共查询到20条相似文献,搜索用时 31 毫秒
1.
Rajiv Dahiya Monika Maheshwari Anil Kumar 《Monatshefte für Chemie / Chemical Monthly》2009,62(5):121-127
Abstract
The present investigation deals with the synthesis of a N-methylated cyclotetrapeptide, hirsutide (2), by coupling of the dipeptide units Boc-l-phenylalanyl-l-N-methylphenylalanine-OH and l-valyl-l-N-methylphenylalanine-OMe followed by cyclization of the linear tetrapeptide fragment. The chemical structure was established on the basis of analytical as well as spectroscopic data. The newly synthesized cyclic peptide was subjected to pharmacological screening and found to be highly potent against the gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae at 6 μg cm−3. In addition, potent antihelmintic activity against the earthworms Megascoplex konkanensis and Pontoscotex corethruses at 1 and 2 mg cm−3, and potent cytotoxic activity against Dalton’s lymphoma ascites and Ehrlich’s ascites carcinoma cell lines with IC50 values of 14 and 22 μM were also observed. Studies revealed that the pentafluorophenyl ester method employing a catalytic amount of N-methylmorpholine proved to be better for cyclization of the linear tetrapeptide unit. 相似文献2.
Abstract Cholesterol complexes with tri-n-butyl phosphate, tri-n-octylamine, N,N-dimethylacetamide, and cyclohexanone in benzene and toluene solutions were studied using conventional IR spectroscopy. The
spectra were recorded in the region of fundamental OH stretching (3,700–3,100 cm−1) at 298 K. The experimental spectra were resolved into bands corresponding to the cholesterol monomer and particular oligomeric
and complex species. The formation constants of complexes were determined from the-least squares plots of the linearized expressions
of Bjerrum’s formation function. The stoichiometry of complexes was also identified in this way. The identification of the
particular resolved bands was performed from their location, and from the dependence of their intensity on the cholesterol
monomer and free base concentration.
Graphical Abstract
相似文献
3.
Ashraf A. Mohamed 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):9-14
Abstract Two simple, sensitive, and selective spectrophotometric methods were developed for determining amodiaquine (AQ) and chloroquine
(CQ) based on their oxidation with potassium iodate and potassium bromate, respectively. The initial rates of oxidation of
AQ and CQ were monitored at 342 and 343 nm, the wavelengths of maximum absorptions of the two drugs. The various experimental
parameters affecting oxidation reactions were thoroughly studied and optimized. Beer’s law was obeyed for 0.2–4.0 and 0.5–5.0 μg cm−3, with correlation coefficients of 0.9999 and 0.9998 (n = 6) and a detection limit (based on the 3S
b
-criterion) of 0.04 and 0.06 μg cm−3 for AQ and CQ. The proposed methods were conveniently applied to determining AQ and CQ in pure and dosage forms.
Graphical abstract
相似文献
4.
Rajiv Dahiya 《Chemical Papers》2008,62(5):527-535
Plant-originated cyclopolypeptide (XIII) was synthesized by coupling of dipeptide Boc-l-asn(bzh)-l-phe-OH and tetrapeptide gly-l-leu-l-ala-l-tyr-OMe followed by cyclization of a linear hexapeptide segment. Structure elucidation of XIII was done on basis of detailed spectral analysis including FTIR, 1H NMR, 13C NMR, FAB MS and elemental analysis. From the results of pharmacological screening, it was concluded that XIII possesses high cytotoxic activity against DLA and EAC cell lines with CTC50 values of 15.1 μM and 18.6 μM, and potent antimicrobial activity against pathogenic fungi C. albicans with MIC of 6 μg mL−1. Moreover, XIII possesses moderate anthelmintic activity against earthworms M. konkanensis, P. corethruses, and Eudrilus sp. at 2 mg mL−1 dose level. 相似文献
5.
Emanuel Makrlík Ji?í Dybal Petr Vaňura 《Monatshefte für Chemie / Chemical Monthly》2009,286(1):1289-1292
Abstract From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant
of protonated tetraethyl p-tert-butylcalix[4]arene tetraacetate in nitrobenzene saturated with water was determined. By using DFT calculations, the most
probable structure of the tetraethyl p-tert-butylcalix[4]arene tetraacetate·H3O+ complex species was derived.
Graphical Abstract
相似文献
6.
Jolanta Rousseau Vilija Kriščiūnienė Ilona Rimkevičiūtė Cyril Rousseau Virginė Amankavičienė Algirdas Šačkus Arnaud Tatibouët Patrick Rollin 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):339-348
Abstract Modular conditions for the formation of thioureas or pyrimidine-4-one-2-thiones connected to the benzo[b]thiophene, benzene and indole structures were performed. A benzo[b]thiophene isothiocyanate derivative was used as a model to study the condensation with simple aromatic amines and amino-l-sorbose derivative. The construction of pyrimidine-4-one-2-thiones using basic conditions afforded efficiently new heterocyclic
aromatics, which were further transformed using the alkylated sulfur as a leaving group in palladium-catalyzed cross-coupling
reactions.
Graphical abstract
相似文献
7.
Waldemar Iwanek Alicja Wzorek Zdzisława Nowakowska Grzegorz Schroeder 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):359-364
Abstract Synthesis of chelates from selected l-amino acids and triethylborane, and the mass spectra of the chelates, are described. Conditions for forming dimers between
the chelates and the sodium ion are discussed, and structures are proposed for the dimers.
Graphical abstract
相似文献
8.
Lu Chen Xu-Jiang Huang Yi-Qun Li Mei-Yun Zhou Wen-Jie Zheng 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):45-47
Abstract A simple, clean, and environmentally benign three-component process to the synthesis of 2-amino-4H-chromenes using N,N-dimethylaminoethylbenzyldimethylammonium chloride, [PhCH2Me2N+CH2CH2NMe2]Cl−, as an efficient catalyst under solvent-free condition is described. A wide range of aromatic aldehydes easily undergo condensations
with α-naphthol and malononitrile under solvent-free condition to afford the desired products of good purity in excellent
yields. Taking into account environmental and economical considerations, the protocol presented here has the merits of environmentally
benign, simple operation, convenient work-up and good yields. Furthermore, the catalyst can be easily recovered and reused
for at least five cycles without losing its activities.
Graphical abstract
相似文献
9.
Jolanta Pawłowska Krzysztof K. Krawczyk Krystyna Wojtasiewicz Jan K. Maurin Zbigniew Czarnocki 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):83-86
Abstract (+)-Lortalamine was synthesised using (S)-(−)-α-methylbenzylamine as a chiral auxiliary. The stereochemistry of an intermediate compound was established on the basis
of X-ray crystallography, allowing unambiguous assignment of the absolute configuration.
Graphical abstract
相似文献
10.
Norbert Stoppacher Fritz Pittner Gerhard Sontag 《Monatshefte für Chemie / Chemical Monthly》2009,140(8):909-914
Abstract In this study a design of an immunosensor for 1-nitropyrene is illustrated. First the response of 1-nitropyrene reduced at
a glassy carbon electrode between 0 and −0.8 V was investigated with respect to pH and solvent. Then polyclonal anti-1-nitropyrene
antibodies isolated from a rabbit antiserum were covalently bound to the surface of the glassy carbon electrode. This modified
electrode was immersed in standard solutions or sample extracts for 5–15 min. 1-Nitropyrene was bound by the antibodies, accumulated
and then analyzed at pH 6.5 in another supporting electrolyte by differential pulse voltammetry. Afterwards the immunosensor
could be regenerated for the next measurement by rinsing with acetonitrile–water (40:60, v/v). A linear response was found between 20 and 100 ng/cm3. The limit of detection was 10 ng/cm3 and the intraday reproducibility of three immunosensors assembled during two months was between 4.5 and 10%. This sensor
was applied to the analysis of 1-nitropyrene in air particulate matter and smoked tea.
Graphical abstract
相似文献
11.
Mohammad Rahimizadeh Mehdi Pordel Mehdi Bakavoli Zahra Bakhtiarpoor Ala Orafaie 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):633-638
Abstract New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl3. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug.
Graphical abstract
相似文献
12.
Adel A.-H. Abdel-Rahman Ahmed E.-S. Abdel-Megied Hamed M. Abdel-Bary Abdel-Aleem H. Abdel-Aleem Emad M. I. Morcy Mohamed T. Shabaan 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):559-564
Abstract A series of peptide derivatives conjugated with N1-protected tryptophan residue was synthesized. The prepared compounds were tested for antimicrobial activity against four
different bacterial species displaying different degrees of antibacterial activities or inhibitory actions.
Graphical Abstract
相似文献
13.
Abstract A classical convergent approach for the synthesis of the anticancer drug imatinib has been substantially improved. Imatinib
was assembled by coupling the amine and carboxylic acid precursors by using N,N′-carbonyldiimidazole (CDI) as a condensing agent. Both intermediates have been synthesized by novel efficient methods.
Graphical abstract
相似文献
14.
Gourisankar Panda Md. Selim Rupali Pal Kalyan K. Mukherjea 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):281-286
Abstract The interaction of cobalt(II)-glutathione (CoGSH) with deoxyribonucleic acid (DNA) has been studied by UV–vis, fluorescence,
circular dichroism (CD), thin-film infrared (IR), and viscometric techniques. From the UV-spectroscopic method, binding constant
(K
b) was determined and was found to be 2.3 × 106 M−1. In fluorimetric analysis, the quenching of fluorescence intensity of DNA bound to ethidium bromide (EB) was investigated.
The Stern–Volmer quenching constant (K
sv) was also estimated from this study and was found to be 2.8 × 106 M−1at 37 °C. The solution CD spectra of DNA and DNA–CoGSH indicate that in each case, DNA exists in the ‘B’ conformation and
suggested an intercalative binding mode. Thin-film IR data also reveal that DNA attains the ‘B’ family of conformations after
interaction with CoGSH complex. The increase in DNA viscosity in the presence of CoGSH complexes is attributed to the lengthening
of DNA helix due to intercalation.
Graphical Abstract The spectrophotometric, CD, thin film IR, viscometric and fluorimetric studies
on the interaction of CoGSH with DNA indicated an intercalative binding mode with the
retention of ‘B’ conformation of DNA.
相似文献
15.
Marko P. Sušnik Michael Schnürch Marko D. Mihovilovic Kurt Mereiter Peter Stanetty 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):423-430
Abstract A short and efficient sequence for the synthesis of a series of 4-(2-amino-5-thiazolyl)-pyrimidine-2-amines was developed.
1-Phenyl-2-(6-pyrimidinyl)-ethanones, obtained via Weinreb’s methodology, were used in a Hantzsch thiazole cyclization reaction,
followed by introduction of the aniline moieties via nucleophilic substitution.
Graphical abstract
相似文献
16.
Synthesis of 5-spirocyclohexyl-2,4-dithiohydantoin derivatives: a potential anti-leishmaniasis agent
Abdel-Sattar S. Hamad Elgazwy Saad R. Atta-Allha Sherif M. A. S. Keshk 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):243-249
Abstract A series of spiro-dithiohydantoins were synthesized by heating a mixture of 5-spirocyclohexyl-2,4-dithiohydantoin potassium
salt and 3-chloropropanoyl chloride. These compounds were synthesized and evaluated for their activity against five Leishmanial strains in the promastigote stage in vitro. Seventy-two hours inoculation of a variety of products gave an IC
100
and average IC
50 values of 1.25 and 0.376 mg/cm3 against all Leishmanial strains tested.
Graphical Abstract
An erratum to this article can be found at 相似文献
17.
Ruta Lazauskaite Maryte Daskeviciene Vytautas Getautis Juozas V. Grazulevicius 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):565-571
Abstract Photoinitiated cationic polymerizations of various epoxy monomers bearing a carbazole moiety, 9-[3-(allyloxy)-2-(oxiran-2-ylmethoxy)propyl]-9H-carbazole, 9-[3-methoxy-2-(oxiran-2-ylmethoxy)propyl]-9H-carbazole, 9-[2-(oxiran-2-ylmethoxy)ethyl]-9H-carbazole, as well as a composition of 3,6-dibromo-9-(oxiran-2-ylmethyl)-9H-carbazole with 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate were investigated in bulk using triphenyl carbenium
salts having anions such as BF4
−, SnCl5
−, and SbCl6
−. Dark polymerizations of the carbazolyl monomers in the presence of the initiators are studied. These photoinduced polymerization
reactions give oligomers of degree of polymerization 4-22. The effect of the anion of the photoinitiator and polymerization
time on the polymerization reaction is discussed.
Graphical abstract
相似文献
18.
Maher F. El-Zohry Thanaa A. Mohamed Essam M. Hussein 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):265-272
Abstract 2-Methylbenzimidazole 1 reacted with 3-dicyanomethylidine-1-ethyl-2-oxoindoline 2 in ethyl acetate to afford 1-amino-2-cyano-3,4-dihydro-1′-ethylspiro{benzimidazo[1,2-a]pyridine-3,3′-indolin}-2′-one 6, which was used as a key intermediate in the synthesis of fused spiropolyheterocyclic derivatives of benzimidazopyridopyrimidine
and/or benzimidazonaphthyridine nucleus incorporating an indoline moiety.
Graphical abstract
相似文献
19.
Bohumil Proksa Richard Hercek Tibor Liptaj Nada Prónayová 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):485-487
Abstract A new compound was isolated from the reaction mixture after O-demethylation of 6-O-acetyl-10α-acetoxycodeine with boron tribromide. The structure of this compound, 10α-hydroxy-β-isomorphine, was elucidated by spectral data, and its spatial arrangement was deduced from an NOE experiment. Capillary zone
electrophoresis was used for separation of morphine and its 10-hydroxy analogues.
Graphical abstract
相似文献
20.
Raghunath B. Toche Bhausaheb K. Ghotekar Muddassar A. Kazi Madhukar N. Jachak 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):235-241
Abstract A novel method for the synthesis of 3-(2-substituted ethyl)-2-methylbenzohetero[3,2-a]pyrimidines in high yield (80–85%) was achieved, which involves a dihydrofuranone intermediate, readily obtained from β-ketolactone
to 2-aminobenzoheterocycles. The major advantage of the methodology is the high yield and product purity.
Graphical Abstract
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