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

HRID 2281713Notes

Reaction equation

Br[C:2]1[CH:3]=[CH:4][C:5]([N:8]2[CH2:13][CH2:12][N:11]([CH3:14])[CH2:10][CH2:9]2)=[N:6][CH:7]=1.N1CCCCC1.[CH3:21][Si:22]([C:25]#[CH:26])([CH3:24])[CH3:23].CCN(CC)CC>CCOCC.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.[Cu]I>[CH3:14][N:11]1[CH2:12][CH2:13][N:8]([C:5]2[CH:4]=[CH:3][C:2]([C:26]#[C:25][Si:22]([CH3:24])([CH3:23])[CH3:21])=[CH:7][N:6]=2)[CH2:9][CH2:10]1

Participants

Conditions

Temperature: 90 °C

Procedure

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.

Workup

customwas flushed with argon for 10 min
temperatureThe reaction mixture was cooled to room temperature
customthe volatiles were removed in vacuo
customChromatography on Biotage (silica, SNAP-25 g, 5-15% MeOH in DCM) yielded an impure product

Sources & evidence

ORD record: ord-4c4609a7ca8244e1896132da315e2fab
Source dataset: uspto-grants-2015_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09139563B2

Reaction notes

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