Propane-1,3-dithiol explained

1,3-Propanedithiol is the chemical compound with the formula HSCH₂CH₂CH₂SH. This dithiol is a useful reagent in organic synthesis. This liquid, which is readily available commercially, has an intense stench.

Use in organic synthesis

1,3-Propanedithiol is mainly used for the protection of aldehydes and ketones via their reversible formation of dithianes.^[1] A prototypical reaction is its formation of 1,3-dithiane from formaldehyde. The reactivity of this dithiane illustrates the concept of umpolung. Alkylation gives thioethers, e.g. 1,5-dithiacyclooctane.

The unpleasant odour of 1,3-propanedithiol has encouraged the development of alternative reagents that generate similar derivatives.^[2]

1,3-Propanedithiol is used in the synthesis of tiapamil.

Use in inorganic synthesis

1,3-Propanedithiol reacts with metal ions to form chelate rings. Illustrative is the synthesis of the derivative diiron propanedithiolate hexacarbonyl upon reaction with triiron dodecacarbonyl:^[3]

Fe₃(CO)₁₂ + C₃H₆(SH)₂ → Fe₂(S₂C₃H₆)(CO)₆ + H₂ + Fe(CO)₅ + CO

Safety

The stench of 1,3-propanedithiol can be neutralized with bleach.

See also

• 1,2-Propanedithiol

Notes and References

1. Encyclopedia: Conrow, R. E. . Le Huérou, Y. . 1,3-Propanedithiol. Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette). 2004. J. Wiley & Sons, New York. 10.1002/047084289X. 10261/236866. 9780471936237 . free.
2. Liu, Q. . Che, G. . Yu, H. . Liu, Y. . Zhang, J. . Zhang, Q. . Dong, D. . The First Nonthiolic, Odorless 1,3-Propanedithiol Equivalent and Its Application in Thioacetalization. Journal of Organic Chemistry. 2003. 68. 9148–9150. 10.1021/jo034702t. 14604400. 23.
3. Winter, A. . Zsolnai, L. . Huttner, G. . Zweikernige und dreikernige Carbonyleisenkomplexe mit 1,2- und 1,3-Dithiolatobrückenliganden. Zeitschrift für Naturforschung. 1982. 37b. 1430–1436. 10.1515/znb-1982-1113 . 98749484 . free.