Yield:917925-71-4 100%

Reaction Conditions:

Stage #1: di-tert-butyl dicarbonate;2-amino-2-(4-bromophenyl)acetic acidwith dmap;triethylamine in 1,4-dioxane;water; for 3 h;
Stage #2: with hydrogenchloride in 1,4-dioxane;water;ethyl acetate;

Steps:

69.1

Preparation of tert-butoxycarbonylamino-[4-(2-methanesulfonyl-ethyl)-phenyl]-acetic acid; (1); To a mixture of amino-(4-bromo-phenyl)-acetic acid (543 mg, 2.4 mmol), triethylamine (822 μL, 5.9 mmol), 4-(dimethylamino)pyridine (29 mg, 0.24 mmol) in dioxane/water (2:1, 12 mL) was added di-tert-butyl dicarbonate (1.1 g, 5.0 mmol) and the resulting solution was allowed to stir for 3 hours. The reaction was diluted with ethyl acetate (50 ml), washed with 0.2 N aqueous hydrochloric acid (10 mL), water (20 mL), brine and the organic layer was dried over sodium sulfate and filtered. The solvent was removed in vacuo to give (4-bromo-phenyl)-tert-butoxycarbonylamino-acetic acid (780 mg, 100%)

References:

US2007/197617,2007,A1 Location in patent:Page/Page column 26