Yield:5959-79-5 3.65 g (64%)

Reaction Conditions:

with sodium carbonate in water;

Steps:

28 EXAMPLE 28

EXAMPLE 28 To a stirred solution of histidine (3.17 g, 20.0 mmol) and sodium carbonate (2.23 g, 21 mmol) in 50 mL of water is added N-carboethoxyphthalimide (4.52 g, 20.0 mmol). After 1.5 hour, the reaction slurry is filtered. The filtrate is stirred and the pH adjusted to 1-2 with 4N hydrochloric acid. The resulting slurry is filtered and the solid washed with water and dried in vacuo (60 C, <1 mm) to afford 3.65 g (64%) of 2-phthalimido-3-(imidazol-4-yl)propionic acid as a white powder: mp 280°-285° C.; ¹ H NMR (dmso-d₆, 250 M Hz) δ12.5 (br s, 1H), 7.90-7.60 (m, 6H), 6.80(s, 1H), 4.94 (t, 1H, J=7.8), 3.36 (d, 2H, J=7.8); ¹³ C NMR (dmso-d₆) δ 170.1, 167.1, 134.8, 134.6, 133.2, 131.1, 123.2, 116.3, 52.4, 25.8; Anal. Calculated for C₁₄ H₁₁ N₃ O₄. Theoretical: C, 58.95; H, 3.89; N, 14.73. Found: C, 58.80; H, 3.88; N, 14.66.

References:

US5463063,1995,A