Cyclopropylacetylene

Cyclopropylacetylene
Names
	Other names Ethynylcyclopropane
Identifiers
CAS Number	6746-94-7;
3D model (JSmol)	Interactive image;
ChemSpider	122425;
ECHA InfoCard	100.102.389
PubChem CID	138823;
	InChI InChI=1S/C5H6/c1-2-5-3-4-5/h1,5H,3-4H2 Key: NPTDXPDGUHAFKC-UHFFFAOYSA-N;
	SMILES C#CC1CC1;
Properties
Chemical formula	C5H6
Molar mass	66.10 g·mol−1
Appearance	Clear, colorless to light yellow liquid
Density	0.9±0.1 g/cm3
Boiling point	51–53 °C (124–127 °F; 324–326 K)
Hazards
GHS pictograms
GHS hazard statements	H225, H315, H319, H412
GHS precautionary statements	P210, P273, P280, P305+351+338
Flash point	−17 °C (1 °F; 256 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	Infobox references

Cyclopropylacetylene is an organic compound with the chemical formula C
₅H
₆.^[1] Under normal conditions, the substance is a clear, flammable liquid. Cyclopropylacetylene is used as an important reagent to synthesize pharmaceuticals and other organic compounds.

Synthesis

Several methods have been published on the synthesis of cyclopropylacetylene. The earliest one start with the chlorination of cyclopropylmethylketone with phosphorus pentachloride.^[2] Thereafter, the reaction product, 1-cyclopropyl-1,1-dichloroethane, is converted into cyclopropylacetylene via double dehydrochlorination. This occurs in presence of a strong base, such as potassium tert-butoxide, in dimethyl sulfoxide:

Synthesis of cyclopropylacetylene

However, the yield of this method is not substantial (20-25%).^[3] 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.^[3]

Synthesis of cyclopropylacetylene

Applications

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

References

↑ "CYCLOPROPYL ACETYLENE". chemicalland21.com. Retrieved 31 May 2017.
↑ Hudson, C.E.; Bauld, N.L. (1972). "Quantitative analysis of cyclopropyl β hyperfine splittings". J. Am. Chem. Soc. 94 (4): 1158.
1 2 Corley, Edward G.; Thompson, Andrew S.; Huntington, Martha. "CYCLOPROPYLACETYLENE". orgsyn.org. p. 231. doi:10.15227/orgsyn.077.0231. Retrieved 31 May 2017.

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[1] "CYCLOPROPYL ACETYLENE". chemicalland21.com. Retrieved 31 May 2017.

[2] Hudson, C.E.; Bauld, N.L. (1972). "Quantitative analysis of cyclopropyl β hyperfine splittings". J. Am. Chem. Soc. 94 (4): 1158.

[orgsyn-3] 1 2 Corley, Edward G.; Thompson, Andrew S.; Huntington, Martha. "CYCLOPROPYLACETYLENE". orgsyn.org. p. 231. doi:10.15227/orgsyn.077.0231. Retrieved 31 May 2017.