In 1883 and 1884 von Pechmannl and others found that phenols condense with ethyl aceto- acetate and malic acid in the presence of concd. sulfuric acid to form members of the coumarin series. Different phenols were found to condense with various degrees of readiness. Thus, phenol, a-and@-cresols, quinol and thymol gave extremely poor yields, but resorcinol, orcinol and pyrogallol condensed readily. Later, Fries and Klostermann2 ...
