Triethylamine → tert-Butyl 4-(1-(pyridin-4-yl)ethyl)piperazine-1-carboxylate

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Reaction Steps

This was prepared using the same procedure as for tert-butyl 4-(1-(pyridin-2-yl)ethyl)piperazine-1-carboxylate, but here using 1-(pyridin-4-yl)ethanol (J. Chem. Soc., Perkin Trans. 1, 2000, 4439-4444) (100 mg, 0.81 mmol), triethylamine (5.0 eq, 4.05 mmol, 0.56 mL), MsCl (2.0 eq, 1.62 mmol, 0.13 mL), CH2Cl2 (4 mL) at 0° C. for 30 minutes, then N—BOC piperazine (4.0 eq, 3.24 mmol, 605 mg), DMSO (3 mL) at 60° C. for 18 h. Work up as described for tert-butyl 4-(1-(pyridin-2-yl)ethyl)piperazine-1-carboxylate, followed by column chromatography (EtOAc-MeOH, 95:5) gave the product (163 mg, 69% for two steps) as a colourless oil; 1H-NMR (500 MHz, CDCl3) 1.50 (s, 9H, C(CH3)3), 1.72 (s, br, 3H, CH3), 2.42-2.60 (m, 4H, piperazine N(CH2)2), 3.49 (s, br, 5H, CH & piperazine N(CH2)2), 7.32 (d, J=5.7 Hz, 2H, pyridine H-3 & H-5), 8.59 (d, J=5.7 Hz, 2H, pyridine H-2 & H-6);

Provenance & Evidence