(S)-methyl 2-(4-(2-(tert-butoxycarbonylamino)-3-(thiophen-2-yl)propanoyl)piperazin-1-yl)benzo[d]thiazole-6-carboxylate (0.61 g, 1.15 mmol) was dissolved in methanol (6 ml) followed by the addition of 1N NaOH (1.26 ml, 1.26 mmol) and the resulting mixture heated to 50° C. overnight. The resulting mixture was then cooled to room temperature, acidified with 10% citric acid and extracted with ethyl acetate. The organic layer was dried (MgSO4) and concentrated in vacuo to yield (S)-2-(4-(2-(tert-butoxycarbonylamino)-3-(thiophen-2-yl)propanoyl)piperazin-1-yl)benzo[d]thiazole-6-carboxylic acid.
