Analytical Properties and Applications

Analytical Properties and Applications.— Thioureas may be determined quantitatively by titration with phenyl iodosoacetate. Chromatography on Si02 is suitable for analytical and preparative separation of thioureas, e.g. the antiviral agent (20) from its isomer (21). Thioureas have found widespread [Pg.146]

Chemical Reactions.— Two typical features of thioureas are the reason for most of their reactions the nucleophilicity (mainly of the sulphur atom), which is responsible for alkylation, oxidation, and related reactions and the bi- or tri-functionality of thiourea molecules, which leads to the formation of a vast number of heterocycles. These two reaction types are not clearly distinguishable, but may be used as a method of classification. [Pg.147]

Alkylation. Theoretical treatment by the CNDO method, and the analysis of orbital interactions, show a frontier orbital control for the S -methylation of MeNHC(S)NHMe. Kinetic measurements of the alkylation of thioureas with alkyl halides or tosylates have shown that this reaction is first-order in thiourea and alkylating agent, implying an 5 n2 mechanism, with direct attack by the sulphur atom. [Pg.147]

Shimizu, H. Takahashi, and K. Tajima, Nippon Sochi Gakkai-Shi, 1974, 20, 173. [Pg.147]

The reaction of halides and subsequent alkaline hydrolysis without isolation of the intermediate isothiouronium salt has been used for the synthesis of thiols. aa -Dimercapto-o-xylene has been obtained from the corresponding bromide in 97% yield. [Pg.148]

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