Dicyclohexylcarbodiimide → HCID 86713102, compound

Participants

Reaction Steps

As shown in scheme F, condensation of 3-iodo-4-nitrobenzoic acid with benzyl glycinate in presence of DCC and catalytic amount of DMAP gave benzyl 2-(3-iodo-4-nitrobenzamido)acetate, which on oxidation using oxidizing agents such as acetic anhydride-hydrogen peroxide gave benzyl 2-(3-iodyl-4-nitrobenzamido)acetate (intermediate 7). The intermediate 7 is treated either with K18F or K19F in the presence of kryptofix[2.2.2] or 18-crown-6 to yield benzyl 2-(3-fluoro-4-nitrobenzamido)acetate, which on reduction with hydrogen gas or hydrogen source in the presence of Pd/C gave 2-(4-amino-3-fluorobenzamido)acetic acid (compound 6). Reaction of 3-iodo-4-nitrobenzoic acid with thionyl chloride gave 3-iodo-4-nitrobenzoyl chloride, which on further treatment with 2,2,2-trichloroethyl glycinate in the presence of triethylamine gave 2,2,2-trichloroethyl 2-(3-iodo-4-nitrobenzamido)acetate. Oxidation of 2,2,2-trichloroethyl 2-(3-iodo-4-nitrobenzamido)acetate with acetic anhydride-hydrogen peroxide gave 2,2,2-trichloroethyl 2-(3-iodyl-4-nitrobenzamido)acetate (intermediate 8). Reaction of intermediate 8 either with K18F or K19F gave 2,2,2-trichloroethyl 2-(3-fluoro-4-nitrobenzamido)acetate, which on reduction with zinc dust gave compound 6. In an analogous manner, treatment of 3-iodo-4-nitrobenzoyl chloride with glycine in presence of sodium carbonate gave 2-(3-iodo-4-nitrobenzamido)acetic acid, which on oxidation with acetic anhydride-hydrogen peroxide and followed by treatment with KOH gave potassium 2-(3-iodyl-4-nitrobenzamido)acetate (intermediate 9). The intermediate 9 is treated either with K18F or K19F to yield 2-(3-fluoro-4-nitrobenzamido)acetic acid, which on reduction with iron powder in presence of acetic acid gave compound 6. Reduction of 2-(3-fluoro-4-nitrobenzamido)acetic acid with iron powder in the presence of acetic anhydride-acetic acid gave 2-(4-acetamido-3-fluorobenzamido)acetic acid (compound 7).

Provenance & Evidence