Trifluoroacetic acid → (5-Ethylthiophen-3-yl)(1-oxa-4,9-diazaspiro[5.5]undecan-4-yl)methanone trifluoroacetate

Participants

Reaction Conditions

Reaction Steps

HATU (1.15 g) was added in one portion to a solution at 0° C. of tert-butyl 1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate hydrochloride (WuXi PharmaTech) (0.682 g) and 5-ethylthiophene-3-carboxylic acid (0.364 g) and triethylamine (1.3 mL) in DMF (10 mL). The mixture was then stirred at 20° C. for 1 hour. The reaction mixture was partitioned between ethyl acetate and brine, the organic layer was washed twice with brine, dried over sodium sulphate, filtered and the solvent evaporated under reduced pressure. The crude product was purified by flash silica chromatography using 50% ethyl acetate in isohexane. Pure fractions were evaporated to dryness to afford the ‘BOC’ protected intermediate. DCM (10 mL) was added followed by trifluoroacetic acid (10 mL) and the resultant solution allowed to stand at 20° C. for 25 minutes. Toluene (30 mL) was added and the solvents evaporated under reduced pressure. The residue was azeotroped twice with acetonitrile to yield the subtitled compound. Yield 0.950 g.

Provenance & Evidence