4-Methyloxybenzyl chloride → 1-(4-Methoxybenzyl)-1H-indazole-6-carbaldehyde

Participants

Reaction Steps

To a solution of 1H-indazole-6-carbaldehyde (1.5 g, 10.3 mmol) in DMF (10 mL) at 0° C. was added KOtBu (1.4 g, 12.4 mmol) and let stir for 10 min. PMBCl (1.7 mL, 12.4 mmol) was then added and let slowly warm to room temperature. After 1.5 h the reaction was quenched with NH4Cl. The product was extracted with Et2O and the organic layers was washed brine and then dried over MgSO4. The solvent was removed and the crude material (mixture of N1 and N2 isomers) was dried under high vacuum. To the resulting residue was added PMBCl (0.70 mL, 5.15 mmol) and the mixture heated to 170° C. for 2.5 h. Cooled to room temperature and purified residue using Biotage Isolera (silica gel, 20-50% EtOAc in hexane) which gave the title compound (1.97 g, 72%). 1H NMR (400 MHz, CDCl3) δ 10.09 (s, 1H), 8.12 (s, 1H), 7.91 (s, 1H), 7.85 (d, J=8.4 Hz, 1H), 7.67 (d, J=8.4 Hz, 1H), 7.21 (d, J=8.5 Hz, 2H), 6.85 (d, J=8.6 Hz, 2H), 5.62 (s, 2H), 3.77 (s, 3H); MS ESI 266.9 [M+H]+, calcd for [C16H14N2O2+H]+ 267.1.

Provenance & Evidence