Reaction Of Thioacetamide Research Articles

Influence of solvent and substituents on the reaction of N-alkylthioacetamides with dimethyl acetylenedicarboxylate: synthesis of functionalized thiophenes containing an exocyclic double bond

The reaction of thioacetamides with dimethyl acetylenedicarboxylate affords 3-oxothien-2-ylidene or 4-oxothiazol-2,5-ylidene derivatives based on the structure of the thioacetamides and the solvent employed. The structural features of the 3-oxothien-2-ylidenes are discussed.

Radiotracer Study of Synergistic Effects of Organophosphorus Compounds on the Extraction of Silver by N-(thio acetyl) benzamide into n-butanol

In the present investigation, systematic study of synergistic effects of phosphine oxides and tributyl phosphate on the extraction of Ag (I) from aqueous nitrate medium with N-(thioacetyl) bezamide into n-butanol is being reported. The ligand was synthesized and cha racter ized in our laborator y. Temperature dependence of extraction equilibrium have been studied in order to evaluate the thermodynamic parameters responsible for the extraction. Finally, IR data were used to support the extraction mechanism. 2. Experimental 2.1. Reagents and instrument. The chelating ligand (Nthio acetyl) benzamide was synthesised by the reaction of thioacetamide and benzoylchloride, derived form benzoic acid, which were obtained from Aldrich, USA. The donor reagents used in this work e.g tri-butyl phosphine oxide (TBPO), triphenyl phosphine oxide (TPPO), tri-butyl phosphate (TBP), were also collected from Aldrich; USA. The solvents were purified by standard procedures. All other reagents used were of A.R. grade. A stock solution of silver was prepared by dissolving A.R. AgNO3 in deionized water and a working stock was prepared by appropriate dilution. In order to spike the solution, an appropriate volume of stock solution of Ag(I) was mixed, with few drops of tracer solution containing, 110m Ag as

Preparation and Characterization of Carbon Nanotubes/ZnS composite

Carbon nanotubes were modified by NH_3·H_2O and EDTA,respectively.Then,ZnS nanopar- ticles were densely and uniformly coated on modified surfaces of carbon nanotubes through reaction of thioacetamide and zinc acetate in water solution.The samples were characterized by XRD,TEM, SAED,SEM,FTIR and PL spectroscope.Experimental results indicate that EDTA treatment of the carbon nanotubes is a key factor for the formation of carbon nanotubes/ZnS composite.The PL spectra show that the photoluminescence peaks of the carbon nanotubes/ZnS composite have a small blue shift in comparison with the as-prepared ZnS.A possible formation mechanism is proposed for the carbon nanotubes/ZnS composite.

Solution-phase synthesis of Ag2S hollow and concave nanocubes

Hollow and concave Ag2S nanocubes have been prepared through the reaction of thioacetamide (TAA) and AgNO3 in carboxymethyl cellulose (CMC) aqueous solution. CMC acts as the templates and capping agents in the solution. The edge length of each cube was about 200±50 nm.

Nature of the transient species formed during pulse radiolysis of thioacetamide in aqueous solutions

Thioacetamide (TA) is an organic compound having thioamide group similar to that in thiourea derivatives. Its reactions with eaq−, H-atom and OH radicals were studied using the pulse radiolysis technique at various pHs and the kinetic and spectral characteristics of the transient species were determined. The initial adduct formed by the reaction of TA with OH radicals at pH 7 does not absorb light in the 300–600 nm region but reacts with the parent compound to give a transient species with an absorption maximum around 400 nm. At pH 0, the reaction of OH radicals with TA directly gives a similar transient species with absorption maximum at 400 nm. Transient species formed by H-atom reaction with TA and pH 0 has no absorption in the 300–600 nm region but at higher acidity a new transient species is formed which has absorption maximum at 400 nm. This transient absorption observed in the case of both OH and H atom reaction with TA is ascribed to the formation of a resonance stabilized radical similar to that obtained in the case of thiourea derivatives. The species produced by electron reaction viz. electron adduct was found to be a strong reductant and could reduce MV2+ with a high rate constant. H2S was produced as a stable product in the reaction of eaq− and its G-value was determined to be about 0.8.

Chloramine-T as a potential scrubbing agent: Removal of odorous sulfur-containing environmental pollutants

A detailed study of the reaction of thioacetamide, thiobenzamide, thiobenzoic acid, thiophenol and ethanethiol (emitted from industrial stacks or as industrial wastewater effluents and ultimately becoming environmental pollutants) with Chloramine-T has been made. Odor studies based on the sensory approach, have been performed on the reactants as well as the reaction mixtures containing the oxidation products, using odor test panels to determine the odor threshold levels. In all cases the median odor threshold concentration has been raised substantially by reaction with CAT. From the preliminary studies it is concluded that this oxidative technique has potential application in air and water pollution odor control.

Selenium heterocycles XXVI. Synthesis of theino[3,4‐b]benzofuran and selenolo[3,4‐b] benzofuran. Two novel heterocycles

AbstractStarting from the readily available aryl 3‐methyl‐2‐benzo[b] furyl ketones a series of 3‐sub‐stituted thieno[3,4‐b] benzofurans and 3‐substituted selenolo[3,4‐b] benzofurans were prepared in high yield. The parent compound, thieno[3,4‐b] benzofuran was prepared through the reaction of thioacetamide with 2‐chloromethyl‐3‐formylbenzo[b] furan in moderate yield.

Reactions of L-ergothioneine and some other aminothiones with2,2'-and 4,4'-dipyridyl disulphides and of L-ergothioneine with iodoacetamide. 2-Mercaptoimidazoles, 2- and 4-thiopyridones, thiourea and thioacetamide as highly reactive neutral sulphur nucleophils.

1. The reactions of 2,2'- and 4,4'-dipyridyl disulphide (2-Py-S-S-2-Py and 4-Py-S-S-4-Py) with l-ergothioneine (2-mercapto-l-histidine betaine), 2-mercaptoimidazole, 1-methyl-2-mercaptoimidazole, thiourea, thioacetamide, 2-thiopyridone (Py-2-SH) and 4-thiopyridone (Py-4-SH) were investigated spectrophotometrically in the pH range approx. 1-9. 2. These reactions involve two sequential reversible thiol-disulphide interchanges. 3. The reaction of l-ergothioneine with 2-Py-S-S-2-Py and/or with the l-ergothioneine-Py-2-SH mixed disulphide, both of which provide Py-2-SH, is characterized by at least three reactive protonic states. This provides definitive evidence that neutral l-ergothioneine is a reactive nucleophile, particularly towards the highly electrophilic protonated disulphides. 4. A similar situation appears to obtain in the reactions of l-ergothioneine and Py-2-SH with 4-Py-S-S-4-Py and in the reactions of the other 2-mercaptoimidazoles, thiourea and Py-4-SH with 2-Py-S-S-2-Py. The nucleophilic reactivity of Py-4-SH suggests that general base catalysis provided by the disulphide in a cyclic or quasi-cyclic transition state is not necessary to generate nucleophilic reactivity in the other amino-thiones whose geometry could permit such catalysis. 5. The existence of a positive deuterium isotope effect in the l-ergothioneine-2-Py-S-S-2-Py system at pH6-7 provides no evidence for general base catalysis but is in accord with a mechanism involving specific acid catalysis and post-transition-state proton transfer. 6. The pH-dependences of the overall equilibrium positions of the various thiol-disulphide interchanges are described. 7. Reaction of thioacetamide with a stoicheiometric quantity of 2-Py-S-S-2-Py at pH1 provides 2 molecules of Py-2-SH per molecule of thioacetamide and elemental sulphur; these findings can be accounted for by thiol-disulphide interchange to provide a thioacetamide-Py-2-SH mixed disulphide followed by fragmentation to provide CH(3)CN, S and Py-2-SH. 8. Provision of high reactivity in the neutral forms of the members of this series of sulphur nucleophiles by electron donation by the amino group is compared with the well known alpha effect that provides enhanced nucleophilicity in compounds containing an electronegative atom adjacent to the nucleophilic atom. 9. The decrease in the u.v. absorption of l-ergothioneine at 257nm consequent on transformation of its aminothione moiety into an S-alkyl-2-mercaptoimidazole moiety provides a convenient method of following the alkylation of l-ergothioneine by iodoacetamide. 10. The pH dependence of the extinction coefficient of l-ergothioneine at 257nm is described by epsilon(257)={8x10(3)/(1+K(a)/[H(+)]} +6x10(3)m(-1).cm(-1) in which pK(a)=10.8. 11. In the pH range 3-11 the reaction is characterized by two reactive protonic states (X and XH). 12. The X state, reaction of the ionized 2-mercaptoimidazole moiety of the l-ergothioneine dianion with neutral iodoacetamide, is characterized by the second-order rate constant 4.0m(-1).s(-1) (25.0 degrees C, I=0.05). The XH state, characterized by the second-order rate constant 0.03m(-1).s(-1), is interpreted as reaction of the thione form of the neutral 2-mercaptoimidazole moiety of the l-ergothioneine monoanion with neutral iodoacetamide. 13. The XH state of the alkylation reaction does not exhibit a deuterium isotope effect.

Amperometric determination of thioacetamide with copper(I)

A method is given for the amperometric determination of thioacetamide (TAA) based on the reaction of TAA with copper(I) in ammoniacal solution. The reduction current due to the copper(I) is used to determine the end-point. The determination is carried out at constant temperature (25°), pH 8.0-9.8 (ammonia-urotropine buffer), and at constant potential (−0.6 V vs. S.C.E.), with a dropping mercury electrode as cathode and a saturated calomel electrode as anode. The solution is deaerated by a stream of electrolytically generated hydrogen. The titrations are carried out simply and rapidly and the results are fairly reproducible. The error is generally ⩽ 1.0% for amounts of TAA ranging from 0.07 to 1.8 mg.