Hydrochloric Acid → 1-[5-(1,1-Difluoro-6-aza-spiro[2.5]oct-6-yl)-pyridin-2-yl]-1,2,3,4-tetrahydroquinoxaline

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Reaction Steps

1.48 g of tert-butyl ester of 4-[5-(1,1-difluoro-6-aza-spiro[2.5]oct-6-yl)-pyridin-2-yl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid is put in 16 mL of dichloromethane. 24 mL of 4M hydrochloric acid in dioxane is added at +4° C. The solution is stirred at room temperature for 4 h and evaporated to dryness. The residue is taken up in a saturated solution of sodium hydrogen carbonate to basic pH. The solution is extracted twice with dichloromethane, washed with water, dried over magnesium sulfate, filtered and evaporated to dryness. 1.4 g of 1-[5-(1,1-difluoro-6-aza-spiro[2.5]oct-6-yl)-pyridin-2-yl]-1,2,3,4-tetrahydroquinoxaline is obtained.

Provenance & Evidence