Toluene → 3-(2-Chloro-3-((4-(2-ethylthiazole-4-carbonyl)-1-oxa-4,9-diazaspiro[5.5]undecan-9-yl)methyl)phenethoxy)propanoic acid

Participants

Reaction Steps

A solution of tert-butyl 3-(2-chloro-3-((4-(2-ethylthiazole-4-carbonyl)-1-oxa-4,9-diazaspiro[5.5]undecan-9-yl)methyl)phenethoxy)propanoate (limiting reagent) (step d) in DCM (2.8 volumes) was cooled to 5° C. Trifluoroacetic acid (10 molar equivalents) was added over 20 min (exotherm to 15° C.). The reaction mixture was warmed to ambient and stirred for 18 hr, Toluene (3 volumes) was added and the mixture was evaporated. The resulting gum was triturated with toluene (2×1.5 volumes) and evaporated to give a brown gum. Yield: 200% of theoretical. (carried through crude—NMR assay shows ˜45% by weight purity with remaining weight due to TFA trapped in the gum)

Provenance & Evidence