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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
“Thio” in the name of a compound is an indication that sulfur is present. Sulfides are sometimes referred to as thioethers or just thiols. The suffix “mercaptans,” which means “mercury-seizing,” is still sometimes used in place of “thiol.” Primarily sulfur compounds are used as chemical intermediates or additives. Oxides of sulfur release hydrogen suflide (H2S) when burning. They are highly toxic and severe skin irritants. H2S toxicity is much the same as the cyanide compounds s (FEMA/NFA).
Odorless, convenient and one-pot synthesis of thioethers from organic halides and thiourea
Published in Journal of Sulfur Chemistry, 2019
Aazam Monfared, Sheida Ahmadi, Zahra Rahmani, Parvaneh Delir Kheirollahi Nezhad, Akram Hosseinian
The main synthetic method for the preparation of thioether derivatives involves the transition-metal-catalyzed C–S cross-coupling reactions of thiols with various electrophilic partners (e.g. organohalides, boronic acids, and carboxylic acids) [12,13]. However, this methodology suffers from various inherent drawbacks, such as volatility, toxicity, and instability of foul-smelling thiols. To overcome these disadvantages, various S-transfer reagents have been applied instead of free thiols for the formation of titled compounds [14]. Among them, the odorless, nontoxic, and inexpensive thiourea is a widely used sulfur source. Recently, significant progress has been made in the synthesis of thioethers via the reaction of organic halides with thiourea (Figure 2). This new route for the synthesis of thioether derivatives offers several advantages, such as: (i) high stable, low toxic and wide commercially available starting materials; (ii) high selectivity; (iii) broad substrate scope and (iv) ease of handling which makes it a useful and attractive method for the construction of new carbon–sulfur bond. In connection with our recent review papers on the new methodologies in organic synthesis [19–24], we summarize here a number of recent discoveries and advances in the synthesis of various symmetrical and unsymmetrical thioethers through the reaction of organic halides with thiourea. We have classified these reactions based on the type of catalysts. The most detailed discussion will be focused on the reactions catalyzed by nanoparticles.