Phenylthiourea Research Articles

Inhibiting action of phenylthiourea towards iron-based metallic glass corrosion in acid environment

The influence exerted by phenylthiourea (PTU) towards the corrosion of Fe 79B 16Si 5 metallic glass in deaerated 0.1N H 2SO 4 was investigated by direct-current (potentiodynamic polarization) and alternating-current (impedance spectroscopy) techniques. The inhibiting action found on the Fe 79B 16Si 5 glassy alloy was compared to the corresponding one obtained on annealed polycrystalline Armco iron and on a previously tested Fe 81B 13.5Si 3C 2 amorphous alloy. The inhibitor film formed more rapidly and was more protective and stable on the amorphous alloys than on polycrystalline iron and a PTU concentration as low as 10 −5 M was sufficient to build instantaneously an efficient film on the surfaces of the metallic glasses. On these surfaces, a greater amount of PTU was chemisorbed than on the crystalline iron, an effect which leads to a more complete and protective film.

A Facile Synthesis of 2-Aminothiazolo[5,4-b]pyridines and 2-Aminobenzoxazoles via Cyclization of Thioureas

2-Aminothiazolo[5,4-b]pyridines and 2-aminobenzoxazoles have been synthesized from 2-hydroxy-3-thioureidopyridine and 2-hydroxy-3-thioureidobenzene respectively via acid catalyzed cyclization, which were prepared by the reaction of isothiocyanates with 2-hydroxy-3-aminopyridine or 2-aminophenol. The hydroxyl group of N-(2-hydroxy-5-phenyl)- N'-phenyl thiourea reacted as nucleophile to thioureido carbon to give 2-aminobenzoxazoles, whereas that of N-(2-hydroxypyridino)-N'-phenylthiourea was reacted as leaving group upon nuclephillic sulfur of thiourea group in the presence of trifluoroacetic acid or phosphoric acid.

Organic sulphur-containing compounds as corrosion inhibitors for mild steel in acidic media: correlation between inhibition efficiency and chemical structure

The effects of thiourea (TU), methylthiourea (MTU) and phenylthiourea (PTU) on the corrosion behaviour of mild steel in 0.1M solution of H2SO4 have been investigated in relation to the concentration of thioamides (CSNH2). These compounds are all similar on one side of the thiocarbonly group and different on the other. The experimental data obtained using the techniques of Rp (polarisation resistance) and EIS (electrochemical impedance spectroscopy). The results showed that these compounds revaled a good corrosion inhibition, phenylthiourea being the most efficient and thiourea the least.The effect of molecular structure on the inhibition efficiency on corrosion has been investigated by ab initio quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, LUMO–HOMO energy gap and molecular orbital densities were calculated. The relations between the inhibition efficiency and some quantum parameters have been discussed and obvious correlations were found. The highest values of the HOMO densities were found in the vicinity of the sulphur atom indicating it as most probable adsorption centre.

New binary accelerator systems for sulphur vulcanisation of styrene butadiene rubber

It is suggested that binary systems of rubber vulcanisation containing thiourea proceed by a nucleophilic reaction mechanism. The exact mechanism of the chemical reactions involved when binary accelerator systems are used in rubber vulcanisation is not fully understood even now. It differs with the systems and the nature of the elastomer used. In the present work, a derivative of thiourea, N-amidino N'-phenyl thiourea (APT), was studied as a secondary accelerator along with tetramethyl thiuram disulphide (TMTD)/mercaptobenzothiazyl disulphide (MBTS) in the sulphur vulcanisation of styrene butadiene rubber. Thiourea binary systems were used as controls. The binary systems containing APT are very effective in reducing the optimum vulcanisation time. APT being more nucleophilic than thiourea, is more reactive here (as observed by the reduction in cure time). A nucleophilic reaction mechanism is indicated in the vulcanisation reaction under review. Different concentrations of APT were tried in various mixes using standard recipes, and reference mixes were also evaluated. The optimum dosage of APT required has been derived based on the cure characteristics of the mixes and the physical properties of the vulcanisates.

Synthesis of Novel Heterocyclic 4-Thiazolidinone Derivatives and their Antibacterial Activity

4-Thiazolidinones have been prepared by the reaction of various substituted Schiff bases 3 with Thioglycolic acid and Thiolactic acid. The intermediate Schiff bases 3 were synthesized by the condensation of various substituted 2-amino benzothiazole 1 with 1-(4'-methyl Phenyl)-3-methyl-5-pyrazolone 2. The starting compound substituted 2-amino benzothiazoles were prepared from various substituted amines via substituted phenyl thiourea. The structures of the compounds have been confirmed by elemental analysis and spectral analysis. The antibacterial activity of the compounds has also been screened againstStaphylococcus aureusandEscherichia coli.

Carminic acid dye from the homopteran Dactylopius coccus hemolymph is consumed during treatment with different microbial elicitors.

The activation of Dactylopius coccus (Costa) hemolymph with microbial polysaccharide molecules was studied. Hemolymph incubated in the presence of laminarin, zymosan, and N-acetyl glucosamine produced a dark fibrillar precipitated, and the red pigment (carminic acid) was consumed (measured spectrophotometrically at 495 nm). Lipopolysaccharide (LPS) did not induce any response. The reaction was inhibited with millimolar concentrations of serine and cysteine protease inhibitors, EGTA and phenyl thiourea. It was also diminished by prostaglandin synthesis inhibitors: dexamethasone, acetylsalicylic acid, and indomethacin. However, Mg2+ chelator EDTA did not inhibit hemolymph activation. Hemolymph proteins were depleted from soluble phase during treatment with laminarin, but a group of around 34 kDa remained unmodified. These results showed that D. coccus hemolymph is activated by microbial elicitors, its activation depends on eicosanoids, and suggest participation of a prophenoloxidase (PPO)-like activation system that could consume carminic acid. We are currently dissecting the molecular factors involved in D. coccus hemolymph activation to determine homologies and differences with other arthropods immune response pathways.

Elimination of shrimp endogenous peroxidase background in immunodot blot assays to detect white spot syndrome virus (WSSV).

False positive results were obtained in immunodot blot assays to detect white spot syndrome virus when horseradish peroxidase-conjugated sheep anti-mouse immunoglobin (Ig) serum was used as a secondary antibody with 3-3'-diaminobenzine tetrahydrochloride dihydrate as the detection substrate. The cause was considered to be a reaction of shrimp endogenous peroxidase (POD) with the substrate. In experiments designed to inhibit POD activity, 9 different reagents were used at different concentrations and for different treatment times. EDTA, sodium azide, HEPES-Na, NaHSO3, H2O2 and phenylthiourea (PTU) were able to inhibit POD activity by 44, 60, 64, 67, 79, and 90%, respectively. Phenylmethylsulfonyl fluoride did not inhibit POD, and neither periodic acid nor H2O2 in methanol were appropriate due to the formation of flocculant precipitates when added to shrimp extracts. It was concluded that of the treatments tested, 10 mM PTU for 2 h yielded optimal inhibition and that such pretreatment of samples eliminates false positive results in immunodot blot assays.

X-ray powder diffraction analysis of a nonlinear optical material N-(p-methoxy benzoyl)-N′-(p-methyl phenyl) thiourea

A nonlinear optical material, N-(p-methoxy benzoyl)-N′-(p-methyl phenyl) thiourea (C16H16N2O2S), has been characterized by X-ray powder diffraction. Experimental values of 2θ corrected for systematic errors, relative peak intensities, values of d, and the Miller indices of 94 observed reflections with 2θ up to 66° are reported. The powder diffraction data and the figure-of-merit are reported. The least-squares refined unit cell parameters are a=25.3291(3) Å, b=11.9478(1) Å, c=10.1407(4) Å, β=103.10(2)°, V=2988.97(6) Å3, Z=8, Dx=1.335(0) g/cm3, with space group P21(4).

X-ray powder diffraction analysis of a nonlinear optical material N-(p-methoxy benzoyl)-N′-(o-methyl phenyl) thiourea

A nonlinear optical material, N-(p-methoxy benzoyl)-N′(o-methyl phenyl) thiourea (C16H16N2O2S), has been characterized by X-ray powder diffraction. Experimental values of 2θ corrected for systematic errors, relative peak intensities, values of d, and the Miller indices of 90 observed reflections with 2θ up to 88° are reported. The powder diffraction data have been evaluated, and the figures-of-merit are reported. The least-squares refined unit cell parameters are a=26.7079(3) Å, b=6.7995(9) Å, c=19.2845(1) Å, β=121.39(4), V=2989.42(3) Å3, Z=8, Dx=1.334(8) g/cm3, space group P2(3).

Synthesis and antimicrobial activity of some pyridinyliminothiazoline derivatives

The synthesis of some pyridinyliminothiazoline derivatives starting from N-pyridine- N′-phenyl thiourea and α-halogenoacetophenones is described. The chemical structures of the compounds were elucidated. The prepared compounds were tested for antimicrobial activity.

Thiourea toxicity in mouse C3H/10T [formula omitted] cells expressing human flavin-dependent monooxygenase 3

Human flavin-dependent monooxygenase (FMO) isoforms 1 and 3 were expressed by retroviral gene transfer in mouse C3H/10T 1 2 cells. FMO function was determined by the sulfoxidation of p-tolylmethylsulfide (TMS). Enzyme activity ranged from 4 to 30 nmol p-tolylmethylsulfoxide (TMSO)/30 min/mg cell protein for FMO 3 clones; for FMO 1 clones, the range was 1–6 nmol TMSO/30 min/mg. Cytotoxicity in these clones after exposure to thiocarbamate compounds was assessed by clonogenic assay. Thiourea (TU), phenylthiourea (PTU), and α-naphthylthiourea (ANTU) were toxic to FMO 3 cells but not to parental and FMO 1 clones; 50% toxicity was attained at 1×10 −4 M TU, 5×10 −6 M PTU, and 1×10 −6 M ANTU. Toxicity was observed after a minimum exposure time of 6 hr. Parental cells were resistant to toxicity for exposure times spanning the entire clonogenic assay period (10 days). Ethylene thiourea (ETU) was not toxic to FMO 3 cells, but preincubation with 1×10 −3 M ETU blocked TU toxicity. Reducing GSH levels by preincubation with 1×10 −5 M buthionine sulfoxime (BSO) increased TU sensitivity in FMO 3 cells from 1×10 −4 to 1×10 −6 M to achieve 50% toxicity. BSO also increased the sensitivity of “low expressor” FMO 3 clones to TU, but did not alter the refractoriness of either parental or FMO 1 expressing cells to TU. N-Acetylcysteine afforded modest protection to TU toxicity by shifting 50% cytotoxicity for TU from 5×10 −5 to 1×10 −3 M. TU mutagenicity was assayed by the development of ouabain resistance in parental and FMO 3 C3H/10T 1 2 cells. Exposure to N-methyl- N′-nitro- N-nitrosoguanidine (MNNG, direct acting mutagen) and TU was executed with and without prior sensitization with BSO. The mutation frequency for MNNG was 76/1×10 6 surviving cells, whereas no mutants were observed for TU-exposed cultures. The results of this study show that, in isolation, the major human hepatic form of FMO is capable of promoting thiocarbamate toxicity. Consistent with the known reactivity of thiocarbamate intermediates with GSH, treatments that alter GSH levels also altered toxicity in either the protective or sensitizing direction. These cell lines expressing variable levels of FMO 3 and TU sensitivity should prove useful as in vitro systems for dissecting the thiocarbamate toxicity pathway.

Catalytic hydrogen evolution in cathodic stripping voltammetry on a mercury electrode in the presence of cobalt(II) ion and phenylthiourea or thiourea.

The system Co(II)-phenylthiourea (PTU)-borax buffer was investigated by cathodic stripping voltammetry (CSV) at a hanging mercury drop electrode. The results of the voltammetric measurements showed that the presence of both PTU and Co(II) gives rise to a new irreversible peak at about -1.5 V. Based upon our previous results obtained in the study of other sulfur compounds and the sulfide ion itself, the peak was ascribed to the catalytic hydrogen evolution superimposed on the reduction of the coordinated Co(II) ion. The catalyst itself is a Co(II) complex with the sulfide ion produced by the decomposition of the analyte during the deposition step. The influence of PTU and cobalt concentration, accumulation conditions and stripping parameters was investigated and complementary data on thiourea are included. The results showed that the measurement of the catalytic hydrogen evolution peak current can be used as a basis for a simple, accurate and rapid method for the determination of PTU within the concentration range 10-100 nM. The catalytic method is relatively free of interferences and could be a suitable alternative for cases in which the stripping peak due to mercury ion reduction in the accumulated mercury compound is disturbed by some interference.

SYNTHESIS AND STRUCTURES OF DICHLOROTETRAKIS-(PHENYLTHIOUREA) CADMIUM(II) AND CATENA-BIS(THIOCYANATE) BIS(PHENYLTHIOUREA)CADMIUM(II)

Two new cadmium(II) complexes with phenylthiourea (PTU), namely Cd(PTU)4Cl2 (1) and [Cd2(NCS)2(μ2-SCN)2(PTU)2(μ2-PTU)2] n (2), have been prepared and characterized structurally by X-ray diffaction. Complex 1 crystallizes in the monoclinic space group C2/c, with a = 27.057(13), b = 8.108(3), c = 16.751(8) Å, β = 114.46°, V = 3345(3) Å3, Z = 4. Complex 2 crystallizes in the triclinic space group P-1, with a = 9.336(3), b = 14.686(5), c = 16.911(5) Å, α = 71.36(2), β = 84.31(2), γ = 72.470(10)°, V = 2095.0(12) Å3 Z = 4. The structural analysis shows that each metal atom in both the mononuclear complex 1 and polynuclear complex 2 is octahedrally coordinated by four sulfur atoms and two chloro ligands or two nitrogen atoms from the thiocyanate groups, respectively. The PTU ligand can serve as either a monodentate ligand or a μ2-bridging ligand upon coordination to a metal atom.

Inhibition of tyrosinase reduces cell viability in catecholaminergic neuronal cells.

The biosynthesis of dopamine (DA) in catecholaminergic neurons is regulated by tyrosine hydroxylase, which converts tyrosine into 3, 4-dihydroxyphenylalanine (L-DOPA). In melanocytes, tyrosinase catalyzes both the hydroxylation of tyrosine and the consequent oxidation of L-DOPA to form melanin. Although it has been demonstrated that tyrosinase is also expressed in the brain, the physiological role of tyrosinase in the brain is still obscure. In this study, to investigate the role of tyrosinase in catecholaminergic neuronal cells, we examined the effects of tyrosinase inhibition on the viability of CATH.a and SH-SY5Y cells using tyrosinase inhibitors-specifically, phenylthiourea (PTU) and 5-hydroxyindole (5-HI)-and the transfection of antisense tyrosinase cDNA. Both inhibitors significantly reduced the cell viability of CATH.a cells in a dose-dependent manner. PTU also specifically enhanced DA-induced cell death, but 5-HI did not. This discrepancy in cell death is probably due to the inhibitors' different mechanism of action: 5-HI inhibits the hydroxylation of tyrosine as a competitor for the substrate to induce cell death that may be due to depletion of DA, whereas PTU mainly inhibits the enzymatic oxidation of L-DOPA and DA rather than tyrosine hydroxylation to increase consequently autooxidation of DA. Indeed, the intracellular DA content in CATH.a cells was enhanced by PTU exposure. In contrast, PTU showed no enhancing effects on DA-induced cell death of SH-SY5Y cells, which express little tyrosinase. Furthermore, transfection with antisense tyrosinase cDNA into CATH.a cells dramatically reduced cell viability and significantly enhanced DA-induced cell death. These results suggest that tyrosinase controls the intracellular DA content by biosynthesis or enzymatic oxidation of DA, and the dysfunction of this activity induces cell death by elevation of intracellular DA level and consequent gradual autooxidation of DA to generate reactive oxygen species.

Isothiocyanates in myrosinase treated herb extract of Cleome chrysantha decne. and their antimicrobial activities.

GC/MS analysis of the volatiles produced by the action of endogenous myrosinase in Cleome chrysantha Decne. herb, showed three major components, 1-isocyano-4-methyl benzene, gamma-muurolene and (cis) nerolidole (21.72%, 12.15% and 10.39%, respectively). 1-isocyano-4-methyl benzene is not produced from myrosinase treated seeds of Cleome chrysantha Decne., while muurolene and nerolidole were found at higher concentrations 16.1% and 13.67%, respectively. Some other isothiocyanates identified in the seeds and leaves, but in low percentages, were 2-methylbutyl isothiocyanate, 4-methylthiobutyl isothiocyanate and isothiocyanatomethyl benzene. Enzymatic hydrolysis of the ethanol extract of Cleome chrysantha Decne., produced two non-volatile isothiocyanates, 4, 6-dimethyltetrahydro-1,3-oxazine-2-thione and N-(-4-methyl-sulphinyl-3-butenyl) isothiocyanate which was established by aniline and methanolic ammonia to give the stable form of phenyl thiourea. They were identified by their spectroscopic data. These two isothiocyanates and the volatiles of the herb showed good antimicrobial activity against E. coli, Pseudomonas putida and Rhizobium meloloti (gram-negative bacteria) and moderate activity against Bacillus subtilis and Streptococcus lactis (gram-positive bacteria).

Inhibition of l-tyrosine-induced micronuclei production by phenylthiourea in human melanoma cells

It was previously found that l-tyrosine oxidation product(s) are cytotoxic, genotoxic and increase the sister chromatid exchange (SCE) levels in human melanoma cells. In this work, the micronucleus assay has been performed on human melanotic and amelanotic melanoma cell lines (Carl-1 MEL and AMEL) in the presence of 1.0, 0.5 and 0.1 mM l-tyrosine concentrations to investigate if melanin synthesis intermediate(s) increase micronuclei production. l-Tyrosine oxidation product(s) increased the frequency of micronuclei in melanoma cells; 0.1 mM phenylthiourea (PTU), an inhibitor of l-tyrosine oxidation by tyrosinase, lowered the micronucleus production to the control levels. The culture of melanoma cells with high l-tyrosine in the culture medium resulted in a positive response to an ELISA-based apoptotic test. For comparison the effect of l-tyrosine on micronuclei production in human amelanotic melanoma cells was also investigated; the micronucleus production in the presence of 1 mM l-tyrosine in the culture medium was lower than that found with melanotic melanoma cells of the same cell line. The data suggest that melanin synthesis intermediates arising from l-tyrosine oxidation may cause micronuclei production in Carl-1 human melanoma cells; the addition of PTU in the presence of l-tyrosine decreased the frequency of micronuclei to about the control values thus the inhibition of melanogenesis may have some clinical implication in melanotic melanoma.

Effect of tyrosinase inhibitors on Tuber borchii mycelium growth in vitro

This paper reports the effect of the tyrosinase (monophenol o-diphenol:oxygen oxidoreductase; EC 1.14.18.1) inhibitors diethyldithiocarbamate (DETC), L-tropolone, kojic acid, phenylthiourea (PTU) and L-mimosine on the in vitro growth of Tuber borchii (a white truffle) mycelium. A significant inhibitory effect on mycelium growth was observed for DETC, PTU and L-tropolone (0% growth compared to control at 100 μg ml −1 DETC, PTU and L-tropolone and at 10 μg ml −1 DETC and L-tropolone). As a comparison the action of the same inhibitors was also tested on the growth and pigmentation of the mould Cladosporium sphaerospermum. In the presence of CuSO 4 10 −6 M T. borchii mycelium acquired pigmentation (as rounded aggregates compared to control revealed by SEM microscopy). Tyrosinase activity in the extract from T. borchii mycelium (18-day culture) was detected spectrophotometrically.

The Addition of Diallylzinc to 5-Substituted 4,5-Dihydroisoxazoles

The addition of diallyl zinc to a range of 5-aryl-4,5-dihydroisoxazoles, occurs with a diastereoselectivity of between 6.9 : 1 and 3.6 : 1. The major product is the trans isomer as demonstrated by an X-ray crystal structure on the phenyl thiourea derivative of one of the major products.

Synthesis of N—Aroyl—N′—hydroxyethyl (Hydroxyphenyl) Thiourea Derivatives Under the Condition of Phase Transfer Catalysis

Reaction of aminoethanol or aminophenol with aroyl chloride and ammonium thiocyanate under the condition of solid-liquid phase transfer catalysis using polyethylene glycol—600 (PEG—600) as the catalyst yielded N—aroyl—N′—hydroxyethyl (hydroxy phenyl) thiourea derivatives. The products have been characterised on the basis of analytical and spectral (IR and ′H—NMR) data.

Synergistic influence of iodide ions on inhibition of corrosion of mild steel in H2SO4byN-phenyl thiourea

Abstract The synergistic action of iodide ions on the inhibition of corrosion of mild steel in 0·5M H2SO4 by N-phenyl thiourea (N-PTU) has been investigated using weight loss measurements, potentiodynamic polarisation studies, linear polarisation studies, and impedance measurements. Inhibition efficiency is found to increase with increase in the concentration of N-PTU. The inhibiting action of N-PTU is considerably enhanced by the addition of potassium iodide. The adsorption of this compound either alone or in combination with iodide ions on the metal surface is found to obey Langmuir's adsorption isotherm. The increase in surface coverage 0 in the presence of iodide ions indicates joint adsorption of N-PTU and iodide ions. The synergism parameter is defined and evaluated from the values of inhibition efficiency and surface coverage. This parameter is found to be greater than unity, which indicates that the enhanced inhibition efficiency caused by the addition of iodide ions is only due to synergism and t...