Of the 20 common amino acids, two (cysteine and methionine) are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur.
While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent.
Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries.
A classical chemical test for the detection of sulfur compounds is the Carius halogen method.
Organosulfur compounds can be classified according to the sulfur-containing functional groups, which are listed (approximately) in decreasing order of their occurrence.
In the Ferrario reaction, phenyl ether is converted to phenoxathiin by action of elemental sulfur and aluminium chloride.
The above classes of sulfur compounds also exist in saturated and unsaturated heterocyclic structures, often in combination with other heteroatoms, as illustrated by thiiranes, thiirenes, thietanes, thietes, dithietanes, thiolanes, thianes, dithianes, thiepanes, thiepines, thiazoles, isothiazoles, and thiophenes, among others.
The reason for this difference is the higher electronegativity for oxygen drawing away electrons to itself at the expense of the aromatic ring current.
Thiols are structurally similar to the alcohol group, but these functionalities are very different in their chemical properties.
[11] S-Nitrosothiols, also known as thionitrites, are compounds containing a nitroso group attached to the sulfur atom of a thiol, e.g. R−S−N=O.
Thioaldehydes are rarer still, reflecting their lack of steric protection ("thioformaldehyde" exists as a cyclic trimer).
Vegetable foods with characteristic flavors due to isothiocyanates include wasabi, horseradish, mustard, radish, Brussels sprouts, watercress, nasturtiums, and capers.
The thione S-oxides have also been known as sulfines, and while IUPAC considers this term obsolete,[16] the name persists in the literature.
Chiral sulfinamides are used in asymmetric synthesis, while sulfenamides are used extensively in the vulcanization process to assist cross-linking.
Thiocarbonyl ylides (RR′C=S+−C−−RR′) can form by ring-opening of thiiranes, photocyclization of aryl vinyl sulfides,[28] as well as by other processes.
Gliotoxin is a sulfur-containing mycotoxin produced by several species of fungi under investigation as an antiviral agent.
By the process of hydrodesulfurization (HDS) in refineries, these compounds are removed as illustrated by the hydrogenolysis of thiophene:
[30] Many of these natural products also have important medicinal properties such as preventing platelet aggregation or fighting cancer.
Humans and other animals have an exquisitely sensitive sense of smell toward the odor of low-valent organosulfur compounds such as thiols, sulfides, and disulfides.
Malodorous volatile thiols are protein-degradation products found in putrid food, so sensitive identification of these compounds is crucial to avoiding intoxication.
Low-valent volatile sulfur compounds are also found in areas where oxygen levels in the air are low, posing a risk of suffocation.
Copper is required for the highly sensitive detection of certain volatile thiols and related organosulfur compounds by olfactory receptors in mice.