Sodium Bicarbonate → Tert-butyl 4-(2-(tert-butoxycarbonyl)hydrazinyl)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of 4-(tert-butoxycarbonyl-hydrazono)-piperidine-1-carboxylic acid tert-butyl ester (from Step 1; 12.0 g, 38.3 mmol) in methanol (60 mL) and tetrahydrofuran (120 mL) was cooled to 0° C. Sodium borohydride (9.0 g, 238 mmol) was added slowly in three portions in 15-30 min intervals. The reaction mixture was heated to 60° C. for 2 h and then cooled to room temperature. A solution of 20% brine (90.0 mL) and 10% sodium bicarbonate (200 mL) were slowly added to the stirred reaction mixture. The organic layer was separated and the aqueous layer was extracted with methyl tert-butyl ether (2×50 mL). The combined organic layers were washed with brine (3×50 mL) and concentrated. To the residue was added acetonitrile (15 mL). The mixture was concentrated again to remove trace amounts of water, to give 4-(tert-butoxycarbonyl-hydrazino)-piperidine-1-carboxylic acid tert-butyl ester (12.0 g, 99%) as a white solid. 1H NMR (CDCl3) δ 1.27 (m, 2H), 1.44 (s, 18H), 1.76 (m, 2H), 2.84 (t, 2H, J=11.7 Hz), 3.00 (m, 1H), 3.95 (m, 3H), 6.03 (br, 1H).

Provenance & Evidence