Chemistry.

SYNTHESIS OF 4-AMINO DERIVATIVES OF 5,7-DICHLOROKINURENIC ACID THAT LED TO UNEXPECTED PRODUCTS VIA DETOSYLATION. Stephen Craig, Al Nichols, and Nagarajan Vasumathi, Dept. of Physical and Earth Sciences, Jacksonville State Univ., Jacksonville, AL 36265. Starting with ethyl 5,7-dichloro-4-{[(4-methylphenyl)sulfonyl]amino}quinoline-2-carboxylate prepared by a previously reported method (Nichols and Yielding, 1993), a reaction was conducted using triphosgene and glycine to produce the corresponding tosyl derivative of [({[5,7-dicholor-2-(ethoxycarbonyl)quinolin-4-yl]amino}carbonyl)amino]acetic acid. It was anticipated that the tosyl group would then be removed by acid hydrolysis. Elemental analysis of a product isolated from this reaction revealed that the tosyl group was no longer a part of the quinoline ring compound. This detosylation had not been observed in previous studies (Nichols and Yielding, 1998). When this product was reacted with anhydrous ethyl alcohol in the presence of thionyl chloride, a product was obtained that was identified by proton NMR and elemental analysis as ethyl 5,7-dichloro-4-[(ethoxycarbonyl)amino]quinoline-2-carboxylate. The formation of a 4-amino isocyanate intermediate could explain these results.