Dialkylammonium

Self-assembly of secondary dialkylammonium ions with macrocyclic polyethers and formation of pseudorotaxanes 96CC1483. 

A new class of compounds able to form lamellar structures consisting of bilayers separated by water-layers are dialkylammonium-salts of 2-[((trifluormethyl)-phenyl)-amino]-benzoic acid (Flufenamic acid) as was found by Eckert and Fischer 80). 

A general preparation of 2-acetonyl-2,4,6-triaryl-2//-thiopyrans 58 was discovered in the reaction of corresponding 2,4,6-triarylthiopyrylium perchlorates with ethanolic acetone catalyzed with various dialkylammonium salts (86GEP235455, 86JPR573). This preparative procedure was successfully extended to cyclohexane- and cyclopentane- 1,2-diones as the carbonyl components (89JPR853 90GEP280324). The action of bases on thiopyrylium salts may caused their dimerization to thiopyranyl derivatives under suitable conditions (89KGS479). 

The macrocydic polyether dibenzo[24]crown-8 (DB24C8, Scheme 3) binds124,251 dialkylammonium-containing guests in solution, as well as in the solid state, to generate complexes with pseudorotaxane co-conformations that are stabilized primarily by [0—H-N+] and [O —H-C] hydrogen bonds. The com-plexation and decomplexation kinetics of these recognition events are influenced by the size of the... 

Figure 5. Initial co-conformation1201 and constraints used for simulating the passage of DB24C8 over the R groups of the dialkylammonium-containing cations 8+-11+.

M. C. T. Fyfe, J. F. Stoddart, (Supra)molecular Systems Based on Crown Ethers and Secondary Dialkylammonium Ions , Adv. Supramol Chem 1998, 5,1-53. 

Structural characterisation of 58 and 59 have demonstrated that the PF, anion is located in the cleft between the two dialkylammonium cations forming hydrogen-bonds with the benzylic hydrogen atoms of one of the cations and with one of the hydrogen atoms of a hydroquinone ring. In contrast, a polymeric as-... 

A crystalline sample of this supramolecular assembly was irradiated with UV light and the formation of the corresponding cyclobutane 91 with syn-anti-syn stereochemistry was observed. In contrast, the photodimerisation of trans-stilbenoid-bis(dialkylammonium) salts does not take place in the absence of the macro cycle, indicating the importance of pre-organizing the stilbenoid units (which requires the presence of the anion) for this solid-state reaction to occur. 

In the foregoing sections, the rate-enhancing effect of alkylammonium micelles has been extensively described. Similar effects can be expected for bilayer membranes of dialkylammonium salts. In addition, specific catalytic processes may be realized in this new system by taking advantage of the peculiar membrane structure. For example, catalyst molecules which are anisotropically bound to the membrane may act in very specific manners, and the liquid-crystalline nature of the bilayer membrane should provide unique microenvironments for catalysis. These are particularly interesting in relation to the mode of action of membrane-bound enzymes. 

The influence of the membrane fluidity was investigated for several types of reaction. Proton abstraction by a hydrophobic hydroxamate (23) is facilitated in the presence of cationic micelles (Okahata et al., 1980). Dialkylammonium... 

Kunitake et al. (1980) subsequently studied the decarboxylation of [52] in a series of dialkylammonium bilayers. The rate constant increased with... 

Publication of reports on the formation of well-characterized SUVs from long-chain dialkylammonium salts [300, 301] has prompted the syntheses of... 

Composite cast multibilayers provided a route to the formation of multilayer, two-dimensional polymer networks [443, 445]. This method utilized the following steps (i) ultrasonic dispersal of 15 mM of the dialkylammonium surfactant, 35, and 15 mM of the bisacrylate monomer. 36 (ii) addition of... 

Pseudorotaxanes and Rotaxanes Incorporating Macrocyclic Polyethers and Secondary Dialkylammonium Salts as their Components... 

K. Dorn 105 > polymerized dialkylammonium lipids with the polymerizable methacryloyl moiety either in the head group (29) or at the end of one of the hydrophobic chains (5). GPC revealed Mw 1.9 x 106, Mn 3.5 x 105, Mw/Mn 5.4 for (29) and Mw 1.9 xl06,Mn 3.9 x 105, Mw/Mn 2.4 for (5). It was also found that Mw varies inversely with the time of sonication, i.e. in smaller liposomes lower-molecular-weight polymers are formed. In a following paper, K. Dorn 108 present data for the permeability of monomeric and polymeric vesicles from (29). 

Extracted polymer material had an IR spectrum identical with an authentic sample of polyfmethacrylic acid). They also report data on Mw (85.000 in 0.002 M HC1) and tacticity of the polyfmethacrylic acid) obtained. On the basis of Kunitake s fundamental investigation of vesicle forming dialkylammonium salts 14) similar results were reported recently by J. E. Brady u2). 

Rotaxanes incorporating dialkylammonium recognition sites have been synthesized,[36] as illustrated in Figure 22. Treatment of the bis(hexafluorophosphate) salts [30-H]-2PF6 and [31-H]-2PF6 with the benzylic bromide 32 in the presence of... 

A reaction specific for mono- and dialkylammonium salts of N-unsubstituted tetrazoles 231 is interaction with formaldehyde under mild conditions and leading to iV-aminomethyltetrazoles 258 and 259 (Equation 41) <2000H(53)1421, 1997RJ0524>. 

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