We report an optimized Fischer indole cyclization process using toluene as both the cosolvent and extraction solvent. The process produced zero wastewater, and a high-purity product was obtained without further purification. The optimized route was applied to synthesize key intermediates of two MmpL3 inhibitors, NITD-304 and NITD-349, on a multi-kilogram scale.

中文翻译：

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环保型工业费歇尔吲哚环化工艺

我们报告了使用甲苯作为助溶剂和萃取溶剂的优化的Fischer吲哚环化工艺。该工艺产生的废水为零，无需进一步纯化即可获得高纯度产品。将优化的路线应用于以千克为单位合成两种MmpL3抑制剂NITD-304和NITD-349的关键中间体。