Benzyl alcohol advantage

Other cases of O-to-C migration have been observed.This type of migration has been used to advantage in the preparation of 2-silylated benzyl alcohols. 

Especially the favorable mass transfer of micro reactors is seen to be advantageous for the oxidation of benzyl alcohol [58]. As one key to this property, the setting and knowledge on flow patterns are mentioned. Owing to the special type of microreactor used, mixing in a mini trickle bed (gas/liquid flows over a packed particle bed) and creation of large specific interfaces are special aspects of the reactor concept. In addition, temperature can be controlled easily and heat transfer is large, as the whole micro-reactor construction acts as a heat sink. 

Miniaturized columns have provided a decisive advantage in speed. Uracil, phenol, and benzyl alcohol were separated in 20 seconds by CEC in an 18 mm column with a propyl reversed phase.29 A19 cm electrophoretic channel was etched into a glass wafer, filled with a y-cyclodextrin buffer, and used to resolve chiral amino acids from a meteorite in 4 minutes.30 A 6 cm channel equipped with a syringe pump to automate sample derivatization was used to separate amino acids modified with fluorescein isothiocyanate.31 Nanovials have been used to perform tryptic digests on the 15 nL scale for subsequent separation on capillary Electrophoresis.32 A microcolumn has also been used to generate fractions representing time-points of digestion from a 40 pL sample.33 A disposable nanoelectrospray emitter has been... 

Taking advantage of this feature, Gitsov et al. used the benzylic alcohol focal... 

Much emphasis has been placed on the selectivity of quaternary ammonium borohydrides in their reduction of aldehydes and ketones [18-20]. Predictably, steric factors are important, as are mesomeric electronic effects in the case of 4-substituted benzaldehydes. However, comparison of the relative merits of the use of tetraethyl-ammonium, or tetra-n-butylammonium borohydride in dichloromethane, and of sodium borohydride in isopropanol, has shown that, in the competitive reduction of benzaldehyde and acetophenone, each system preferentially reduces the aldehyde and that the ratio of benzyl alcohol to 1-phenylethanol is invariably ca. 4 1 [18-20], Thus, the only advantage in the use of the ammonium salts would appear to facilitate the use of non-hydroxylic solvents. In all reductions, the use of the more lipophilic tetra-n-butylammonium salt is to be preferred and the only advantage in using the tetraethylammonium salt is its ready removal from the reaction mixture by dissolution in water. 

Antimony(III) trichloride can be used as a catalytic mediator in the electroreduction of carbonyl compounds. The advantage of the procedure is illustrated by the selective reduction of acetophenones (497), leading to the corresponding benzylic alcohols (498) (Scheme 173) [575]. The electroreduction is performed in an EtOH/BuOH(l/1.5)-aq.HCl-(Pt/Pb) system in the presence... 

The Boots Hoechst Celanese (BHC) ibuprofen process involves palladium-catalyzed carbonylation of a benzylic alcohol (IBPE). More recently, we performed this reaction in an aqueous biphasic system using Pd/tppts as the catalyst (Figure 9.6 tppts = triphenylphosphinetrisulfonate). This process has the advantage of easy removal of the catalyst, resulting in less contamination of the product. 

In Figure 3, the active steroid (triamcinolone acetonide) and preservative (benzyl alcohol) are determined from a steroid cream. The higher molecular weight components of the cream base are well separated from the analytes. The ability to elute all the components of a cream or ointment in a SMGPC analysis gives an important sample preparation advantage over competing separation techniques. 

Other hydrides used for the conversion of esters to alcohols are magnesium aluminum hydride in tetrahydrofuran [89, 577] and magnesium bromohydride prepared by decomposition of ethylmagnesium bromide at 235° for 2.5 hours at 0.5mm [7055]. They do not offer special advantages (the latter giving only 35% yield of benzyl alcohols from ethyl benzoate). 

The benzylic alcohols (48) arc probable intermediates in another very good synthesis, the condensation of oe,/3-unsaturated aldehydes with resorcinols in the presence of pyridine (Scheme 8).210-213 Advantages of this procedure are the high yields and the use of the easily accessible 3-methyl-3-hydroxybutyraldehyde dimethylacetal214 instead of the unstable 3,3-dimethylaerolein. The method has been particularly useful... 

Neither the trialkoxybenzhydryl alcohol linker nor other types of benzhydryl alcohols [44,45,48] have found widespread use as linkers for carboxylic acids. These linkers do not seem to offer special advantages compared with benzyl alcohol or trityl linkers. 

The main advantage of ferr-alkyl esters as linkers is their stability towards nucleophiles. For instance, no diketopiperazine formation is observed during the preparation of peptides containing carboxy-terminal proline, an otherwise common side reaction when using benzyl alcohol linkers (Section 15.22.1). 

Support-bound non-benzylic alcohols can also be used to immobilize carboxylic acids as esters (Table 3.3). The advantage of this type of linker is its stability towards electrophiles. Attachment of carboxylic acids is usually realized by acylation of the resin-bound alcohol with a reactive acid derivative. 

The photoionization of benzylic alcohols leading to carbocations has recently been reported197. Taking advantage of the stabilization provided by the /J-silicon effect, flash photolysis of 380 in trifluoroethanol gave rise to the fluorenyl cation 381 which was characterized spectroscopically (equation 46). 

On the other hand, 2-phenylethanol has a similar chemical structure to benzyl alcohol and hence a similar solubilizing capacity after incorporation in MM. The saturation solubility of 2-phenylethanol in the aqueous 5% MM phase is about 4%, while this is about 5% for benzyl alcohol. From the pharmaceutical point of view, the increase in clonazepam solubility in MM by addition of either benzyl alcohol or 2-phenylethanol makes their usual use as preservatives more advantageous owin< to the possibility of decreasing the concentration of MM. 

Another advantage of this approach is that we can now use electrophilic substitution on the pyrrole to add the rest of the molecule. So the secondary benzylic alcohol 106 might well cyclise to 105 with Lewis acid catalysis as the cation will be reasonably stable and the reaction is intramolecular. But the Friedel-Crafts alkylation to give 107 will not succeed as the cation would be primary. 

Catalysis by TEMPO has the advantage of being general for oxidation of both benzylic or non benzylic alcohols to aldehydes, whereas catalysis by PINO, although limited to the synthesis of aromatic aldehydes, has the advantage that the radical is generated in situ from the less expensive N-hydroxyphthalimide, which can be more easily recovered and recycled. 

The acylation of alcohol-containing monomers, e.g. hydroxyethyl acrylates or vinyl benzyl alcohol with maleic, succinic or sulfosuccinic anhydride leads to bifunctional polymerizable surfactants. A range of such products has been synthesized and tested in batch polymerization and core-shell polymerization of styrene and butyl acrylate [26]. In both cases good stability, high conversion and little burying of the Surfmers were observed. Water rebound was also limited. These advantageous features were however offset by an unacceptable resistance to electrolytes and to freeze-thaw. 

However, it is best to produce the compound in the absence of iron since this obviates the problem of subsequent removal of the metal. In the zwitterion form pyrimine may be extracted into benzyl alcohol and eventually crystallized (119). Alternatively, pyrimine may be isolated directly from the medium in crude form by taking advantage of the extreme attraction of substances of this type for Dowex 50H resin. 

Immobilization of 133 on a polymeric resin shows several advantages over the corresponding monomeric species.199 Oxidation of 133 with sodium periodate affords the corresponding bis-(p ra-methoxyphenyl) tellurone (An2Te02) 134, which presents a peculiar reactivity.198 For example, the tellurone 134 oxidizes benzyl alcohols to benzaldehydes in good yields (Scheme 72), and also converts hydrobenzoin in benzaldehyde in good yield. 

In summary, we have developed a recyclable heterogeneous catalyst for the bleach oxidation of alcohols and polyols. In contrast to previously reported systems, neither a chlorinated hydrocarbon solvent nor a bromide cocatalyst is necessary to achieve good activity. Besides bleach-oxidation, PIPO is also effective in the CuCl/nitroxyl catalysed aerobic oxidation of benzyl alcohol. A further advantage of our system is that PIPO is readily prepared from inexpensive and commercially available raw materials. We believe that it will find wide application in organic synthesis. 

The gold-catalyzed oxidation of alcohols is a less-explored field. In one example, oxygen was used as the oxidant and the authors take advantage of the coordination of benzylic alcohols to an Au(l)-complex generated in situ from AuCl and a diamine anionic ligand. ... 

The benzylic alcohols (48) are probable intermediates in another very good synthesis, the condensation of a, 3-unsaturated aldehydes with resorcinols in the ]iresence of pyridine (Scheme Advantages of... 

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