Synthesis and mechanism of formation of novel 2,5-dihydro-2,5-diimino-3,4-di[(N,N-dimethylamino)methylideneamino]pyrroles and 5-amino-3,4-di[(N,N-dimethylamino)methylideneamino]-2H-2-iminopyrroles

Formation of 5-amino-3,4-di[(N,N-dimethylarnino)methylidenearnino]-2H-2-iminopyrroles 3 from the reaction of (Z)-N¹-(2-amino-1,2-dicyanovinyl)-N²-substituted-formamidines 1 with dimethylformamide diethyl acetal has been shown to occur by initial formation of (Z)-N¹-{l,2-dicyano-2-[N,N-dimethylamino)methylideneamino]vinyl}formamidines 8 (isolated), followed by base catalysed cyclisation and imi dazole ring opening by dimethyl amine. The kinetic product of the ring opening reaction is the 2,5-diimino2,5-dihydropyrrole derivatives 11, which have been isolated and characterized spectroscopically and by a single crystal X-ray analysis on the R = Ph derivative. In solution at room temperature the N-aryl derivatives undergo a rapid Dimroth rearrangement to give the thermodynamic ally more stable isomer 3 , but compound 11 (R = Me) is much more stable in solution.     

Solid state N and C NMR study of dioxomolybdenum (VI) complexes of Schiff bases derived from trans-1,2-cyclohexanediamine

The ¹³C, ¹⁵N CP MAS NMR and FT-IR spectra of dioxomolybdenum (VI) complexes of trans-N,N′-bis-(R-salicylidene)-1,2-cyclohexanediamine (R=H, R=3,5-diCl, R=3,5-diBr, R=4,6-diOCH₃), trans-N,N′-bis-(2-OH-naphthylidene)-1,2-cyclohexanediamine and trans-N-(salicylidene)-N′-(2-OH-naphthylidene)-1,2-cyclohexanediamine have been measured. Comparative analysis of the NMR and IR spectra of the complexes with those of the corresponding ligands has shown that the complexation of the di-Schiff bases leads to changes in the conformation of the ligands and the charge redistribution. The asymmetric structure and non-planar structure of the complexes have been suggested.     

N-Acylureas in Peptide Synthesis: An X-Ray Diffraction and IR-Absorption Study

An X-ray diffraction analysts of two N-acyl derivatives of symmetrical dialkylureas, N-[N^α-(benzyloxycarbonyl)-L -valyl] -N, N′-diisopropylurea ( 1 ) and N-{Nα(tert-butyloxy)carbonyl -L -valyl}-N-N′-dicyclohexylurea ( 2 ), and one N-acyl derivative of an unsymmetrical N-N′-dialkylurea, N-[N^α-(benzyloxycarbonyl)-L -valyl] -N′-(tert-butyl)-N-ethylurea ( 3 ), has been performed. It was established that it is the least hindered O-acylisourca N-atom that attacks intramolecularly the carbonyl group of the N^α-protected amino acid activated by the unsymmetrical carbodiimide to form the major rearrangement product. The occurrence and nature of intra- and intermolecularly H? bonded forms of the N-acylureas in the crystal state were also assessed. It was also shown that soluble N-acylureas may compete with intermolecular (peptide)N? H…O?C(peptide) H-bonds in CH₂Cl₂.     

Novel dialkylaminoalkyl- and dialkylaminoalcoxi-benzophenones as photoinitiators of polymerization. I. Photochemical characteristics and radical efficiencies

The behavior of the nonconjugated aminated benzophenones—4-[2′-N,N-(diethylamino)ethoxy]benzophenone (E4), 2-[2′-N,N-(diethylamino)ethoxy]-4-methoxybenzophenone (E2), and 4-N,N-dimethylaminomethylbenzophenone (DM)—as photoinitiators of MMA polymerization has been studied and the results compared with those obtained with the conjugated aminobenzophenone 4-N,N-dimethylamino-4′-isopropyl-benzophenone (CU—MI). Photoreduction behavior of these compounds in various solvents in the presence and absence of MMA has been also examined. The order of the polymerization reaction with respect to monomer and initiator concentrations has been investigated; values of initiation quantum yield (Φ_i), K_p/K^1/2_t and efficiencies of the different radicals have also been determined. Similar polymerization rates (R_p) of methyl methacrylate (MMA) were found when E4 and CU-MI were used as photoinitiators under the same range of absorbed irradiation intensity. This fact results from a compensation between the higher rate of E4 radical production (n-π* transition type) and the greater reactivity of the radicals generated from CU-MI.     

Mono- and dinuclear Zn(II) complexes of Schiff-base ligands: syntheses,characterization and studies of photoluminescence

Six Schiff-bases HL¹-HL⁴, L⁵ and L⁶ [HL¹ = 2,6-bis[1-(2-aminoethyl)pyrolidine-iminomethyl]-4-methyl-phenol, HL² = 2,6-bis[1-(2-aminoethyl)piperidine-iminomethyl]-4-methyl-phenol, HL³ = N-{1-(2-aminoethyl)pyrolidine}salicylideneimine, HL⁴ = N-{1-(2-aminoethyl)piperidine}salicylideneimine, L⁵ = 2-benzoyl pyridine-N-{1-(2-aminoethyl)pyrolidine}, L⁶ = 2-benzoylpyridine-N-{1-(2-aminoethyl)piperidine}] have been synthesized and characterized. Zn(II) complexes of those ligands have been prepared by conventional sequential route as well as by template synthesis. The same complexes are obtained from the two routes as evident from routine physicochemical characterizations. All the Schiff-bases exhibit photoluminescence originating from intraligand (π–π*) transitions. Metal mediated fluorescence enhancement is observed on complexation of HL¹-HL⁴ with Zn(II), whereas metal mediated fluorescence quenching occurs in Zn(II) complexes of L⁵ and L⁶.     

13C nuclear magnetic resonance spectroscopy of selected adenine nucleosides: Structural correlation and conformation about the glycosidic bond

Structural correlations have been carried out from ¹³C chemical shifts (δ) and by analysis of ¹J(CH) coupling constants, and the conformation about the glycosidic bond has been studied by means of the ³J(CH) vicinal coupling constants between C-8 and H-1′ of some adenine nucleosides such as adenosine (Ado), N(7)-β-D-ribofuranosyladenine (N(7)-Ado), N(9)- and N(7)-β-D-xylofuranosyladenine (N(9)-xylAde and N(7)-xylAde), N(9)-(3-chloro-3-deoxy-β-D-xylofuranosyl)adenine (3′-Cl-xylAde) and N(9)-(2-chloro-2-deoxy-β-D-arabinofuranosyl)adenine (2′-Cl-araAde). The analysis of the influence on δ¹³C of the nature and configuration of the substituent in the carbohydrate fragment of the molecule has revealed two types of effects, namely, 1,2-cis and 1,2-trans. This approach, as well as the ³J(CH) values and the analysis of the C-3′-endo?C-2′-endo equilibrium of the carbohydrate fragment of nucleosides, and circular dichroism (CD) data, provides important information on the conformation about the glycosidic bond. The magnitudes of ³J(C-4, H) are indicative of the position of attachment of the carbohydrate fragment to the heterocyclic base.     

Synthesis and antiproliferative activity of (1R,2R)-N1-(2-butyl)-1,2-cyclohexanediamine platinum(II) complexes with malonate derivatives

Three new platinum(II) complexes of (1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine with malonate derivatives as leaving groups have been synthesized and spectrally characterized. They were tested in vitro against four human cancer cell lines. [(1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine-N,N′](2-ethylmalonato-O,O′)platinum(II) turned out to be more active (IC₅₀ = 4.65 μM) than oxaliplatin (IC₅₀ = 6.55 μM) against the MCF-7 cell line and is superior to its parent complex, [(1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine-N,N′](malonato-O,O′)platinum(II). In addition, agarose gel electrophoresis study revealed that the interaction of the complex with pET22b plasmid DNA had a different behavior from that of cisplatin or oxaliplatin.     

Chemosensor properties of mono- and bisthioureas based on 9-anthrylmethyl-substituted alkylamines and diamines

Mono- and bisthioureas were synthesized based on N-(9-anthrylmethyl)-substituted alkylamines and diamines. Their luminescent and complexing properties were studied by the electronic, IR, and NMR ¹H spectroscopy. N-(9-Anthrylmethyl)-N-(6-{9-anthrylmethyl[(phenylamino)carbothioyl]amino}hexyl)-N′-phenylthiourea was shown to be a highly effective fluorescent chemosensor for Hg²⁺ cations.     

Synthese von threo-cis/threo-trans- und erythro-cis/erythro-trans-Dihydropalustrin. 17. Mitteilung über Schachtelhalmalkaloide

Synthesis of threo-cis/threo-trans- and erythro-cis/erythro-trans-dihydropalustrin The first synthesis of a threefold protected spermidine, namely ³-benzyloxycarbonyl-N¹-phthaloyl-N²-tosylspermidin ( 9 ) is presented. Each of the protecting groups can be removed selectively. After hydrazinolysis the resulting N³-benzyloxy-carbonyl-N²-tosylspermidine ( 10 ) has been condensed with methyl (2 E)-cis-7,8-epoxy-2-decenoate to the threo-cis/trans piperidines 17 , and with methyl (2 E)-trans-7,8-epoxy-2-decenoate to the erythro-cis/trans piperidines 17 , respectively. After catalytic removal of the Z group, the resulting aminoesters 13 and 18 , in a melt with imidazole, underwent ring closure to the 13-membered lactames 14 and 19 , respectively. reductive deprotection of the N-tosyl group with sodium/ammonia led to the stereoisomeric palustrines 15 and 20 , respectively.     

Multicomponent one pot synthesis of C-glucosides of 1-azaindolizines

Abstract

A protocol based on Groebke-Blackburn-Bienayame (GBB) multicomponent reaction has been developed for efficient and atom economical synthesis of C-glucosides of 1-azaindolizine, i.e. 2-(β-D-glucopyranosyl)-3-N-alkylamino-1-azaindolizine. Thus, a series of fourteen novel 2-(β-D-glucopyranosyl)-3-N-alkylamino-1-azaindolizines have been synthesized in moderate to good yields by reaction of a perbenzylated β-C-glucopyranosyl aldehyde with differently substituted 2-aminopyridines and alkyl isocyanides using InCl₃ as acid catalyst. All synthesized β-C-glucosides were unambiguously characterized with the help of spectroscopic (IR, ¹H-NMR, ¹³C-NMR and mass spectra) data analysis.     

Supramolecular Complexes of Calix[4]resorcinolarene Tetramethylsulfonate with Organophosphorus Compounds

Supramolecular complexes of calix[4]resorcinolarene tetramethylsulfonate with certain organophosphorus compounds, such as dimethyl (1,1-dimethyl-3-oxobutyl)phosphonate, 1-O-[bis(N,N-diethylamino)thiophosphinoyl]-3,5-O-[(N,N-diethylamino)thiophosphonoyl)-2,4-O-methylenexylitol, and 2-O-[bis(N,N-diethylamino)thiophosphinoyl]-3,5-O-[(N,N-diethylamino)thiophosphonoyl)-1,4-anhydroxylitol, were prepared in aqueous and organic media. The complexes were isolated and characterized by elemental analysis and ¹H and ¹³C NMR spectroscopy.     

Copper(II) complexes of 2-formyl-,2-acetyl- and 2-benzoylpyridine N(4)-o-, N(4)-m-, N(4)-p-chlorophenylthiosemicarbazones

Summary Cu^II complexes of 2-formyl, 2-acetyl- and 2-benzoylpyridine N(4)-o-, N(4)-m- and N(4)-p-chlorophenylthiosemicarbazones, coordinated either as a neutral or monoanionic ligand, have been prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as ¹H- and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. Both the thiosemicarbazones and their Cu^II complexes show either modest or no growth inhibitory activity against Paecilomyces variotii. Some of the thiosemicarbazones demonstrated significant activity against tumour cell strains.     

Synthesis,structure, ADME and biological activity of three 2,6-disubstituted thiosemicarbazone derivatives

Three new 2,6-disubstituted thiosemicarbazone derivatives of pyridine, namely, 2-{amino[6-(pyrrolidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C₁₃H₂₀N₆S, 2-{amino[6-(piperidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C₁₄H₂₂N₆S, and 2-[amino(6-phenoxypyridin-2-yl)methylidene]-N,N-dimethylhydrazine-1-carbothioamide monohydrate, C₁₅H₁₇N₅OS·H₂O, have been synthesized and characterized by NMR spectroscopy and low-temperature single-crystal X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The ability of the tested compounds to inhibit bacterial growth was comparable to vancomycin as a reference drug. Compared to isoniazid (MIC 0.125 and 8 µg ml⁻¹), the compounds showed the ability to inhibit the growth of Mycobacterium tuberculosis to a moderate degree for the standard strain and at the same level or higher (MIC 4–8 µg ml⁻¹) for the resistant strain. All three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules.     

Synthesis of Dye-Labeled Lysine Derivatives

The N′-dabcyl-N ^α-(9-fluorenylmethoxy)-carbonyllysine was prepared by reaction of lysine-Cu²⁺ complex with the N-hydroxysuccinimide (HOSu) activated ester of [4-(4'-dimethylamino)phenylazo]benzoic acid (dabcyl acid) followed by treatment with EDTA and acylation with Fmoc-OSu, and the N ^α-tert-butyloxycarbonyl-N′-dabcyllysine was prepared by reaction of N ^α-tert-butyloxycarbonyllysine with dabcyl-OSu.     

N-(安替比林-4-基)-N'-取代芳甲酰基硫脲的合成及其生物活性

合成了12个含安替比林基的取代芳甲酰基硫脲类化合物, 用¹H NMR, IR和元素分析确证了它们的结构, 并进行了室内生物活性测试. 生测实验证明部分酰基硫脲类化合物, 比如N-(安替比林-4-基)-N'-m(或o)-甲苯甲酰基硫脲, N-(安替比林-4-基)-N-o-硝基苯甲酰基硫脲, N-(安替比林-4-基)-N'-m(或p)-氯苯甲酰基硫脲, 具有一定的细胞分裂素活性.     

Synthesis of some benzimidazole-, pyridine- and imidazole-derived chelating agents

Procedures are described for the preparation of various bidentate and potentially tridentate chelating agents. These incorporate pyridyl, benzimidazole, imidazole or phenolic moieties. Phillips condensations of carboxylic acids with o-phenylenediamines were carried out in 4 M hydrochloric acid. Syntheses are reported for 2, 6-bis(N′-methylimidazol-2′-ylthiomethyl)pyridine, 2, 6-bis(benzimidazol-2′-ylthiomethyl)pyridine, 2-(4′-piperidyl)benzimidazole, 2-(3′-piperidyl)benzimidazole, 2-(3-N′-methylpiperidyl)benziinidazole, 2-(3-N′-methylpiperidyl)-N-methylbenzimidazole, 2-(2′-hydroxybenzyl)benzimidazole and 2-(2′-hydroxyben-zyl)N-methylbenzimidazole. The compounds were characterized where appropriate by their mass, uv, and ¹H-nmr spectra. 2-(2′-Hydroxybenzyl)benzimidazole hydrochloride acts as a gelling agent in aqueous solution.     

Click synthesis of N1-(β-D-ribofuranosyl)-C4-(coumarin-4″-yl)-1,2,3-triazoles

A series of eight N¹-(β-D-ribofuranosyl)-C⁴-(coumarin-4′′-yl)-1,2,3-triazoles have been synthesized by Cu(I)-catalyzed click reaction of 1-azido-1-deoxy-2,3,5-tri-O-benzoyl-β-D-ribofuranose with differently substituted 4-ethynylcoumarins followed by debenzoylation of the resulted N¹-(2′,3′,5′-tri-O-benzoyl-β-D-ribofuranosyl)-C⁴-(coumarin-4″-yl)-1,2,3-triazoles in 71 to 89% overall yields. The structures of all the synthesized compounds were established on the basis of their spectral data analysis that was further confirmed by X-ray data analysis of one of the model benzoylated compounds, i.e. N¹-(2′,3′,5′-tri-O-benzoyl-β-D-ribofuranosyl)-C⁴-(7″-isopropoxycoumarin-4″-yl)-1,2,3-triazole.     

Synthesis and biodistribution of p-iodophenyl analogues of a naturally occurring imidazole ribonucleoside

A model iodophenyl imidazole ribonucleoside has been synthesized to study biodistribution properties in laboratory animals. The key intermediate 5-amino-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)imidazole-4-[N-(p-iodophenyl)carboxamide] ( 5 ) was synthesized by coupling N-succinimidyl-5-amino-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)imidazole-4-carboxylate ( 4 ) and p-iodoaniline. Deacetylation of the intermediate compound gave 5-amino-1-β-D-ribofuranosylimidazole-4-[N-(p-iodophenyl)]carboxamide ( 6 ). Ring annulation via diazotization of 5 gave 7-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)imidazo[4,5-d]-v-triazin-[3-N-(p-iodophenyl)]-4-one ( 7 ). Subsequent deacetylation of 7 afforded 7-β-D-ribofuranosylimidazo[4,5-d]-v-triazin-[3-N-(p-iodophenyl)]-4-one ( 8 ). The radiolabeled compounds, [¹²⁵I] 5 and [¹²⁵I] 6 were prepared in a manner similar to the corresponding unlabeled compounds except that p-[¹²⁵I]iodoaniline was used for coupling with 4 . Biodistribution studies of iodine-125-labeled 5 and 6 were performed in female Fischer rats and tumor bearing nude mice. Compound 6 showed uptake in the brain and proliferating tissues such as tumor and bone-marrow.     

季胺基修饰的Salen配合物的合成及性质

采用季胺基取代的水杨醛(由2,4-二羟基水杨醛、1,2-二溴乙烷、高氯酸钠等为原料合成)合成了两个新型Salen配体N,N'-二{4-[[2-(三甲胺基)乙基]氧化]水杨醛}-邻苯二胺二高氯酸盐(L¹), N-(2-羟基-5-甲基二苯甲基)-N'-{4-[[2-(三甲胺基)乙基]氧化]水杨醛}-邻苯二胺高氯酸盐(L²), 并进一步合成了8个新型Salen金属配合物[ZnL¹, NiL¹, CuL¹, ZnL², NiL², CuL², MnL², CoL²]. 用¹H NMR, ¹³C NMR, FT-IR, UV-vis, MS对配体和配合物进行了表征, 测定了金属配合物的水溶性及在水中的摩尔电导率. 结果表明, 与相应母体配合物的水溶性比较, 含有季胺基修饰的Salen金属配合物的水溶性有了较大提高.     

Synthesis,characterization, thermogravimetry,and structural study of uranium complexes derived from dibasic S-alkylated thiosemicarbazone ligands

Two pentagonal bipyramidal complexes, ethanol-(S-ethyl-N¹,N⁴-bis(3-methoxy-2-hydroxybenzaldehyde)-isothiosemicarbazide-N,N′,O,O′)-dioxidouranium(VI) (1) and ethanol-(S-ethyl-N¹-(2-hydroxyacetophenone)-N⁴-(5-bromo-2-hydroxybenzaldehyde)-isothiosemicarbazide-N,N′,O,O′)-dioxidouranium(VI) (2), have been prepared and characterized. Their structures have been determined by X-ray crystallography, and the structural parameters are discussed with those observed in related complexes. Electronic absorption, proton magnetic resonance, and FT-IR spectra have been recorded and analyzed. In both complexes, the U(VI) centers are surrounded by N₂O₂ donor ligands, two oxido groups, and one ethanol in a distorted pentagonal bipyramid. The thermal stability of the new complexes has also been determined.