Benzyl alcohol a-methyl-4-

Table 4 The effects of a-carbonyl and a-thiocarbonyl substituents on the relative stabilities of a-methyl benzyl alcohols R-[16]-OH and the corresponding styrenes R-[17] (Scheme 13)"...

A fruitful approach to obtain asymmetric polymer synthesis was proposed by Overberger (126) who suggested that propagation could be influenced and optically active polymers could be synthesized by using optically active gegen-ions. Schmidt and Schuerch (127) followed up this suggestion and used boron trifluoride in conjunction with asymmetric Lewis bases (1-a-methyl benzyl alcohol, tosyl L-valine, camphor) to polymerize certain cyclic olefins. However, in spite of careful work and various modifications in reaction conditions, no optical activity was obtained in the polymers in this first attempt to test this ingenious hypothesis. 

C8H9BrO (2-bromoethoxy)benzene 589-10-6 513.15 45.149 2 13640 C8H9FO 4-ftuoro a-methyl benzyl alcohol 403-41-8 445.88 38.709 2... 

An integrated process has also been reported, but not implemented at a commercial level, by ARCO (now Lyondell) [21]. In this case, the O-donor species is produced by the autoxidation of aryl-substituted secondary alcohols (a-methyl benzyl alcohol) to ketones, and the resulting solution is used to feed the epoxidation reactor. The alcohol is then recovered by hydrogenating the ketone. The main difference with respect to the EniChem process is the higher temperature of the autoxidation process (90-140 instead of 40 °C). 

Lipase (PsL)-mediated acylation reaction of a-methyl benzyl alcohol by vinyl acetate (Scheme 10.5) gives high enantioselectivity (E value 200) in [BMIM][Tf2N] than in methyl t r-butyl ether (MTBE) (E=4) at 55°C. At the boiling point of vinyl acetate, the E value was reduced to 150 from 200 [86, 87]. Similarly, lipase from Pseudomonas fluorescens (Lipase AK)-catalyzed enantioselective acylation of phosphate substituted primary alcohols in [BMIM][PF ] with enantioselectivity comparable to DIPE, though no selectivity was obtained in [BMIM][BF ] [87]. 

Styrene is obtained almost exclusively by dehydrogenation of ethyl benzene, and in small quantities by the dehydration of a-methyl benzyl alcohol, the by-product of the propylene oxide synthesis from propylene and a-methyl benzyl hydroperoxide. Styrene can be polymerized free radically, cationically, anionically, and with Ziegler-Natta catalysts. Only the free radical polymerizations have commercial significance. 

Subsequent studies by Wittig demonstrated that deprotonation of benzyl alkyl ether derivatives with phenyllithium could provide the requisite carbanion and induce [1,2]-Wittig rearrangement. For example, treatment of benzyl methyl ether (9) with phenyllithium provided a-methyl benzyl alcohol (10) in 35% yield upon workup. 

In 2010, Fossey et al. developed a new class of planar chiral ferrocene nucleophilic catalysts combining both central and planar chirality [59]. Inspired by Fu s planar chiral DMAP and by Birman s 2-phenyl-2,3-dihydroimidazo[l,2-a]pyridine, Rp-57 proved to be a remarkably effective catalyst for the KR of various racemic secondary aryl alkyl alcohols, particularly bulky aryl alkyl alcohols, which are usually difficult to resolve. Typically, by performing the reaction in the presence of Rp-57 (2mol%), propionic anhydride (0.75 equiv.) and i-Pr2NEt (0.75 equiv.) in toluene at 0°C, selectivity factors ranging from s = 31 for substrates such as a-methyl benzyl alcohol to s = 534 in the case of the more bulky a-tert-butyl benzyl alcohol could be obtained (Scheme 41.13). Remarkably, the selectivity could be further increased by running the reaction at lower temperatures (s = 801 at -20 °C and up to s = 1892 at -40 °C), albeit with a concomitant loss in activity. 

Chemical Name 3,5-dihydroxy-0 -[ [(p-hydroxy-a -methylphenethyl)amino] methyl] benzyl alcohol hydrobromide... 

Wang used method D to fashion a key intermediate for the synthesis of rishirilide B (Fig. 4.20).21 The 2,4-bis-OBoc-3-methyl-benzyl alcohol (31) undergoes the addition of two equivalents of corresponding Grignard reagent to afford phenol 32 in 75% yield (Fig. 4.20). This material was subsequently elaborated by Mejorado in three steps (61% yield) to the corresponding 2,5-chiral cyclohexadienone 33, which was ultimately transformed into ( + )-rishirilide B (34).22... 

The partitioning of ferrocenyl-stabilized carbocations [30] between nucleophile addition and deprotonation (Scheme 18) has been studied by Bunton and coworkers. In some cases the rate constants for deprotonation and nucleophile addition are comparable, but in others they favor formation of the nucleophile adduct. However, the alkene product of deprotonation of [30] is always the thermodynamically favored product.120. In other words, the addition of water to [30] gives an alcohol that is thermodynamically less stable than the alkene that forms by deprotonation of [30], but the reaction passes over an activation barrier whose height is equal to, or smaller than, the barrier for deprotonation of [30], These data require that the intrinsic barrier for thermoneutral addition of water to [30] (As) be smaller than the intrinsic barrier for deprotonation of [30] (Ap). It is not known whether the magnitude of (Ap — As) for the reactions of [30] is similar to the values of (Ap - As) = 4-6 kcal mol 1 reported here for the partitioning of a-methyl benzyl carbocations. 

Racemization of chiral a-methyl benzyl cation/methanol adducts. The rate of exchange between water and the chiral labeled alcohols as a function of racemization has been extensively used as a criterion for discriminating the Sn2 from the SnI solvolytic mechanisms in solution. The expected ratio of exchange vs. racemization rate is 0.5 for the Sn2 mechanism and 1.0 for a pure SnI process. With chiral 0-enriched 1-phenylethanol in aqueous acids, this ratio is found to be equal to 0.84 0.05. This value has been interpreted in terms of the kinetic pattern of Scheme 22 involving the reversible dissociation of the oxonium ion (5 )-40 (XOH = H2 0) to the chiral intimate ion-dipole pair (5 )-41 k-i > In (5 )-41, the leaving H2 0 molecule does not equilibrate immediately with the solvent (i.e., H2 0), but remains closely associated with the ion. This means that A inv is of the same order of magnitude of In contrast, the rate constant ratio of... 

The reactor effluent is distilled and unreacted EB is recycled. The EB hydroperoxide is then reacted with propylene at 250°F and pressure in the range of 250-700 psi in the presence of a metal catalyst to produce propylene oxide and methylbenzyl alcohol B in Figure 8-7). The reactor mixture is separated by multiple fractionators. Unreacted propylene and EB are recycled. PO is recovered overhead. The methyl benzyl alcohol is easily dehydrated in the vapor stage at 450—500° F and 500 psi pressure over a titanium dioxide or silica gel catalyst to form styrene. Acephenone is one of the by-products. 

Kinetic and mechanistic investigations on the o-xylene oxidation over V205—Ti02 catalysts were carried out by Vanhove and Blanchard [335, 336] using a flow reactor at 450°C. Possible intermediates like o-methyl-benzyl alcohol, o-xylene-a,a -diol, toluic acid and phthalaldehyde were studied by comparing their oxidation product distribution with that of toluene. Moreover, a competitive oxidation of o-methylbenzyl alcohol and l4C-labelled o-xylene was carried out. The compounds investigated are all very rapidly oxidized, compared with o-xylene, and essentially yield the same products. It is concluded, therefore, that these compounds, or their adsorbed forms may very well be intermediates in the oxidation of o-xylene to phthalic anhydride. The ratio in which the partial oxidation products are formed appears to depend on the nature of the oxidized compounds, i.e. o-methylbenzyl alcohol yields relatively more phthalide, whereas o-xylene-diol produces detectable amounts of phthalan. This... 

FIGURE 22.8 The 200-MHz 1H NMR spectra of (a) 4-methylbenzylamine and ( >) 4-methyl benzyl alcohol. The singlet corresponding to CH2N in (a) is more shielded than that of CH20 in (b). 

A mixture of 8.64 g of sodium methylate, 14.6 g of p-anilinepropionitrtile and 22.0 g of 4-amino-3,5-dimethoxy-a-(methylsulfonylmethyl)benzyl alcohol in 50 ml of absolute dimethyl sulfoxide was stirred at 50°C for 1 hour under nitrogen and with the exclusion of moisture. The solution was poured into 500 ml of ice-water and the resulting emulsion was extracted with two 500 ml portions of ethyl acetate. The ethyl acetate extracts were washed with two 250 ml portions of water, dried over magnesium sulfate and evaporated in vacuum. The residue was dissolved in 60 ml ethyl acetate. After standing at room temperature for 20 hours, the crystallized 4-amino-a-(anilinemethylene)-3,5-dimethoxyhydrocinnamic acid nitrile was filtered off under suction, washed with a small amount of ethyl acetate and dried MP 150°-151°C. 

A preparatively more useful form of this reaction is the crossed Cannizzaro reaction which ensues when a mixture of an aromatic aldehyde and formaldehyde is allowed to react under the influence of strong base (e.g. the preparation of p-methyl benzyl alcohol, Expt 6.134). A substantial proportion of the aromatic aldehyde is reduced to the corresponding alcohol while the formaldehyde is... 

The electro-Fenton method (or EFR) was initially used for synthetic purposes considering the hydroxylation of aromatics in the cathodic compartment of a divided cell. Thus, the production of phenol from benzene (Tomat and Vecchi 1971 Tzedakis et al. 1989), (methyl)benzaldehydes and (methyl)benzyl alcohols from toluene or polymethylbenzenes (Tomat and Rigo 1976,1979,1984,1985) by adding Fe3+ to generate Fe2+ via reaction (19.13), as well as benzaldehyde and cresol isomers from toluene or acetophenone and ethylphenol isomers from ethylbenzene (Matsue et al. 1981) with direct addition of Fe2+, have been described. Further studies have reported the polyhydroxylation of salicylic acid (Oturan et al. 1992)... 

The main large-scale metal catalyzed reactions involving addition of CO (rather than CO + H2) to an organic substrate are the manufacture of acetic acid from methanol and the related production of acetic anhydride from methyl acetate. The syntheses of some other carboxylic acids and the conversion of a substituted benzyl alcohol to ibuprofen involve similar reactions. 

DIHYDROXY-a-((ISOPROPYL-AMINO)-METHYL)BENZYL ALCOHOL... 

S YN S 1 -a-HYDROXY- 3-xMETHYLAMINO-3-HYDRO-XY-l-ETHYLBENZENE (R)-3-HYDROXY-0-((METHYL-AMINO)METHYL)BENZENEMETHANOL 1-m-HYDROXY-0-((METHYLAMINO)METHYL)-BENZYL ALCOHOL (-)-m-HYDROXY-a-(METHYLAMINO-METHYL)BENZYL ALCOHOL l-l-(m-HYDROXY-PHENYL)-2-METHYLAMINOETHANOL l-(3-HYDROXYPHENYL)-N-METHYLETHANOLAMINE ISOPHRIN MESATON METAOXEDRIN METASYMPATOL METASYNEPHRINE m-METHYLAMINOETHANOLPHENOL MEZATON R(-)-MEZATON tn-OXEDRINE (-)-tn-OXEDRINE PHENYLEPHRINE (-)-PHENYLEPHRINE R(-)-PHENYLEPHRINE m-SYMPATHOL m-SYMPATOL... 

C10H12O a-cyclopropyl benzyl alcohol 1007-03-0 502.76 44.150 2 19602 C10H12O2 a-methyl benzyl acetate 93-92-5 504.61 44.327 2... 

Quinones et al. have measured equilibrium isotherm data for benzyl alcohol, 2-methyl benzyl alcohol and 2-phenylethanol on a Cig-bonded silica at different temperatures between 20 and 60 °C [129]. The results for benzyl alcohol are shown in Figure 3.34 left. From these isotherms, they derived the Clausius-Clape)non... 

Quinones et al. [17] measured by frontal analysis multisolute adsorption equilibrium data for the system benzyl alcohol, 2-phenylethanol and 2-methyl benzyl alcohol in a reversed-phase system. Data were acquired for the pure compoimds, for nine binary mixtures (1 3,1 1, and 3 1) and four ternary mixtures (1 1 3,1 3 1, 3 1 1, and 1 1 1). These data exhibited very good thermod5mamic consistency. The thermodynamic functions of adsorption were derived from the single-solute ad-... 

Figure 4.6 illustrates the use of the IAS model to account for the competitive isotherm data of a ternary mixture of benzyl alcohol (BA), 2-phenylethanol (PE) and 2-methyl benzyl alcohol (MBA) in reversed phase liquid chromatography. The RAS model accounts for the nonideal behaviors in the mobile and the stationary phases through the variation of the activity coefficients with the concentrations. Figures 4.6d and 4.6e illustrate the variations of the activity coefficients in the stationary and the mobile phases, respectively. The solutes exhibit positive deviations from ideal behavior in the adsorbed phase and negative deviations from ideal behavior in the mobile phase. 

Figure 4.6 Competitive isotherms of a ternary mixture of benzyl alcohol (BA), phenyl-2-ethanol (PE) and methyl-benzyl alcohol (MBA) on Cig-sUica with MeOH/H20 as the mobile phase, at different relative concentrations. Adsorbed amormts of (a) benzyl alcohol, (b) 2-phenylethanol, (c) 2-methyl benzyl alcohol, (d) activity coefficient in the mobile phase versus concentration. In Figures (a), (b), (c), the open circles are for equal parts of BA, PE and MBA, the diamonds for three parts of BA, 1 part PE and 1 part MBA), the triangles for one part of BA, one part of PE and three parts of MBA and the stars for the singlecomponent isotherms. The solid line is the Flory-Huggins model and the dashed lines are the IAS model isotherms. In Figures (d) and (e), the circles are for BA, the squares for PE, the triangles for MBA and the diamonds for the solvent. Reproduced from I. Quinones, J. Ford, G. Guiochon, Chem. Eng. Set, 55 (2000) 909 (Figs. 12,13 and 14).

Quinones et al. measured by frontal analysis the single-component, binary and ternary isotherms of benzyl alcohol (BA), 2-phenyl ethanol (PE) and 2-methyl benzyl alcohol (MBA) on Symmetry-Cis, using a binary mobile phase (MeOH HaO... 

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