Methylbenzo-12-crown

In the synthesis of the twelve-membered ring, LiC104 was used as a templating ion and the methylbenzo-12-crown-4 (mp 46—48°) was obtained in 15% yield. Alpha-bro-mination was effected in 70% yield and conversion to the bridged species occurred in 20% and 25% yield when n = lor n = 2 respectively. 

The log K value for the formation of the Na+-fluorenyl complex with tetraglyme, CHs(OCH2CH2)40CH3, is reported to be over 3 log units lower than that of the corresponding complex with 4 -methylbenzo-15-crown-5 in tetrahydrofuran (18, 36). 

In systems where the soluble ligand can form both 1 1 and 2 1 ligand-cation complexes,plots of equation (6) tend to curve upward at high ligand concentration, that is, at increased l/f values. This was observed when 4 -methylbenzo-15-crown-5 was added to Pi K "/R18C6 in dioxane or 4 -methylbenzo-18-crown-6 to Pi ... 

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