Thiourea, exchange reactions with

Claisen condensation, 6, 156 reactions, S, 92 IsothiazoIe-3-carboxyIic acids decarboxylation, 6, 156 Isothiazole-4-carboxylic acids decarboxylation, 6, 156 Isothiazole-5-carboxylic acids decarboxylation, S, 92 6, 156 IR spectroscopy, 6, 142 Isothiazole-3-diazonium borofluoride decomposition, 6, 158 IsothiazoIe-4-diazonium chloride, 3-methyl-reactions with thiourea, 6, 158 Isothiazole-5-diazonium chloride, 4-bromo-3-methyl-halogen exchange, 6, 163 Isothiazole-5-diazonium chloride, 3-methyl-reactions... 

An example of chemical destruction of an anionic species is the elution of aurocyanide from an anion-exchange resin with thiourea, a neutral ligand that reacts with gold cyanide in the presence of acid to form a cationic complex. The elution reaction can be described by the following equation ... 

Chloro substituents both in the pyrimidine and the pyridine part of pyrido[3,2-d]pyrimidines 8 have been exchanged for sulfanyl groups by reaction with alkyl-77,442 as well as aryl-458 thiolates. For the introduction of sulfanyl groups, thiourea is the reagent of choice.77,134... 

Thioureas react readily with ) -diketones, and reactions with thioureas in many cases give higher yields than ureas in pyrimidine cyclizations. 5-Alkylisothioureas are frequently used instead of thioureas. The 2-alkylthio group in the pyrimidine is readily exchangeable, especially after oxidation. As a typical example, thiourea with benzoy lace tone in acidic ethanol gives 6-methyl-4-phenyl-2(l //)-pyrimidinethione (566) <84AJC155>. 

Thiiranes, which are the simplest sulfur heterocycles, are useful from both theoretical and synthetic points of view. The most important method for their s)mthesis is the conversion of oxiranes to thiiranes by an oxygen-sulfur exchange reaction. Oxiranes react smoothly with thiourea in the presence of j3-CD to afford the corresponding thiiranes and the jS-CD can be recycled (Figure 4.18). ... 

For infrared lithography the wet-gel filling solvent is exchanged with a solution of precursors that react spontaneously albeit slowly at room temperature, such as Cd(N03)2 and thiourea. The reaction proceeds in two steps, hydrolysis of thiourea in basic environment (19.1), followed by reaction of sulfur and Cd " ions (19.2). The overall reaction is summarized by (19.3). 

The synthesis of 38 began with 39. Acetal formation and chlorination adjacent to sulfur provided 40. Thiourea was used to introduce sulfur. Hydrolysis of 41 provided the free thiol and a ketal exchange (hydrolysis-protection) gave 42. This compound was configurationally stable at the anomeric center and thus, was resolved via the thioester derived from reaction with (-)-camphanyl chloride. The absolute configuration of the proper enantiomer was established by X-ray crystallography of this thioester. S-Alkylation of 43 with racemic mesylate 46 provided a mixture of diastereomers 47 (Erythronolide-6). 

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