Iodine → 4-Iodophenylalanine

Participants

Reaction Conditions

Reaction Steps

To a solution (S)-2-amino-3-phenylpropanoic acid 91 (4.01 g, 24.3 mmol) in acetic acid (22 mL) was added sulfuric acid (2.9 mL, 5.14 mmol), iodine (2.47 g, 4.7 mmol) and sodium iodate (1.02 g, 5.14 mmol). The mixture was heated to 70° C. and allowed to stir at this temperature for 16 h before an additional portion of sodium iodate (1.02 g, 5.14 mmol) was added. The reaction was left for a further 2 h before being concentrated, dissolved in methanol (20 mL) and treated with NaOH (60 mL). The mixture was left to precipitate out of the basic solution overnight and the resulting solid was filtered by vacuum filtration to yield the title compound (7.07 g, 24.3 mmol, 100%) as a pink solid, which had spectral data in agreement with that reported.93 [α]D21 −10.6 (c. 0.3, HCl). Mp 258-260° C. (lit. 261-262° C.)93 1H NMR (CD3OD, 300 MHz): δ 7.71 (d, J=8.4 Hz, 2H, ArH2′ and ArH6′); 7.10 (d, J=8.4 Hz, 2H, ArH3′ and ArH5′); 4.26 (dd, J=6.3, 7.2 Hz, H2); 3.26 (dd, J=5.4, 14.1 Hz, 1H, H3a); 3.04 (dd, J=7.2, 14.4 Hz, 1H, H3b). Mass Spectrum (CI, +ve) m/z 279 (100%), 292 (70%) [M+]. HRMS calcd for C9H11NO2 291.9834 found 291.9568.

Provenance & Evidence