Bis salts

Triple bonds have been prepared by pyrolysis of 1,2-bis salts. 

Bi promoted Pt catalysts were prepared using JM proprietary methods. Aqueous solutions of Pt and Bi salts were co-precipitated onto the catalyst support and reduced using chemical reducing agents. Thereafter the materials were washed, filtered and retained as pastes. Graphite supported materials were dried prior to use. Similar preparation methods were used for all Pt and Pt-Bi catalysts. 

The data plotted in Figure 4 dramatically exemplifies the effect of reducing catalyst levels for a pyridinium salt vs a bispy ridini urn salt. It is clearly apparent that the rate of reaction does not drop nearly as rapidly for the bis-salt when the catalyst level is decreased. Although exact first order kinetics are not observed, the reaction rate appears to be nearer first than second order in catalyst. It is also apparent that the bis-salts are more than twice as effective as the mono-salts on a molar basis. Results with displacements of other dianions or substrates are summarized in Table V. 

Figure 4. Preparation of the bis-(4-nitrophenyl) ether of bisphenol A via reaction of bisphenol A disodium salt with 4-chloronitrobenzene. Bis salt = biS (4 dihexylaminopyridinium) decane dibromide. Mono salt = N-(2-ethylhexyl) 4-dihexylaminopyridinium mesylate.

Bi salts proved to be as active as RET or other metallic triflates in the FC acylation of aromatic compounds using acyl chlorides or anhydrides [13, 66]. While... 

In the case of sulfonylation (Scheme 10) [56] and sulfinylation reactions [34], Bi salts proved again to be efficient catalysts. In contrast to the arylsulfonylation, which is under partial control of triflic acid, depending on the substrates, a complete synergistic effect between triflic acid and Bi chloride has been found in the alkanesulfonylation of arenes. In this case, the formation of mixed triflic/alkane-sulfonic anhydrides leads to the active electrophilic species. The formation of the latter exclusively requires the transient formation of a Bi chlorobistriflate species that acts as an intermediate shuttle for triflic acid, leading to the formation of the mixed anhydride precited (Scheme 11). Our experiments have shown that triflic... 

Since our group has discovered that BiCl3 and Bi(0Tf)3-xH20 are mild and efficient catalysts for Diels-Alder and related reactions [72-74], Bi salts have been largely used in different synthesis involving Diels-Alder reactions. 

J. F. Liebman, M. Ponikvar, Ion selective electrode determination of free versus total fluoride ion in simple and fluoroligand coordinated hexafluoropnictate (PnF6-, Pn = P, As, Sb, Bi) salts. Struct. Chem. 16 (2005) 521-528. 

A range of condensed 1,3,2-dithiazolium mono- and bis-salts 43-45, 70, and 71 are formed in the ring-closure reaction of o-bis(sulfenylchloride)heteroarenes with trimethylsilyl azide (Equation 18) <1997JA2633, 2001JMC1992, 2004JA8256, 1998JA352>. 

Dihydrooxazoles 275 can be made by the condensation of aryl nitriles with amino alcohols catalyzed by Bi(iii) salts <2005SL2747> or acidic clay <1998TL459> in good yields (Bi salts - 70-92% kaolinitic clay -56-96%) (Equation 16). The use of Bi salts is only applicable to the formation of 2-aryloxazolines while the latter method works well for both aromatic as well as aliphatic substrates. The conversion of carboxylic esters to 2-oxazolines 276 in good (44-82%) yields with lanthanide chloride as catalyst <1997TL7019> has also been described (Equation 17). 

Direct irradiation through quartz of the dibenzobarrelene (151) in pentane or benzene results in the formation of the cyclooctatetraene (152) and this process is not affected even when the amino functions are converted into the HCl or HBr salts.In the solid state, however, irradiation of the bis salt yields a semibullvalene (153), as the main product and the authors suggest that this change in reactivity is due to a change in the excited state that is operative. Thus in the solid the chloride or bromide ions act as heavy atoms that enhance the intersystem crossing within the excited state of (151) but apparently this does not occur in solution. 

Bi(III) is an efficient catalyst for the formation of tetrahydropyran-4-ols from homoallylic alcohols by the Prins reaction application to styrenes leads to 1,3-dioxanes <05SC1177> cr i-2,6-Disubstituted tetrahydropyrans are selectively formed in a Bi-mediated intramolecular oxa-conjugate addition of a,P-unsaturated ketones 10 the actual catalyst is considered to be the Bronsted acid derived from the Bi salt <05TL5625>. cat. BiXa... 

Whilst bismuth (III) chloride is an efficient catalyst for the aromatic ether acylation by acid chlorides or anhydrides, it is not strong enough to carry out the acylation of non activated aromatics. However, the potential of using a wide range of Bi (III) salts as catalysts (ref. 41), in particular the oxide, the oxychloride and the carboxylates, all non hygroscopic compounds, offers advantages, and is indicative of the great versatility of Bi (III) derivatives. Moreover, the Bi salts obtained after hydrolytic workup are directly reusable. 

Dihydroxyacetone (DHA), the oxidation product of the secondary hydroxy group of glycerol, is an artificial tanning agent in cosmetics and a pharmaceutical intermediate. Glycerol oxidation in acidic medium on a platinum-bismuth catalyst (Bi/ Pt atomic ratio = 3) prepared by coprecipitation of Pt and Bi salts, yielded 20 % DHA at 30 % conversion [70]. The deposition of bismuth on platinum particles by oxido-reduction (Bi/Pt = 0.13) yielded 37 % DHA at 70% conversion... 

Bismiithous Hvdrate—BiH,0,—261—is formed os a white precipitate when potash or ammonium hydrate is added to a cold solution of a Bi salt When dried, it loses H,0 and is converted into bi muihyl hydrate... 

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