lanthanide amido complexes stabilized by ferrocene‐containing N‐aryloxo functionalized β‐ketoiminate ligand FcCOCH2C(Me)N(2‐HO‐5‐But‐C6H3) (LH2, Fc = ferrocenyl) are described. The lanthanide amido complexes [LLnN(SiMe3)2(THF)]2 [Ln = Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] were synthesized in good yields by the amine elimination reactions of LH2 with Ln[N(SiMe3)2]3(µ‐Cl)Li(THF)3 in a 1:1 molar ratio in THF. These complexes were characterized by IR spectroscopy and elemental analysis, and 1H NMR spectroscopy was added for the analysis of complex 4 . The definitive molecular structures of complexes 1 and 3 were determined by X‐ray diffraction studies. Complexes 1 – 4 can initiate the ring‐opening polymerization of ε‐caprolactone with moderate activity. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
6.
Qing Liu Ping Zhao Xing‐Cong Li Melissa R. Jacob Chong‐Ren Yang Ying‐Jun Zhang 《Helvetica chimica acta》2010,93(2):265-271
Three new α‐tetralone galloylglucosides, 1 – 3 , were isolated from the fresh pericarps of Juglans sigillata (Juglandaceae), together with six known compounds. The structures of the new compounds were determined as 1,2,3,4‐tetrahydro‐7‐hydroxy‐4‐oxonaphthalen‐1‐yl 6‐O‐[(3,4,5‐trihydroxyphenyl)carbonyl]‐β‐D ‐glucopyranoside ( 1 ), (1S)‐1,2,3,4‐tetrahydro‐8‐hydroxy‐4‐oxonaphthalen‐1‐yl 6‐O‐[(3,4,5‐trihydroxyphenyl)carbonyl]‐β‐D ‐glucopyranoside ( 2 ), and 1,2,3,4‐tetrahydro‐7,8‐dihydroxy‐4‐oxonaphthalen‐1‐yl 6‐O‐[(3,4,5‐trihydroxyphenyl)carbonyl]‐β‐D ‐glucopyranoside ( 3 ), respectively, on the basis of detailed spectroscopic analyses, and acidic and enzymatic hydrolysis. The antimicrobial activities of the isolated compounds 2, 4 , and 7 – 9 were evaluated. 相似文献
7.
The first synthetic approach to (±)‐Δ3‐2‐hydroxybakuchiol (=4‐[(1E,5E)‐3‐ethenyl‐7‐hydroxy‐3,7‐dimethylocta‐1,5‐dien‐1‐yl]phenol; 14 ) and its analogues 13a – 13f was developed by 12 steps (Schemes 2 and 3). The key features of the approach are the construction of the quaternary C‐center bearing the ethenyl group by a Johnson–Claisen rearrangement (→ 6 ); and of an (E)‐alkenyl iodide via a Takai–Utimoto reaction (→ 11 ); and an arylation via a Negishi cross‐coupling reaction (→ 12e – 12f ). 相似文献
8.
Flavonol Glycosides with α‐Glucosidase Inhibitory Activities and New Flavone C‐Diosides from the Leaves of Machilus konishii
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Seventeen flavonoids, five of which are flavone C‐diosides, 1 – 5 , were isolated from the BuOH‐ and AcOEt‐soluble fractions of the leaf extract of Machilus konishii. Among 1 – 5 , apigenin 6‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 2 ), apigenin 8‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 4 ), and apigenin 8‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 5 ) are new. Both 4 and 5 are present as rotamer pairs. The structures of the new compounds were elucidated on the basis of NMR‐spectroscopic analyses and MS data. In addition, the 1H‐ and 13C‐NMR data of apigenin 6‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 3 ) were assigned for the first time. The isolated compounds were assayed against α‐glucosidase (type IV from Bacillus stearothermophilus). Kaempferol 3‐O‐(2‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside ( 12 ) was found to possess the best inhibitory activity with an IC50 value of 29.3 μM . 相似文献
9.
Diastereoisomeric isopropyl‐, 2‐ethoxyethyl‐, 2,2‐dichloroethyl‐ and 2,2,2‐trichloroethyl uridine 3′‐thiomonophosphates, 1a – 1d , respectively, have been synthesized, and their hydrolyses in aqueous alkali at 25° have been followed by HPLC. According to the time‐dependent product distributions obtained, the alkyl phosphorothioates 1a – 1d undergo cleavage to uridine 2′‐ and 3′‐thiophosphates, 7a and 7b , respectively, via a uridine 2′,3′‐cyclic thiophosphate ( 6 ). The rate of the hydroxide ion‐catalyzed cyclization of both (RP)‐ and (SP)‐diastereoisomer is highly dependent on the polar nature of the leaving group, the βlg values being ?1.23±0.03 and ?1.24±0.03, respectively. Brønsted dependence of the second‐order rate constants (kOH [dm3 mol?1 s?1]) on the pKa values of the leaving alcohols shows a convex breakpoint on going from alkyl esters 1a – 1d to aryl esters studied earlier. This may be considered as a strong evidence for a stepwise mechanism, where the formation and breakdown of the phosphorane intermediate is the rate‐limiting step with aryl and alkyl esters, respectively. 相似文献
10.
Mohammad Navid Soltani Rad Somayeh Behrouz Fatemeh Karimitabar Ali Khalafi‐Nezhad 《Helvetica chimica acta》2012,95(3):491-501
The ‘click synthesis’ of some novel O‐substituted oximes, 7a – 7t , which contain 1,2,3‐triazolediyl residues, as new analogs of β‐adrenoceptor antagonists is described (Schemes 1–4). The synthesis of these compounds was achieved in four to five steps. The formation of oximes of 9H‐fluoren‐9‐one and benzophenone, i.e., 9a and 9b , respectively, followed by their reaction with propargyl bromide, afforded O‐propargyl oximes 10a and 10b , respectively, which by a subsequent CuI‐catalyzed Huisgen cycloaddition with prepared β‐azido alcohols 11a – 11j (Schemes 2 and 3), led to the target compounds 7a – 7t in good yields. 相似文献
11.
Hong‐Bo Huang Ze‐En Xiao Xiao‐Jun Feng Cai‐Huan Huang Xun Zhu Jian‐Hua Ju Meng‐Feng Li Yong‐Cheng Lin Lan Liu Zhi‐Gang She 《Helvetica chimica acta》2011,94(9):1732-1740
Four new dimeric naphtho‐γ‐pyrones, named rubasperone D ( 1 ), rubasperone E ( 2 ), rubasperone F ( 3 ), and its atropisomer rubasperone G ( 4 ), together with four known monomeric naphtho‐γ‐pyrones, TMC 256 A1 ( 5 ), rubrofusarin B ( 6 ), fonsecin ( 7 ), and flavasperone ( 8 ), were isolated from the mangrove endophytic fungus Aspergillus tubingensis (GX1‐5E) cultivated in solid rice medium. Their structures were elucidated by spectroscopic methods, including IR, 1D‐ and 2D‐NMR, and MS. In the in vitro cytotoxicity assays, 5 displayed inhibitory activities against tumor cell lines of MCF‐7, MDA‐MB‐435, Hep3B, Huh7, SNB19, and U87 MG with IC50 values between 19.92 and 47.98 μM . Compounds 1, 6 , and 8 also showed mild cytotoxic activity. 相似文献
12.
In this study, (5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐carboxylic acid hydrazide ( 5 ) was synthesized by the condensation of methyl (5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐carboxylate ( 4 ) with NH2NH2⋅H2O. The (5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐carboxylic acid 2‐[(arylamino)carbonyl]hydrazides 6a – 6q were prepared by the reaction of 5 with corresponding substituted aryl isocyanates, and the N‐{5‐[(5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐yl]‐1,3,4‐oxadiazol‐2‐yl}arenamines 7a – 7q were obtained via the cyclization reaction of 6a – 6q in the presence of POCl3. The synthesized compounds have a rigid morphine structure, including the 6,14‐endo‐etheno bridge and the 5‐(arylamino)‐1,3,4‐oxadiazol‐2‐yl residue at C(7) adopting the (S)‐configuration (7α). The structures of the compounds were confirmed by high‐resolution mass spectrometry (HR‐MS) and various spectroscopic methods such as FT‐IR, 1H‐NMR, 13C‐NMR, APT, and 2D‐NMR (HETCOR, COSY, INADEQUATE). 相似文献
13.
β‐Bromo‐α,β‐unsaturated ketones are condensed with arylhydrazines to form hydrazones, which are in situ intramolecularly cyclized into 3‐substituted 1‐aryl‐1 H‐pyrazoles under a catalytic system of Pd(OAc)2/1,3‐bis(diphenylhosphino)propane (dppp)/NaOtBu. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
14.
Brigida D'Abrosca Severina Pacifico Monica Scognamiglio Nikolaos Tsafantakis Emanuela Pagliari Pietro Monaco Antonio Fiorentino 《Helvetica chimica acta》2013,96(7):1273-1280
Four novel γ‐pyrone (=4H‐pyran‐4‐one) metabolites, petrorhagiosides A–D, along with four known analogs, have been isolated from the MeOH extract of Petrorhagia saxifraga, a perennial herbaceous plant typical of Mediterranean vegetation. The structures of the new compounds were established on the basis of extensive spectroscopic analyses including 1D‐ an 2D‐NMR (1H,1H‐DQ‐COSY, TOCSY, HSQC, CIGAR‐HMBC, and HSQC‐TOCSY) experiments. 相似文献
15.
Synthesis and Characterization of β‐Diketiminate Aluminum Compounds and Their Use in the Ring‐Opening Polymerization of ε‐Caprolactone
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Xiaoli Ma Miaomiao Yao Mingdong Zhong Ziyan Deng Wenling Li Zhi Yang Herbert W. Roesky 《无机化学与普通化学杂志》2017,643(2):198-202
Four aluminum alkyl compounds, [CH{(CH3)CN‐2,4,6‐MeC6H2}2AlMe2] ( 1 ), [CH{(CH3)CN‐2,4,6‐MeC6H2}2AlEt2] ( 2 ), [CH{(CH3)CN‐2‐iPrC6H4}2AlMe2] ( 3 ), and [CH{(CH3)CN‐2‐iPrC6H4}2AlEt2] ( 4 ), bearing β‐diketiminate ligands [CH{(Me)CN‐2,4,6‐MeC6H2}]2 (L1H) and [CH{(Me)CN‐2‐iPrC6H4}]2 (L2H) were obtained from the reactions of trimethylaluminum, triethylaluminum with the corresponding β‐diketiminate, respectively. All compounds were characterized by 1H NMR and 13C NMR spectroscopy, single‐crystal X‐ray structural analysis, and elemental analysis. Compounds 1 – 4 were found to catalyze the ring‐opening polymerization (ROP) of ε‐caprolactone (ε‐CL) with good activity. 相似文献
16.
The preparation of (2S,3S)‐ and (2R,3S)‐2‐fluoro and of (3S)‐2,2‐difluoro‐3‐amino carboxylic acid derivatives, 1 – 3 , from alanine, valine, leucine, threonine, and β3h‐alanine (Schemes 1 and 2, Table) is described. The stereochemical course of (diethylamino)sulfur trifluoride (DAST) reactions with N,N‐dibenzyl‐2‐amino‐3‐hydroxy and 3‐amino‐2‐hydroxy carboxylic acid esters is discussed (Fig. 1). The fluoro‐β‐amino acid residues have been incorporated into pyrimidinones ( 11 – 13 ; Fig. 2) and into cyclic β‐tri‐ and β‐tetrapeptides 17 – 19 and 21 – 23 (Scheme 3) with rigid skeletons, so that reliable structural data (bond lengths, bond angles, and Karplus parameters) can be obtained. β‐Hexapeptides Boc[(2S)‐β3hXaa(αF)]6OBn and Boc[β3hXaa(α,αF2)]6‐OBn, 24 – 26 , with the side chains of Ala, Val, and Leu, have been synthesized (Scheme 4), and their CD spectra (Fig. 3) are discussed. Most compounds and many intermediates are fully characterized by IR‐ and 1H‐, 13C‐ and 19F‐NMR spectroscopy, by MS spectrometry, and by elemental analyses, [α]D and melting‐point values. 相似文献
17.
2, 4‐Dimethylpenta‐1, 3‐diene and 2, 4‐Dimethylpentadienyl Complexes of Rhodium and Iridium The complexes [(η4‐C7H12)RhCl]2 ( 1 ) (C7H12 = 2, 4‐dimethylpenta‐1, 3‐diene) and [(η4‐C7H12)2IrCl] ( 2 ) were obtained by interaction of C7H12 with [(η2‐C2H4)2RhCl]2 and [(η2‐cyclooctene)2IrCl]2, respectively. The reaction of 1 or 2 with CpTl (Cp = η5‐C5H5) yields the compounds [CpM(η4‐C7H12)] ( 3a : M = Rh; 3b : M = Ir). The hydride abstraction at the pentadiene ligand of 3a , b with Ph3CBF4 proceeds differently depending on the solvent. In acetone or THF the “half‐open” metallocenium complexes [CpM(η5‐C7H11)]BF4 ( 4a : M = Rh; 4b : M = Ir) are obtained exclusively. In dichloromethane mixtures are produced which additionally contain the species [(η5‐C7H11)M(η5‐C5H4CPh3)]BF4 ( 5a : M = Rh; 5b : M = Ir) formed by electrophilic substitution at the Cp ring, as well as the η3‐2, 4‐dimethylpentenyl compound [(η3‐C7H13)Rh{η5‐C5H3(CPh3)2}]BF4 ( 6 ). By interaction of 2, 4‐dimethylpentadienyl potassium with 1 or 2 the complexes [(η4‐C7H12)M(η5‐C7H11)] ( 7a : M = Rh; 7b : M = Ir) are generated which show dynamic behaviour in solution; however, attempts to synthesize the “open” metallocenium cations [(η5‐C7H11)2M]+ by hydride abstraction from 7a , b failed. The new compounds were characterized by elemental analysis and spectroscopically, 4b and 5a also by X‐ray structure analysis. 相似文献
18.
Fumio Sanda Taizo Fujiyama Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2001,39(5):732-741
α‐Methyl glutamic acid (L ‐L )‐, (L ‐D )‐, (D ‐L )‐, and (D ‐D )‐γ‐dimers were synthesized from L ‐ and D ‐glutamic acids, and the obtained dimers were subjected to polycondensation with 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride and 1‐hydroxybenzotriazole hydrate as condensation reagents. Poly‐γ‐glutamic acid (γ‐PGA) methyl ester with the number‐average molecular weights of 5000∼20,000 were obtained by polycondensation in N,N‐dimethylformamide in 44∼91% yields. The polycondensation of (L ‐L )‐ and (D ‐D )‐dimers afforded the polymers with much larger |[α]D | compared with the corresponding dimers. The polymer could be transformed into γ‐PGA by alkaline hydrolysis or transesterification into α‐benzyl ester followed by hydrogenation. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 732–741, 2001 相似文献
19.
Palladium(II) Complexes of 1,1,3,3,5,5‐Hexakis(dimethylamino)‐λ5‐[1,3,5]triphosphinine 1,1,3,3,5,5‐Hexakis(dimethylamino)‐1λ5‐3λ5‐5λ5‐[1,3,5]triphosphinine ( 5 ) reacts with (benzonitrile)2PdCl2 to give the chelate complex dichloro(dodeca‐N‐methyl‐1λ5,3λ5,5λ5‐1,3,5‐triphosphinine‐1,1,3,3,5,5‐hexaamin‐C2,C4)palladium ( 6 ). In a pyridine‐d5 solution of 6 the complex dichloro(dodeca‐N‐methyl‐1λ5,3λ5,5λ5‐1,3,5‐triphosphinine‐1,1,3,3,5,5‐hexaamin‐C2)((2H5)pyridine‐N)palladium ( 7 ) is formed. The solute 7 could not be isolated as a solid, because elimination of the solvent regenerates 6 quantitatively. Properties, nmr and ir spectra of 6 and 7 are reported. 6 is characterized by the results of an X‐ray structural analysis. 相似文献
20.
Mingqiang Xue Hongmei Sun Hui Zhou Yingming Yao Qi Shen Yong Zhang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(3):1147-1152
Ring‐opening polymerization of ε‐caprolactone (ε‐CL) was carried out using β‐diketiminato‐supported monoaryloxo ytterbium chlorides L1Yb(OAr)Cl(THF) (1) [L1 = N,N′‐bis(2,6‐dimethylphenyl)‐2,4‐pentanediiminato, OAr = 2,6‐di‐tert‐butylphenoxo‐], and L2Yb(OAr′)Cl(THF) (2) [L2 = N,N′‐bis(2,6‐diisopropylphenyl)‐2,4‐pentanediiminato, OAr′ = 2,6‐di‐tert‐butyl‐4‐methylphenoxo‐], respectively, as single‐component initiator. The influence of reaction conditions, such as polymerization temperature, polymerization time, initiator, and initiator concentration, on the monomer conversion, molecular weight, and molecular weight distribution of the resulting polymers was investigated. Complex 1 was well characterized and its crystal structure was determined. Some features and kinetic behaviors of the CL polymerization initiated by these two complexes were studied. The polymerization rate is first order with respect to monomer. The Mn of the polymer increases linearly with the increase of the polymer yield, while polydispersity remained narrow and unchanged throughout the polymerization in a broad range of temperatures from 0 to 50 °C. The results indicated that the present system has a “living character”. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1147–1152, 2006 相似文献