Lithium Hydroxide → HCID 59708794, compound

Participants

Reaction Steps

To a solution of 5-[4-(4-tert-butoxycarbonylaminobutyl)piperazin-1-yl]pentanoic acid ethyl ester (18) (1.62 g, 4.20 mmol) in methanol (12 mL)/THF (10 mL) was added a solution of lithium hydroxide (0.35 g, 8.40 mmol) in water (4 mL). The reaction mixture was stirred at room temperature for 20 h and then concentrated in vacuo. The resulting residue was diluted with water (5 mL) and acidified to pH ˜5 with 1 N aqueous HCl. The aqueous solution was extracted with chloroform/2-propanol (3:1, 3×10 mL). The combined extracts were concentrated under vacuum to dryness. The resulting residue was further co-evaporated with toluene and dried under high vacuum to give the desired acid 19 as a colorless, thick oil (1.42 g, 95%): 1H NMR (300 MHz, CDCl3) δ 1.44 (s, 9H), 1.63 (m, 8H), 2.30 (m, 2H), 2.58 (m, 2H), 2.68 (m, 2H), 2.92 (m, 8H), 3.12 (m, 2H), 4.92 (br, 1H); ESI MS m/z 358 [C18H35N3O4+H]+.

Provenance & Evidence