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Cyclopropylacetylene

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Cyclopropylacetylene
Names
Preferred IUPAC name Ethynylcyclopropane
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.102.389 Edit this at Wikidata
EC Number
  • 425-430-1
PubChem CID
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C5H6/c1-2-5-3-4-5/h1,5H,3-4H2Key: NPTDXPDGUHAFKC-UHFFFAOYSA-N
SMILES
  • C#CC1CC1
Properties
Chemical formula C5H6
Molar mass 66.103 g·mol
Appearance colorless liquid
Density 0.781 g/cm at 25°C
Boiling point 51–53 °C (124–127 °F; 324–326 K)
Hazards
GHS labelling:
Pictograms GHS02: Flammable GHS05: Corrosive
Hazard statements H225, H315, H319, H412
Precautionary statements P210, P273, P280, P305+P351+P338
Flash point −17 °C (1 °F; 256 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references
Chemical compound

Cyclopropylacetylene is an hydrocarbon with the chemical formula C
5H
6. Under normal conditions, the substance is a colorless liquid. Cyclopropylacetylene is a precursor pharmaceuticals and other organic compounds.

Synthesis

Several methods have been published on the synthesis of cyclopropylacetylene. The earliest preparation starts with the chlorination of cyclopropylmethylketone with phosphorus pentachloride. Thereafter, the reaction product, 1-cyclopropyl-1,1-dichloroethane, is converted into cyclopropylacetylene via double dehydrochlorination. This occurs in presence of a strongly basic solution, such as potassium tert-butoxide in dimethyl sulfoxide:

Synthesis scheme 1

However, the yield of this method is not substantial (20-25%). A one-pot synthesis of cyclopropylacetylene has been reported in which 5-chloro-1-pentyne reacts with n-butyl lithium or n-hexyl lithium. Cyclohexane is used as a solvent. The reaction is a metalation followed by a cyclization. The reaction product is then cooled, and an aqueous solution of ammonium chloride is added slowly. There is a two-phase mixture: a heavy water phase and a lighter organic phase containing cyclopropylacetylene.

Synthesis scheme 2

Applications

Cyclopropylacetylene is used as reagent in organic reactions. It is, for example, a building block of the antiretroviral and psychotropic drug efavirenz. It can also be used in the azide-alkyne Huisgen cycloaddition.

References

  1. "Cyclopropylacetylene : density 0.781 g/mL at 25 °C". Sigmaaldrich.com. Retrieved 26 April 2022.
  2. "CYCLOPROPYL ACETYLENE". chemicalland21.com. Retrieved 31 May 2017.
  3. Hudson, C.E.; Bauld, N.L. (1972). "Quantitative analysis of cyclopropyl β hyperfine splittings". J. Am. Chem. Soc. 94 (4): 1158. doi:10.1021/ja00759a021.
  4. ^ Corley, Edward G.; Thompson, Andrew S.; Huntington, Martha (2000). "CYCLOPROPYLACETYLENE". Organic Syntheses. 77. orgsyn.org: 231. doi:10.15227/orgsyn.077.0231. Retrieved 31 May 2017.
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