An efficient one-pot four-component synthesis of 5H-spiro[benzo[7, 8]chromeno[2, 3-c]pyrazole-7, 3′-indoline]-2′, 5, 6(9H)-trione derivatives catalyzed by MgCl2. Issue 9 (25th February 2015) - Shen, Tianhua
Graphical abstract: Abstract: An efficient one-pot synthesis of 5 H -spiro[benzo[7, 8]chromeno[2, 3- c ]pyrazole-7, 3′-indoline]-2′, 5, 6(9 H )-trione derivatives via a four-component reaction of hydrazine hydrate, β-keto esters, isatins, and 2-hydroxynaphthalene-1, 4-dione catalyzed by MgCl2 in ethanol is reported. This reaction provides the advantages of excellent yields, environmental friendliness solvent, simple workup procedure, and short reaction time.