An efficient three-step sequence has been developed for the synthesis of 2-aminoquinoline-6-carboxylic acid benzyl ester starting from commercially available 6-quinolinecarboxylic acid. The process features a novel and exceptionally mild conversion of a quinoline N-oxide to a 2-aminoquinoline using a triethylamine/ammonium chloride buffered system. The development of this procedure is especially important since gaseous ammonia, ammonium hydroxide, and solutions of ammonia in alcohols all failed to deliver a safe and reliable process.

中文翻译：

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安全实用的2-氨基喹啉-6-羧酸苄酯的大规模合成

已经开发了一种有效的三步序列，用于从商业上可获得的6-喹啉羧酸开始合成2-氨基喹啉-6-羧酸苄基酯。该方法的特征在于使用三乙胺/氯化铵缓冲系统将新型的喹啉N-氧化物异常温和地转化为2-氨基喹啉。由于气态氨，氢氧化铵和氨在醇中的溶液均不能提供安全可靠的工艺，因此开发此程序尤为重要。