P-Phenylethanol

PHENYLETHANOL see PDD750 P-PHENYLETHANOL see PDD750 PHENYL ETHANOLAMINE see AOR750 N-PHENYLETHANOLAMINE see AOR750... 

A wide variety of sulfamate esters have been synthesised and screened as herbicides, pharmaceutical agents and sweeteners (see Chapter 11, p. 240). Sulfamates containing a primary amino group (124) are conveniently prepared by condensation of the appropriate alcohol with sulfamoyl chloride (125) in DMF in the presence of sodium hydride (Scheme 50). An illustrative example is provided by the conversion of substituted p-phenylethanols (126) to the corresponding sulfamates (127) (Scheme 50). Compounds of type (127) exhibit anticonvulsant and carbonic anhydrase activity and may be useful in the treatment of epilepsy and glaucoma. Sulfamoyl chlorides (125) may be prepared by treatment of amines or amine hydrochlorides with sulfuryl chloride (128). An analogous reaction also occurs with dialkyl sulfonamides (129) (Scheme 51). 

Figure 4.8. The GC/MS-EI (70eV) SCAN mode chromatogram of compounds formed by acid hydrolysis of a Raboso grape skins extract. Peak 1. frans-furanlinalool oxide peak 2. cfs-furanlinalool oxide I.S.l, internal standard (1-octanol) peak 3. (Z)-ocimenol peak 4. ( )-ocimenol peak 5. a-terpineol I.S.2, internal standard (1-decanol) peak 6. 2-exo-hydroxy-l,8-cineol peak 7. benzyl alcohol peak 8. P-phenylethanol peak 9. actinidols A peak 10. actinidols B peak 11. endiol peak 12. eugenol peak 13. vinylguaiacol peak 14. p-menthenediol I peak 15. 3-hydroxy-P-damascone peak 16. vanillin peak 17. methyl vanillate peak 18. 3-oxo-a-ionol peak 19. 3-hydroxy-7,8-dihydro-P-ionol peak 20. homovanillic alcohol peak 21. vomifoliol.

Oxo-a-ionol P-Phenylethanol Benzenepropanol a-Methylbenzenepropanol Coniferyl alcohol Benzotriazole... 

Beilstein Handbook Reference) AI3-00744 Benzeneethanol Benzylcarbinol Benzyi-methanol BRN 1905732 Caswell No. 655C EINECS 200-466-2 EPA Pesticide Chemical Code 001503 Ethanol, 2-phenyl- FEMA No. 2858 FEMA Number 2858 p-Fenethylalkohol P-Fenylethanol HSDB 5002 p-Hydroxyethylbenzene Methanol, benzyl- NSC 406252 PEA Phenethanol p-Phenylethanol Phenethyl alcohol Phenylethyl alcohol. Has the smell of roses. Used In perfumery and as an antimicrobial agent. Clear liquid mp= -27° bp760 = 219-221° dS = 1.017 n6 = 1.530 soluble in H2O (2 g/100 ml), mote soluble in organic solvents LDso (rat orl)= 1790 mg/kg. Lancaster Synthesis Co. Sigma-Aldrich Fine Chem. 

Phenethyl alcohol p-Phenethyl alcohol 2-Phenylethanol p-Phenylethanol Phenylethyl alcohol... 

Principal component analysis is another statistical technique that has been applied to the results of profile analysis [55]. Ales and lagers were examined and two-dimensional plots of the results using the first two principal components as axes showed resolution of the ales from the lagers and the close proximity of the majority of duplicate samples. Profile analysis has also been used to differentiate various brands of whisky [56]. Throughout the work on profile analysis hedonic expressions have been strictly excluded but other workers [57] have used principal component analysis to classify Continental European beers correctly as good, average or poor on the basis of nine physicochemical parameters colloidal stability (7 days at 40°C/1 day at 0°C), cold sensitivity (24 hours at 0°C), brightness at 12°C, six months test, the content of p-phenylethanol, ethyl caprylate, isoamyl acetate, and isobutanol and foam stability. 

Another approach has been limited to the correlation of the headspace volatiles with flavour characteristics [30, 58]. Of the substances distinguished on the gas chromatograms the levels of the isoamyl alcohols, ethyl acetate, isoamyl acetate, and isobutanol have been shown to be important in the discriminant analyses discussed above. p-Phenylethanol and ethyl caprylate are not sufficiently volatile to be included in headspace analyses [39]. In this method [30, 58] the peak areas on the chromatograms were expressed as the percentage of the total peak area (excluding ethanol and the internal standard xylene). A chronologically updated data base was used to calculate... 

Substituted isochromans (19) are obtained from acid-mediated cyclocondensation of P-phenylethanols 18 with formaldehyde, the alcohols 18 are readily available from addition of benzyl Grignard compounds to aldehydes [75]. The isochromans 19 are chemoselectively oxidized to 1-oxoisochromans 20 by means of Cr03 in ACOH/H2O. 

Benzyl alcohol (1) and P-phenethyl alcohol (2) (2-phenylethanol) are the simplest of the aromatic alcohols, and, as such, are chemically similar. Their physical properties are given in Table 1. 

The oxa-Pictet-Spengler reaction has been used with success to prepare dihydrofurano[2,3-c]pyrans and isochromans from l-(3-furyl)alkan-2-ols and 2-(3 ,4 -dihydroxy)phenylethanol, respectively. Furanyl alcohol 32 reacted with isobutyraldehyde 33 in the presence of p-toluenesulfonic acid to give the corresponding CI5-5,7-diisopropyl 4,5-dihydro-7H-furano[2,3-c]pyran 34 in good yield. ... 

Lipases from C. antarctica and P. cepacia showed higher enantioselectivity in the two ionic liquids l-ethyl-3-methylimidazolium tetrafluoroborate and l-butyl-3-methylimidazolium hexafluoroborate than in THE and toluene, in the kinetic resolution of several secondary alcohols [49]. Similarly, with lipases from Pseudomonas species and Alcaligenes species, increased enantioselectivity was observed in the resolution of 1 -phenylethanol in several ionic liquids as compared to methyl tert-butyl ether [50]. Another study has demonstrated that lipase from Candida rugosa is at least 100% more selective in l-butyl-3-methylimidazolium hexafluoroborate and l-octyl-3-nonylimidazolium hexafluorophosphate than in n-hexane, in the resolution of racemic 2-chloro-propanoic acid [51]. 

The research group of Backvall employed the Shvo s ruthenium complex (1) [21] for the racemization. This complex is activated by heat. For the KR they used p-chlorophenyl acetate as the acyl donor in combination with thermostable enzymes, such as CALB [20] (Figure 4.7). This was the first practical chemoenzymatic DKR affording acetylated sec-alcohols in high yields and excellent enantioselectivities. In the best case 100% conversion (92% isolated yield) with 99% ee was obtained. This method was subsequently applied to a variety of different substrates and it is employed (with a different ruthenium complex) by the Dutch company DSM for the large-scale production of (R)-phenylethanol [22]. 

The oxidation of a series of meta- and para-substituted a-phenylethanols shows that electron-donating substituents facilitate reaction (p = —1.01) . A similar study of primary aliphatic alcohols confirmed this trend p = —1.06 + 0.06). 

The reaction was followed by TLC (eluent petroleum ether-ethyl acetate 75 25). The acetophenone was UV active, stained yellow with p-anisalde-hyde, Rf 0.68. Phenylethanol had a low UV activity, stained purple with p-anisaldehyde, R 0.46. 

Adults of some species also produce 4-oxo-( )-2-alkenals. Other types of simple compounds that have been found in the defensive secretions of true bugs include common terpenoids such as a- and (3-pinenes, limonene, linalool, and Z, -oc-farnesene, and simple aromatic compounds such as benzyl alcohol, ben-zaldehyde,p-hydroxybenzaldehyde, methyl p-hydroxybenzoate,phenylethanol, and guaicol. In general, although a number of species may share particular components, each species does appear to produce its own particular blend. In at least one species, the blend of defensive compounds is reported to vary with season and/or diet [36]. 

FIGURE 4.5 Chromatograms of a-phenylethanol enantiomers nsing (a) SFC and (b) open tubular column GC. Conditions (a) 12 cmx250 p.m ID capillary packed with 5-p.m porous (300 A) silica particles encapsulated with fS-CD polymethylsiloxane (10% w/w) and end-capped with HMDS, 30°C, 140 atm, CO2, FID, 10 cmxl2 p.m ID restrictor, (b) 25 mx250 p.m ID cyano-deactivated capillary cross-linked with fi-CD polymethylsiloxane (0.25 xm df) 130°C He FID. (Reprinted from Wu, N. et al. 2000. J. Microcol. Sep. 12 454-461. With permission.)... 

TeClf catalysed Friedel-Crafts aromatic alkylation (typical procedure. To a solution of 1-phenylethanol (3.7 g, 30 mmol) in toluene (30 mL) is added slowly TeCl4 (9.7 g, 36 mmol), keeping the temperature at 25°C (exothermic reaction). Small amounts of white precipitate appear immediately, and after a few minutes the colour of the mixture becomes dark brown. The mixture is stirred for 3 h and then quenched with HgO (20 mL). The organic layer is separated, washed with brine (2x20 mL) and dried (MgS04). Evaporation of the solvent leaves an oily residue which is distilled under vacuum, giving a mixture of 1-phenyl-1-tolylethanes (4.9 g (83.3%) b.p. 117-128°C/1 torr). GLC analysis (silicone OV-101, 0.24 mm X 30 m capillary column at 100-260°C, 4°C min i) reveals an ortholpara ratio of 12 88. 

The empirical observation that (—)-sparteine 55 is necessary for catalysis implicates a base-promoted pathway in the mechanism. In the first step, a palladium alk-oxide is formed after alcohol binding, followed by p-hydride elimination of the alkoxide to yield a ketone product. On the basis of a kinetic study of the enantio-selective oxidation of 1-phenylethanol, it was revealed that (—)-sparteine plays a dual role in the oxidative kinetic resolution of alcohols, as a ligand on palladium and an exogeneous base " ... 

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