Scope and Limitations of Lithium-Ethylenediamine-THF-Mediated Cleavage at the α-Position of Aromatics: Deprotection of Aryl Methyl Ethers and Benzyl Ethers under Mild Conditions
作者:Takeshi Sugai、Takeyuki Shindo、Yasuaki Fukuyama
DOI:10.1055/s-2004-815977
日期:——
and limitation of lithium-ethylenediamine-THF-mediated reductive bond cleavage at the α-position of aromatics were examined. Very mild conditions such as lithium metal (5 equiv) and ethylenediamine (7 equiv) in oxygen-free THF were quite effective for the demethylation of aromaticethers even at as low as -10 °C. Allyl benzyl ethers were also deprotected under these conditions with very little change
With the aim of obtaining compounds with strong antitumor activity, a quantitative structure-activity relationship (QSAR) of antitumor phenolic compounds (long-chain phenols) was derived using the Hansch-Fujita equation. The ED50 values against Chinese hamster V-79 cells were analyzed in terms of log P as the hydrophobic parameter and the energy of the lowest unoccupied molecular orbital (ELUMO) calculated by using the modified neglect of differential overlap (MNDO) method as the electronic parameter, by means of multiple regression analysis. It was found that the activities mainly depended on log P (an optimum log P of 8.3) and a low-lying ELUMO value. 4-Undecylcatechol, selected on the basis of the above results, exhibited strong antitumor activity against Sarcoma 180 ascites and P-388 lymphocytic leukemia.
215. Some derivatives of catechol and pyrogallol. Part I
作者:Robert D. Haworth、David Woodcock
DOI:10.1039/jr9460000999
日期:——
US4011181A
申请人:——
公开号:US4011181A
公开(公告)日:1977-03-08
Synthesis of 3-Alkylcatechols via Intramolecular Cyclization
作者:Tetsuo Miyakoshi、Hiroyasu Togashi
DOI:10.1055/s-1990-26889
日期:——
The intramolecular cyclization of 2-alkanoyl-2,5-dimethoxytetrahydrofurans 4 with aqueous acid is described. 3-Alkylcatechols 7 were prepared in generally good yields by boiling the dioxane solution of compounds 4 in the presence of 1M hydrochloric acid. In addition, 4,5-dioxoalkanals 6 were obtained in good to high yields when the dioxane solution of compounds 4 was treated with 0.1 M hydrochloric acid.