Multiple-heteroatom-containing sulfur

Multiple-Heteroatom-Containing Sulfur Compounds in a High Sulfur Coal... 

Two recent papers examining coal extracts showed little evidence for multiple heteroatom species in the small molecules (1-2Y The extracts of an abnormally high sulfur coal from Yugoslavia were found to contain species with several sulfurs per molecule (3). HRMS analysis of extracts from the Argonne Premium Coal Sample used in this study showed evidence for species containing both SO and SN (4-5 Y Specific compounds containing sulfur and... 

Quite a number of other electron withdrawing groups containing multiple heteroatomic bonds, such as the ester carbonyl, nitrile, carboxamide, etc., can likewise stabilize carbanions. The lithium salt of tert-butyl acetate 32 is an example of an enolate anion sufficiently stable as a salt to be used as a shelf reagent. Substituents containing easily polarizable atoms, such as sulfur or selenium, are also capable of stabilizing an adjacent anionic center. 

As mentioned above, AED is a technique particularly well-suited to screen complex samples for multiple compounds containing heteroatoms, such as phosphorus, sulfur or nitrogen, which are especially relevant in the study of chemical warfare agents. Among other GC detectors, AED has unique characteristics, such as compound independent calibration and possible raw formula determination [56]. Albro and Lip-pert have summarized the strengths and weaknesses of the performance of AED relative to other classical detectors for the analysis of chemical warfare agents and their breakdown products. Their conclusions illustrated that AED offers the best combination of sensitivity and selectivity of the detectors investigated for the analysis of sulfur compounds [57]. 

Sections 10.5 through 10.8 envisage single or, more commonly, multiple replacements of the peptide bond functionality. In particular, substitutions characterized by single, double, or triple C—C bonds are covered in Section 10.5, while substitutions containing C/O, C/N, and C/N/O amide bond replacements are described in Sections 10.6,10.7, and 10.8, respectively. Sections 10.9 and 10.10 focus on the known types of sulfur- or phosphorus-based peptide bond replacements, 1,2 6 7 including different oxidation states of the heteroatoms. 

Heterocyclic compounds make up the third and largest class of molecular frameworks for organic compounds. In heterocyclic compounds, at least one atom in the ring must be a heteroatom, an atom that is not carbon. The most common heteroatoms are oxygen, nitrogen, and sulfur, but heterocyclics with other elements are also known. More than one heteroatom may be present and, if so, the heteroatoms may be alike or different. Heterocyclic rings come in many sizes, may contain multiple bonds, may have... 

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