Bicatenar Compounds

Based on lysine as before, single chain derivatives (18) and bicatenar compounds (19) have been prepared by a strategy the inverse of that described earlier [46]. The products (18 and 19) are obtained with higher overall yields than 17. As before, no protection or deprotection steps are needed in this case [46,47]. The synthesis consists of a reaction between two moduU prepared beforehand, one representing the polar head group in the final product and the other the junction modulus. The preparation of this intermediate starts from aldoses or acids derived Irom them that are coupled with lysine in its basic form (Scheme 15). The yields for this step are quantitative. A subsequent amidation reaction with a hydrogenated or perfluorinated fatty acid (Scheme 16) leads to the monosubstituted compounds (18). Esterification of the free acid function of lysine (Scheme 17) yields in a final step the bicatenar structures (19). 

The bicatenar compounds are, of course, in most cases classical rod-like molecules, which have been dealt with already. However, there are some examples in which the two substituents are not in the para position, and these deserve special attention. 

Compound 15 [207,208] compares a classical rod-like molecule with the analogous bicatenar compound, which has an addi-... 

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