K Ranganadha Rao
Articles written in Proceedings – Section A
Volume 19 Issue 1 January 1944 pp 5-13
Claisen migrations of the allyl ether of 4∶7-dimethyl-5-hydroxy-coumarin gives rise to three isomeric compounds depending upon the conditions, (I) 6-allyl-5-hydroxy-4∶7-dimethyl coumarin (high yield), (II) the corresponding chroman (high yield), and (III) 8-allyl-5-hydroxy-4∶7-dimethyl coumarin (low yield). (II) has been shown to be a chroman by comparison with the corresponding methyl coumaran obtained by authentic methods from (I). The acetate of the above coumarin undergoes Fries reaction to give the 6-acetyl compound. Claisen migrations of the allyl ether of 7-hydroxy-5-methyl-coumarin yields only the 8-allyl-derivative. The difference in the behaviour of the derivatives of 5- and 7-hydroxy coumarins and the special conditions of the chroman and coumaran ring closure of
Volume 19 Issue 1 January 1944 pp 14-16
The 5-hydroxycoumarins behave very similar to 7-hydroxycoumarins in regard to azo-dye formation with one and more than two molecular proportions of diazotised
The authors desire to express their grateful thanks to Prof. T. R. Seshadri for his kind interest in this work.