Malic Acid → 7-hydroxy-5-methylcoumarin

Participants

Reaction Steps

A mixture of 5-methylresorcin (25.0 g), malic acid (26.0 g) and conc.H2SO4 (55 ml) was gently heated with the gaseous development almost ceased. The reaction mixture was then poured with vigorous stirring into a mixture of water and ice (700 ml), and stirred until the gummy mass initially formed was completely dispersed. The precipitate was collected by filtration, washed with water and crystallized twice (Me2CO) producing 5-methyl-7-hydroxycoumarin (I; 15 g; m.p. 256° C.) ##STR4## free from the isomer 5-hydroxy-7-methylcoumarin (II). ##STR5##

Provenance & Evidence