Molecules 1998, 3, M55

2(S,R),3(R,S)-2,3-Dibromo-3-methyl-5-phenyl-2-pentanoic 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)-3-methyl-5-phenyl-2-pentenoic acid (2.26 g, 12 mmol) in dry chloroform (50 ml) was added a solution of bromine (0.75 ml, 15 mmol) in dry chloroform (5 ml) dropwise. The mixture was stirred at room temperature for 16 hours and evaporated under reduced pressure to yield 2(S,R),3(R,S)-2,3-dibromo-3-methyl-5-phenyl-2-pentenoic acid (4.18 g, 100%) as yellow plates from chloroform/light petroleum.

M.p. 115-8°

UV (ethanol) 206 (11360) nm.

IR (CDCl3) 3260-2758(bs, OH), 1728 (s, C=O) cm-1.

1H-NMR (90 MHz, CDCl3) 2.03-2.40 (2H, m, CH2), 2.06 (3H, s, CH3), 2.70-3.03 (2H, m, CH2), 4.66 (1H, s, -CHBr), 7.02-7.40 (5H, m, ArH), 10.22 (1H, bs, COOH).

13C-NMR (15 MHz, CDCl3) 26.75 (CH3), 31.88, 45.91 (CH2), 51.75 (CHBr), 65.77 (C3), 126.3, 128.5 128.6 (ArCH), 140.5 (quat, C1'), 172.2 (quat, C1).

EI-MS 352(M++4, 3%), 350(M++2, 6), 348 (M+, 4), 146(40), 145(68), 143(36), 131(40), 129(36), 128(37), 115(30), 105(30), 103(30), 92(49), 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.

©1998 MDPI. All rights reserved. Molecules website http://www.mdpi.org/molecules/