Organic sulfur containing structures

Distribution of Organic-Sulfur-Containing Structures in High Organic Sulfur Coals... 

TORRES-ORDONEZ ET AL. Organic-Sulfur-Containing Structures... 

Until recently, there have been only a few reports of aliphatic sulfur structures in coal (1,12). These results together with the experiments of Gorbaty et al. (11), give further support for the presence of labile (presumably aliphatic) sulfur moieties in high-organic sulfur-containing coals. In the previous sulfur study (1), one bituminous coal was analyzed for organic sulfur forms both by the... 

There are quite a number of crown compounds known which contain a thiophene or other sulfur-containing subunit. The reader is directed to the tables at the end of each chapter in order to locate these species. Because of the expense of including each structure under each possible category, some sulfur-containing compounds may not be listed in this chapter. It is hoped that the tables are well enough organized that the desired compound can be located if it is known by considering other structural features. 

Nitrogen and oxygen can be Incorporated Into the backbone such that they are surrounded by different atom types. For example, organic peroxides contain two covalently bonded oxygen atoms that form the peroxide linkage. These molecules are Inherently unstable. Two covalently bonded nitrogen atoms are also similarly unstable. These unstable structures decompose to form smaller unstable molecules that are used to start the polymerization for some types of monomers. Thus, to be incorporated implies that the molecules are found only singularly in the backbone chain. Sulfur and silicon are considered to be chain formers. They can be found in the backbone in multiple units connected covalently to molecules of the same type or with carbon. Complete molecules with a silicon backbone are possible, and molecules with multiple sulfur links incorporated into the system are common, particularly in sulfur-crosslinked rubber. 

ABSTRACT This chapter provides a comprehensive overview of the sulfur-containing natural products that are non-sulfated and have been isolated from marine organisms. The overview covers the published literature from 1985 to 1999. A total of 482 compounds and 371 references are recorded. These secondary metabolites are organized in sections according to structural classifications by sulfur functional groups and by structural families of compounds. Comments on structural characterization, biogenesis, and biological activity have also been included. 

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