Tetrabutylammonium benzoate

Tetrabutylammonium benzoate has been used as a catalyst for the polymerization of PO over the temperature range 40—108°C and the yield of polymer was typically low (2—78%) a large amount of unsaturation was present due to chain transfer (95). When synthetic hydrotalcite,... 

Figure 1. Conversion versus time for substitution by tetrabutylammonium benzoate on poly(epichlorohydrin) (A, A, separate runs) poly[(2-chloroethyl)-oxirane] (O) poly[(3-chloropropyl)oxirane] (V) and poly[(4-chlorobutyl)-oxirane] ( ). (Reproduced with permission from ref. 1. Copyright 1982 Wiley.)...

In this case the alcohol component is activated. By treating an imidazolesulfonate, prepared from an alcohol and sulfonyldiimidazole, with tetrabutylammonium benzoate, the corresponding benzoic ester is obtained 11331... 

Similarly to classical PTC reaction conditions, under solid-liquid PTC conditions with use of microwaves the role of catalyst is very important. On several occasions it has been found that in the absence of a catalyst the reaction proceeds very slowly or not at all. The need to use a phase-transfer catalyst implies also the application of at least one liquid component (i.e. the electrophilic reagent or solvent). It has been shown [9] that ion-pair exchange between the catalyst and nucleophilic anions proceeds efficiently only in the presence of a liquid phase. During investigation of the formation of tetrabutylammonium benzoate from potassium benzoate and tetrabu-tylammonium bromide, and the thermal effects related to it under the action of microwave irradiation, it was shown that potassium benzoate did not absorb micro-waves significantly (Fig. 5.1, curves a and b). Even in the presence of tetrabutylammonium bromide (TBAB) the temperature increase for solid potassium benzoate... 

General Procedure with Tetrabutylammonium Benzoate [68]. A solution of imidazylate (1 mmol) and tetrabutylammonium benzoate (1.1 g, 3 mmol, 3 eq.) in 10 mL of toluene was heated for a period. The reaction mixture was cooled, washed twice with water, dried (Na2SQ4), and evaporated to dryness. 

Ring Contraction Reactions Synthesis of a o-talitol Derivative. A mixture of disaccharide 47 (4.74 g, 6.4 mmol) and tetrabutylammonium benzoate (7 g, 19 mmol, 3 eq.) in 50 mL of toluene was heated 6 h at 80°C and then was evaporated to dryness. Flash... 

Depending on their location on a sugar, sulfonates have very different reactivities. This is apparent, for example, in the behaviour of tosylates. The tosylate of the primary alcohol function can be substituted without difficulty, even in solvents which are not polar or aprotic. Substitution at positions 3 and 4 are only possible in DMF solution. Substitution at position 2 is absolutely impossible. On the other hand, it is often observed without problems at position 2 starting from a triflate or an imidazylate. These reactivity differences clearly appear in the triple substitution reaction of the tris-triflate P-D-galacto 7 J by benzoate (Alais and David 1990). The latter is prepared from the triol in 5 h at 0 C. It reacts quantitatively with tetrabutylammonium benzoate in toluene in 45 min at room temperature to give the D-gluco substitution product at C-4 and C-6. Heating for 1 h at 100 C then leads to the D-manno tribenzoate 74. 

Benzoate participation by way of six-membered orthoester ions can be visualized, but it was not realized in work reported by Hughes and Speak-man. The D-ribose derivative (81), with tetrabutylammonium benzoate... 

Trimethylsilyloxy ethyltrimethylsilyl dimethyl ketene was the initiator used for the preparation of PMMA macromonomers. Tetrabutylammonium benzoate was the catalyst. Treatment with dilute HCl provided the -OH functional macromonomers, whereas the subsequent reaction with acryloylchloride formed the final structure of the macromonomer [219] (Scheme 68). 

During investigation of the formation of tetrabutylammonium benzoate from potassium benzoate and tetrabutylammonium bromide, and thermal effects related to this under the action of MW irradiation, it was shown that potassium benzoate did not absorb MW significantly (Fig. 6.1, curves a and b). Even in the pres-... 

Crystals of the tetrabutylammonium benzoate complex of receptor 42 were obtained by slow evaporation from a DMSO solution containing excess tetrabutylammonium benzoate. The structure shows that each receptor binds three... 

Crystals of 43, suitable for X-ray diffraction analysis, were grown by slow diffusion of pentane into a solution of 43 in THF. The structure was elucidated by single crystal X-ray diffraction, which reveals that compound 43 adopts a wing-like conformation (Figure 30). Crystals of the tetrabutylammonium benzoate complex of 43 were... 

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