2,3-Dibromo-2-methyl-5-phenylpentanoic Acid

Molecules 1998, 3, M65

2,3-Dibromo-2-methyl-5-phenylpentanoic 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. To a stirred solution of (E)-2-methyl-5-phenyl-2-pentenoic acid (1.255 g, 6.6 mmol) in dry chloroform (15 ml) was added a solution of bromine (0.38 ml, 7.4 mmol) in dry chloroform (5 ml) dropwise. The mixture was stirred at room temperature for 6 hours and the chloroform solution was washed with sodium bisulfite solution (5%, 20 ml), brine (10 ml), dried (Na₂SO₄), filtered and evaporated under reduced pressure to yield 2,3-dibromo-2-methyl-5-phenyl-2-pentanoic acid (1.95 g, 84%) as yellow plates from chloroform/light petroleum.

M.p. 68-70° (resolidified and melted again at 86-8°)

Anal. calc. for C₁₂H₁₄Br₂O₂ (350.05): C 41.2, H 4.0; found: C 41.0, H 4.2.

IR (CDCl₃) 3500-2800(bs, OH), 2954, 1722 (s, C=O), 1497, 1455, 1054 cm^-1.

¹H-NMR (400 MHz, CDCl₃) 1.98 (3H, s, CH₃), 2.04 (1H, m, 1/2 of CH₂), 2.73 (2H, m, 1/2 of CH₂ and 1/2 of Ph-CH₂), 3.09 (1H, m, 1/2 of Ph-CH₂), 4.56 (1H, m, -CHBr), 7.18-7.49 (5H, m, ArH), 8.10 (1H, bs, COOH).

¹³C-NMR (15 MHz, CDCl₃ + DMSO-d₆) 21.56 (CH₃), 33.05, 34.35 (CH₂), 58.31 (CHBr), 62.40 (C2), 125.5, 127.8, 127.8 (ArCH), 139.3 (quat, C1'), 169.7 (quat, C1).

EI-MS 352(M⁺+4, 3%), 350(M⁺+2, 6), 348 (M⁺, 3), 189(27), 143(41), 91(100), 65(19).

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.