4-Nitroanthranilic acid (I) is combined with terephthalic acid by reaction with the half ester chloride, followed by hydrolysis, to give the nitro diacid (II), which is catalytically hydrogenated to the amino diacid (III). Amidation and selective half-esterification of the amino diacid (III) is believed to occur through an oxazinone-type intermediate (IV), which is opened by alcoholysis under basic conditions to afford AM-682 free acid (V).