Phenylethyl acetate alcohol

Williams employed complexes of Al, Rh, or Ir in combination with Pseudomonas Jluorescens lipase (PFL) for the DKR of 1-phenylethanol. The best results were obtained using Rh2(OAc)4 as the catalyst for the racemization, and 60% conversion of the alcohol to give 1-phenylethyl acetate in 98% ee was obtained (Figure 4.6) [19]. At higher conversion, the enantiomeric excess dropped and 76% conversion gave 80% ee. 

The first use of a metal catalyst in the DKR of secondary alcohols was reported by Williams et al. [7]. In this work, various rhodium, iridium, ruthenium and aluminum complexes were tested. Among them, only Rh2(OAc)4 and [Rh(cod)Cl]2 showed reasonable activity as the racemization catalyst in the DKR of 1-phenylethanol. The racemization occurred through transfer-hydrogenation reactions and required stoichiometric amounts of ketone as hydrogen acceptor. The DKR of 1-phenylethanol performed with Rh2(OAc)4 and Pseudomonas Jluore-scens lipase gave (R)-l-phenylethyl acetate of 98%e.e. at 60% conversion after 72 h. 

We synthesized 8 by the one-step reaction of [Ph4(Tl -C4CO)]Ru(CO)3 with benzyl chloride. In contrast to previous alcohol racemization catalysts, 8 was stable in the air during racemization [30]. The racemization was performed even under 1 atm of molecular oxygen. Thus, alcohol DKR was for the first time possible with 8 in the air at room temperature (R)-l-phenylethyl acetate (99% yield, greater than 99%e.e.) was obtained from 1-phenylethanol by using 4mol% of 8, CALB and isopropenyl acetate in the presence of potassium phosphate (Scheme 1.22). This catalyst system was effective for both benzylic and aliphatic alcohols. The synthetic method for 8 was applied to the preparation of a polymer-bound derivative (9). Hydroxymethyl polystyrene was reacted with 4-(chloromethyl)benzoyl chloride to... 

Phenylethyl alcohol Phenylethyl acetate Phenylethyl formate... 

Ethyl acetate, which is a comparatively small molecule, has the typical fruity character associated with all the lower esters, and a more or less equal balance between the influence of the two structural units, derived from ethyl alcohol and acetic acid. Linalyl acetate and geranyl acetate, however, although retaining the typical character of an acetate have much less of the ester fruitiness and are more closely related to the corresponding alcohols, linalool, and geraniol. The dominance of the alcohol appears to be even greater in phenylethyl acetate and paracresyl acetate (a phenolic ester). 

For example, ethyl phenylacetate is far more volatile than phenylacetic acid, although the molecular size is greater. Similarly phenylethyl acetate is slightly more volatile than phenylethyl alcohol. However, phenylethyl phenylacetate is very much less volatile than... 

In this research the kinetic resolution of 1-phenylethanol catalyzed by commercially available immobilized lipase from CALB was assayed in non-aqueous conditions in SC-CO2 and IL/SC-CO2 systems with the aim of studying the enan-tioselectivity of Novozym 435. The influence of different reaction parameters, such as pressure, the acyl donor/alcohol molar ratio and different ILs, on the enantio-merically pure compound (R)-l-phenylethyl acetate formation via kinetic resolution of 1-phenylethanol was investigated. 

For a reversible reaction an increase in the acyl donor concentration results in higher product yields. In this case the chemical equilibrium is shifted towards synthesis. On the other hand, high concentrations of substrates may cause inhibition and the reaction is slowed down. For (R)-l-phenylethyl acetate formation the effect of the substrate vinyl acetate/l-phenylethanol molar ratio on the final conversion was studied. The results are presented on Figure 8.3. A higher yield of the enantiopure compound was achieved when raising the acyl donor molar concentration with respect to the alcohol concentration. A conversion of 49.9% was obtained at an acyl donor/alcohol molar ratio of 9/1. After 5 h of reaction at tested conditions a complete conversion of (R)-l-phenylethanol into the enantiopure (R)-l-phenylethyl acetate was attained. The enantiomeric excess for reactants (eeR) was 99.9%. 

Guterman, L, Masci, T., Chen, X., Negre, R, Pichersky, E., Dudareva, N., Weiss, D. and Vainstein, A. (2006) Generation of phenylpropanoid pathway-derived volatiles in transgenic plants rose alcohol acetyltransferase produces phenylethyl acetate and benzyl acetate in petunia flowers. Plant Mol. Biol, 60, 555-63. 

The production of the higher alcohols, the acetates of isoamyl alcohol and phenylethyl alcohol, and the ethyl esters of the C6-C10 fatty acids has been studied in semiaerobic sugar fermentations by strains of . cerevisiae and S. uvarum. S. cerevisiae generally produced more esters than S. uvarum. Isoamyl acetate was the main ester produced by >. cerevisiae. and others, in decreasing order, were ethyl caprylate, ethyl caproate, ethyl caprate and phenylethyl acetate(39). Several unusual thio compounds have been produced by Saccharomvces in model anaerobic fermentations using amino acids such as methionine as the sole carbon source(21). These model fermentations produce methylthiopropanal and traces of other sulfur containing compounds, such as methionyl acetate and 2-methyltetrahydrothiophene-3-one. 

Volatile product accumulation kinetics in cultures of Kluvveromvces strains includes short chain alcohols and esters such as 2 phenylethyl acetate. These cultures typically have a fruity,... 

The main volatiles in wines are the higher aliphatic alcohols, ethyl esters, and acetates formed from yeasts during fermentation. Acetates are very important flavors characterized by fruity notes, C4-Ci0 fatty acid ethyl esters manly confer fruity scents to the wine. Other wine aroma compounds are C6 alcohols, such as 1-hexanol and cis- and trans-3-hexen-l-ol, 2-phenylethanol, and 2-phenylethyl acetate. Contents of these compounds in wine are linked to the winemaking processes used fermentation temperature, yeast strain type, nitrogen level in must available for yeasts during fermentation, clarification of wine (Rapp and Versini, 1991). Much literature on the wine aroma compounds was reported in reviews by Schreier (1979) and Rapp (1988). 

Figure 5.1. HS (headspace)-SPME-GC/MS chromatogram recorded in the analysis of a Gewiirztraminer wine volatiles performed using a CAR-PDMS-DVB fiber and the experimental conditions reported in Table 5.1. (1) ethyl hexanoate (2) 2- and 3-methyl-1-butanol (isoamyl alcohols) (3) ethyl lactate (4) 1-hexanol (5) ethyl octanoate (6) 1-heptanol (internal standard) (7) benzaldehyde (8) linalool (9) ethyl decanoate (10) diethyl succinate (11) a-terpineol (12) 2-phenylethyl acetate (13) 2-phenylethanol (14) octanoic acid.

Novel mixtures of optical isomers of natural and kosher styrallyl alcohol (a-phenylethyl alcohol), and their corresponding acetate esters of styrallyl alcohol (a-phenylethyl acetate) were prepared by multiple fermentation processes and an azeotropic esterification reaction. In the first step, natural acetophenone was produced by bioconversion of cinnamic acid by Pseudomonas sp. (P), Comanonas sp, and Arthrobacter sp. 6). In the first microbial oxidation process, the side chain of cinnamic acid was oxidized to the ketone to form acetophenone that was transiently accumulated in the fermentation broth (P). The current commercial fermentation process yielded >5g/L of acetophenone in the fermentation broth following 2 days of incubation using Arthrobacter sp. The resulting acetophenone was recovered and purified from the fermentation broth by solvent extraction followed by fractional distillation. Acetophenone itself can be used in creating flavor formulations and in enhancement of aroma and taste or both. 

Acetic esters of higher alcohols (isoamyl acetate and phenylethyl acetate) should also be included... 

Synonyms Acetic acid, 1-phenylethyl ester Benzenemethanol, a-methyl-, acetate Benzyl alcohol, o-methyl-, acetate Gardenol a-M ethyl benzenemethanol acetate Methylphenylcarbinol acetate Methylphenylcarbinyl acetate s-Phenethyl acetate 1-Phenylethyl acetate o-Phenylethyl acetate... 

Aluminum bromohydrate Aluminum chloride anhydrous Aluminum chlorohydrate Aluminum citrate Aluminum dichlorohydrate Aluminum phenolsulfonate Aluminum sesquichlorohydrate Aluminum sulfate Aluminum zirconium octachlorohydrate Aluminum zirconium octachlorohydrex GLY Aluminum zirconium pentachlorohydrate Aluminum zirconium pentachlorohydrex GLY Aluminum/zirconium tetrachlorohydrate Aluminum zirconium tetrachlorohydrex GLY Aluminum zirconium trichlorohydrate Aluminum/zirconium trichlorohydrex GLY Ammonium phenolsulfonate Cetyl pyridinium chloride Chlorothymol Cloflucarban Farnesol Lapyrium chloride Lichen (Usnea barbata) extract Linalool Methylbenzethonium chloride Phenethyl alcohol Phenol 2-Phenylethyl acetate Potassium alum anhydrous Quaternium-18 methosulfate Sodium aluminum chlorohydroxy lactate Sodium phenolsulfonate Steapyrium... 

As part of their metabolism, all yeasts are known to produce a wide range of esters such as ethyl acetate, isoamyl acetate, isobutyl acetate, ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, and 2-phenylethyl acetate (Nykanen and Nykanen, 1977 Soles et al., 1982 Edwards et al., 1990 Webster et al., 1993 Rojas et al., 2001 2003 Plata et al., 2003 Lee et al., 2004). Esters are synthesized through reaction of alcohols (commonly, ethanol) and carboxylic acids by different acyltransferases or ester synthases (Mason and Dufour, 2000). Factors that affect ester synthesis include grape maturity, sugar content, fermentation temperature, and juice clarity (Houtman et al., 1980a 1980b Edwards etal., 1990). 

Phenylethyl acetate - 663 Phenylethyl alcohol - 63, 226 Phenylethyl ether (see Ethyl phenyl ether) Phenylformic acid (see Benzoic acid) Phenylglycine, potassium salt - 259 Phenylhydrazine - 219, 259, 268, 364,834,... 

The leaf oil of C. cassia grown in Australia contains mostly cinnamic aldehyde 112%), coumarin (15.3%), cinnamyl acetate (3.6%), benzaldehyde (1.2%), and in lesser amounts, 4-ethylguaiacol, ethyl cinnamate, 2-phenylethyl acetate, a-terpineol, terpinen-4-ol, and others. The leaf oil of China-grown trees contains mostly cinnamic aldehyde (74.1%), 2-methoxycinnamaldehyde (10.3%), cinnamyl acetate (6.6%), coumarin (1.2%), and lesser amounts of benzaldehyde (1.1%), sal-icyaldehyde, cinnamyl alcohol, 2-phenylethyl acetate, a-pinene, and others (ravindran). 

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