Ammonium bis

Not long thereafter, Tarnowski and Cram reported the first example of a hinged bis-crown ether. The compound was prepared in the usual Williamson reaction by heating a mixture of 2,2, 3,3 -tetrahydroxy-l, r-binaphthyl with pentaethylene glycol ditosylate and KOH in aqueous THF solution. The product (mp 159.5—161°) shown in Eq. (3.30) was obtained in 30% yield. This compound was shown to complex bis-ammonium cations of several varieties . 

More recently, Johnson and Sutherland have used bridged monoazacrowns as host molecules for bis-ammonium salts. The intramolecular bis-crown diammonium complex formed when the size relationships are appropriate is shown below as structure 8. 

The nitrogen atom in quinolizidine derivatives behaves as a tertiary amine and hence it can undergo quaternization by reaction with alkyl halides. For instance, berberine derivative 101 was transformed into 102 by treatment with 3-iodopropanol followed by anion exchange. Compound 102 was then transformed into intermediate 103, which was employed as a precursor for the the preparation of bis-ammonium salt 104 (Scheme 10). This compound showed ultrashort curare-like activity in rhesus monkeys <2001JOC3495>. 

The high affinity of ammonium cations for tetra-bridged phosphorus(IV) P=0 cavitands was used to complex bis-ammonium guests. The highly insoluble NjAT-dimethyl-bipyridinium dication [paraquat " ] was readily dissolved in chloroform solution in presence of 12b in a 2 1 host-guest ratio. 

Particularly rapid are the quantitative salt formations of gaseous ammonia with 2-furancarboxylic (24), 2-furylacrylic (25), and 3,4-furandicarboxylic acid (26), and maleic (27) or fumaric acid (28) (bis-ammonium salts) (Scheme 3). Applications in removal of ammonia from atmospheric gases appear promising [22,28]. 

Moreover, one of the chiral bis-ammonium salts (i.e., 44b) was used to determine the enantiomeric excess of three mixtures of Mosher s acids by NMR spectroscopy. 

A related reaction results in the formation of the bis(ammonium chloride) inclusion species [2NH4, 2C1 ci V 4022(0H)4(H20)2(CgH5P03)g] in which a... 

Undecaprenyl monophosphate bis-ammonium salt may be purchased from Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106 Warszawa, Poland. 

Arai et al. also reported another BINOL-derived two-center phase-transfer catalyst 31 for an asymmetric Michael reaction (Scheme 6.11) [8b]. Based on the fact that BINOL and its derivatives are versatile chiral catalysts, and that bis-ammonium salts are expected to accelerate the reaction due to the two reaction sites - thus preventing an undesired reaction pathway - catalyst 31 was designed and synthesized from the di-MOM ether of (S)-BINOL in six steps. After optimization of the reaction conditions, the use of 1 mol% of catalyst 31a promoted the asymmetric Michael reaction of glycine Schiff base 8 to various Michael acceptors, with up to 75% ee. When catalyst 31b or 31c was used as a catalyst, a lower chemical yield and selectivity were obtained, indicating the importance of the interaction between tt-electrons of the aromatic rings in the catalyst and substrate. In addition, the amine moiety in catalyst 31 had an important role in enantioselectivity (34d and 34e lower yield and selectivity), while catalyst 31a gave the best results. 

In the same year, MacFarland reported another BINOL-derived two-center phase-transfer catalyst 33, in which bis-ammonium units were introduced at the 6,6 ... 

Gibson et al. recently demonstrated that a pseudorotaxane-like linear assembly can be synthesized from a bis crown ether moiety and a bis ammonium salt... 

Silicat Chlormethyl-pentafluor- (Bis-ammonium-Salz) XIII/5. 322... 

Molecular boxes , capable of binding a decanediyldiammonium or dodecanediyl-diammonium ion in their cavities, have been constructed from diazacrown ethers and pendant nucleotide bases. ° For example, structure 25 is based on hydrogen-bonded adenine-diazacrown-adenine and thymine-diazacrown-thiamine monomer units. The bis(ammonium) salt interacts with the oxygen atoms of two azacrown rings contained in each half of the cyclic 1 1 host-guest box . Characterisation of this product was largely performed using H-NMR spectroscopy and vapour... 

The simplest of the diazirines, diazirine itself, has now been obtained by a number of different routes. Perhaps the most convenient prepa ration is from a methylene-bis-ammonium salt by reaction with hypochlorite. Diazirine is a colorless gas, b.p. — 14°C. It is explosive and should always be handled with caution. Schmitz reported that it... 

Triple bonds have been prepared by pyrolysis of l,2-bis(ammonium) salts. ... 

Kostenis, E., Holzgrabe, U., Mohr, K., 1994. Allosteric effect on Mj-cholinoceptors of derivatives of the alkane-bis-ammonium compound W84 — comparison with bispyridinium-type allosteric modulators. Eur. J. Med. Chem. 29, 947-953. 

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