4-Methylmorpholine → methyl(S)-N-[2-amino-3-nitro-5-(trifluoromethyl)benzoyl]alanine

Participants

Reaction Steps

To a cooled (−5° C.) mixture of 20.0 parts of 2-amino-3-nitro-5-(trifluoromethyl)benzoic acid, 11.17 parts of methyl(S)-alanine monohydrochloride, 21.62 parts of 1-hydroxy-1H-1,2,4-benzotriazole monohydrate and 356 parts of tetrahydrofuran under argon there were added 8.1 parts of N-methylmorpholine and, after stirring for 10 min 16.5 parts of N,N-methanetetraylbis[cyclohexanamine]. Stirring was continued for 1 hour at −5° C. and overnight at room temperature. After cooling on ice, the reaction mixture was filtered and the filtrate was evaporated. The residue was dissolved in dichloromethane and this solution was washed with NaHCO3 (aq.), dried, filtered and evaporated. The residue was recrystallized from methylcyclohexane (2×), yielding 19.1 parts (71.2%) of methyl(S)-N-[2-amino-3-nitro-5-(trifluoromethyl)benzoyl]alanine; mp. 136.4° C. (interm. 33).

Provenance & Evidence