We can induce or alter supramolecular expression of chirality in the aggregates of a series of chiral amide‐containing surfactants (1, R = C(O)C3H7, C6H5; R′ = C11H23, C17H35; X = phosphate, imidazole) by changing the pH or by addition of metal ions. Chirality at a higher level, such as in the formation of helical structures, is found to depend strongly on the head‐group organisation of the surfactant molecules.
Optically active aziridines can be used as precursors in the synthesis of several enantiopure amidecontaining surfactants. Acylation of the aziridines is a convenient method for both the activation of the aziridine ring and the introduction of the hydrocarbon chain. The regioselectivity of the ring-opening reactions using dibenzyl phosphate could be controlled by varying the reaction tem perature. In this way both regioisomers of the phospholipid analogues could be obtained. In the course of these experiments, an unprecedented rearrangem ent of a-acylamino phosphotriesters was observed. A mechanism for this group exchange reaction was proposed based on the compared reactivities of related compounds and FT-IR spectroscopic data. Application of high pressures (12 kBar) for the ring opening of the activated aziridines with imidazole led to the efficient formation of the desired surfactant with complete regioselectivity.
carboxylic amidescarboxylic amides (acyclic compounds) P 0320
-084Aziridines as Precursors for Chiral Amide-Containing Surfactants.-Optically active aziridines (I) are used as precursors for the title surfactants. The hydrocarbon chain is introduced by acylation, that also activates the aziridine ring for opening with either dibenzyl phosphate or imidazole. The reaction temperature controls the ratio of regioisomers (V) and (VI) from the cleavage with phosphate. At high pressure the ring opening with imidazole proceeds completely regioselective. -(SOMMERDIJK, N. A. J. M.; BUYNSTERS, P. J. J. A.; AKDEMIR, H.; GEURTS, D. G.; NOLTE, R. J. M.; ZWANENBURG, B.; J. Org. Chem. 62 (1997) 15, 4955-4960; Dep. Org. Chem., NSR Cent. Mol. Struct., Des. Synth., Univ. Nijmegen, NL-6525 ED Nijmegen, Neth.; EN)
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