Several ring-fused 4-diazomethylcoumarins 4a-f were prepared as stable diazoalkanes, and their usefulness for the fluorescent labeling of acidic substances was examined. The most easily accessible product, 4-diazomethyl-2H-naphtho[1, 2-b]pyran-2-one 4a, reacted readily with carboxylic acids in the presence of silica gel catalyst, and also with alcohols in the presence of fluoroboric acid catalyst, to produce fluorescent esters and ethers in good yields.
准备了几种环状融合的4-季
铵基甲基
香豆素4a-f,作为稳定的偶氮烃,并且探讨了它们在酸性物质荧光标记中的应用。最容易获得的产物4-季
铵甲基-2H-
萘[1,2-b]
吡喃-2-酮4a,在
硅胶催化剂的存在下能够与
羧酸反应,并且在
氟硼酸催化剂的存在下也能与醇反应,产生良产率的荧光酯和醚。