Inhibition Effect of Hydantoin Compounds on the Corrosion of Iron in Nitric and Sulfuric Acid Solutions

Summary.  The inhibition of corrosion of iron in 2 M nitric acid and 2 M sulfuric acid solutions by substituted phenylhydantoin, thiohydantoin, and dithiohydantoin compounds was measured using thermometric, weight loss, and polarization methods. The three methods gave consistent results. The polarization curves indicated that the hydantoin compounds act as mixed-type inhibitors. The adsorption of the inhibitors were found to obey the Temkin adsorption isotherm. The higher inhibition efficiency of the additives in nitric with respect to sulfuric acid solution may be attributed to the reduced formation of soluble quaternary nitrogen salts in nitric acid medium, favouring adsorption of the parent additive on the metal surface. The obtained results indicate that the corrosion rate of iron in both acids increases with increasing temperature, both in absence and presence of the tested inhibitors. Kinetic-thermodynamic model functions and Temkin isotherm data are compared and discussed. The synergistic effect of halide anions on the inhibition efficiency of the hydantoin compounds was also investigated. Received June 5, 2000. Accepted (revised) September 13, 2000     

Study on Synthesis of Heterocycle-Fused Troponoid Compounds

3,4,5-Trimethoxybenzaldehyde(TMB)isimportantintermediateforthesynthesisofTMPanditisalsothestaFtingmaterialofthesynthesisof3,4,5-trimethoxycinnamide,whichwasusedasanticonvulsantmedicine'.ThetropolonenucleusisweI1knowntobesusceptibletomanyeletrophilicsubstitutionreactions2.Thereactionswithnucleophilicreagentsarealsoofinterest,sincechaIconesreactedwithhydroxylamine'andhydrazines'togiverespectivelydiary-substituteisoxazoIinesandpyrazolines.Thispaperdealswiththereactionsof3-acetyltropoloneand2-…     

Synthesis and Bioactivity of Novel Bis‐heterocyclic Compounds Containing Pyrazole and Oxadiazoline

Nucleophilic addition of the starting material 3‐aryl‐1‐phenyl‐4‐formylpyrazoles ( 1～3 ) and 4‐substituted aryloxyacetyl hydrazine ( 4a～4e ) afford hydrazone compounds containg pyrazolyl ( 5a～5e, 6a～6e, 7a～7e ) in the ethanol. These adducts were refluxed in Ac₂O and furnished a series of novel bis‐hetero‐cyclic compounds. ( 8a～8e, 9a～9e, 10a～10e ) via cyclic reaction. The structures of all newly synthesized compounds were established by IR, ¹H NMR, MS and elemental analysis. New compounds conducted preliminary tests of antibacterial activities about Fusarium oxyaporium, Verticillium dahliae, Rhizoctonia solani, Pychium aphanidermatum, Alternaria solani, Sclerotinia sclerotiorum. The results showed that the inhibiting rate of the bis‐heterocyclic compounds ( 8a～8e, 9a～9e, 10a～10e ) was higher than the pyrazolyl hydrazones ( 5a～5e, 6a～6e, 7a～7e ) obviously.     

Allene-Eneyne Related Cycloaromatization: Design and Synthesis of New DNA-Cleaving Compounds

(Z)-7-Sulfonyl-3-hexen-1,5-diyne containing molecules are stable at room temperature and isomerized to eneyne-allene-sulfones under alkaline conditions. These eneyne-allene-sulfones were not isolable, spontaneously cyclized to form biradical intermediates under mild conditions, and exhibited good DNA-cleaving and human tumor cell line growth inhibition properties. Further studies indicated that compounds bearing on aromatic ring at C(3) and C(4), such as 25 , proved to be more active against those tumor cell lines. Removal of acetylene unit at C(1) and C(2), made the resulting compound less active. A related compound, (Z,Z)-12-(2-tetrahydropyranyl)oxy-1-phenylsulfonyldodeca-4,8-diene-2,6,10-triyne ( 37 ), was synthesized. Upon treatment of triethylamine at refluxing benzene, this compound undergoes double cycloaromatization to form a naphalene adduct, which possesses excellent DNA-cleaving activity.     

MP-C60(M=Cu,Co)化合物的合成、表征及光电性能研究

The convalently linked porphyrin-fullerene ligand was synthesized by 1,3 dipolar cycloaddition reaction. The ligand and complexes were characterized by means of FT-IR, Uv-Vis, 1HNMR, ESI-MS and elemental analysis. The photoelectricity transform performance of the compounds was studied.The result indicated that the photovoltaic effect of (n+n) heterojunction electrode formed by MP-C60/GaAs was super, especially in the I2/I3- and O2／H2O redox couples, and photovoltaic potential was preferable. The photovoltaic performance of a MP-C60/GaAs electrode at 1-2 μm thinck MP-C60 film of appeared peak value.     

Synthesis of Some New Fused/Spiroheterocyclic Compounds Incorporating Quinone Compounds

A series of fused and spiro pyrazolones, isoxazolines, pyrimidines, β‐lactams, and thiazolidinones incorporating 4‐amino‐2‐methyl‐5,10‐dioxo‐1,5,10,11‐tetrahydrobenz[g]quinoline 3‐carbonitrile 1 and 4‐amino‐2‐methyl‐5,6,11‐trioxo‐1,4,4a,5,6,11,12,12a‐octahydro‐1,12‐diazanaphthacene 3‐carbonitrile 2. 7,8a‐c, 15,16a‐c, 19,20a‐d, 21,22a‐d , have been synthesised by cyclocondensation addition reaction and cycloaddition reaction of hydrazines, hydroxylamine, urea, thiourea, monochloroacetyl chloride and mercaptoacetic acid with the synthesised 15,16a‐c and 17,18a‐c .     

Synthesis of 4,6-dimethyl-tetrahydro- and hexahydro-dibenzothiophene

2-Bromo-3-methylcyclohexanone was synthesized by conjugate addition of trimethylaluminium to 2-bromo-2-cyclohexen-1-one with copper bromide as catalyst, coupled with 2-methylthiophenol and annulated with the aid of polyphosphoric acid to 4,6-dimethyl-1,2,3,4-tetrahydrodibenzothiophene. The latter was hydrogenated to 4,6-dimethyl-1,2,3,4,4a,9b-hexahydrodibenzothiophene, another intermediate in the hydrodesulfurization of 4,6-dimethyldibenzothiophene, by zinc and trifluoroacetic acid, and dehydrogenated to 4,6-dimethyldibenzothiophene.     

Inhibition Effect of Hydantoin Compounds on the Corrosion of Iron in Nitric and Sulfuric Acid Solutions

 The inhibition of corrosion of iron in 2 M nitric acid and 2 M sulfuric acid solutions by substituted phenylhydantoin, thiohydantoin, and dithiohydantoin compounds was measured using thermometric, weight loss, and polarization methods. The three methods gave consistent results. The polarization curves indicated that the hydantoin compounds act as mixed-type inhibitors. The adsorption of the inhibitors were found to obey the Temkin adsorption isotherm. The higher inhibition efficiency of the additives in nitric with respect to sulfuric acid solution may be attributed to the reduced formation of soluble quaternary nitrogen salts in nitric acid medium, favouring adsorption of the parent additive on the metal surface. The obtained results indicate that the corrosion rate of iron in both acids increases with increasing temperature, both in absence and presence of the tested inhibitors. Kinetic-thermodynamic model functions and Temkin isotherm data are compared and discussed. The synergistic effect of halide anions on the inhibition efficiency of the hydantoin compounds was also investigated.     

Function Oriented Synthesis: Preparation and Initial Biological Evaluation of New A-Ring-Modified Bryologs

The synthesis and biological evaluation of the first members of a new series of designed bryostatin A-ring analogues (bryologs) are described. An advanced intermediate is produced that allows for step economical access to diverse analogs. The first of these analogues, bearing side chains of completely different polarities from alkyl to hydroxyl and carboxyl functionalities, were evaluated. All exhibit potent protein kinase C binding (54.7-2.4 nM) with affinities increasing with decreasing side chain polarity. This series of bryostatin analogues demonstrates that A-ring surrogates can indeed be used for tuning pharmacophore and ADME characteristics as needed to improve bryolog function.     

Synthesis and structure of 2-substituted pyrene-derived scaffolds

Pyrenes bear a propensity to form fluorescent excimers, and thus this chromophore is often found in sensors and fluorescent probes. 2-Functionalized pyrenes are of particular interest, however the preparation of these scaffolds is not trivial, involving synthetic routes that require 4,5,9,10-tetrahydropyrene as a key intermediate. Herein, the development and optimization of routes for the synthesis of 2-functionalized pyrene-derived building blocks, with potential to be used as tags in the preparation of fluorescent probes, is described. Additionally, the crystal structures of ethyl 4,5,9,10-tetrahydro-2-pyrene-5-oxopentanoate and 2-acetyl-4,5,9,10-tetrahydropyrene revealed distinct conformations of the saturated tetrahydropyrene rings.     

含有二氢吡唑环的新三唑类化合物的设计与合成

设计并合成了１０种含有二氢吡唑环的新三唑类化合物，对新化合物结构进行了确证，讨论了二氢吡唑环的成环方式，所合成的化合物均具有一定的生物活性。     

选择性合成手性八氢NOBIN和四氢NOBIN

通过部分氢化手性的(S)-NOBIN [(S)-2-氨基-2’-羟基-1,1’-联萘]选择性地合成了(S)-H8-NOBIN和(S)- -NOBIN. 弱极性溶剂(环己烷)和强极性溶剂(2,2,2-三氟乙醇和含乙酸的乙醇)几乎专一地得到(S)-H8-NOBIN (92%). 而中等极性溶剂(甲醇, 乙醇和异丙醇)以中等产率得到(S)- -NOBIN (66%).     

Synthesis of benzyl halide derivatives of spirohydantoins via [2+2+2] cyclotrimerization reaction

Generally, synthesis of hydantoin derivatives involve use of carbonyl compounds which in turn require multistep synthesis. Here, we report a new approach to assemble spirohydantoins via [2+2+2] cyclotrimerization reaction using commercially available, inexpensive hydantoin as a starting material.     

Synthesis of New 7-O-Modified Chrysin Derivatives and Their Anti-proliferative and Apoptotic Effects on Human Gastric Carcinoma MGC-803 Cells

Two series of 7-O-modified chrysin derivatives were prepared from 7-O-carboxymethy! chrysin（2a）, 7-O-carboxypropylchrysin（2b） and short-chain alcohols by using 1-ethyl-3-（3-dimethylaminopropyl）carbodiimide hydrochloride（EDCI）, N-hydroxybenzotriazole（HOBt） and 4-dimethylamiopryidine（DMAP） as coupling reagents. Taking cisplatin as a reference substance, their anti-proliferative activities in vitro against human gastric carcinoma MGC-803 cells were evaluated by the standard 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl-2H-tetrazolium bromide （MTT） method. The results show that among the compounds tested, hepty 4-（5-hydroxy-4-oxo-2-phenyl-4H- chromen-7-yloxy） acetate（3f） displayed the most potent growth-inhibitory effect on MGC-803 cells with half maximal inhibitory concentration（ICso） value of 3.23 pmol/L. The preliminary mechanism of inhibitory effect of compound 3f was also detected by flow cytometry（FCM）, and the compound exerted anti- cancer activity via inducing the apoptosis of MGC-803 cells in a dose dependent manner, which suggested that compound 3f would be a potential anti-cancer agent.     

Synthesis of hydantoins and dihydrouracils via thermally-promoted cyclization of ureidoacetamides

The synthesis of hydantoins and dihydrouracils from ureidoacetamides has been carried out at high temperature in glycol solvents. A series of substrates were prepared and examined to determine the effect of substrate structure, N-acyl substitution (X), and solvent on the course of the reaction. A dramatic effect was observed when using ureidoacetamides (e.g., X=N-methyl-N-phenyl), which led to higher yields, faster reaction times, and lower racemization of chiral substrates. The rate of racemization of a chiral hydantoin in the presence of dibenzylamine and N-methyl aniline has also been determined. The thermal cyclization methodology has been applied to the preparation of a complex hydantoin.     

Synthesis of Carboxylactones and New Heterocyclic Compounds

The Michael reaction of 2‐ethoxycarbonyl‐4‐alkoxymethylbutanolides with methyl acrylate affords esterolactones in high yields. Alkaline hydrolysis of the latter resulted in carboxylactones that were transformed into ethyl α‐bromolactonoesters. The reactions of the latter with thiourea and arylthioureas result in heterocyclic compounds of an original structure joint with a butanolide ring.     

Synthesis, Metal Complexation and Spectroscopic Characterization of Three New Azo Compounds

The synthesis of azo compounds [4-(N'-2-thiazol-2-ylsulfanyl)-4'-hydroxyazo benzene (1), 4-(N'-2-thiazol-2-ylsulfanyl)-2'-hydroxy-5-tert-butylazobenzene (2), 7-[4-(N'-2-thiazol-2-ylsulfanyl)phenylazo-8-hydroxy quinoline (3)] have been carried out by reacting phenol, 4-tert-butyl phenol and 8-hydroxy quinoline with N'-2-thiazol-2-ylsulfanylamide as coupling component. The resulting ligands (2 and 3) were treated with two transition metal salts (e.g., CuCl₂2H₂O andNiCl₂6H₂O). Cu(II) and Ni(II) complexes of the azo derivative ofphenol were obtained and characterised by IR, UV-Vis, ¹H NMR, spectroscopic and elemental analysis techniques. All the complexes have a metal : ligand ratio of 1 : 2 and are square-planar.     

苯并噻唑螺萘并吡喃类化合物的微波合成与性质

苯并噻唑螺萘并吡喃类化合物的微波合成与性质;微波辐射法;溶剂效应;荧光效应