Piperidine → 1-Methyl-4-(5-((trimethylsilyl)ethynyl)pyridin-2-yl)piperazine

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-(5-bromopyridin-2-yl)-4-methylpiperazine (501.7 mg, 1.96 mmol), PdCl2(PPh3)2 (51.1 mg, 0.073 mmol) and copper(I) iodide (39.9 mg, 0.21 mmol) was flushed with argon for 10 min prior to addition of piperidine (1.25 mL, 12.7 mmol) and trimethylsilylacetylene (1.40 mL, 9.9 mmol). The resulting mixture was heated at 90° C. in a sealed vial for 3 d. The reaction mixture was cooled to room temperature and the volatiles were removed in vacuo. Chromatography on Biotage (silica, SNAP-25 g, 5-15% MeOH in DCM) yielded an impure product. A second chromatography on Biotage (silica, SNAP-25 g, 0-3% Et3N in Et2O) gave 1-methyl-4-(5-((trimethylsilyl)ethynyl)pyridin-2-yl)piperazine (325.7 mg, 61%). 1H NMR (400 MHz, CDCl3) δ ppm 8.29 (d, J=1.3 Hz, 1 H), 7.53 (dd, J=8.9, 2.4 Hz, 1 H), 6.55 (d, J=8.8 Hz, 1 H), 3.67-3.52 (m, 4 H), 2.57-2.44 (m, 4 H), 2.35 (s, 3 H); MS ESI [M+H]+ 274.0, calcd for [C15H23N3Si+H]+ 274.2.

Provenance & Evidence