Thiuram disulfides are a class of organosulfur compounds with the formula (R₂NCSS)₂. Many examples are known, but popular ones include R = Me and Et. They are

disulfide In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

s obtained by oxidation of the

dithiocarbamate In organic chemistry, a dithiocarbamate is a functional group with the general formula and structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only 1 oxygen is replaced the result is thioca ...

s. These compounds are used in sulfur vulcanization of rubber as well as pesticides and drugs. They are typically white or pale yellow solids that are soluble in organic solvents.

Preparation, structure, reactions

They are prepared by the oxidation of the salts of the corresponding dithiocarbamates (e.g.

sodium diethyldithiocarbamate Sodium diethyldithiocarbamate is the organosulfur compound with the formula NaS2CN(C2H5)2. It is a pale yellow, water soluble salt. Preparation This salt is obtained by treating carbon disulfide with diethylamine in the presence of sodium hydr ...

). Typical oxidants are

chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...

and

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...

: :2 R₂NCSSNa + Cl₂ → (R₂NCSS)₂ + 2

NaCl Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/ ...

Thiuram disulfides react with Grignard reagents to give esters of dithiocarbamic acid, as in the preparation of

methyl dimethyldithiocarbamate Methyl dimethyldithiocarbamate is the organosulfur compound with the formula (CH3)2NC(S)SCH3. It is the one of simplest dithiocarbamic esters. It is a white volatile solid that is poorly soluble in water but soluble in many organic solvents. ...

: : e₂NC(S)Ssub>2 + MeMgX → Me₂NC(S)SMe + Me₂NCS₂MgX The compounds feature planar dithiocarbamate subunits and are linked by an S−S bond of 2.00 Å. The C(S)−N bond is short (1.33 Å), indicative of multiple bonding. The

dihedral angle A dihedral angle is the angle between two intersecting planes or half-planes. In chemistry, it is the clockwise angle between half-planes through two sets of three atoms, having two atoms in common. In solid geometry, it is defined as the uni ...

between the two dithiocarbamate subunits approaches 90°. METHUS03skew2

Thiuram disulfides are weak oxidant. They can be reduced to dithiocarbamates. Treatment of thiuram disulfides with

triphenylphosphine Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists ...

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

salts gives the thiuram sulfide: :(R₂NCSS)₂ + PPh₃ → (R₂NCS)₂S + SPPh₃ Chlorination of the above-mentioned thiuram disulfide affords the

thiocarbamoyl chloride Dimethylthiocarbamoyl chloride is an organosulfur compound with the formula (CH3)2NC(S)Cl. A yellow solid, it is often encountered as a yellow syrup. It is a key reagent in the synthesis of arylthiols via the Newman-Kwart rearrangement. Synthes ...

Applications

The tetramethyl derivative, known as

thiram Thiram is the simplest thiuram disulfide and the oxidized dimer of dimethyldithiocarbamate. It is used as a fungicide, ectoparasiticide to prevent fungal diseases in seed and crops and similarly as an animal repellent to protect fruit trees and o ...

, is a widely used fungicide. The tetraethyl derivative, known as

disulfiram Disulfiram is a medication used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol (drinking alcohol). Disulfiram works by inhibiting the enzyme acetaldehyde dehydrogenase, causing many of the effects of ...

, is commonly used to treat chronic

alcoholism Alcoholism is, broadly, any drinking of alcohol (drug), alcohol that results in significant Mental health, mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognize ...

. It produces an acute sensitivity to alcohol ingestion by blocking

acetaldehyde dehydrogenase Acetaldehyde dehydrogenases () are dehydrogenase enzymes which catalyze the conversion of acetaldehyde into acetic acid. The oxidation of acetaldehyde to acetate can be summarized as follows: Acetaldehyde + NAD+ + Coenzyme A ↔ Acetyl-CoA + NA ...

conversion of

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the mos ...

leading to a higher concentration of the aldehyde in the blood producing symptoms of a severe

hangover A hangover is the experience of various unpleasant physiological and psychological effects usually following the consumption of alcohol, such as wine, beer, and liquor. Hangovers can last for several hours or for more than 24 hours. Typical sympto ...

Safety

In 2005–06, thiuram mix was the 13th most prevalent

allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms ...

in patch tests (3.9%).

References

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