Tetrahedron

Orientation effects in the pechmann reaction: Synthesis of 5, 6-dimethylcoumarin and an examination of ortho-proximity effects in 13C NMR spectroscopy

AG Osborne

文献索引：Osborne, A. G. Tetrahedron, 1981 , vol. 37, p. 2021 - 2025

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被引用次数: 25

摘要

In the Pechmann reaction with malic acid, m-cresol and 3, 4-xylenol give mixtures of alkylcoumarins containing about 10% of the 5-and 5, 6-isomers respectively. 7- Alkylcoumarins only are obtained from the reaction with ethylacetoacetate. A study of ortho- proximity effects on the 13C NMR of dimethylcoumarins is reported, and the results have been correlated with similar effects in other aromatic and heteroaromatic systems.