Thioquinanthrene, also known as thiochinathren, is an aromatic organic chemical compound. It has the chemical formula C₁₈H₁₀N₂S₂ and reacts with alcoholates or

alkoxide In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organyl substituent. Alkoxides are strong bases and, whe ...

s. One of the key uses is to act as a catalyst poison in the Rosenmund reduction. It has the

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

name of 2,13-dithia-10,21-diazapentacyclo 2.8.0.0^3,12.0^4,9.0^15,20ocosa-1(14),3(12),4,6,8,10,15,17,19,21-decaene.

Rosenmund catalyst poison

In the Rosenmeund reaction, an

acid chloride In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example o ...

is reduced to an

aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

. Continuing the reduction produces an

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

. This further reaction is undesirable as the alcohol will now react with the acyl chloride to produce the unwanted

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

product. For this reaction (over reduction) to be prevented, the catalyst needs to be poisoned. Thioquinanthrene was used initially, although other materials have been used since.

References

{{reflist Aromatic compounds Catalysis Heterocyclic compounds with 5 rings Dithiins Nitrogen heterocycles Quinolines