4-N-(Acylmethyl)aminocoumarins or their ketal derivatives were prepared  from 4-chlorocoumarin and α-amino ketones (chlorohydrates or ketal  derivatives) in ethanol/triethylamine media. Their subsequent treatment in  acidic or basic media readily led to [1] benzopyrano[4,3-b]  pyrrol-4(1H)-ones.
                                    4-N-(酰基甲基)
氨基
香豆素或其
缩醛衍
生物是通过在
乙醇/
三乙胺介质中将4-
氯香豆素与α-
氨基酮(
氯水合物或
缩醛衍
生物)反应制备的。随后在酸性或碱性介质中的处理,容易生成[1]苯并
吡喃[4,3-b]
吡咯-4(1H)-酮。