Ethers, alkylation with basic behavior

The base-catalyzed conversion of 5-alkyl-substituted isothiazolium salts 88 (R = Me, R = Et) to 2,3-dihydrothio-phene derivatives 329 occurs in basic conditions via intermediates 328. The distribution of diastereomers 329 is dependent on the base and aryl substituent <1997SUL35>. Similar behavior was observed in the case of 88 (R = R =-(0112)4-) <1996JPG424>. The condensation of 5-Me-substituted isothiazolium salts 88 with a second molecule of a different isothiazolium salts affords haA -thia-Eh-diazapentalenes 330. In this way, macrocyclic ethers 332 were prepared from 331 and their complexation behavior toward sodium(l), silver(l), and mercury(n) studied <2001PS(170)29>. 

For the jair of ionizable crown ethers Z and 6, the structural modification is to replace four alkyl aryl Fther oxygens with more el ctr n-rjch ialjcyl ether oxygens. The transport selectivity of Na K >L1, Rb, Cs was the same for both carriers which indicates that the variation of oxygen basicity has little Influence upon bulk liquid membrane transport behavior for this compound series. 

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