Triethylamine → [(S)-2-((S)-8-Azidomethyl-7,8-dihydro-[1,4]dioxino[2,3-g]indazol-1-yl)-1-methyl-ethyl]-carbamic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

To a ° C. stirred solution of the alcohol from Step B of Example 1 (0.43 g, 1.08 mmol) in anhydrous tetrahydrofuran (30 mL) was added triethylamine (0.88 g, 8.6 mmol) and methanesulfonic anhydride (0.76 g, 4.4 mmol) under nitrogen atmosphere. After 1 h the volatiles were evaporated. To the residue was added anhydrous DMSO (30 mL) and sodium azide (0.7 g, 11 mmol). The resulting mixture was heated at 85° C. for 3 h, 95° C. for 1 h, cooled, mixed with a saturated aqueous solution of sodium bicarbonate (100 mL) and extracted with ethyl acetate (50 mL×3). Chromatography on silica eluting with a gradient of 15% to 60% ethyl acetate/hexane gave an oil (0.29 g, 63%): LCMS (+APCI) 423 (M+H).

Provenance & Evidence