Benzothiophene is an aromatic organic compound with a molecular formula C₈H₆S and an odor similar to

naphthalene Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromati ...

(mothballs). It occurs naturally as a constituent of petroleum-related deposits such as

lignite Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...

tar. Benzothiophene has no household use. In addition to benzo hiophene, a second isomer is known: benzo hiophene. Benzothiophene finds use in research as a starting material for the synthesis of larger, usually bioactive structures. It is found within the chemical structures of pharmaceutical drugs such as raloxifene,

zileuton Zileuton (trade name Zyflo) is an orally active inhibitor of 5-lipoxygenase, and thus inhibits leukotrienes (LTB4, LTC4, LTD4, and LTE4) formation, used for the maintenance treatment of asthma. Zileuton was introduced in 1996 by Abbott Laborat ...

, and sertaconazole, and also

BTCP Benocyclidine, also known as benzothiophenylcyclohexylpiperidine (BTCP), is a psychoactive recreational drug of the arylcyclohexylamine class which is related to phencyclidine (PCP). It was first described in a patent application naming Marc C ...

. It is also used in the manufacturing of dyes such as

thioindigo Thioindigo is an organosulfur compound that is used to dye polyester fabric. A synthetic dye, thioindigo is related to the plant-derived dye Indigo dye, indigo, replacing two NH groups with two sulfur atoms to create a shade of pink. Thioindigo ...

Synthesis

Most syntheses of benzothiophene create substituted benzothiophenes as a precursor to further reactions. An example is the reaction of an alkyne-substituted 2-bromobenzene with either

sodium sulphide Sodium sulfide is a chemical compound with the formula Na2 S, or more commonly its hydrate Na2S·9 H2O. Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are gener ...

potassium sulphide Potassium sulfide is an inorganic compound with the formula K2 S. The colourless solid is rarely encountered, because it reacts readily with water, a reaction that affords potassium hydrosulfide (KSH) and potassium hydroxide (KOH). Most commonly ...

to form benzothiophene with an alkyl substitution at position 2. 2-bromo-alkynylbenzene reacting to form 2-substituted benzothiophene

Thiourea can be used as a reagent in place of sodium sulphide or potassium sulphide. 2-bromo-alkynylbenzene reacting with thiourea to form 2-substituted benzothiophene

2-bromo-alkynylbenzene reacting with thiourea to form 2-substituted benzothiophene

In the presence of a gold catalyst, a more complex 2,3-disubstituted benzothiophene can be synthesised. Carbothiolation to form substituted benzothiophene

Carbothiolation to form substituted benzothiophene

References

{{Simple aromatic rings Simple aromatic rings