Hydrochloric Acid → HCID 66666457, compound

Participants

Reaction Steps

Ethyl 7-(2,3-diphenyl-7,8-dihydropyrido[3,2-b]pyrazin-5(6H)-yl)heptanoate (step 2)(6.1 g, 13.8 mmol) in THF (300 ml) and MeOH (100 ml) was treated with a solution of lithium hydroxide monohydrate (3.5 g, 83 mmol) in water (100 ml). The reaction mixture was heated at reflux for 5 h and allowed to cool to room temperature. The pH of the mixture was adjusted to <pH5 using 2M HCl. The volatile solvents were removed in vacuo and the remaining residue was diluted with water (50 ml) and extracted with EtOAc (3×). The combined organic extracts were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to yield a greenish grey solid. The crude material was dissolved in MeOH (30 ml) and purified in 2 portions on a cartridge packed with 113 g LiChroprep® RP-18 (40-63 μm, supplier Merck, reverse phase column) eluting with 10-100% MeCN in water. The resulting solid was re-crystallized from a hot mixture of EtOH (120 ml) and water (90 ml). After seeding and stirring for 1 h at 5° C., the crystals were filtered off and the product dried for 2 days at 40° C. in a vacuum oven to afford the title compound;

Provenance & Evidence