Amino-azidobenzoic acid derivatives

TSUNODA YAMAOKA Amino-azidobenzoic Acid Derivatives... 

Photochemical Reaction of Monosubstituted Amino-azidobenzoic Acid Derivatives in Novolak... 

Reduction of 9-azido-NeuAc (3) with H2/PdO in acidic aqueous methanol affords 9-amino-NeuAc quantitatively. Acylation of 9-amino-NeuAc with NHS esters of various carboxylic acids at basic conditions (pH 8-9) readily affords various 9-substituted NeuAc derivatives in the yields ranging from 45% to 25%. To the solution of 3 in aqueous methanol, PdO was added and stirred under Ha atmosphere with pH maintained at 1-2 by addition of acetic acid. The reaction mixture was filtered to remove the catalyst when it was complete as determined by TLC. To the titrate was added dioxane, and 4-azidobenzoic acid NHS ester with pH maintained between 8.0-9.0 with saturated sodium bicarbonate solution. The mixture was stirred in the dark for 48 hr. The solvent was evaporated and the residue was purified by flash chromatography to give 4 in 45% yield. Rf ... 

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