Synthesis of a Fluorescent,Cardioactive Analogue Digoxin

Abstract

In order to develop a better understanding of the mechanism of action of the cardioactive steroid glycoside digoxin, we have synthesized a fluorescent analogue of this drug which retains biological activity. Fluoroscein isothiocyanate has been coupled to digoxin via an ethyl lysine bridge, after mild periodate oxidation of the terminal glycase moiety. The conjugate can displace oubain from the plasma membrane digoxin receptor, Na⁺/K⁺ ATPase and can itself be displaced by native digoxin. The structure of the conjugate based on FAB mass spectroscopy is presented.     

Zn(II) Complexes with Quinoline Supported Amidate Ligands: Synthesis,Fluorescence, and Catalytic Activity

Zn(II) complexes of N-(quinolin-8-yl)picolinamide (HL¹) (1) and N²,N⁶-di(quinolin-8-yl)pyridine-2,6-dicarboxamide (H₂L²) (2) have been synthesized by deprotonation of the ligands and characterized by IR, NMR, and Single crystal X-ray crystallography. The mononuclear [Zn(L¹)₂] (3) and homodinuclear [Zn₂(L²)₂] (4) complexes are characterized by distorted octahedral geometries stabilized by hydrogen bonding and weak π···π interaction. The complexes demonstrate intense fluorescence bands in comparison with their corresponding ligands with well-distinguished intensity. The complexes act as efficient catalysts in various transesterification reactions. Among those, the best results have been achieved with complex 3 in conversion of 4-nitrophenylacetate into methyl acetate within 3 h.

     

Synthesis,Structures, and Fungitoxicity of Novel Organophosphorus Compounds

Abstract

A series of biologically active organophosphorus compounds have been synthesized by the reactions of O,O-diethylchlorophosphate with Schiff bases derived from 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-oxadiazole and salicylaldehyde/2-hydroxyacetophenone. The compounds have been characterized on the basis of analyses and spectral (IR, ¹H, ¹³C NMR) data. Fungicidal activities of these derivatives against Colletotrichum falcatum, Fusarium oxysporum, and Curvularia pallescence have been evaluated. All compounds showed moderate to significant antifungal activity.     

Diorganotin Complexes with N(4)-Phenylthiosemicarbazones: Synthesis,Spectroscopic Characterization,and Antibacterial Activity

Abstract

The organotin(IV) complexes, SnPh₂L^a (1), SnMe₂L^a (2), SnBu₂L^a (3), SnPh₂L^b (4), SnMe₂L^b (5), SnPh₂L^c (6), SnMe₂L^c (7), and SnBu₂L^c (8) were obtained by reaction of SnR ₂Cl₂ (R = Ph, Me, and Bu) with 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide (H₂L^a), 1-((2-hydroxynaphthalen-1-yl)methylene)-4-phenylthiosemicarbazide (H₂L^b), and 1-(2-hydroxy-3-methoxybenzylidene)-4-phenylthiosemicarbazide (H₂L^c). The synthesized complexes have been investigated by elemental analysis, IR, ¹H NMR, and ¹¹⁹Sn NMR spectroscopy. The data show that the thiosemicarbazone acts as a tridentate dianionic ligand and coordinates via the thiol group, imine nitrogen, and phenolic oxygen. The coordination number of tin is 5. The in vitro antibacterial activities of the ligands and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and compared with the standard antibacterial drugs.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the following free supplemental files: Additional figures and tables]     

HIGH YIELD SYNTHESIS OF α-ALKOXYPHOSPHONIUM SALTS AND α-ALKOXYPHOSPHONATES

Abstract

The recent work of Ley et al. ¹ on α-alkoxyphosphorane compounds from cyclic enolethers has prompted us to report our findings in this area. In addition to cyclic enol ethers we have studied the acyclic case as well as the use of phosphite in place of triphenylphosphine. Using this approach we have prepared alkoxy-as well as 5-and 6-membered oxyheterocyclic phosphonium salts and phosphonates in high yield.     

A Thermolysis Study of Poly(Trimethylene Phenylphosphinate) and Poly(2,2-Dimethyltrimethylene Phenylphosphinate). NMR and X-Ray Structure of 2-Oxo-2-Phenyl-4,4-Dimethyl-1,2-Oxaphospholan

Abstract

The syntheses of polyphosphinates 2 and 2a by the ring-opening polymerization of cyclic phosphonites 1 and 1a with CH₃I as an initiator have been reported in literature^1–3. These polymers thermally decompose to give oxaphospholan 3 and 3a. In this paper, we present evidence on the mechanism of their formation.     

Continental and Antarctic Lichens: isolation,identification and molecular modeling of the depside tenuiorin from the Antarctic lichen Umbilicaria antarctica as tau protein inhibitor

Abstract

Alzheimer´s disease (AD) is the most common form of dementia involving Aβ and tau protein. So far, AD cure remains elusive, but considering that AD progresses throughout tau pathology, which turns tau protein an appropriate target, besides tau is also included in other neurodegenerative disorders named as tauopathies. Here, we have isolated seventeen compounds belonging to six lichens species. Due to scarce of spectroscopic data of the compound 5,7-dihydroxy-6-methylphthalide, we explained their structural elucidation based on NMR data. In this study, we show that only tenuiorin from Umbilicaria antarctica inhibited 50% of tau 4R at 100?µM. Then, we shown that molecular interactions of tenuiorin with the steric zipper model of the hexapeptide ³⁰⁶VQIVYK³¹¹ were studied by docking calculations and the results suggested that tenuiorin forms both hydrogen bonds with lysine and glutamine side chains and forms several hydrophobic interactions with valine and lysine from ³⁰⁶VQIVYK³¹¹ motif.     

Synthesis,NMR and Conformational Studies of Fucoidan Fragments 1:1 Desulfated 2,3- and 3,4-Branched Trisaccharide Fragments and Constituting Disaccharides

ABSTRACT

Two fucotriosides with vicinal disubstitution α-L-Fuc-(1→2)[α-L-Fuc-(1→3)]α-L-Fuc-OPr (1) and α-L-Fuc-(1→3)[α-L-Fuc-(1→4)]α-L-Fuc-OPr (2), which are related to fragments of natural polysaccharides fucoidans, have been synthesized together with constituent disaccharides 3-5. Spectral and conformational properties of tri- and disaccharides have been investigated by ¹H, ¹³C and NOE NMR spectroscopy.     

The Synthesis,Characterization, and Electrochemical Investigation of Novel Thio- and Alkoxy-Substituted Benzoquinone Derivatives

Abstract

Novel thio- and alkoxy-substituted benzoquinone derivatives were synthesized from the reactions of p-chloranil (1) and related nucleophiles in a sodium carbonate (Na₂CO₃) solution of acetonitrile or in chloroform with Et₃N. The structures of novel compounds were characterized by using microanalysis, FTIR, ¹H NMR, ¹³C NMR, MS, CV, and fluorescence spectroscopy.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Syntheses,Reactions, Characterization,and Antifungal Activities of Chloro-bis-(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)bismuth(III)

Abstract

Chloro-bis(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)bismuth(III) compounds have been synthesized by the reaction of bismuth trichloride with sodium 2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane in 1:2 molar ratio in benzene solution. Reactions of these chloro-bis(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)-bismuth(III) compounds with sodium tetraisopropoxyborate in equimolar ratio in benzene solution yield the corresponding heterobinuclear bismuth derivatives with boron. All compounds were characterized by elemental analyses and molecular weight measurements. Plausible structures are proposed on the basis of IR and ¹H, ¹¹B, ¹³C, and ³¹P spectroscopic studies. 2-Mercapto-2-thioxo-1,3,2-dioxaphospholanes-/dioxaphosphorinanes and the corresponding chloro-bis(2,2-dithio-1,3,2-dioxaphospholane/dioxaphosphorinane)bismuth (III) compounds show antifungal activities against Fusarium and Trichoderma.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

Synthesis,crystal structure,spectral and electrochemical characterization,DNA binding and free radical scavenging studies of ferrocene-based thioureas

Abstract

Thioureas are important building blocks in medicinal chemistry; ferrocenes as highly hydrophobic moieties induce very interesting qualities in medicinal compounds. In this article, we have synthesized four ferrocene incorporated N,N′-disubstituted benzoyl thioureas (3a–3d) with general formula C₅H₅-Fe-C₅H₄C₆H₄Cl-NH-CS-NH-CO-C₆H₄(H/CH₃). Molecular structures of these compounds were characterized in solid and solution phases. In solution molecular structures were established by ¹H and ¹³C NMR and cyclic voltammetry. In the solid state their structures were characterized by elemental analyses and FTIR spectroscopy. Two of the compounds (3a and 3d) had also been structurally determined by single crystal X-ray diffraction analysis. The electrochemical characterization showed a reversible process with one electron transfer from Fe(II) to Fe(III). The single crystal analysis showed strong intermolecular non-covalent interactions in these compounds. Molecular structures of these compounds were also studied by density functional theory (DFT) calculation . DFT studies showed good correlation between calculated parameters and experimental results of solution phase and solid state characterizations. Compounds 3a–3d were evaluated for DNA interaction and antioxidant activity. These compounds interact with DNA via electrostatic forces and liberate significant binding constants and energies. Antioxidant potential –CSNH and –CONH groups induce same level of free radical scavenging ability in these compounds.     

Design,Synthesis, and Anticancer Activity of Amide Derivatives of Structurally Modified Combretastatin-A4

A new series of amide derivatives of structurally modified combretastatin-A4 10a–10j are synthesized, and their structures are confirmed by ¹H and ¹³C NMR, and mass spectral data. The products are tested for their anticancer activity towards human cancer cell lines, MCF-7 (breast), A-549 (lung), Colo-205 (colon), and A-2780 (ovarian). The compounds 10b, 10c, and 10d demonstrate the most promising activity.

     

Tris(dialkylamino)phosphine Chalcogenide Complexes of Tin(IV) Chloride: A Multinuclear (31P, 77Se,and 119Sn) NMR Characterization

Abstract

Four octahedral complexes of the type SnCl₄.2L [L = (R₂N)₃P(E): E = Se; R = Me(1), Et(2) and E = S; R = Me(3), Et(4)] have been studied in solution by multinuclear (³¹P, ⁷⁷Se, and ¹¹⁹Sn) NMR spectroscopy. ³¹P and ⁷⁷Se NMR data were informative of changes associated with complex formation. The solution structure of the complexes was confirmed by their ¹¹⁹Sn NMR spectra that showed two triplet features for each complex, attributed to a mixture of the expected cis and trans isomers. The triplet signal is due to the coupling with two equivalent phosphorus atoms, consistent with an octahedral geometry around the tin center. In addition, density functional theory (DFT)/B3LYP calculations have been carried out to support the interpretations of NMR data. The results are discussed and compared with those reported for related complexes.

GRAPHICAL ABSTRACT      

Synthesis,Spectroscopic Analysis,and In-Vitro Antimicrobial Evaluation of some Tetrahydrobenzo[a]Xanthene-11-Thiones

Abstract

A series of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-thiones were synthesized by the reaction of substituted 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-ones with Lawesson's Reagent in toluene under standard reaction conditions. All synthesized compounds were characterized by IR, NMR (¹H and ¹³C), and mass spectra. Moreover, 2D-NMR (HOMOCOSY, HSQC, and HMBC) studies were also performed for compound 10b. The synthesized compounds were also screened for their antibacterial activities.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]     

Synthesis,Characterization, and Activity of Cyclotriphosphazene-Cyclene Conjugates

Abstract

Two novel cyclotriphosphazene derivatives were synthesized from hexachloro cyclotriphosphzene. Their structures were characterized by ¹H, ³¹P, and ¹³C NMR spectroscopy as well as by IR spectroscopy and electrospray ionization-mass spectrometry (ESI-MS). The Zn complex of 4d was effective in hydrolytic DNA cleavage reactions.     

Bis(Diethyldithiocarbamato)Antimony(III) Derivatives with Oxygen- and Sulfur-Donor Ligands: Synthesis,Esi-Mass,and Spectral Characterization

Abstract

Replacement reactions of bis(diethyldithiocarbamato)antimony(III) chloride have been carried out with oxygen and sulfur donor ligands such as disodium oxalate, sodium acetate, sodium salicylate, benzoic acid, thioglycolic acid, acetylacetone, thiphenol, ethane-1,2-dithiol, and 2,2-dimethylpropane-1,3-diol to give mixed bis(diethyldithiocarbamato)antimony(III) derivatives of the corresponding ligands. These derivatives have been characterized by the physicochemical [melting point and molecular weight determination, elemental analysis (C, H, N, S, and Sb)], spectral [FT-IR, far-IR, NMR (¹H and ¹³C)], ESI-mass, powder XRD, and SEM studies.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables]     

Simultaneous Determination of Lonidamine, 1-(2,4-Dichlorobenzyl)-1h-indazole-3-carboxylic Acid,a New Antitumoral,and Its Impurity,N2 Substituted Isomer,by UV Derivative Spectrophotometry

Abstract

A direct and fast analytical method for the determination of Lonidamine and its impurity of synthesis, the N₂ alkylated isomer, by UV derivative spectrophotometry, is described.

The procedure was defined by regression analysis for a high number of standard solutions.

Linear relationships were obtained between mixture composition and maximum amplitude in <²D at 316 nm for Lonidamine quantitation, and peak trough ⁴D 226,234 and ⁴D 323,316 amplitudes by utilising polynomial equation for N₂ isomer quantitation.

The method, yielding accurate and precise results, was satisfactorily applied to laboratory mixtures and to a commercial formulation.     

Spectral Assignment of Phenanthrene Derivatives Based on 6H-Dibenzo[C,E][1,2] Oxaphosphinine 6-Oxide by NMR and Quantum Chemical Calculations

Abstract

Organophosphorus compounds such as 6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO, 1) and its derivatives are important and versatile compounds for a broad field of applications. However, a thorough spectral assignment is often subordinate to its chemical properties. This article presents and unambiguously attributes the ¹H and ¹³C NMR spectra of DOPO (1), selected products yielded from the Atherton–Todd reaction (2–4), DOPO-HQ (5) as well as sulfur derivatives (6–7) via a set of 1D- and 2D-NMR experiments. The complex P-C and P-H coupling patterns are discussed and compared with the derivatives possessing different chemical environments around the phosphorus atom. In addition, we compared our results with density functional theory calculations. Even though the prediction of NMR data of organophosphorus compounds via molecular modeling is limited, this study presents a method that yields good results for this class of heterocycles. This knowledge should help to quickly assign NMR spectroscopic data of other DOPO (1) derivatives and can be extrapolated to organophosphorus compounds in general.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: NMR Spectra of Compounds 1-7 (Figures S1 - S15).     

Synthesis,anti-hyperglycaemic activity,and in-silico studies of N-substituted 5-(furan-2-ylmethylene)thiazolidine-2,4-dione derivatives

Thiazolidinedione derivatives have been used as anti-hyperglycemic agents in diabetic patients since last decade. In the present study, a series of N-substituted-5-(furan-2-ylmethylene)thiazolidine-2,4-dione derivatives were synthesized and characterized by ¹H-NMR, ¹³C-NMR and mass spectra. The introduction of the alkyl/haloalkyl moiety onto the amidic nitrogen of the thiazolidine-2,4-dione ring was intended to enhance the anti-hyperglycaemic activity, which was further tested in vivo by using alloxan-induced diabetic laca mice. Molecular docking simulation studies further helped in understanding the nature of the interactions and the binding mode of ligands inside the active site of the protein tyrosine phosphatase 1B enzyme, which negatively regulates the insulin signaling pathway. The compounds were screened for in-vivo anti-hyperglycaemic activity in which compounds 9 and 10 have exhibited significant decreases in blood glucose level comparable to that of pioglitazone.

     

A bis(rhodamine 6G)-based fluorescent sensor for Hg2+: microwave-assisted synthesis,photophysical properties,and computational studies

A fluorescent and colorimetric sensor based on rhodamine 6 g (RD6g) was designed, synthesized, and characterized using microwave irradiation. The sensing behavior of this compound was studied by UV–visible and fluorescence spectroscopy. Sensor RD6g exhibits a high selectivity and an excellent sensitivity and is a dual-responsive colorimetric and fluorescent Hg²⁺-specific sensor in aqueous buffer solution. Mercury ions give rise to the development of a very fluorescent ring-open amide spirolactam system. The detection limit for Hg²⁺ was found to be 1.2?×?10^?8 M. The binding ratio of RD6g-Hg²⁺ complex was determined to be 1:1 according to the Job’s plot. The reversibility of RD6g?Hg²⁺ complex has been achieved with CN^? anions. The test strip based on RD6g was developed, which could be used as a suitable and methodical Hg²⁺ test kit.