Chemical syntheses thiourea synthesis

Chemical synthesis and characterization of palm oil-based difatty acyl thiourea. Journal of Oleo Science 59, 229-233. 

Crystals of [Tc(tu)6]Cl3 or [TcCl(tu)5]Cl2 are often employed for the synthesis of technetium(III) complexes. However, since the direct reduction of pertechnetate with excess thiourea in a hydrochloric acid solution yields [Tc(tu)6]3+ in high yield [37], direct use of the aqueous solution of the thiourea complex would be preferable for the synthesis of the technetium(III) complex without isolation of the crystals of the thiourea complex. In fact, technetium could be extracted from the aqueous solution of the Tc-thiourea complex with acetylacetone-benzene solution in two steps [38]. More than 95% extraction of technetium was attained using the following procedure [39] First a pertechnetate solution was added to a 0.5 M thiourea solution in 1 M hydrochloric acid. The solution turned red-orange as the Tc(III)-thiourea complex formed. Next, a benzene solution containing a suitable concentration of acetylacetone was added. After the mixture was shaken for a sufficient time (preliminary extraction), the pH of the aqueous phase was adjusted to 4.3 and the aqueous solution was shaken with a freshly prepared acetylacetonebenzene solution (main extraction). The extraction behavior of the technetium complex is shown in Fig. 6. The chemical species extracted into the organic phase seemed to differ from tris(acetylacetonato)technetium(III). Kinetic analysis of the two step extraction mechanism showed that the formation of 4,6-dimethylpyrimidine-... 

In a chemical model for oxidative phosphorylation77 the anaerobic oxidation of iV-benzyl 1,4-dihydronicotinamide by a pyridine solution of haemin was accompanied by the synthesis of ATP from ADP and inorganic phosphate. In support of an alternative chemical model involving sulphenyl phosphates as the reactive species,78 lipophilic thioureas have been shown to inhibit mitochondrial oxidative phos-... 

Vassilev, G. N., and N. P. Mashev. Synthesis, chemical structure and cy-tokinin-like activity of some derivatives of N-Phenyl N -alk-yl or arylt thiourea and their influence on the nitrogen metabolism in barley seedlings. Biochem Physiol Pflanz 1974 165 467. 

Chemical. In addition to its intrinsic interest, sulfur serves as a starting point for the synthesis of many labeled molecules. Digestion of sulfur in aqueous sulfites yields thiosulfates, which when heated with iodine lead to tetra-thionates and trithionates. Digestion of sulfur in alcoholic cyanide solutions yields thiocyanates, thence thiocyanogen and thiourea with its derivatives and coordination complexes. Oxidation of sulfur to sulfur dioxide is a potential route to labeled sulfamic acid and its derivatives and to labeled sulfuryl chloride. The intermediate sodium sulfide readily yields hydrogen sulfide and metallic sulfides. 

The wet synthesis of CdS nanoparticles used in this work is based on the reaction between a dissolved cadmium salt (CdCl2) and a S-containing compound (thiourea (NH2)2CS) in an aqueous solution. Chemical deposition of CdS nanoparticles in the CdCl2 - NH3 - NaOH - (NH2)2CS - H2O bath was described elsewhere [3]. In the present work all the baths had the same composition and were prepared from solutions of cadmium chloride CdCl2 (0.005 mold-1), ammonia NH3-H2O (1.5 moll"1), sodium hydroxide NaOH (0.074 mold-1) and thiourea (NH2)2CS (0.025 mol-F1) using distilled water. The synthesis temperature was varied from 294 to 325 K. The primary concentrations of the precursors have been chosen according to the thermodynamic analysis [4]. A supersaturation of the solution with Cd(OH)2 takes place in the baths. It means that the mechanism of the cadmium sulfide formation could involve the stage of Cd(OH)2 formation. When the deposition process of CdS particles in the solution completed, the residue was filtered at an ambient pressure and dried at room temperature. 

Chen et al. (2007) demonstrated a very simple, efficient, and practical method for the synthesis of DHPMs and thioderivatives through a one-pot, three-component condensation of aldehydes, 1,3-dicarbonyl compounds, and urea or thiourea catalyzed by SSA under solvent-free conditions (Scheme 6.3). The main features of this method are its operational simplicity, good yields, use of cheap, commercially available chemicals, recyclability with the comparable activity of the catalyst, and that it is cost effective and environmentally benign. 

A rapid and efficient method for the preparation of some new pyrimidine, pyr-azoline and isoxazoline derivatives by the reaction of chalcones with hydroxyl-amine, urea and hydrazine hydrate has been reported under microwave exposure. This technique gives yes or no answer for a particular chemical transformation within 5 to 10 min as compared to several hours in conventional protocol in industry and academia. Chalcones are convenient starting material for the synthesis of pyrozolines, pyrimidines and isoxazolines due to their a, p-unsaturated moiety. When the chalcone reacts with different moieties like urea, thiourea, hydroxylamine hydrochloride, phenylhydrazine hydrate and other substituted hydrazides, it affords corresponding heterocycles in 6 to 8 min. with 62 to 80% yield, which is much more than classical method (Tiwari et al., 2013a). 

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