Trifluoroacetic acid → HCID 89544598, compound

Participants

Reaction Steps

238 mg (0.25 mmol) of the compound of example 1B was dissolved in 10 ml dichloroethane. 0.12 ml Triethylsilane, approx. 10 ml trifluoroacetic acid and approx. 0.5 ml water was added. The reaction mixture was stirred for approx. 30 min at room temperature. 100 ml dichloroethane were added and the reaction mixture was evaporated under reduced pressure to approx. 1 ml of solvent volume. Approx. 100 ml water was added and the reaction mixture was extracted three times with approx. 50 ml dichloromethane. To the aqueous phase 15 ml of acetic acid was added. The aqueous phase was frozen and lyophilized. The lyophylistae was dissolved in approx. 50 ml methanol and 0.183 mg (0.98 mmol) N-benzylmaleimide was added. The reaction mixture was stirred over night at room temperature. The reaction mixture was evaporated to dryness and redissolved in approx. 5 ml methanol and purified by preparative RP-HPLC on a C18 with a water/methanol gradient. The fractions were collected in test tubes of 20 ml on an automated fraction collector. To ensure sufficient acidity each vial was filled with 0.5 ml acedic acid prior to collection. All fractions containing the compound of example 1C were combined. Acetonitrile was partially removed on a rotary evaporator at 30° C. water bath temperature and approx. 50 mbar for approx. 30 min. After addition of 0.5 ml acedic acid, the remaining solution was lyophilized. The total yield was 168 mg (0.24 mmol, 98% of theory) of the desired product.

Provenance & Evidence