Synthesis of bioactive heterocycles: tandem reaction of 4-N-(4′-aryloxybut-2′-ynyl),N-methylaminocoumarin with 3-chloroperoxybenzoic acid

A number of 4-N-(4′-aryloxybut-2′-ynyl),N-methylaminocoumarins (4a–e) on treatment with one equivalent of 3-chloroperoxybenzoic acid at 0–5°C for 10 min and then stirring at rt for 10 h afforded pyrrolo[3,2-c]coumarin derivatives in 70–75% yields. The 4-N-(4′-aryloxybut-2′-ynyl),N-methylaminocoumarins 4a–e were in turn prepared from 4-tosyloxycoumarin (2) and (4-aryloxybut-2-ynyl)-N-methylamine (3a–e).