首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
The ortho-metalated complex [Pd(x){κ 2 (C,N)-[C6H4CH2NRR′ (Y)}] (2a4a and 2b3b) was prepared by refluxing in benzene equimolecular amounts of Pd(OAc)2 and secondary benzylamine [a, EtNHCH2Ph; b, t-BuNHCH2Ph followed by addition of excess NaCl. The reaction of the complexes [Pd(x){κ 2 (C,N)-[C6H4CH2NRR′ (Y)}] (2a4a and 2b3b) with a stoichiometric amount of Ph3P=C(H)COC6H4-4-Z (Z = Br, Ph) (ZBPPY) (1:1 molar ratio), in THF at low temperature, gives the cationic derivatives [Pd(OC(Z-4-C6H4C=CHPPh3){κ 2 (C,N)-[C6H4CH2NRR′(Y)}] (5a9a, 4b6b, and 4b′6b′), in which the ylide ligand is O-coordinated to the Pd(II) center and trans to the ortho-metalated C(6)H(4) group, in an “end-on carbonyl”. Ortho-metallation, ylide O-coordination, and C-coordination in complexes (5a9a, 4b6b, and 4b′6b′) were characterized by elemental analysis as well as various spectroscopic techniques.  相似文献   

2.
Summary. Four new organic ammonium tetrathiotungstates (NMeenH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (NMeenH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis, infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 14 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than 0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric stretching vibration of the W–S bond.  相似文献   

3.
Four new organic ammonium tetrathiotungstates (NMeenH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (NMeenH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis, infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 14 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than 0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric stretching vibration of the W–S bond.  相似文献   

4.
1,3-Bis(bromomethyl)-2-methoxy-5-methylbenzene, 1,3-bis(bromomethyl)-2,4,6-trimethylbenzene, 1,3- and 1,4-bis(bromomethyl)benzene undergo nucleophilic substitution with methyl mercaptoacetate to provide respective diesters 6–9. These diesters (6–9) on stirring with bis(3-aminopropyl)amine and diethylenetriamine in methanol–toluene (1:1) mixture undergo intermolecular cyclization to give respective thia-aza macrocycles 10–15. The alkylation of macrocycles 10–13 with 9-anthracenylmethyl chloride gave amine N-(anthracenylmethyl) substituted macrocycles 16–19. The extraction profile of macrocycles 10–15 towards alkali (Li+, Na+, K+), alkaline earth (Mg2+, Ca2+, Sr2+, Ba2+), Ag+, Tl+ and Pb2+ picrates shows preferential extraction of Ag+ with these macrocycles. The macrocycles 16–19 show fluorescence spectrum typical of anthracene moiety and depending on their structures exhibit 0–80 times increase in fluorescence on addition of transition metal ions. Fluorescent receptors 16, 17, and 19 are capable of functioning as a very efficient multi input OR logic gate.
Graphical abstract 1,3- and 1,4-Bis(bromomethyl)benzene and its substituted derivatives undergo nucleophilic substitution with methyl mercaptoacetate to provide respective diesters 6–8. These diesters (6–8) on stirring with bis(3-aminopropyl)amine in methanol–toluene (1:1) mixture undergo intermolecular cyclization to give respective thia-aza macrocycles 10–12. The alkylation of macrocycles 10–12 with 9-anthracenylmethyl chloride gave amine N-(anthracenylmethyl) substituted macrocycles 16–18. The macrocycles 16–18 exhibit 0–80 times increase in fluorescence on addition of transition metal ions.
  相似文献   

5.
 Homochiral Nα-methyl-2,3-diaminopropionic and Nα-methyl-2,4-diaminobutyric acid derivatives 8a,b were obtained via a stereoconservative four-step synthesis starting from hexafluoroacetone protected L-aspartic and L-glutamic acid 2a,b, respectively. Hexafluoroacetone protected ω-isocyanato-α-methylamino acids 4a,b– the key intermediates of the synthesis – are versatile building blocks for amino acid and peptide modification and promising candidates for combinatorial chemistry. Upon reaction with alcohols, compounds 4 give activated N ω-urethane protected ω-amino-α-methylamino acid derivatives 57; upon reaction with amines, ω-ureido-α-methylamino acid derivatives 1012 and 3-methylamino-pyrrolidin-2-ones 13 are available.  相似文献   

6.
The substituent effects on the geometrical parameters and the individual hydrogen bond (HB) energies of base pairs such as X–adenine–thymine (X–AT), X–thymine–adenine (X–TA), X–guanine–cytosine (X–GC), and X–cytosine–guanine (X–CG) have been studied by the quantum mechanical calculations at the B3LYP and MP2 levels with the 6–311++G(d,p) basis set. The electron withdrawing (EW) substituents (F and NO2) increase the total binding energy (ΔE) of X–GC derivatives and the electron donating (ED) substituent (CH3) decreases it when they are introduced in the 8 and 9 positions of G. The effects of substituents are reversed when they are located in the 1, 5, and 6 positions of C, with exception of CH3 in the 1 position and F in the 5 position, which in both cases the ΔE value decreases negligibly small. With minor exceptions (X=8–CH3, 8–F, and 9–NO2), both ED and EW substituents increase slightly the ΔE values of X–AT derivatives. The individual HB energies (∆E HBs) have been estimated using electron densities that calculated at the hydrogen bond critical points (HBCPs) by the atoms in molecules (AIM) method. Most of changes of individual HBs are in consistent with the ED/EW nature of substituents and the role of atoms entered H-bonding. The remarkable change is observed for NO2 substituted derivative in each case.  相似文献   

7.
Two new phenolic compounds, 4-O-β-D-(6-O-gentisoylglucopyranosyl) vanillic acid (1), 2-O-β-D-(6-O-gentisoylglucopyranosyl) gentisic acid (2), together with three known compounds, vanillic acid (3), syringic acid (4), and gentisic acid (5), were isolated from the whole part of Stenoloma chusanum (L.) Ching. Structures of the two new compounds 1, 2 were elucidated on the basis of spectroscopic methods, including twodimensional NMR techniques and HR ESI-MS analysis. The compounds′ activities against Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Epidermophyton floccosum, and Aspergillus niger were determined, and the minimal inhibitory concentrations (MIC) were 25–100 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 161–164, March–April, 2009.  相似文献   

8.
The conformational behavior of 1,2-difluoroethane (1), 1,2-dichloroethane (2), 1,2-dibromoethane (3), and 1,2-diiodoethane (4) have been analyzed by means of complete basis set CBS-QB3, hybrid-density functional theory (B3LYP/Def2-TZVPP) based methods and natural bond orbital (NBO) interpretation. Both methods showed the expected greater stability of the gauche conformation of compound 1 compared to its anti conformation. Contrary to compound 1, the anti conformations of compounds 24 are more stable than their gauche conformation. The stability of the anti conformation compared to the gauche conformation increases from compound 1 to compound 4. The NBO analysis of donor–acceptor (σ → σ*) interactions showed that the generalized anomeric effect (GAE) is in favor of the gauche conformation of compound 1. Contrary to compound 1, GAE is in favor of the anti conformations of compounds 24. The GAE values calculated (i.e., GAEanti − GAEgauche) increase from compound 1 to compound 4. On the other hand, the calculated dipole moment values for the gauche conformations decrease from compound 1 to compound 4. In the conflict between the GAE and dipole moments, the former succeeded in accounting for the increase of the anti conformation stability from compound 1 to compound 4. There is a direct correlation between the calculated GAE, ∆[r c–c(G) − r c–c(A)] and ∆[r c–x(A) − r c–x(G)] parameters. The correlations between the GAE, bond orders, total steric exchange energies (TSEEs), ΔG Anti–Gauche, ΔG (Gauche → Gauche′, C 2v), ΔG (Anti → Gauche, C 2), dipole–dipole interactions, structural parameters, and conformational behaviors of compounds 14 have been investigated.  相似文献   

9.
Three new glutinane-type triterpenes, 19α-glutin-5-en-19-ol (1), 2β,15α,21β-glutin-11-ene-2,15,21-triol (2), and 2β,19α-glutin-7,21-diene-2,19-diol (3), were isolated from the stem bark of Euonymus hamiltonianus. Their structures were determined by 1D and 2D NMR along with MS and IR. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 321–323, May–June, 2009.  相似文献   

10.
New substituted anilides of the heterocyclic series 2, 4, 5, 6, 7 together with the earlier described compounds 1 and 3 (Jarak I et al. (2005) J Med Chem 48:2346), were synthesized from the corresponding heterocyclic carbonyl chlorides, methoxycarbonyl- and cyano-substituted anilines. Compounds 2 and 7 were prepared by methylation with methyl-iodide on the amide and the pyridine nitrogen. The Pinner reaction was used in the preparations of amidino-substituted compounds. It seems that all the prepared compounds could be biologically interesting, especially amidino-substituted anilides prepared in the form of water-soluble hydrochlorides or hydroiodides. Molecular and crystal structures of the three compounds, namely, 4′-methoxycarbonyl-N-phenyl-3-chlorobenzo[b]thiophene-2-carboxamide (1), N-(4′-amidinophenyl)-3-chlorobenzo[b]thiophene-2-carboxamide hydrochloride monohydrate (4) and 1-methyl-N-(4-amidinophenyl)-3-pyridine carboxamide iodide hydroiodide (7) have been determined by X-ray single-crystal diffractometry in the solid state. Compounds 1, 4 and 7 are not planar and the amide group (C=O in relation to NH group) is in trans position in all three compounds. The 3-chlorobenzo[b]thiophene moiety in 1 and 4 is oriented with the chloro substituent in cis position in relation to amide NH group. The conformational characteristics of the compounds result from the introduction of different substituents or solvent molecules (water molecule in 4), which leads to various intermolecular hydrogen bonds formation (N–H⋯O, N–H⋯Cl, O–H⋯Cl, N–H⋯I) in 1, 4 and 7. Hydrogen bond formation could be responsible for the potential biological activity of the compounds.  相似文献   

11.
Summary.  Homochiral Nα-methyl-2,3-diaminopropionic and Nα-methyl-2,4-diaminobutyric acid derivatives 8a,b were obtained via a stereoconservative four-step synthesis starting from hexafluoroacetone protected L-aspartic and L-glutamic acid 2a,b, respectively. Hexafluoroacetone protected ω-isocyanato-α-methylamino acids 4a,b– the key intermediates of the synthesis – are versatile building blocks for amino acid and peptide modification and promising candidates for combinatorial chemistry. Upon reaction with alcohols, compounds 4 give activated N ω-urethane protected ω-amino-α-methylamino acid derivatives 57; upon reaction with amines, ω-ureido-α-methylamino acid derivatives 1012 and 3-methylamino-pyrrolidin-2-ones 13 are available. Received November 17, 1999. Accepted November 26, 1999  相似文献   

12.
A series of trichlorogermyl-substituted dicarboxylic acids of general formula HOOC–R′–COOH where R′=–CH2CH(GeCl3)CH21, –CH(CH2GeCl3)CH22, –CH(GeCl3)CH23 and –CH(CH3)CH(GeCl3)– 4 were synthesized by the hydrogermylation reaction of unsaturated acids, such as trans-glutaconic (2-pentenedioic acid), itaconic (methylenebutanedioic acid), fumaric (2-butenedioic acid), and citraconic (2-methyl-2-butenedioic acid) acids with HGeCl3, which was produced in situ by the reaction of GeO2 with 37% HCl in presence of NaH2PO2 · H2O. All these compounds were characterized by melting point, CHN analysis, FTIR, and multinuclear NMR (1H; 13C; H,H-COSY). X-Ray crystal structures of 1 and 2 were analyzed to show supramolecular structures in which central Ge atom in each of these structures is four-coordinated with a slightly distorted tetrahedral geometry. Structurally, both compounds adopt supramolecular forms via strong intermolecular O–H–O interactions through 8-membered and 22-membered hydrogen bonded rings. Supplementary material to this paper is available in electronic form at Correspondence: Muhammad Mazhar, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.  相似文献   

13.
We present the crystal structures of the chloride salts of the mono-guanidinium 1 (–CH2CH2– linker) and the bis-isouronium 2 (–O– linker) that have been resolved by us indicating that these compounds are diprotonated in the solid state as informed by the counterions positions. To determine the pK a values of these compounds as well as those of their analogues 3 (mono-2-aminoimidazolinium with a –CH2CH2– linker) and 4 (mono-guanidinium with a –O– linker), the corresponding UV–Vis titrations were carried out. Thus, in aqueous solution compounds 1, 3 and 4 were present as mono-cationic species while derivative 2 was a bis-cation.  相似文献   

14.
Molecular and electronic structure of four polyhydrogenated (n,0)-tubulenes, namely, [−C24H4−] m (1), two isomers of composition [−C28H4−] m (2 and3), and [−C32H4−] m (4) withn benzene rings in the cross section (n=6, 7, 7, and 8, respectively), was simulated atm>1 (m is the number of repeating fragemnts). It was assumed that hydrogen atoms are attached to all carbon atoms lying on the two most distant elements of the cylinders of the corresponding tubulenes. The energy band structures of macromolecules1–4 and their Li-intercalated analogs [−C24H4Li−] m (5) [−C28H4Li−] m (two isomers,6 and7), and [−C32H4Li−] m (8), containing one Li atom per repeating unit at each center, were obtained in the EHT approximation by the crystal orbital method. Geometric parameters of repeating units of structures1–8 were found after MNDO/PM3 optimization of the energies of hydrocarbon molecules C72H24, C84H26 (two geometric isomers), and C96H28, containing three repeating units of corresponding tubulenes1–4 each. The conductivity types of polyhydrogenated tubulenes1–4 are the same as those of their precursors, (6,0)-, (7,0)-, and (8,0)-tubulenes. Dispersion curves of systems5–8 are much the same as those of macromolecules1–4; however, electron energy spectra of5–8 possess metallic conductivity type and the positions of Fermi levels for these systems are higher than for compounds1–4. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2061–2067, November, 1999.  相似文献   

15.
The γ-ray-induced copolymerization of styrene and the surfactant monomer (surfmer) (11-acryloyloxy)undecyltrimethylammonium bromide, 1, – with and without the presence of the nonreactive surfactant N-dodecyltrimethyammonium bromide, 2, – was studied in a single-phase (1Φ) oil-in-water microemulsion. Upon exchange of 50 weight percent of 1 against 2 the 1Φ region could be increased to higher styrene content. Upon γ-ray irradiation a copolymer is formed: this copolymer exhibits a larger styrene-to-surfmer ratio than the original monomer mixture. This allowed the styrene-to-surfmer molar ratio in the resulting polymer to be varied from 0:1 to 4.3:1. The larger styrene-to-surfmer ratio originates from the simultaneous formation of homopolymer P-1, which is in accordance with the Candau–Leong–Fitch model of polymerization. Further information on particle size and material properties of the copolymers, which is not accessible by other preparation methods, is also given. Received: 30 July 1999 /Accepted: 24 November 1999  相似文献   

16.
6-Aroyl-7-arylindolo[3,4-jk]phenanthridin-5(4H)-ones (2a–i) were synthesized by heating 3-(2-aryl-2-oxoethylidene)-2,3-dihydroindol-2-ones (1a–i) in DMF. Compounds 2a–i are formed via the dimerization of two molecules of unsaturated ketones 1a–i proceeding as the [2+4] cycloaddition through the formation of intermediate spiro adducts. The further Pfitzinger rearrangement, decarboxylation, and heteroaromatization afford compounds 2a–i. The structures of the reaction products were established by spectroscopic methods and X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 609–618, March, 2008.  相似文献   

17.
A series of halogenated nucleobase derivatives 14 is reported to yield solvent-free (2) and DMSO solvated crystals (1, 3, 4) on the crystallization from DMSO with one of them (4) containing an additional molecule of water. The molecular and crystal structures are described and comparatively discussed with reference to previous results on related compounds. The molecule of 1 is planar, molecules of 2 and 3 show syn alignment with reference to the heterocyclic ring and common C2′-endo conformation of the ribose residue, while 4 is also syn aligned but C4′-exo in the sugar conformation. The packing structures reveal typical aggregations created via networks of hydrogen bonds. These involve conventional N–H···N, N–H···O and O–H···O interactions between nucleobase and ribose units as well as solvent molecules, additionally supported by weak C–H···O contacts but excluding the participation of halogen···halogen interactions as well as halogen···heteroatom contacts in the supramolecular structure formation.  相似文献   

18.
A new bicyclo[3.2.1]octanoid neolignan rel-(7S,8R,1′S,2′R,3′S)-Δ8′-2′-hydroxy-5,1′,3′-trimethoxy-3,4methylenedioxy-7,3′,8,1′-neolignan (1) was isolated from ethanol extract from the fruit of Ocotea heterochroma Mez & Sodiro ex Mez as well as the known compounds β-friedelanol (2), meso-dehydroguaiaretic acid (3), and yangambin (4), whose structures were elucidated on the basis of their comprehensive spectroscopic analysis including 2D NMR data. Lethality bioassay using brine shrimp (Artemia salina Leach) was evaluated with the ethanol extract from the Ocotea heterochroma’s fruit. The toxicity of this extract was greater than the toxicity of those fractions obtained in a first solvent partition (benzene, ethyl acetate, and butanol subfractions) and that of a mixture of acetylated 2′-epimers from the new neolignan 1. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 158–160, March–April, 2009.  相似文献   

19.
A new briarane diterpene, juncin ZII (1), along with three known briaranes (2–4), was isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian Junceella juncea. The structure of 1 was established by extensive spectroscopic analysis, including 1D and 2D NMR data. For compounds 1–4 and eight other briaranes (5–12) isolated from J. juncea previously, the antifeedant activity against second-instar larvae of Spodoptera litura and cytotoxicity against S. litura cells were investigated, and it was observed that they all exhibit medium antifeedant activity. Compounds 1, 8, 9, and 12 also showed potent antifouling activity against the larval settlement of barnacle Balanus amphitrite at nontoxic concentrations with EC50 values of 0.004, 0.005, 2.82, and 0.447 μg/mL, respectively, while all compounds did not show obvious cytotoxicity against tumor cell lines K562, A549, Hela, and Hep-2. Their structure-activity relationship was discussed. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 44–47, January–February, 2009.  相似文献   

20.
The complexes were synthesized by the reaction between sodium salt of p-aminosalicylic acid (PAS) and Cu(II) for 1 and corresponding ethylenediamine (en) or its derivatives for 26. The complexes were characterized by using elemental analyses, FT-IR, UV–Vis, magnetic moment measurements, and thermal analyses techniques. In complex 1[Cu2(PA)4(H2O)2], two Cu(II) ions were found as bridged by four μ-O:O′ p-aminosalicylato (PA) ligands, forming a cage structure, and two aqua ligands to form dinuclear square-pyramidal geometry around Cu(II) ions. In the complexes 26, the PA (anionic form of p-aminosalicylic acid) coordinated to Cu(II) ions as monodentate manner by using its oxygen atom of deprotonated carboxylic acid and ethylenediamine derivatives coordinated to the Cu(II) ions in bidentate manner to form mononuclear octahedral complexes [Cu(PA)2(L)2] (L = ethylendiamine, N,N-dimethylethylendiamine, N,N′-dimethylethylendiamine, N,N,N′,N′-tetramethylethylendiamine, and 1,3-propanediamine, for complexes 2, 3, 4, 5, and 6, respectively). In all the complexes OH and NH2 groups of PA ligands were not coordinated to metals.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号