Urea Compounds Research Articles

Study of fireproof properties of textile materials safe when in contact with human skin

The methods of surface fire retardant treatment of textile materials (TM) and the chemical basis of the fire retardants used are considered. The possibility of developing a fire retardant composition for tissues that would not adversely affect the human skin upon contact has been studied. To determine the degree of danger of contact and of the penetration of chemicals through skin in contact with the fireproof TM, special studies were conducted to study the local irritating effect and resorption of the composition according to special developed laboratory methodological instructions. As the result the evidence was found that the irritating effect of the fire retardant composition developed on the skin and mucous membranes of the eyes of experimental animals was not detected. Comparative thermo analytical studies showing the effectiveness of the fire retardant action of the composition developed on the main stage of thermal decomposition of cellulose-containing TM are presented. Thus, the development of a fire retardant composition based on phosphorus-containing compounds and urea compounds and the selection of the optimum ratio of stabilizers for the processing of decorative and finishing fabrics with safe contact with human skin can be one of the effective ways to solve the problem under consideration.

Bioremediation and metabolism of clothianidin by mixed bacterial consortia enriched from contaminated soils in Chinese greenhouse

Abstract Clothianidin has been widely used for the long-term control of a variety of insect pests. However, extensive use of this pesticide is leading to serious environmental concerns. In this study, the degradation of clothianidin by bacterial consortia SCAH constructed using four potential strains isolated from contaminated soils in vegetable greenhouse was investigated. The strains in the consortia were Ochrobactrum anthropi, Acinetobacter johnsonii, Pseudomonas sp. and Stenotrophomonas maltophilia. In the mineral salt medium, 79.3% of clothianidin (500 mg L−1) was degraded by bacterial consortia SCAH after 15 days. Three metabolites of clothianidin were identified by LC–MS. Results revealed that the consortia SCAH metabolized clothianidin by transformation of the nitroimino moiety to the urea compound and the cleavage of different bonds. The bacterial consortia was applied to bioremediate clothianidin contaminated soil in the presence or absence of additional nutrients. For the treatment with the addition of nutrients, the degradation rate of clothianidin was enhanced in the whole process compared with the treatment without added nutrients, and the clothianidin was almost completely degraded after 45 days. Meanwhile, in the treatment where only consortia SCAH were added, the degradation rate of clothianidin was obviously higher than the natural attenuation (CK) and biostimulation (BS).

Impact of a Single Hydrogen Substitution by Fluorine on the Molecular Interaction and Miscibility between Sorafenib and Polymers.

We aim to understand the potential impact of a modest chemical modification of a drug molecule on the downstream design of its amorphous solid dispersion (ASD) formulation. To this end, we used sorafenib (SOR) and its fluorinated form, regorafenib (REG), as model drugs, to assess the impact of a single hydrogen substitution by fluorine on the molecular interaction and miscibility between drug and PVP or PVP-VA, two commonly used polymers for ASDs. In this study, we observed that the Tg values of PVP or PVP-VA based ASDs of SOR deviated positively from the Gordon-Taylor prediction, which assumes ideal mixing, yet the Tg of REG ASDs deviated negatively from or matched well with the ideal mixing model, suggesting much stronger drug-polymer interactions in SOR ASDs compared with the REG ASDs. Using solution NMR and computational methods, we proved that a six-member-ring formed between the carbonyl groups on the polymers and the uramido hydrogen of SOR or REG, through intermolecular hydrogen bonding. However, steric hindrance resulting from fluorination in REG caused weaker interaction between REG-polymer than SOR-polymer. To further confirm this mechanism, we investigated the molecular interactions of other two uramido-containing model compounds, triclocarban (TCC) and gliclazide (GCZ), with PVP. We found that TCC but not GCZ formed a hexatomic ring with PVP. We concluded that PVP based polymers can easily interact with N, N'-disubstituted urea compounds with a trans-trans structure in the form of hexatomic rings, and the interaction strength of the hexatomic ring largely depended on the chemistry of drug molecules. This study illustrated that even a slight chemical modification on drug molecules could result in substantial difference in drug-polymer interactions, thus significantly impacting polymer selection and pharmaceutical performance of their ASD formulations.

Experimental enthalpies of formation and sublimation of urea compounds: An accuracy assessment

The thermochemical network of 91 isodesmic and other balanced reactions was used to adjust simultaneously the enthalpies of formation of 14 urea compounds. The experimental enthalpies of formation of these compounds were treated as unknowns in the least-squares minimization of deviations between the theoretically predicted enthalpies of reaction and experimental values. A result of a least-squares fit confirms the accuracy of experimental enthalpies of formation of 8 ureas, whereas the experimental measurements for 6 urea compounds require re-examination. The gas-phase standard enthalpies of formation of 8 ureas were used as a consistent basis to obtain values for other 15 ureas through isodesmic reactions. To estimate the enthalpies of formation in crystalline state, the sublimation enthalpies were predicted using the molecular electrostatic potential model.

Triazole Ureas Covalently Bind to Strigolactone Receptor and Antagonize Strigolactone Responses

Strigolactones, a class of plant hormones with multiple functions, mediate plant–plant and plant–microorganism communications in the rhizosphere. In this study, we developed potent strigolactone antagonists, which covalently bind to the strigolactone receptor D14, by preparing an array of triazole urea compounds. Using yeast two-hybrid and rice-tillering assays, we identified a triazole urea compound KK094 as a potent inhibitor of strigolactone receptors. Liquid chromatography–tandem mass spectrometry analysis and X-ray crystallography revealed that KK094 was hydrolyzed by D14, and that a reaction product of this degradation covalently binds to the Ser residue of the catalytic triad of D14. Furthermore, we identified two triazole urea compounds KK052 and KK073, whose effects on D14–D53/D14–SLR1 complex formation were opposite due to the absence (KK052) or presence (KK073) of a trifluoromethyl group on their phenyl ring. These results demonstrate that triazole urea compounds are potentially powerful tools for agricultural application and may be useful for the elucidation of the complicated mechanism underlying strigolactone perception.

Enhanced Mechanical and Thermal Strength in Mixed-Enantiomers-Based Supramolecular Gel.

Mixing supramolecular gels based on enantiomers leads to re-arrangement of gel fibers at the molecular level, which results in more favorable packing and tunable properties. Bis(urea) compounds tagged with a phenylalanine methyl ester in racemic and enantiopure forms were synthesized. Both enantiopure and racemate compounds formed gels in a wide range of solvents and the racemate (1-rac) formed a stronger gel network compared with the enantiomers. The gel (1R+1S) obtained by mixing equimolar amount of enantiomers (1R and 1S) showed enhanced mechanical and thermal stability compared to enantiomers and racemate gels. The preservation of chirality in these compounds was analyzed by circular dichroism and optical rotation measurements. Analysis of the scanning electron microscopy (SEM) and atomic force microscopy (AFM) images revealed that the network in the mixed gel is a combination of enantiomers and racemate fibers, which was further supported by solid-state NMR. The analysis of the packing in xerogels by solid-state NMR spectra and the existence of twisted-tape morphology in SEM and AFM images confirmed the presence of both self-sorted and co-assembled fibers in mixed gel. The enhanced thermal and mechanical strength may be attributed to the enhanced intermolecular forces between the racemate and the enantiomer and the combination of both self-sorted and co-assembled enantiomers in the mixed gel.

Derivation of a point of departure for alkyl-substituted urea compounds using a category-based read-across approach

Derivation of a point of departure for alkyl-substituted urea compounds using a category-based read-across approach

Laser Irradiation of Organic Tattoo Pigments Releases Carcinogens with 3,3′-Dichlorobenzidine Inducing DNA Strand Breaks in Human Skin Cells

Laser Irradiation of Organic Tattoo Pigments Releases Carcinogens with 3,3′-Dichlorobenzidine Inducing DNA Strand Breaks in Human Skin Cells

A novel biphenyl urea compound, TPD7, stimulates apoptosis through modulating Fas signaling and Bcl-2 family proteins in cervical cancer.

We recently reported that TPD7 suppressed tumor cell proliferation, and inhibited invasion, through the suppression of C-X-C chemokine receptor type4 (CXCR4). In the present study, we investigated the anticancer effect of TPD7 on apoptosis and invasion of cervical cancer HeLa cells. Cell cycle analysis revealed that TPD7 decreased cyclin-dependent kinase (CDK)1 and cyclinD1 expression, and increased cyclin A expression, following Sphase blockade. TPD7 induced chromatin condensation and significantly elevated the number of apoptotic cells, suggesting that its inhibitory effect on HeLa cells was due to the induction of cell cycle blockade and apoptosis. Mechanistically, TPD7 altered the extrinsic apoptosis pathway by upregulating Fas expression, and the intrinsic pathway by modulating Bcl-2 family proteins, p53, and NF-κB p65, leading to enhanced apoptosis. TPD7 inhibited HeLa cell invasion by downregulating the expression of matrix metalloproteinase (MMP)-9 and CXCR4 proteins. Invivo experiments revealed that TPD7 inhibited tumor growth in HeLa cell xenografted mice. These findings indicated that TPD7 may be a potential chemoprevention agent for the management of cervical carcinoma.

In silico and in vivo investigation of ferrocene-incorporated acyl ureas and homoleptic cadmium carboxylate derivatives for anticonvulsant, anxiolytic, and sedative potential.

In this study different derivatives of ferrocene-incorporated acyl ureas and homoleptic cadmium carboxylates were investigated for potential anticonvulsant, anxiolytic and sedative properties, using in-silico and in-vivo techniques. The molecular docking studies reveled that ferrocene compounds derivative 1-(4-bromobenzoyl)-3-(4-ferrocenylphenyl) urea (PB1) and cadmium compounds derivative bis (diphenylacetato) cadmium (II) (DPAA) exhibit binding affinities against various neurotherapeutic molecular targets involved in epilepsy, anxiety, and sedation. Both PB1 and DPAA showed high binding affinities against protein targets like mammalian shaker voltage dependent potassium channel beta subunit complex, calcium release-activated calcium channel, sodium channel 2A inactivation gate, human sodium/hydrogen exchanger regulatory factor, and gamma amino butyric acid A receptor associated protein. PB1 (2-10 mg/kg) and DPAA (1-5 mg/kg) delayed onset time of pentylenetetrazole-induced myoclonic jerks and tonic-clonic seizures in mice while decreased duration of tonic-clonic seizures, determining the anticonvulsant effect of these compounds. PB1 and DPAA (0.5-1 mg/kg) exhibited anxiolytic effect by increasing time spent and number of animals entries into open arms, while decreasing time spent in dark compartment. Furthermore, PB1 (0.5-1 mg/kg) and DPAA (0.1-1 mg/kg) reduced onset time of sleep and increased duration time of sleep in mice, showing sedative effect. Taken together, our results indicate that aforementioned derivatives of ferrocene and cadmium are potent neurotherapeutic agents possessing anticonvulsant, anxiolytic and sedative properties.

Discovery of the pyridylphenylureas as novel molluscicides against the invasive snail Biomphalaria straminea, intermediate host of Schistosoma mansoni

BackgroundThe snail Biomphalaria straminea is one of the intermediate hosts of Schistosoma mansoni. Biomphalaria straminea is also an invasive species, known for its strong capability on peripheral expansion, long-distance dispersal and colonization. Using molluscicides to control snail populations is an important strategy to interrupt schistosomiasis transmission and to prevent the spread of the invasive species. In this study, a series of pyridylphenylurea derivatives were synthesized as potential molluscicides. Their impact on adult snails and egg masses was evaluated. Acute toxicity to fish of the derivatives was also examined to assess their effect on non-target organisms. The preliminary mechanisms of action of the derivatives were studied by enzyme activity assays.ResultsThe representative compounds, 1-(4-chlorophenyl)-3-(pyridin-3-yl)urea (compound 8) and 1-(4-bromophenyl)-3-(pyridin-3-yl)urea (compound 9), exhibited strong molluscicidal activity against adult snails with LD50 values of 0.50 and 0.51 mg/l and potent inhibitory effects on snail egg hatchability with IC50 values of 0.05 and 0.09 mg/l. Notably, both compounds showed good target specificity with potent molluscicidal capability observed in snails, but very low toxicity to local fishes. Furthermore, the exposure of compounds 8 and 9 significantly elevated the enzyme activities of acid phosphatase and nitric oxide synthase of the snails, while no significant change was recorded in the activities of alkaline phosphatase, acetylcholine esterase and superoxide dismutase.ConclusionThe results suggested that compounds 8 and 9 of pyridylphenylurea derivatives could be developed as promising molluscicide candidates for snail control.

Polycyclic aromatic compounds-modified graphitic carbon nitride for efficient visible-light-driven hydrogen evolution

Polycyclic aromatic compounds with strong conjugated effect, possess the advantage of improving electronic polarizability, thus accelerating the electron transportation. Here, a facile copolymerization between urea and polycyclic aromatic compounds (benzoic acid, naphthoic acid and anthroic acid) has been applied to constructing aromatic rings-grafted graphitic carbon nitride (GCN) photocatalysts. Incorporation of aromatic rings in the GCN network is an effective protocol to extend its π-conjugated system for visible light harvesting and improves the charge transfer efficiency for prolonging lifetime of photogenerated charge carriers in photocatalytic reactions. The corresponding characterization methods demonstrate that the aromatic rings-modified GCN can effectively narrow the bandgap to favor broad band visible light absorption and suppress recombination of electrons and holes. Remarkably, the moderate conjugated effect of aromatic rings (naphthalene) is crucial to promote charge separation. The developed naphthalene-grafted GCN achieves the highest water splitting performance with hydrogen evolution rate up to 102.1 μmol h−1, nearly 3.5 times of that of the GCN, and apparent quantum efficiency reaches 5.6% at 450 nm. This finding reveals that the conjugated effect of aromatic rings is significant to control photocatalytic property and brings new ideas for designing aromatic system-modified GCN as highly active photocatalysts towards solar-to-chemical energy conversion.

The Switching from Cis-to-trans One-way Photoisomerization to Mutual Photoisomerization of a Stilbene–Urea Compound Triggered by Proton Transfer Reaction

We have developed a new photochromic material containing a stilbene moiety and a urea moiety based on cooperative effect of photoisomerization and proton transfer. An anthracene–urea–stilbene compound (stAn) exhibited cis-to-trans one-way photoisomerization via the excited triplet state. Furthermore, we succeeded in the switching from one-way to mutual photoisomerizations by the addition of a fluoride ion, which causes the ground state intermolecular proton transfer of stAn leading to negligible intersystem crossing from the excited singlet state.

Synthesis and In Vitro Antiproliferative Activity of New 1-Phenyl-3-(4-(pyridin-3-yl)phenyl)urea Scaffold-Based Compounds.

A new series of 1-phenyl-3-(4-(pyridin-3-yl)phenyl)urea derivatives were synthesized and subjected to in vitro antiproliferative screening against National Cancer Institute (NCI)-60 human cancer cell lines of nine different cancer types. Fourteen compounds 5a–n were synthesized with three different solvent exposure moieties (4-hydroxylmethylpiperidinyl and trimethoxyphenyloxy and 4-hydroxyethylpiperazine) attached to the core structure. Substituents with different π and σ values were added on the terminal phenyl group. Compounds 5a–e with a 4-hydroxymethylpiperidine moiety showed broad-spectrum antiproliferative activity with higher mean percentage inhibition values over the 60-cell line panel at 10 µM concentration. Compound 5a elicited lethal rather than inhibition effects on SK-MEL-5 melanoma cell line, 786-0, A498, RXF 393 renal cancer cell lines, and MDA-MB-468 breast cancer cell line. Two compounds, 5a and 5d showed promising mean growth inhibitions and thus were further tested at five-dose mode to determine median inhibitory concentration (IC50) values. The data revealed that urea compounds 5a and 5d are the most active derivatives, with significant efficacies and superior potencies than paclitaxel in 21 different cancer cell lines belonging particularly to renal cancer and melanoma cell lines. Moreover, 5a and 5d had superior potencies than gefitinib in 38 and 34 cancer cell lines, respectively, particularly colon cancer, breast cancer and melanoma cell lines.

Efficient and Reproducible CH3NH3PbI3 Perovskite Layer Prepared Using a Binary Solvent Containing a Cyclic Urea Additive.

An efficient CH3NH3PbI3 perovskite solar cell whose performance is reproducible and shows reduced dependence on the processing conditions is fabricated using the cyclic urea compound 1,3-dimethyl-2-imidazolidinone (DMI) as an additive to the precursor solution of CH3NH3PbI3. X-ray diffraction analysis reveals that DMI weakly coordinates with PbI2 and forms a CH3NH3PbI3 film (film-DMI) with no intermediate phase. The surface of annealed film-DMI (film-DMI-A) was smooth, with an average crystal size of 1 μm. Photoluminescence and transient photovoltage measurements show that film-DMI-A exhibits a longer carrier lifetime than a CH3NH3PbI3 film prepared using the strongly coordinating additive dimethyl sulfoxide (DMSO) (film-DMSO-A) because of the reduced number of defect sites in film-DMI-A. A solar cell based on film-DMI-A exhibits a higher power conversion efficiency (17.6%) than that of a cell based on film-DMSO-A (15.8%). Furthermore, the performance of the film-DMI-A solar cell is less sensitive to the ratio between PbI2 and DMI, and film-DMI can be fabricated under a high relative humidity of 55%.

A Drastic Red-shift of Tautomer Fluorescence Depending on the Substitution Pattern of Pyrene–Urea Compounds Generated by Excited State Intermolecular Proton Transfer

We investigated the excited state intermolecular proton transfer of pyrene–urea compounds, 1PUP and 4PUP, followed by a tautomer formation in the presence of an acetate ion. The drastic red-shift and enhancement of fluorescence intensity of tautomer of 4PUP were obtained in comparison to 1PUP. The kinetics of formation and decay of excited state tautomer was revealed spectroscopically. Our findings will contribute to the molecular design of fluorescence materials with pyrene moieties based on the substitution patterns.

Effect of Supplementing Slow Release Nitrogen Product on the Lactation Performance of Dairy Cows

A study was undertaken to evaluate the effect of feeding slow-release nitrogen product (SRNP) on the lactation performance of crossbred dairy cows. Eight crossbred cows in mid-late lactation were used in a Youden Latin square design. Treatment diets were T1 containing 2% urea in the concentrate portion of diet, and T2 and T3 diets containing 2 and 4 percent of SRNP, replacing urea on iso-nitrogen and iso-soluble nitrogen basis. The SRNP used in the study was a polymer coated urea compound containing 42% total N with 52.1% soluble N. The diet of the experimental cows comprised corn silage and finger millet straw as roughage source and a compounded feed mixture. There were no differences (P>0.05) in DM intake, milk yield (both total and 4%fat FCM) or milk constituents of cows among the treatment groups. A similar (P>0.05) digestibility of nutrients in the diets of three experimental groups indicated that the supplementation of SRNP had no influence on the utilization of nutrients in the lactating dairy cows. In the current feeding management system, comprising of corn silage, finger millet straw and a compounded feed mixturein the diet of dairy cows, feeding SRNP to replace urea on isonitrogenbasis was found not advantageous. It is concluded that the slow-release nitrogen product used in the present study can replace urea in the diet of lactating dairy cowswithout affecting their performance.

Novel Direct Synthesis of Asymmetrical Urea Compounds from Trichloroethyl Carbamates Using Catalytic DBU

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Raman spectroscopy applied to identify metabolites in urine of physically active subjects

Raman spectroscopy is a rapid and non-destructive technique suitable for biological fluids analysis. In this work, dispersive Raman spectroscopy has been employed as a rapid and nondestructive technique to detect the metabolites in urine of physically active subjects before and after vigorous 30min pedaling or running compared to sedentary subjects. For so, urine samples from 9 subjects were obtained before and immediately after physical activities and submitted to Raman spectroscopy (830nm excitation, 250mW laser power, 20s integration time) and compared to urine from 5 sedentary subjects. The Raman spectra of urine from sedentary showed peaks related to urea, creatinine, ketone bodies, phosphate and other nitrogenous compounds. These metabolic biomarkers presented peaks with different intensities in the urine of physically active individuals after exercises compared to before, measured by the intensity of selected peaks the Raman spectra, which means different concentrations after training. These peaks presented different intensity values for each subject before physical activity, also behaving differently compared to the post-training: some subjects presented increase while others decrease the intensity. Raman spectroscopy may allow the development of a rapid and non-destructive test for metabolic evaluation of the physical training in active and trained subjects using urine samples, allowing nutrition adjustment with the sport's performance.

Synthesis and evaluation of a novel near-infrared fluorescent probe based on succinimidyl-Cys-C(O)-Glu that targets prostate-specific membrane antigen for optical imaging

Prostate-specific membrane antigen (PSMA), which is highly expressed in both localized and metastatic prostate cancer (PCa), is an ideal target for imaging and therapy of PCa. We previously reported radiolabeled asymmetric urea derivatives asa PSMA-targeting radiotracer for single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging. Here, based on these radiopharmaceutical probes, we designed a novel near-infrared (NIR) fluorescent imaging probe (800CW-SCE) by chemical conjugation between IRDye 800CW-Maleimide and an asymmetric urea compound, known as PSMA inhibitor, for optical imaging. In the in vitro cellular uptake study, 800CW-SCE was internalized into PSMA-positive PCa cells (LNCaP cells) but not into PSMA-negative PCa cells (PC-3 cells). Moreover, in the in vivo imaging study, the probe was highly accumulated in LNCaP tumors but not in PC-3 tumors, and remained in LNCaP tumors until 24h after intravenous administration. These results suggest that the potent NIR conjugate may contribute to clinical intraoperative optical imaging.