e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Crown cation complex effects. 22. Enhancement of cation binding in lariat ethers bearing a methyl group at the quaternary, pivot carbon atom
Y Nakatsuji, T Nakamura, M Okahara…
Index: Nakatsuji, Yohji; Nakamura, Tetsuya; Okahara, Mitsuo; Dishong, Dennis M.; Gokel, George W. Journal of Organic Chemistry, 1983 , vol. 48, # 8 p. 1237 - 1242
A number of carbon-pivot lariat ethers have been prepared and compared, with their counterparts having a methyl group bonded to the side-arm-bearing or pivot carbon. All of the compounds examined are 15-crown-5 derivatives, and in this series, the methyl lariats invariably show a higher affinity for sodium than do the nonmethylated species. The results are less consistent in the case of potassium cation which is larger than the 15-crown-5 ...