Bianca H.M. Ruel

Syn-1,2-dialkylated calix[4]arenes: general intermediates in the NaH/DMF tetraalkylation of calix[4]arenes

In DMF or acetonitrile with NaH as a base at room temperature the tetraalkylation of calix[4]arenes 1a and 1b proceeds via the syn-1,2-disubstituted products to the tetraalkylated calix[4]arenes in the cone conformation. With KH as a base the tetraalkylated calix[4]arenes are predominantly formed in the partial cone conformation, and the reaction proceeds via both the syn-1,3-di and the syn-1,2-disubstituted products. Also the solvent influences the pathway via which tetraalkylation takes place. The syn-1,2-disubstituted calix[4]arenes 4-6 can be isolated in 15-55 % from the NaH/DMF or MeCN reactions when only 2.2 equiv of the electrophile are used.

Synthesis of Monoalkylated Calix(4)arenes via Direct Alkylation

A new one-step procedure for the synthesis of monoalkylated calix[4]arenes is presented. Reaction of calix[4]arene 1a or 1b with 1.2 equivalent of a weak base (K2CO3 in MeCN or CsF in DMF) and excess of alkylating agent affords the monoalkylated calix[4]arenes in moderate to good yields

Synthesis and binding properties of novel cyclodextrin dimers

The synthesis of three cyclodextrin dimers from the novel building block 3-amino-3-deoxy-heptakis(6-O-tert-butyldimethylsilyl)-s-cyclodextrin is reported. The cyclodextrins are linked with an amide bond on their secondary sides to an ethylene, octamethylene, or a metal binding bipyridyl group. Complexation studies with the substrate 6-(p-toluidino)-2-naphthalenesulfonic acid are presented and discussed.