Hydrochloric Acid → rac-Methyl 5,5,6,6,6-pentafluoronorleucinate hydrochloride

Participants

Reaction Conditions

Reaction Steps

132 g (521.0 mmol) of methyl N-(diphenylmethylene)glycinate [described in: WO2010/123792 A1, 2010; p. 11-13] were initially charged in 1000 ml of THF (anhydrous) under argon and cooled to −40° C. 625.2 ml (625.20 mmol) of bis(trimethylsilyl)lithium amide (1 M in THF) were added dropwise within 30 min. After 10 min at −40° C., the internal temperature was allowed to rise to 0° C. within 35 min 192.86 g (651.25 mmol) of 3,3,4,4,4-pentafluorobutyl trifluoromethanesulphonate from Example 24A, dissolved in 400 ml of THF, were added dropwise to the reaction solution at 0° C. After 10 min, the cooling bath was removed and the mixture was stirred at RT for 3 days. Subsequently, the reaction mixture was cooled to 0° C. and 410 ml (1.33 mol) of 3 N aqueous hydrochloric acid were added dropwise. The cooling bath was removed and the reaction mixture was stirred at RT for two hours. The mixture was subsequently concentrated. This gave 141.5 g of the target compound as a crude mixture (purity unknown), which was used in the subsequent stage without further purification.

Provenance & Evidence