Chemical Properties
Ethyl propiolate is a clear colorless to pale yellow liquid that is soluble in ethanol, ether and chloroform. It an important organic chemical raw material and pharmaceutical intermediate. Ethyl propargylate is obtained by oxidation of propargyl alcohol to propargylic acid followed by esterification.
Uses
In organic synthesis; peptide coupling reagent.
Uses
Ethyl propiolate is used as a precursor in the preparation of substituted anthraquinones and pyrazolo[1,5-a]pyridine, which exhibits anti-inflammatory activity. Further, it is employed in the synthesis of benzene-1,2,3,5-tetracarboxylates promoted by triphenylphosphine. Its halogenated derivatives are used as a substrate for direct, asymmetric alkynylation of cyclic beta-ketoesters using chiral phase-transfer catalysts.
Uses
Halogenated derivatives were used as substrates for direct, asymmetric alkynylation of cyclic ?-ketoesters using chiral phase-transfer catalysts. Also employed in a one-pot , four-component synthesis of benzene-1,2,3,5-tetracarboxylates promoted by Ph3P.
Definition
ChEBI: Ethyl propiolate is the ethyl ester of prop-2-ynoic acid. It is a ynoate ester, a terminal acetylenic compound and an ethyl ester.
Hazard
Flammable; lachrymator.
Synthesis
The general procedure for the synthesis of ethyl propargylate from ethanol and propargylate was as follows: propargylate (310 μL, 5 mmol; Alfa Aesar, Ward Hill, MA; Catalog No. A13245) was dissolved in 13 mL of ethanol to form a colorless solution, followed by the slow addition of concentrated sulfuric acid (139 μL, 2.5 mmol) to this solution. The reaction mixture was heated to reflux for 24 hours. Upon completion of the reaction, the reaction was quenched with 13 mL of water followed by extraction with dichloromethane (10 mL; three times). The organic phases were combined, washed sequentially with water (10 mL; three times) and brine (10 mL), and then dried with anhydrous Na2SO4 (Thermo Fisher Scientific, Pittsburgh, PA; catalog number S421-3). The solvent was removed by distillation under reduced pressure to give the light yellow oily product ethyl propiolate (177 mg, 36% yield). The product was characterized by 1H NMR (400 MHz, CDCl3, δ): 4.26 (q, 3JH-H = 7.1 Hz, CH2, 2H), 2.92 (s, C≡CH, 1H), 1.33 (t, 3JH-H = 7.2 Hz, CH3, 3H).
References
[1] Journal of the American Chemical Society, 1988, vol. 110, p. 3965
[2] Patent: US2016/264506, 2016, A1. Location in patent: Paragraph 0035
[3] Chemische Berichte, 1926, vol. 59, p. 1689
[4] Nippon Kagaku Zasshi, 1956, vol. 77, p. 1689,1691
[5] Chem.Abstr., 1959, p. 5163
