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Solution and Solid Phase Synthesis of Unusual a-Amino Acids From

Solution and Solid Phase Synthesis of Unusual a-Amino Acids From

Solution and Solid Phase Synthesis of Unusual a-Amino Acids From

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hotu before benzyl brornide (0.21 mt, 1.80 mrnol) was added by syringe. The mixture<br />

was allowed to stir for 6 hours at -78'C More king poured into 3% N&C1(20 mL) <strong>and</strong><br />

extracted with Et20 (100 m.). The organic layer was then extracted with 3% N ml (20<br />

mL), saturated NaHC03 (20 mL), brine (20 mL) <strong>and</strong> dried over MgS04. The solvent was<br />

removed in vacuo to reveal a yellow oil which was further purified by flash<br />

chromatography (1: 1 EtOAc:Hex, 0.5% Etm to give a clear oil in 75% yield (0.199 g).<br />

[a120D = -51.3 (c = 1 .W. EtOAc); TLC (1: 1, EtOAc:Hex), Rf = 0.60; 'H NMR (Acetone-<br />

&, 300 MHz) 6 7.40-7.02 (m, 10H, ArH), 5.75 (d, IH, J= 10.3Hz, NH), 5.13 (d, lH, J =<br />

22.7Hz, CbzCHHO), 5.00 (d, lH, J = 12.7Hz, CbzCHHO), 3.97 (dt, lH, J = 3.4, 10.3Hz,<br />

a-CH), 3.87 (s, 6H, OB0 ester C m), 3.41 (s, 3H, C02CH3), 2.97-2.89 (m, lHT y -0,<br />

2.78-2.60 (m, 2H, PhCHz), 1.93-1.85 (m, lH, $-CHH), 1.80-1.69 (m, lH, p-CHH), 0.76<br />

(s, 3H, OB0 ester CC&); 13c NMR (Acetone-cl6, 75 MHz) 6 175.3 (C=O), 156.5<br />

CONH), 139.5, 139.5 (Cbz-sz, Ph

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