To a mixture of (S)-methyl 5-hydroxy-5-(5-(4-methyl-6-((4-(trifluoromethyl)pyridin-2-yl)amino)pyridin-2-yl)thiazol-2-yl)-5,6,7,8-tetrahydronaphthalene-2-carboxylate (100 mg, 0.185 mmol) and sodium azide (36.1 mg, 0.555 mmol) in DCM (2 mL) at rt was added TFA (0.016 mL, 0.203 mmol) dropwise and the mixture was stirred at rt for 16 h, after which time the reaction was heated to 40° C. for 5 days. The mixture was filtered, and the filtrate was concentrated under reduced pressure to give crude methyl 5-azido-5-(5-(4-methyl-6-((4-(trifluoromethyl)pyridin-2-yl)amino)pyridin-2-yl)thiazol-2-yl)-5,6,7,8-tetrahydronaphthalene-2-carboxylate as a brown oil, which was used as such for the following transformation. MS ESI calcd for C27H22F3N7O2S [M+H]+ 566, found 566.
