P L Sawhney
Articles written in Proceedings – Section A
Volume 33 Issue 1 January 1951 pp 11-21
It is suggested that umbelliferone is a fundamental compound in the biogenesis of coumarins and that other important hydroxycoumarins involve further stages of oxidation. In support of this idea experiments are described for the preparation from umbelliferone of æsculetin by
Volume 37 Issue 5 May 1953 pp 592-598
Earlier investigations have shown that partial methylation of the 7-position of 6∶7-dihydroxy coumarin is definitely possible. Claims were made by Schmid that in 5∶7-dihydroxy-4-methyl coumarin also partial methylation takes place in the 7-position. But no proof was provided. This has now been given by the ethylation of the partial methyl ether and subjecting it to nuclear oxidation and final ethylation. The product is found to be 7-methoxy-5∶6-diethoxy-4-methyl coumarin which has also been made by an independent and unambiguous method for purposes of comparison. The constitution of the partial methyl ether is thus established as 7-methoxy-5-hydroxy-4-methyl coumarin.