(Z)-3-Methyl-5-phenyl-2-pentenoic Acid

Molecules 1998, 3, M54

(Z)-3-Methyl-5-phenyl-2-pentenoic Acid

Martin J. Stoermer* and John T. Pinhey

Division of Organic Chemistry, School of Chemistry F11, The University of Sydney, N.S.W 2006, Australia.
Current address: Victorian College of Pharmacy, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia. Phone: +61 3 990 39000, Fax: +61 3 99039582, e-mail: [email protected], http://synapse.vcp.monash.edu.au/martin/

Received: 27 February 1998 / Published: 6 March 1998

The general part of the experimental section [1] has been presented elsewhere. Ethyl (Z)-3-methyl-5-phenyl-2-pentenoate (0.10 g, 0.5 mmol) was refluxed with potassium hydroxide (0.07 g, 1.25 mmol) in a mixture of water (8 ml) and methanol (1 ml) for 3 hours, cooled and washed with ether (10 ml). The aqueous phase was acidified with concentrated hydrochloric acid to below pH 1. The mixture was extracted with ether (3x10 ml). The combined ether extracts were dried (Na₂SO₄), filtered and evaporated under reduced pressure. (Z)-3-Methyl-5-phenyl-2-pentenoic acid (0.0497 g, 57%) was obtained as a viscous pale yellow oil that crystallized on standing at room temperature overnight.

M.p. 51-3°

UV (ethanol) 303 (250) nm.

IR (CDCl₃) 3300-2800(bs, OH), 3103, 2941, 1692 (s, C=O), 1639, 1290, 1260 cm^-1.

¹H-NMR (90 MHz, CDCl₃) 1.88 (3H, d, J 1.3 Hz, CH₃), 2.55-2.98 (4H, m, 2xCH₂), 5.65 (1H, m, =CH), 6.92-7.35 (5H, m, ArH), 9.28 (1H, bs, COOH).

EI-MS 190(M⁺, 7%), 144(9), 131(8), 91(100).

Acknowledgment: The authors gratefully acknowledge financial support from the Australian Research Council and The University of Sydney.

References and Notes

1. Moloney, M.G.; Pinhey, J.T.; Stoermer, M.J. "Vinyl Cation Formation by Decomposition of Vinyl-lead Triacetates. The reactions of Vinylmercury and Vinyltin Compounds with Lead Tetraacetate." J. Chem. Soc. Perkin Trans. 1 1990, 10, 2645.

Sample Availability: No sample available.