Oxamide Groups Research Articles

Epoxyeicosatrienoic Acid Mimics Protect Mesangial Cells from Sorafenib Induced Cell Death

Study objective: Sorafenib an antiangiogenic drug which are widely used in cancer treatment, and it inhibits vascular endothelial growth factor (VEGF) and tyrosine kinases (TK)involved in both tumor cell proliferation and angiogenesis. Unfortunately, VEGF and TK inhibitors cause severe kidney glomerular injury and proteinuria. Kidney injury that occurs with sorafenib chemotherapeutic treatment is a major clinical challenge that lacks a drug to revert or reduce this kidney glomerular cell damage. Hypothesis: Epoxyeicosatrienoic acid (EET) mimics reduce the nephrotoxic effects of sorafenib on glomerular mesangial cells. Methodology: Human renal mesangial cells (HRMCs) were cultured at 37˚C in RPMI 1640 medium containing 10% FBS, 100 U/ml penicillin, and 0.1 mg/ml streptomycin. Live cell imaging was performed to monitor real-time cell death activity in HRMCs. Apoptosis was determined using the caspase 3/7 dye and the HRMCs cells were imaged every 2 hours for 72 hours using the Incucyte system. HMRCs were tested under four conditions: 1) Sorafenib (10 μM), 2) Sorafenib (10 μM) plus 8,9-EET analogs (1 μM), 3) Sorafenib (10 μM) plus 8,9-EET analogs (3 μM), 4) Sorafenib (10 μM) plus 8,9-EET analogs (10 μM). Thirteen 8,9-EET analogs were also tested for soluble epoxide hydrolase (sEH) inhibitory activity against human sEH recombinant protein. Results: Sorafenib caused significant cell death and increased caspase 3/7 activity in HRMCs. Nine of the 8,9-EET analogs were ineffective in reducing sorafenib induced HRMC cell death and caspase 3/7 activity. Four 8,9-EET analogs in a dose-dependent manner reduced sorafenib induced cell death in HRMCs. This preliminary structure activity relationship analysis revealed an oxamide group as a bioisostere for the epoxide in the 8,9-position of the fatty acid chain, producing protective effects against sorafenib induced cell death in HRMCs. Gratifyingly, this group lacked significant sEH-inhibitory activity. The 8,9-EET analogs RM-84 and MBD-32 reduced sorafenib induced caspase 3/7 activity by 20-40% in HRMCs. Additional protective action was found with the 8,9-EET analogs MDB-52-I the MDB-52-II which dose dependently reduced sorafenib induced caspase 3/7 activity by 60-90% in HRMCs. Conclusion: Collectively, these findings demonstrate the potential for 8,9-EET analogs as a therapeutic strategy against sorafenib-induced glomerular nephrotoxicity. Arkansas Research Alliance This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Rigid polyurethane foams modified with borate and oxamide groups – Preparation and properties

In this work the results of the research on modification of rigid polyurethane foams properties by new polyols with borate and oxamide groups have been presented. Propylene glycols — the products of hydroxyalkylation of N,N′-bis(2-hydroxypropyl)oxamide bis(dihydrogenborate) by excess of propylene carbonate (PC) was used as a polyol component. The new polyols have been foamed using polymeric 4,4′-diphenylmethane diisocyanate, water and triethylamine. The modification of the foam structure by oxamide and borate groups guarantees their low water uptake, very good heat-insulating properties, good dimension stability and decreases their flammability, and does not worsen their mechanical properties and thermal stability.

Hydrothermal Synthesis, Crystal Structures, and Fluorescence Properties of Ni(II)–Ln(III) Complexes (Ln = Sm, Pr, Eu)

Three novel 3d–4f heterometal complexes [Ln(NiL)3(Btca)(NO3)] · xH2O (Ln = Sm(III) (I), Pr(III) (II), Eu(III) (III) (H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H2Btca = benzotriazole-5-carboxylic acid) were solvothermally synthesized and characterized by singlecrystal X-ray diffraction (CIF files CCDC nos. 1555557 (I), 1555555 (II), 1555556 (III)). They crystallized in the monoclinic space group P21/n for I (x = 1.5) and C2/c for (II) and (III) (x = 1), respectively. In these complexes, the central Ln(III) and external nickel ions are bridged by macrocyclic oxamide groups. The metal center of Ln(III) resides in a distorted bicapped square antiprism surrounding with six oxygen atoms of three oxamide groups, two oxygen atoms of Btca2– ion and two oxygen atoms of NO3-. Furthermore, there are C–H···O and/or C–H···N hydrogen bond interactions among nitrate, benzotriazole-5-carboxylate, macrocyclic oxamide and water to form three-dimensional superamolecular architecture. The fluorescence properties of the compounds I and II are also discussed.

Thermogravimetric and qualitative analysis of thermal decomposition characteristics of polyurethane foams based on polyols with carbamide or oxamide and borate groups

The thermal stability and the kinds of products of thermal decomposition of polyurethane foams modified with urea or oxamide and borate groups were studied. Incorporation of urea or oxamide groups and borate groups enhances the thermal stability of polyurethane foams compared to polyurethane foams based on typical polyols. Thermal stability of foams modified with oxamide groups is somewhat higher that of foams modified with urea groups. In turn, simultaneous incorporation of borate groups results in an increase in thermal stability of the foams modified with urea. The temperature of thermal decomposition of the foams with oxamide and borate groups does not change or undergoes a slight decrease. The thermal degradation products of investigated foams are similar and they are usually water, ammonia, carbon dioxide and/or nitrous oxide. Additionally, hydrogen cyanide can be released during thermal decomposition of polyurethane foams modified with urea groups. The presence of borate groups prevents the formation of hydrogen cyanide. The opposite situation is observed in the case of the foams modified with oxamide and borate groups. Thus, from the point of view of a fire hazard, the use of the foams modified with urea and borate groups is safer. © 2017 Society of Chemical Industry

Polyurethane foams obtained from new polyols modified by oxamide and borate groups

New polyols have been obtained in reactions of N, N, N’, N’-tetrakis(2-hydroxyethyl)-derivatives of oxamide, esterified with boric acid (BA), with the excess of ethylene carbonate (EC). The preparation conditions of polyols and next the production of polyurethane foams with the use of these new polyols have been presented. The foaming process parameters as well as the testing of the foam properties have been given. The structure modification of the polyurethane foams by means of oxamide and borate groups resulted in high thermal stability and thermal resistance, dimensional stability, compressive strength as well as the reduced flammability.

Effect of the Additive Fire Retardants on the Properties of Rigid Polyurethane Foams, Obtained Using Hydroxyethyl Derivatives of Oxamide and Polymeric 4,4′-diphenylmethane Diisocyanate

The present work investigates the effect of polyol structure and physical addition of boric acid and N,N′-bis(2-hydroxyethyl)oxamide on the properties of rigid polyurethane foams. The product of hydroxyalkylation of oxamide by ethylene carbonate has been used as a polyol component. The new polyol has been foamed using polymeric 4,4′-diphenylmethane diisocyanate, water, and triethylamine. To decrease the flammability of the foams, boric acid, and N,N′-bis(2-hydroxyethyl)oxamide were used as the additive flame retardants. It has been found, that chemical modification of the foam structure by means of oxamide groups decreases their flammability only to a small extent, whereas physical addition of N,N′-bis(2-hydroxyethyl)oxamide does not influence the flammability. However, the addition of boric acid to the foam composition resulted in a distinct decrease of foam flammability, according to the amount of boric acid added. All the foams, modified and nonmodified by boron, have been categorized into flammability class HF-1, according to the applicable standard. The introduction of flame retardants had its impact on the properties of polyurethane foams obtained, as described in this work.

Oligomers with structural elements of imidazolidinetrione obtained from oxamic acid and oxamide: polyurethane foams modified by structural elements of imidazolidinetrione

Abstract Hydroxyalkyl derivatives containing oxamidoester and oxamide fragments have been separately obtained using oxamic acid, oxamide and alkylene carbonates. It has been proven that the presence of oxamidoester and oxamide structural fragments in oligomer structures is responsible for the thermal stability of these products. Rigid, thermally stable polyurethane foams were obtained with the use of oligomers with oxamidoestercarbamidoimide, carbamide, oxamidoester and oxamide groups as polyols components. The properties of these foamed materials were compared with each other and with the properties of reference foams. It was found that the polyurethane foams characterized by the best properties were obtained from hydroxypropyl derivatives of oxamide.

Synthesis and characterization of siloxane-containing poly(urea oxamide) segmented copolymers

An unprecedented family of segmented polydimethylsiloxane poly(urea oxamide) (PDMS-UOx) copolymers displayed thermoplastic elastomeric behavior with improved thermomechanical properties compared to PDMS polyurea (PDMS-U) analogs. A two-step, PDMS end-capping sequence using diethyl oxalate and hydrazine generated difunctional oxamic hydrazide capped oligomers. Polymerization with HMDI provided high molecular weight copolymers, which yielded elastomeric films with monodisperse hard segments. Dynamic mechanical analysis (DMA) of PDMS-UOx copolymers revealed a broad, rubbery plateau that extended for >180 °C. The PDMS-UOx service window extended ∼120 °C further than a PDMS-U analog, presumably due to enhanced hydrogen bonding and concomitant microphase separation. DSC and WAXD elucidated the amorphous morphology of PDMS-UOx, and DMA, SAXS, and AFM confirmed a well-defined microphase-separated morphology. Incorporation of urea oxamide groups significantly affected microphase separation and thermomechanical properties, and these copolymers offer impact in adhesive and biomedical technologies due to low temperature reaction conditions for unique hydrogen bond containing segmented copolymers.

Synthesis and crystal structure of a new tetranuclear copper(II) complex with N-(2-hydroxyphenyl)-N′-(3-aminopropyl)oxamide ligand: cytotoxicity, DNA and BSA-binding studies

A new tetracopper(II) complex, [Cu4(papo)2(dabt)2](NO3)2·2H2O, where H3papo and dabt stand for N-(2-hydroxyphenyl)-N′-(3-aminopropyl)oxamide and 2,2′-diamino-4,4′-bithiazole, respectively, has been synthesized and characterized by elemental analyses, molar conductivity, infrared and electronic spectra, and single-crystal X-ray diffraction. The crystal structure reveals that the presence of a circular tetracopper(II) cation [Cu4(papo)2(dabt)2]2+ with an embedded center of inversion is assembled by a pair of cis-oxamido-bridged dicopper(II) units through μ2-phenolato bridges, in which the Cu(II) atoms at the inner sites of papo3− have square-planar environments and those at the outer sites are in square-pyramidal geometries. The separations of the Cu(II) ions bridged by oxamide and phenolate groups are 5.2039(14) and 3.7159(12) A, respectively. In the crystal, two-dimensional supramolecular structures are formed by hydrogen bonds and π–π stacking interactions. An in vitro cytotoxicity experiment indicates that the tetracopper(II) complex exhibits cytotoxic effects against human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549. The reactivity toward HS-DNA and protein BSA suggested that the tetracopper(II) complex can interact with HS-DNA in the mode of intercalation, and the complex binds to BSA responsible for quenching of tryptophan fluorescence by a static quenching mechanism. The present tetracopper(II) complex constructed from N-(2-hydroxyphenyl)-N′-(3-aminopropyl)oxamide has been synthesized and characterized by X-ray single-crystal diffraction. The cytotoxicities and reactivities toward DNA and protein of the complex have been investigated.

A novel 2D oxalate- and dissymmetrical oxamidato-bridged heterometallic CuII–GdIII complex: Synthesis, crystal structure and magnetic properties

A novel 2D framework, {[Cu2(aeoe)2Gd2(C2O4)(H2O)6]·7H2O}n (1) (H4aeoe=N′-(2-aminoterephthalic acid)-N″-(ethylenediamine) oxamidato), has been synthesized and characterized by elemental analysis, IR spectrum, thermogravimetric analysis (TGA), single-crystal X-ray diffraction and magnetic properties. Single-crystal structural analysis shows that complex 1 displays a novel 2D layered structure. The asymmetry unit of complex 1 contains a heterotetranuclear CuII2GdIII2 building block. The Cu(II) ions are in a distorted square pyramidal CuN3O2 surrounding. The Gd(III) ions are eight-coordinated and surrounded by two oxygen atoms from oxamide group, one oxygen atom from carboxylate, two oxygen atoms from oxalate and three oxygen atoms from coordination water molecules. The framework formed using dissymmetrical oxamide and oxalate anions as mixed ligands is the first examples of 3d–4f complexes involving dissymmetrical oxamide. Its magnetic properties have also been investigated, and show weak ferromagnetic coupling between the Cu(II)–Gd(III) ions.

N-[3-(Dimethylamino)propyl]-N′-(2-hydroxy-5-methylphenyl)oxamide

In the title compound, C14H21N3O3, the oxamide group has a transoid conformation. In the crystal, the mol­ecules are connected by N—H⋯O and O—H⋯N hydrogen bonds into a double chain running along the b axis.

Synthesis, crystal structure, and luminescence of a heterotrinuclear Cu2Cd complex containing macrocyclic oxamide and thiocyanate ligands

The complex incorporating macrocyclic oxamide of the formula [(CuL)2Cd(NCS)2] (H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene) has been synthesized and structurally characterized. The crystals crystallize in the monoclinic system, space group C2/c, a = 13.865(3), b = 14.390(3), c = 38.252(8) A, β = 92.45(3)°, Z = 8. The crystal structure unit is a trianuclear complex in which the Cd2+ and Cu2+ ions are bridged by the macrocyclic oxamide groups. The [(CuL)2Cd(NCS)2] units are alternately bridged by C-H···O to C-H···S hydrogen bond to form a 2D framework. The luminescent property of the compound is also discussed.

Tetrakis(2,2′-bipyridine)-1κ4N,N′;4κ4N,N′-{μ4-N,N′-bis[3-(2-oxidoethylamino)propyl]oxamidato(4−)-1:2:3:4κO:κ3N,N′,O′:κ3O′′,N′′,N′′′:κO′′′}tetracopper(II) tetrakis(perchlorate)

The title complex, [Cu(4)(C(12)H(22)N(4)O(4))(C(10)H(8)N(2))(4)](ClO(4))(4), has a novel tetranuclear copper(II) cation with the oxamidate and ethanolate groups of a trans tetraanion of N,N'-bis[3-(hydroxyethylamino)propyl]oxamide (H(4)heap) as bridges. The Cu...Cu separation through the oxamide group is 5.1592 (15) A, while those through the two ethanolate bridges are 3.3845 (13) and 3.3392 (13) A. The two central copper(II) ions are in square-planar N(2)O(2) environments, while the two terminal copper(II) ions have distorted N(4)O square-pyramidal geometries. The heap(4-) ligand, with an iminoalcohol form, has both an oxamide and two ethanolate bridges. Two of the four perchlorate anions are disordered and have long contacts with the square-planar Cu(II) ions. The three-dimensional structure features arene-perchlorate C-H...O hydrogen bonds and pi-pi stacking.

Oxalylbis(azanediyl)]bis{[amino(2-pyridyl)methylene]ammonium}

The title compound, C14H16N8O2 2+·2ClO4 −, was prepared by reaction of bis­[amino­(2-pyrid­yl)methyl­ene]oxalohydrazide with perchloric acid. The mol­ecular symmetry is Ci and thus the asymmetric unit comprises one half-mol­ecule. The dihedral angle between the aromatic ring and the plane of the oxamide group is 70.8 (3)°. The perchlorate anions and the cations are connected by inter­molecular N—H⋯O hydrogen bonds.

A new two-dimensional polymeric copper(II) complex bridged both by oxamidate and azide groups: synthesis, structure and DNA binding properties

A new two-dimensional polymeric copper(II) complex, [Cu2(heae)(N3)2] n , where heae stands for the dianion of N,N′-bis(N-hydroxyethylaminoethyl)oxamide, has been synthesized and characterized by elemental analysis, molar conductivity measurement, IR, electronic spectral studies and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, P21/c space group with crystallographic data: a = 9.1588(18) Å, b = 6.6238(13) Å, c = 14.602(3) Å and Z = 2. The X-ray analysis reveals a two-dimensional copper(II) polymeric coordination network constructed by bis-tridentate chelated [Cu(trans-heae)Cu]2+ building blocks and end-on azido ligands. The environment around the copper(II) atom can be described as a square-based pyramid. The azido bridge is very asymmetric with one Cu–N bond distance short and the other long. The Cu ··· Cu separations through μ-trans-oxamidate and μ-azido bridges are 5.2996(13) Å and 4.2464(7) Å, respectively. The copper(II) complex is a polymer in the solid state, whereas in solution it exists as discrete neutral binuclear copper(II) species. Coordination mode of the azide in solution is proved by electronic spectra. The DNA-binding properties of the binuclear copper(II) species were investigated by emission spectral and electrochemical techniques, indicating the binuclear copper(II) complex binds to HS-DNA via a groove mode.

2-{N′-[3-(Dimethylammonio)propyl]oxamido}benzoate

The title compound, C14H19N3O4, exists as a zwitterion, with a tertiary N atom protonated and a carboxyl group deprotonated. In the crystal structure, the planar oxamide group displays a transoid conformation. The mol­ecules link to each other via hydrogen bonding, resulting in an extended supra­molecular chain along the b axis.

N,N′-Bis[2-(dimethylammonio)ethyl]oxamide dinitrate

In the crystal structure of the title compound, C10H24N4O2 2+·2NO3 − or [H4dmaeoxd](NO3)2 {H2dmaeoxd is N,N′-bis[2-(dimethylamino)ethyl]oxamide}, the diprotonated H4dmaeoxd dication occupies a special position on an inversion centre and exhibits a transoid conformation. The six non-H atoms of the oxamide group are almost exactly coplanar. Two symmetry-independent NH groups of the dication form hydrogen bonds with two O atoms belonging to one NO3 − anion. Four independent C—H...O interactions link dications and anions into an infinite three-dimensional system.

A trinuclear Cu2Mn complex, [Mn(CuL)2(DMF)2](SCN)2, where H2Lis 3,10,18,21-tetraazatetracyclo[20.4.0.04,9.012,17]hexacosa-2,10,12,14,16,22,24,26-octaene-19,20-dionate(2−) and DMF is dimethylformamide

A new trinuclear Cu2Mn complex, bis­(dimethylformamide)bis­[μ-3,10,18,21-tetra­azatetra­cyclo[20.4.0.04,9.012,17]hexa­cosa-2,10,12,14,16,22,24,26-octa­ene-19,20-dionato(2−)]bis­(thio­cyanato)dicopper(II)manganese(II),[Cu2Mn(C22H20N4O2)2(NCS)2(C3H7NO)2], has been synthesized and structurally characterized. The CuII atom is five-coordinated by four N atoms from the tetraza macrocycle and one dimethyl­formamide N atom. The central MnII atom is coordinated by four O atoms of the oxamide group and two N atoms. The MnII atom lies on a centre of symmetry. The CuII atoms reside in the cavities of the macrocyclic ligands.

A new heterotrinuclear macrocyclic complex: bis(μ-diethyl 5,6,7,8,15,16-hexahydro-6,7-dioxo-5,8,14,17-tetraazadibenzo[a,g]cyclotetradecine-13,18-dicarboxylato)-1κ4N:2κ2O6,O7;2κO6,O7:3κ4N-dimethanoldinickel(II)zinc(II) bis(perchlorate)

The title compound, [Ni2Zn(C24H22N4O6)2(CH4O)2](ClO4)2, was synthesized using a mononuclear complex ligand NiL (L is diethyl 5,6,7,8,15,16-hexa­hydro-6,7-dioxo-5,8,14,17-tetraazadibenzo[a,g]cyclo­tetra­decine-13,18-dicarboxyl­ate), Zn(ClO4)2·6H2O and CH3OH. X-ray single-crystal analysis reveals that the Zn2+ ion is in a slightly distorted octa­hedral O6 environment. The trinuclear complex cation is centrosymmetric. The Zn2+ and both Ni2+ ions are bridged by the oxamide group from the macrocyclic ligand L. Inter­molecular O—H⋯O hydrogen bonds exist between the perchlorate anion and the complex cation, and π–π inter­actions organize the trinuclear cations to form supramolecular one-dimensional chains in the crystal structure.

Hydrothermal synthesis, crystal structure and fluorescence quenching in oxamidato-bridged tetranuclear [formula omitted]Ln III complexes containing macrocyclic ligands (Ln=Tb, Dy)

Two novel oxamidato-bridged complexes incorporating macrocyclic oxamide of formula [(NiL) 3Tb(DMF) 2(H 2O)](ClO 4) 32DMF 1, [(NiL) 3Dy(DMF) 2](ClO 4) 3DMF CH 3OH·H 2O 2 (NiL, H 2L=2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien), have been hydrothermally synthesized and structurally determined. Both crystals crystallize in the triclinic system, space group P−1, for 1 a=13.959(4) Å, b=15.038(5) Å, c=19.488(6) Å, α=104.653(5)°, β=92.431(5)°, γ=97.328(5)°; for 2 a=13.949(4) Å, b=15.031(4) Å, c=19.487(6) Å, α=104.633(5)°, β=92.439(5)°, γ=97.351(6)°. In both complexes, the central Ln III and external nickel ions are bridged by macrocyclic oxamide groups. Fluorescences of Tb III and Dy III are almost completely quenched in 1 and 2.