Hydrochloric Acid → HCID 57935272, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of (2-Methyl-4-{2-[4-(6,6,6-trifluoro-hexyloxy)-phenyl]-ethyl}-4,5-dihydro-oxazol-4-yl)-methanol (300 mg, 0.80 mmol) and tetrazole (337.4 mg, 4.82 mmol, 6 eq., recrystallized from toluene) in dry THF (6 ml) is added 3-diethylamino-1,5-dihydrobenzo[e]-[1,3,2]dioxaphosphepine (433.5 μl, 1.56 mmol, 1.95 eq.). The reaction mixture is stirred under argon at room temperature for 3 h. Then, H2O2 (30%, 75 μl, 4.0 mmol, 5 eq.) is injected at 0° C. with vigorous stirring. The reaction mixture is stirred for further 30 min, followed by addition of saturated sodium thiosulfate solution (1 ml). The organic layer is separated and the aqueous phase is extracted with ether (3×20 ml). The combined organic extracts are washed with brine, dried over MgSO4, and evaporated to dryness. Purification by flash chromatography (AcOEt) affords phosphoric acid di-tert-butyl ester 2-methyl-4-{2-[4-(6,6,6-trifluoro-hexyloxy)-phenyl]-ethyl}-4,5-dihydro-oxazol-4-ylmethyl ester as colorless oil. To a solution of phosphoric acid di-tert-butyl ester 2-methyl-4-{2-[4-(6,6,6-trifluoro-hexyloxy)-phenyl]-ethyl}-4,5-dihydro-oxazol-4-ylmethyl ester (33 mg, 0.050 mmol) in ethanol (2 ml) is added conc. HCl (2 ml). The reaction mixture is stirred at 85° C. for 2 hours, then concentrated to dryness. The residue is re-dissolved in AcOEt and precipitated with hexanes. The solid is filtered off, washed with dry ether and dried under vacuum to afford phosphoric acid mono-{2-amino-2-hydroxymethyl-4-[4-(6,6,6-trifluoro-hexyloxy)-phenyl]-butyl}ester as a colorless powder. MS (ESI−): 428.2 (MH−)

Provenance & Evidence