Triethylamine → Tert-butyl 2,2-difluoro-4-(5-methylthiophene-2-carbonyl)-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate

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Reaction Conditions

Reaction Steps

HATU (0.541 g) was added in one portion to a stirred solution at 0° C. of tert-butyl 2,2-difluoro-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate (example 37, step c) (0.32 g) and 5-methylthiophene-2-carboxylic acid (0.171 g) and triethylamine (0.458 mL) in DMF (20 mL). The mixture was then stirred at 20° C. for 7 hours. The 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, elution gradient 0.5 to 5% methanol in dichloromethane. Pure fractions were evaporated to dryness to afford the subtitled compound. Yield 0.4 g.

Provenance & Evidence