Triethylamine → HCID 58748281, compound

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Reaction Steps

89.1 To a stirred, cooled (0° C.) solution of 1.48 g (2S,4R)-4-[(5-chloro-thiophene-2-carbonyl)-amino]-2-hydroxymethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (example 17.1) in 30 ml CH2Cl2/DMSO 1:1 under an argon atmosphere were added 5.7 ml triethylamine and 3.92 g SO3-pyridine complex in one portion. The clear solution (slowly warming up to room temperature) was then stirred for 3 h. The mixture was diluted with EtOAc and washed with 1 N HCl. The aqueous phase was back extracted with EtOAc. The combined organics were washed with 1 N HCl, H2O and brine, dried over MgSO4, filtered and concentrated. The crude product was purified by chromatography (silica gel; cyclohexane/EtOAc 1:1) to give 985 mg (2S,4R)-4-[(5-chloro-thiophene-2-carbonyl)-amino]-2-formyl-pyrrolidine-1-carboxylic acid tert-butyl ester as white amorphous solid. MS 359.0 ([M+H]+)

Provenance & Evidence