Trifluoroacetic acid → Methyl-(2-methyl-3,4,5,6-tetrahydro-2H-[1,4]bipyridinyl-3'-yl)-amine trifluoroacetic acid salt

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Reaction Steps

Methyl-(2-methyl-3,4,5,6-tetrahydro-2H-[1,4]bipyridinyl-3′-yl)-carbamic acid tert-butyl ester (60 mg, 0.20 mmol, example 20, intermediate b) was stirred in a solution of TFA (300 μL) and CH2Cl2 (2 mL) for 1 h after which all volatiles were removed under reduced pressure to give crude methyl-(2-methyl-3,4,5,6-tetrahydro-2H-[1,4]bipyridinyl-3′-yl)-amine TFA salt. The crude TFA salt was dissolved in CH2Cl2 (2 mL) and treated with DIPEA (100 μL, 590 mmol) and 3,5-dichlorobenzoyl chloride (54 mg, 0.26 mmol, CAS RN 2905-62-6). The reaction mixture was loaded directly on a silica gel column and elution with 66% EtOAc in n-hexane gave the title product (12 mg, 16%). MS (ESI): m/z=378.0 [M+H]+.

Provenance & Evidence