thiourea and selenourea

A series of chiral and achiral cyclic seleno- and thiourea compounds bearing benzyl groups on N-atoms were prepared from enetetramines and appropriate Group VI elements in good yields. All the synthesized compounds were characterized by elemental analysis, FT-IR,

Topics: Acetylcholinesterase; Butyrylcholinesterase; Cholinesterase Inhibitors; Glycoside Hydrolases; Molecular Docking Simulation; Molecular Structure; Organoselenium Compounds; Spectroscopy, Fourier Transform Infrared; Structure-Activity Relationship; Thiourea; Urea

β-Amino esters are obtained with high levels of enantioselectivity via the conjugate addition of cyclic amines to unactivated α,β-unsaturated esters. A related strategy enables the kinetic resolution of racemic cyclic 2-arylamines, using benzyl acrylate as the resolving agent. Reactions are facilitated by an unprecedented selenourea-thiourea organocatalyst. As elucidated by DFT calculations and

Topics: Amines; Catalysis; Density Functional Theory; Esters; Kinetics; Models, Chemical; Organoselenium Compounds; Thiourea; Urea

A novel series of thirty-one N-substituted urea, thiourea, and selenourea derivatives containing diphenyldiselenide entities were synthesized, fully characterized by spectroscopic and analytical methods, and screened for their

Topics: Antiprotozoal Agents; Humans; Leishmania infantum; Macrophages; NADH, NADPH Oxidoreductases; Organoselenium Compounds; Parasitic Sensitivity Tests; Structure-Activity Relationship; Thiourea; Urea

A series of novel selenourea derivatives and corresponding thiourea analogs were synthesized and tested against a panel of six human cancer cell lines: melanoma (1205Lu), lung carcinoma (A549), prostatic carcinoma (DU145), colorectal carcinoma (HCT116), pancreatic epithelioid carcinoma (PANC-1) and pancreatic adenocarcinoma (BxPC3). In general, we found that the selenium-containing derivatives were more potent than their isosteric sulfur analogs. Four selenourea derivatives (1e, 1f, 1g and 1i) showed IC50 values below 10 μM in all of tested cell lines at 72 h. On the basis of its potent activity, compound 1g was selected for further biological evaluation in different colon cancer cell lines. Our results indicated that compound 1g induced apoptosis by caspase activation, along with inhibition of anti-apoptotic proteins.

Topics: Antineoplastic Agents; Apoptosis; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Organoselenium Compounds; Structure-Activity Relationship; Thiourea; Tumor Cells, Cultured; Urea

Nearly isosteric oxo to thioxo substitution was employed to interrogate the structure of foldamers with a urea backbone and explore the relationship between helical folding and hydrogen-bonding interactions. A series of oligomers with urea bonds substituted by thiourea bonds at discrete or all positions in the sequence have been prepared and their folding propensity was studied by using a combination of spectroscopic methods and X-ray diffraction. The outcome of oxo to thioxo replacements on the helical folding was found to depend on whether central or terminal ureas were modified. The canonical helix geometry was not affected upon insertion of thioureas close to the negative end of the helix dipole, whereas thioureas close to the positive pole were found to increase the terminal flexibility and cause helix fraying. Perturbation was amplified when a selenourea was incorporated instead, leading to a structure that is only partly folded.

Topics: Circular Dichroism; Models, Molecular; Molecular Structure; Organoselenium Compounds; Thiourea; Urea

The complexes formed in methanol solutions of Cd(CF(3)SO(3))(2) with selenourea (SeU) or thiourea (TU), for thiourea also in aqueous solution, were studied by combining (113)Cd NMR and X-ray absorption spectroscopy. At low temperature (~200 K), distinct (113)Cd NMR signals were observed, corresponding to CdL(n)(2+) species (n = 0-4, L = TU or SeU) in slow ligand exchange. Peak integrals were used to obtain the speciation in the methanol solutions, allowing stability constants to be estimated. For cadmium(II) complexes with thione (C═S) or selone (C═Se) groups coordinated in Cd(S/Se)O(5) or Cd(S/Se)(2)O(4) (O from MeOH or CF(3)SO(3)(-)) environments, the (113)Cd chemical shifts were quite similar, within 93-97 ppm and 189-193 ppm, respectively. However, the difference in the chemical shift for the Cd(SeU)(4)(2+) (578 pm) and Cd(TU)(4)(2+) (526 ppm) species, with CdSe(4) and CdS(4) coordination, respectively, shows less chemical shielding for the coordinated Se atoms than for S, in contrast to the common trend with increasing shielding in the following order: O > N > Se > S. In solutions dominated by mono- and tetra-thiourea/selenourea complexes, their coordination and bond distances could be evaluated by Cd K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. At ~200 K and high excess of thiourea, a minor amount (up to ~30%) of [Cd(TU)(5-6)](2+) species was detected by an upfield shift of the (113)Cd NMR signal (up to 423 ppm) and an amplitude reduction of the EXAFS oscillation. The amount was estimated by fitting linear combinations of simulated EXAFS spectra for [Cd(TU)(4)](2+) and [Cd(TU)(6)](2+) complexes. At room temperature, [Cd(TU)(4)](2+) was the highest complex formed, also in aqueous solution. Cd L(3)-edge X-ray absorption near edge structure (XANES) spectra of cadmium(II) thiourea solutions in methanol were used to follow changes in the CdS(x)O(y) coordination. The correlations found from the current and previous studies between (113)Cd NMR chemical shifts and different Cd(II) coordination environments are generally useful for evaluating cadmium coordination to thione-containing or Se-donor ligands in biochemical systems or for monitoring speciation in solution.

Topics: Cadmium; Magnetic Resonance Spectroscopy; Organometallic Compounds; Organoselenium Compounds; Solutions; Thiourea; Urea; X-Ray Absorption Spectroscopy

In the present study, the synthesis and characterization of a series of N-methylimidazole-based thiourea and selenourea derivatives are described. The new compounds were also studied for their ability to inhibit peroxynitrite (PN)- and peroxidase-mediated nitration of protein tyrosine residues. It has been observed that the selenourea derivatives are more efficient than the thiourea-based compounds in the inhibition of protein nitration. The higher activity of selenoureas as compared to that of the corresponding thioureas can be ascribed to the zwitterionic nature of the selenourea moiety. Single crystal X-ray diffraction studies on some of the thiourea and selenourea derivatives reveal that the C=S bonds in thioureas possess more of double bond character than the C=Se bonds in the corresponding selenoureas. Therefore, the selenium compounds can react with PN or hydrogen peroxide much faster than their sulfur analogues. The reactions of thiourea and selenourea derivatives with PN or hydrogen peroxide produce the corresponding sulfinic or seleninic acid derivatives, which upon elimination of sulfurous/selenous acids produce the corresponding N-methylimdazole derivatives.

Topics: Animals; Cattle; Crystallography, X-Ray; Imidazoles; Models, Molecular; Molecular Structure; Nitrates; Organoselenium Compounds; Peroxidase; Peroxynitrous Acid; Serum Albumin, Bovine; Stereoisomerism; Thiourea; Tyrosine; Urea

The gas-phase reactions between Ca(2+) and selenourea were investigated by means of electrospray/tandem mass spectrometry techniques. The MS/MS spectra of [Ca(selenourea)](2+) complexes show intense peaks at m/z 43, 121, 124, and 146 and assigned to monocations produced in different coulomb explosion processes. The structures and bonding characteristics of the stationary points of the [Ca(selenourea)](2+) potential energy surface (PES) were theoretically studied by DFT calculations carried out at the B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) level. The analysis of the topology of this PES allows identification of H(2)NCNH(+), CaSeH(+), selenourea(+). and CaNCSe(+) ion peaks at m/z 43, 121, 124, and 146, respectively. The reactivity of selenourea and the topology of the corresponding potential energy surface mimic that of thiourea. However, significant dissimilarities are found with respect to urea. The dissociative electron-transfer processes, not observed for urea, is one of the dominant fragmentations for selenourea, reflecting its much lower ionization energy. Similarly, the coulomb explosions yielding CaXH(+) + H(2)NCNH(+) (X = O or Se), which for urea are not observed, are very favorable for selenourea. Finally, while in urea the loss of NH(3) competes with the formation of NH(4+), for selenourea the latter process is clearly dominant.

Topics: Calcium; Gases; Macromolecular Substances; Models, Chemical; Organoselenium Compounds; Phase Transition; Quantum Theory; Spectrometry, Mass, Electrospray Ionization; Thiourea; Urea

A facile, one-pot synthesis of thio and selenourea derivatives from amines using tetrathiomolybdate 1 and tetraselenotungstate 2 as sulfur and selenium transfer reagents, respectively, is reported. The compounds were tested for their activity as urease inhibitors and some of the compounds showed potent activity in the nanomolar range towards jack bean urease.

Topics: Canavalia; Drug Evaluation, Preclinical; Enzyme Inhibitors; Models, Molecular; Molecular Structure; Molybdenum; Organoselenium Compounds; Thiourea; Urea; Urease

Oxygen radicals, such as superoxide radicals, embellishing DNA, protein, lipids, etc., and carrying out the obstacle of the function of a cell is known. It depends for the oxidant level in the living body on the balance of a generation system and an elimination system of oxygen radicals, and research which controls an oxidant level in the living body is briskly done by taking in the substance which eliminates an oxygen radical. We investigated scavenging effects of superoxide radicals by selenoureas and thioureas using a highly sensitive and quantitative chemiluminescence method. At 330 nM, five selenoureas and five thioureas scavenged fractions of superoxide radicals (O2-) ranging from 8.4% to 87.6%. Among five N,N-unsubstituted selenoureas and N,N-unsubstituted thioureas 1-selenocarbamoylpiperidine and 1-thiocarbamoylpyrrolidine were the most effective scavengers. A possibility that selenoureas could use it as a new superoxide anion-scavenging substance from the result of this research became clear.

Topics: Dose-Response Relationship, Drug; Firefly Luciferin; Free Radical Scavengers; Indicators and Reagents; Organoselenium Compounds; Oxidants; Reactive Oxygen Species; Superoxides; Thiourea; Urea