Trifluoroacetic acid → HCID 59333345, compound

To a solution of 4-[4-(3-hydroxy-propylamino)-7-trifluoromethyl-imidazo[1,2-a]quinoxalin-1-yl]-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (1.10 g; 2.30 mmol; 1 eq) in anhydrous dichloromethane (12 mL) is slowly added trifluoroacetic acid (1.77 mL; 23.0 mmol; 10 eq). The solution is allowed to stir for 6 hours at room temperature until completion of the reaction. The reaction mixture is concentrated and the residual traces of trifluoroacetic acid are removed by co-distillation with toluene (2×10 mL). The red gum is taken up in water (73 mL) and the resulting aqueous solution is washed with ethyl acetate (375 mL) before adjusting the pH to 8 by addition of sodium bicarbonate in powder. This basic aqueous layer is then extracted with ethyl acetate (5×100 mL). The organic extracts are combined, dried over sodium sulfate and concentrated in vacuum. The resulting crude residue is then passed through a silica gel column (ethyl acetate/methanol 8:2 then ethyl acetate/methanol/triethylamine 8:2:0.3) to afford the title compound still contaminated with minor impurities. The powder is then washed with ether to afford the title compound as an off-white solid (170 mg; 0.44 mmol; 19%)

1. concentrationThe reaction mixture is concentrated
2. customthe residual traces of trifluoroacetic acid are removed by co-distillation with toluene (2×10 mL)
3. washthe resulting aqueous solution is washed with ethyl acetate (375 mL)
4. additionby addition of sodium bicarbonate in powder
5. extractionThis basic aqueous layer is then extracted with ethyl acetate (5×100 mL)
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated in vacuum

ORD record

ord-5e8fcb59da544ad8ac401e4b104faaa5

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08513250B2