Imidazolinium, salts

Imidazolinium salts are not hydrolysed by acids under mild conditions. 

Alkali. Ring opening occurs, with formation of an ethylenediamine derivative. 

The product is a tertiary base, which is cationic in acid solution and can still be titrated with sodium dodecyl sulphate. 

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Imidazolinium perchlorate, 4-hydroxy-2,5,5-trimethyl-4-phenyl-synthesis, S, 487 Imidazolinium salts antistatic agents, 1, 409 Imidazolinium salts, 1-vinyl-polymerization, 1, 280 Imidazolin-2-one, 1-cyano-synthesis, S, 482 Imidazolin-2-one, 4,5-dialkyl-synthesis, S, 491 Imidazolin-2-one, 4,5-diaryl-bromination, S, 399-400 lmidazolin-2-one, 4,5-di( p-bromophenyl)-reactions... 

Figure 5.25 Cyclization of maleamic acid with imidazolinium salt.

These salts are obtained from 1,2 (or l,3)-diamines. The cyclization step is generally the condensation of the diamines on ethyl orthoformate in the presence of ammonium tetrafluoroborate (Scheme 19). By using enantiop-ure diamines, chiral salts 34 bearing stereogenic centers on the backbone, on the nitrogen substituents, or on both were prepared [1,2,4,5,26]. Several dicyclophane imidazolinium salts have been prepared by one-pot three-step procedure [27]. 

Grubbs reported the synthesis of several N, N -aryl substituted imidazolinium salts 35 from chiral Ar,AT -aryl diamines obtained by palladium-catalyzed amination of the appropriate aryl bromide with (li, 2i )-diaminocyclohexane... 

In 2003, Sigman et al. reported the use of a chiral carbene ligand in conjunction with the chiral base (-)-sparteine in the palladium(II) catalyzed oxidative kinetic resolution of secondary alcohols [26]. The dimeric palladium complexes 51a-b used in this reaction were obtained in two steps from N,N -diaryl chiral imidazolinium salts derived from (S, S) or (R,R) diphenylethane diamine (Scheme 28). The carbenes were generated by deprotonation of the salts with t-BuOK in THF and reacted in situ with dimeric palladium al-lyl chloride. The intermediate NHC - Pd(allyl)Cl complexes 52 are air-stable and were isolated in 92-95% yield after silica gel chromatography. Two diaster corners in a ratio of approximately 2 1 are present in solution (CDCI3). 

The complex 65 was synthesized by reaction of the imidazolinium salt with the precursor ruthenium complex 67 (catalytically inactive) in the presence of silver carbonate (Scheme 42). The complex being air-stable and stable on silicagel was isolated in 52% yield after chromatography. The diastereomeric and enantiomeric purity of 65 was determined by HPLC analysis and found to be above 98% (de and ee). The molecular structure was determined by X-ray analysis and showed the unusual twist geometry of this complex. 

The carbene-copper complex was not isolated but generated in situ by deprotonation of the imidazolinium salt 77 by n-BuLi in ether, in the presence of copper(II) triflate (Scheme 51). The use of two equivalents of ligand caused a dramatic decrease in reactivity. 

On 100% acrylic materials the quaternary ammonium retarders are used almost exclusively. Other types have been evaluated, however. For example, saturated alkylamines (RNH2 R = C10, C12, C14 and C16 hydrophobes) were found to be just as effective as the quaternary types although other factors, such as aqueous solubility at the optimal dyebath pH and resistance to subsequent discoloration, favour the quaternary compounds [34]- On the other hand, bis (hydroxyethyl) coco amine (12.10) had relatively little effect and the amphoteric carboxymethyldimethylcocoamine (12.11) none at all, although dimethyl-cocoamine oxide (12.12) was quite an effective retarder [34]- Other cationic compounds used [43,44] have included alkylpyridinium salts, imidazoles and imidazolinium salts, alkyldiamines, alkylpolyamines, as well as sulphonium and phosphonium derivatives. 

Secondary alkane-sulfonates (SAS) Alkylphenol polyglycol ethers, Imidazolinium Salts ... 

The first Ru(III) antimetastic complex to be introduced into clinical trials is the imidazolinium salt of rafts-[Ru(III)Cl4(DMSO)Im] (30) (NAMI-A) (166), which contains both DMSO and a heterocyclic ligand. 

The reaction of an imidazolinium salt (413) and diethyl malonate in THF in the presence of sodium hydride at room temperature gave the aminomethylenemalonate derivative (414) in 65% and 82% yields... 

The ionic liquid [bmim][BF ] is known to catalyze the aza-Diels-Alder reaction in the synthesis of pyrano- and furanoquinolines [190]. This reaction was also catalyzed by the enantiopure bis-imidazolinium salt 67 in 67% yield with an endo. exo ratio of 60 40 (Scheme 69) [191]. The product was obtained as a race-mate. In addition the aza-Diels-Alder reaction with imines and Danishefsky s diene was catalyzed by the salt 67 giving racemic product. The salt and its analogues could be easily prepared via the oxidation of the corresponding aminals [192]. Investigation of the influence of the counter anion in achiral C2-substituted imidazolinium salts, which can be also described as 4,5-dihydroimidazolium or saturated imidazolium salts, in the aza-Diels-Alder reaction showed, that the catalytic activity increased, the more lipophilic the counter anion and therefore the more hydrophobic the salt was [193]. 

R.R.Bums,USP 2920937(1960) CA 54,7958 (1960)(Caking of inorg salts such as AN, Amm sulfate or borax is prevented by the addn of a small quantity of 1,2- subsituted imidazolinium salts)... 

A single example of a coupling reaction of a primary alkyl iodide with (allyldimethylsilylmethyl)magnesium chloride was reported by Oshima in the presence of a Co(NHC) catalyst generated in situ from imidazolinium salt 210 and CoCl2 (entry 6) [283]. The reaction is, however, not useful for secondary iodides, since (3-hydride elimination prevailed. 

Mauduit et al. reported the synthesis of the related, potentially biden-tate carbene precursor 13 [32,33]. The synthesis of the imidazolinium salt is straightforward and achieved by reaction of /3-aminoalcohols and ethyl-... 

The imidazolinium salts, which are being used as ligand precursors, are generally prepared from C2-symmetric chiral vicinal diamines [43,44]. 

Scheme 16 Synthesis of N-arylated chiral imidazolinium salts...

Scheme 37 Synthesis of the chiral paracyclophane imidazolinium salts 54a-54d...

Unexpectedly, Tilset observed that coordinated Cp ligands deprotonated imidazolium and imidazolinium salt. [(Cp)2Cr] (135) reacts with IMes-HCl to give [(IMes)CrCl(Cp)] (136) and cyclopentadiene (equation 18). 

Imidazolinium salts, such as l-alkylamidoethyl-2-alkyl-3-methylim-idazolinium methylsulfate have been used as rinse-cycle softening agents, but in less significance compared to DSDMAC [4]. 

When imidazolinium salts lacking a 2-substituent such as l-(3-nitrobenzenesulfonyl)-3,4-dimethylimidazolinium iodide 582 reacted with the sodium salt of indole, 583 was formed <2005H(65)2893>. In contrast, 1,3-diacetylimi-dazolium acetate, which is derived from compound 584, reacts at the indole 3-position to give 585 (Scheme 138) <1996HCO305>. 

Difenchyl imidazolinium salt 587 when treated with a strong base (to form the putative carbene) followed by the addition of copper(II) triflate, gave the unexpected piperazin-2-one 589 and urea 588 (Scheme 140) <20060L3049>. The formation of 589 was confirmed by X-ray structural analyses and probably results via dimerization following deprotonation of 587. The putative carbene intermediate has not been isolated. 

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