Selective dehydrogenation of 2-amino-3-cyano 4H-chromenes to the corresponding 2-iminochromenes mediated by diisopropyl azodicarboxylate under neutral conditions is reported. The dehydrogenation reaction is compatible with phenolic hydroxyl group and generates iminochromene in high yields. The methodology provides an easy access to coumarin and N-tosyl 2-amino-3-cyano-4-aryl 4H-chromenes.

中文翻译：

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偶氮二羧酸二异丙酯介导的2-氨基-3-氰基4H-色烯的选择性脱氢

据报道，在中性条件下，由偶氮二羧酸二异丙酯介导的2-氨基-3-氰基4H-色烯选择性脱氢为相应的2-亚氨基色酮。脱氢反应与酚羟基相容，并以高收率产生亚氨基色烯。该方法可轻松获得香豆素和N-甲苯磺酰基2-氨基-3-氰基-4-芳基4H-色烯。