Reactions of 3-(1-Hydroxyalkyl)phthalides with Acids: Synthesis of (<i>Z</i>)-3-Alkylidenephthalides and 3-Alkyl-8-hydroxyisocoumarins
作者:Raghao S. Mali、Kantipudi N. Babu
DOI:10.1021/jo971622e
日期:1998.4.1
acid-catalyzed method for the synthesis of (Z)-3-butylidenephthalides 5 and a novel and general route to 3-alkyl-8-hydroxy/methoxyisocoumarins 6-8 fromphthalides 9 is described. The hydroxyphthalides 4 and 10 were obtained by condensation of the phthalide anion with butyraldehyde and acetaldehyde. Reaction of hydroxyphthalides 4 with a mixture of orthophosphoric acid and formic acid gave the (Z)-3
A simple and efficient synthesis of isocoumarins and alkylidenephthalides from 3-(1-hydroxycarbethoxy/alkyl)phthalides with a DEAD/PPh<sub>3</sub>/TBHP system
作者:Sunita K. Gadakh、Arumugam Sudalai
DOI:10.1039/c4ra10372f
日期:——
to the synthesis of 3-carbethoxy-isocoumarins and 3-alkylidenephthalides is described. The methodology employs DEAD/PPh3/TBHP as the reagent system proceeding through unprecedented 1,2-shift intramolecular ring expansion or simple elimination depending upon substituents present on 3-substituted phthalides, with broader substrate scope. This strategy is amply demonstrated in the short synthesis of bioactive