Synthesis
General procedure for the synthesis of 5-(benzyloxy)-1H-indazole from 1H-indazol-5-ol and benzyl bromide: Benzyl bromide (0.089 mL, 0.745 mmol) and potassium carbonate (103 mg, 0.745 mmol) were sequentially added to a N,N-dimethylformamide (2 mL) containing 1H-indazol-5-ol (100 mg, 0.745 mmol) ) solution. The reaction mixture was heated to 40 °C and maintained at this temperature for 2 hours. Upon completion of the reaction, the mixture was poured into water (20 mL) and extracted with ethyl acetate (20 mL x 2). The organic layers were combined and dried with anhydrous magnesium sulfate. The dried organic layer was concentrated under reduced pressure and the resulting residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate) to afford the target product 5-(benzyloxy)-1H-indazole (63 mg, 38% yield). The melting point of the product was 179-181 °C.
References
[1] Patent: WO2011/123937, 2011, A1. Location in patent: Page/Page column 152-153
[2] Bioorganic and Medicinal Chemistry, 2014, vol. 22, # 17, p. 4968 - 4997
[3] Patent: EP1403255, 2004, A1. Location in patent: Page 97
