Trimethylsilylacetylene → tert-butyl 3-((trimethylsilyl)ethynyl)-1H-indazole-1-carboxylate

Participants

Reaction Steps

A mixture of tert-butyl 3-iodo-1H-indazole-1-carboxylate (prepared as described in J. Med. Chem. (2008), 51(12), 3460-3465); (34 g; 99 mmol; 1.00 eq.), (trimethylsilyl)acetylene (16.6 mL; 119 mmol; 1.20 eq.), PdCl2(PPh3)2 (2.77 g; 3.95 mmol; 0.04 eq.) and TEA (41 mL) was heated overnight at 50° C. The reaction mixture was then diluted with DCM and washed three times with an aqueous saturated solution of NH4Cl. Organic layer was dried over magnesium sulfate, filtered and concentrated. This crude was solubilized in DCM and the precipitate obtained was removed by filtration through a celite pad. Purification by flash chromatography on silica (Heptane/EtOAc; gradient from 98:2 to 2:98) afforded the title compound as a beige solid (20 g, 69% yield). 1H NMR (300 MHz, DMSO-d6) δ: 8.12 (d, J=8.5 Hz, 1H), 7.78 (d, J=8.5 Hz, 1H), 7.70 (m, 1H), 7.46 (m, 1H), 1.65 (s, 9H), 0.32 (s, 9H).

Provenance & Evidence