Search results for "Amide"

H2-Antihistaminika, 33. Mitt. Synthese und H2-antagonistische Aktivität heteroaromatischer (Thio)Carboxamide und Triazol(thi)on-Derivate des Piperidi…

1987

Die Zyklisierung der (Thio)Semicarbazide la, b mit N-Cyan-diphenylimidocarbonat, N-Cyan-dimethyldithioimidocarbonat, Aminocrotonsaurenitril und Acetessigester gibt die heteroaromatischen (Thio)Carboxamide 5a, b und 7–9. Beim Einwirken von NaOH auf die (Thio)Biharnstoffe 12 und 13 sowie die (Oxa)Thiadiazoldiamine 19 und 20 werden die Triazol(thi)one 15 und 17 erhalten. Am Vorhof des Meerschweinchens zeigen 5a, 7 und 8 eine mit Cimetidin vergleichbare Histamin-H2-antagonistische Wirkung. H2-Antihistaminics, XXXIII: Synthesis and H2-Antagonistic Activity of Heteroaromatic (Thio)Carboxamides and Triazole(thi)one-Derivatives of Piperidinomethylphenoxypropylamine The (thio)semicarbazides la, b ar…

Cyclic Analogs of Desferrioxamine E Siderophore for 68Ga Nuclear Imaging: Coordination Chemistry and Biological Activity in Staphylococcus aureus

2021

As multidrug-resistant bacteria are an emerging problem and threat to humanity, novel strategies for treatment and diagnostics are actively sought. We aim to utilize siderophores, iron-specific strong chelating agents produced by microbes, as gallium ion carriers for diagnosis, applying that Fe(III) can be successfully replaced by Ga(III) without losing biological properties of the investigated complex, which allows molecular imaging by positron emission tomography (PET). Here, we report synthesis, full solution chemistry, thermodynamic characterization, and the preliminary biological evaluation of biomimetic derivatives (FOX) of desferrioxamine E (FOXE) siderophore, radiolabeled with 68Ga …

Asymmetric Synthesis of Spiro Tetrahydrothiophene-indan-1,3-diones via a Squaramide-Catalyzed Sulfa-Michael/Aldol Domino Reaction

2016

Synthesis 48(08), 1131-1138(2016). doi:10.1055/s-0035-1560412

Substituent effects on axle binding in amide pseudorotaxanes: comparison of NMR titration and ITC data with DFT calculations

2012

The binding behaviour of differently substituted diamide axle molecules to Hunter/Vögtle tetralactam macrocycles was studied with a combination of NMR titration, isothermal titration calorimetry (ITC) experiments and calculations employing density functional theory (DFT), along with dispersion-corrected exchange-correlation functionals. Guests with alkyl or alkenyl chains attached to the diamide carbonyl groups have a significantly higher binding affinity to the macrocycle than guests with benzoyl amides and their substituted analogues. While the binding of the benzoyl and alkenyl substituted axles is enthalpically driven, the alkyl-substituted guest binds mainly because of a positive bindi…

Design, synthesis and antiproliferative activity of methyl 4-Iodo-1-β-D-ribofuranosyl-pyrazole-3-carboxylate and related compounds

1996

Abstract In a SAR study on azole-related nucleosides we have designed some pyrazole-nucleoside analogs characterised, for the first time, by a carboxylic ester moiety. 4-Iodo-1-β-D-ribofuranosyl-pyrazole-3-carboxylate showed a wide spectrum of antiproliferative activity and a particularly low cytotoxicity against resting PBL, being, unlike the other azole nucleosides, more active than the corresponding primary amide.

Stereoselective reactions of a thioester butanediacetal with various electrophiles

2014

Abstract The reactions of the lithium enolate of S -ethyl (2 R ,5 R ,6 R )-5,6-dimethoxy-5,6-dimethyl-[1,4]-dioxane-2-carbothioate were investigated in the presence or absence of hexamethylphosphoramide (HMPA). Fluorination gave a single isomer with a much better yield than for the corresponding methyl ester. Alkylation with alkyl halides strongly depended upon their structure. Without HMPA, only methyl iodide reacted with moderate yield and gave a single isomer. In the presence of HMPA, all of the alkyl halides reacted almost quantitatively (81–98% yield) with moderate stereoselectivity and preferentially gave products with the alkyl chain attached at the equatorial position. The silyl eno…

Studies on the biosynthesis of paraherquamide. Construction of the amino acid framework

2001

Abstract It has been previously established in this laboratory that the β-methyl-β-hydroxyproline moiety of the potent anthelmintic agent paraherquamide A, is biosynthetically derived from l -isoleucine. The downstream events from l -Ile to paraherquamide A have now been investigated. The synthesis of [1- 13 C]-labeled l -β-methylproline is described by means of a Hoffman–Loeffler–Freytag reaction sequence from [1- 13 C]- l -Ile. This amino acid is shown to be a direct biosynthetic precursor to paraherquamide A by feeding and incorporation experiments in growing cultures of Penicillium fellutanum . Three tryptophan-containing dipeptides of l -β-methylproline have been constructed: [ 13 C 2 …

Co-ordination of copper(II) ions by prolyl-α,β-dehydroamino acids: comparative studies and general considerations

1996

Potentiometric and spectroscopic measurements and theoretical calculations have revealed that α,β-dehydroamino acid residues have a considerable effect on the co-ordination ability of an adjacent amide nitrogen towards Cu2+ ions. Also the side chain of such residues affects the stability constants and, in some cases, the binding mode of short peptides containing α,β-dehydroamino acid residues. The theoretical calculations showed that all dehydroamino acids except α,β-dehydroalanine tend to bend a peptide chain towards a turn conformation. This has a very strong impact on the co-ordination ability of a dehydropeptide ligand.

1976

A number of acryl and methacryl derivatives of different sulfanilamides (1a—I) were prepared and polymerized. The fixation of the sulfonamide to the polymerizable group was carried out directly, using the acryl- and methacrylamides, and by means of spacer groups, to favour the enzymatic or hydrolytic release of the drug moiety. Selected sulfonamide types of different pKA values were used, and the pH-dependant solubility of the corresponding polymers was studied. The monomeric acryloyl and methacryloyl sulfonamides were homopolymerized radically by AIBN. For distribution studies polysulfadiazineacrylamide, 14C-labelled in the main chain (2e'), was synthesized. Copolymerization with 2-methyls…

Investigation of polymers in the mass spectrometer, 7. Pyrolysis-gas chromatography-mass spectrometry of low molecular and high polymeric sulfanilami…

1975

A number of low molecular, monomeric and polymeric sulfanilamide derivatives, which have found interest as possibly selective antitumour agents, were investigated by pyrolysis-gas chromatography (GC)-mass spectrometry (MS). Thermal degradation mechanisms were studied using also direct polymer pyrolysis in the ion source of the mass spectrometer. Thermal degradation products as well as low molecular weight sulfanilamides and related model compounds were characterized in their fragmentation behaviour by low and high resolution electron impact and field desorption mass spectrometry. Thermal fragments of structural significance were found, and a differentiation of the low and high molecular sul…