L-Alanine → (S)-2-(2,4-dinitrobenzamido)propanoic acid

Beteiligte Stoffe

Reaktionsschritte

As shown in scheme H, 2,4-dinitrobenzoyl chloride prepared from 2,4-dinitrobenzoic acid is treated with L-alanine in presence of sodium carbonate to yield (S)-2-(2,4-dinitrobenzamido)propanoic acid (intermediate 11). Treatment of intermediate 11 either with K18F or K19F gave (S)-2-(2-fluoro-4-nitrobenzamido)propanoic acid, which on reduction with iron powder in presence of acetic acid gave (S)-2-(4-amino-2-fluorobenzamido)propanoic acid (compound 10). In an analogous manner, treatment of 2,4-dinitrobenzoyl chloride with D-alanine gave (R)-2-(2,4-dinitrobenzamido)propanoic acid (intermediate 12), which on treatment either with K18F or K19F and further reduction with iron powder gave (R)-2-(4-amino-2-fluorobenzamido)propanoic acid (compound 11).

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