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

Martin J. Stoermer; John T. Pinhey

doi:10.3390/M53

and

Division of Organic Chemistry, School of Chemistry F11, The University of Sydney, N.S.W 2006, Australia

^*

Author to whom correspondence should be addressed.

^*

Current address: Victorian College of Pharmacy, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia

Molecules1998, 3(3), M53;https://doi.org/10.3390/M53

This article belongs to the Section Molbank Section of Molecules, 1997-2001

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The general part of the experimental section [] has been presented elsewhere. Ethyl (E)-3-methyl-

5-phenyl-2-pentenoate (3.363 g, 15.4 mmol) was refluxed with sodium hydroxide (2.161 g, 38.5 mmol) in a mixture of water (50 ml) and methanol (10 ml) for 3 hours, cooled and washed with ether (30 ml). The aqueous phase was acidified with concentrated hydrochloric acid to below pH 1. The mixture was extracted with ether (3x30 ml). The combined ether extracts were washed with brine (20 ml), dried (Na2SO4), filtered and evaporated under reduced pressure. (E)-3-Methyl-5-phenyl-2-pentenoic acid (2.79 g, 95%) was obtained as colourless plates from cyclohexane/light petroleum.

M.p. 58°

Anal. calc. for C₁₂H₁₄O₂ (190.24): C 75.8, H 7.4; found: C 76.2, H 7.3.

UV (ethanol) 305 (208) nm.

IR (CDCl3) 3500–2800(bs, OH), 3104, 2950, 1694 (s, C=O), 1641, 1260 cm⁻¹.

¹H-NMR (90 MHz, CDCl₃) 2.16 (3H, d, J 1.1 Hz, CH₃), 2.43 (2H, m, =C(CH₂), 2.73 (2H, m, Ph-CH₂),

5.61 (1H, m, =CH), 6.92–7.40 (5H, m, ArH), 9.98 (1H, bs, COOH).

¹³C-NMR (15 MHz, CDCl₃) 19.22 (CH₃), 34.02, 42.85 (CH₂), 115.7 (=CH); 126.2, 128.2 128.5 (ArCH),

140.9 (quat, C1’), 161.7 (quat, C3), 171.5 (quat, C1).

EI-MS 190(M⁺, 3%), 144(10), 91(100).

Supplementary Materials

Acknowledgments

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

Reference

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. [Google Scholar] [CrossRef]

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