Phenyl acetate, preparation

Phenyl-ethyl alcohol can be prepared by numerous methods, several of which are the subject-matter of patents. It may be prepared, for example, by the conversion of phenyl-bromo-lactic acid into phenyl-acetaldehyde, and then reducing this body with sodium. Or it may be prepared by reducing phenyl-acetic esters with sodium and absolute alcohol in the folio-wing manner —... 

Methyl Phenyl-acetate. — Phenyl-acetic acid can be prepared by... 

Preparation of 3 5-diiodo-4-(4 -hydroxyphenoxy)phenylacetic acid (diac) A solution of ethyl 3 5-diiodo-4-(4 -methoxyphenoxy)phenyl acetate (9.5 g) in acetic acid (60 ml) was heated under reflux with hydriodic acid (SG 1.7, 50 ml) and red phosphorus (0.5 g) for 1 hour. The hot solution was filtered and the filtrate concentrated at 50°C and 15 mm of mercury to above 20 ml. The residue was treated with water (70 ml) containing a little sodium thiosulfate to decolorize the product. The solid was collected by filtration and purified by the method of Harington and Pitt-Rivers [Biochem. J. (1952), Vol. 50, page 438]. Yield 8,36 g (95%). After crystallization from 70% (v/v) acetic acid it melted at 219°C. 

A suspension of sodium amide2 (0.1 mole) in liquid ammonia is prepared in a 500-ml. three-necked, round-bottomed flask fitted with a West condenser, a ball and socket glass mechanical stirrer (Note 1), and a dropping funnel. In the preparation of this reagent a small piece of clean sodium metal is added to 350 ml. of commercial anhydrous liquid ammonia. After the appearance of a blue color, a few crystals of hydrated ferric nitrate are added, whereupon the blue color is discharged. The remainder of the 2.3 g. (0.1 mole) of sodium (Note 2) is then rapidly added as small pieces. After all the sodium has been converted to sodium amide (Note 3), a solution of 16.4 g. (0.1 mole) of ethyl phenyl-acetate (Note 4) in 35 ml. of anhydrous ethyl ether is added dropwise over a 2-minute period, and the mixture is stirred for 20 minutes. To the dark green suspension is added over an 8-minute period a solution of 18.5 g. (0.1 mole) of (2-bromo-... 

The chiral acetate reagent is readily prepared from methyl mandelate [methyl (A)-hydroxy-phenyl acetate] which is first converted by treatment with phcnylmagnesium bromide into the triphenylglycol783, c (see Section 1.3.4.2.2.2.) and subsequently transformed into the acetate by reaction with acetyl chloride in the presence of pyridine. Thereby, the secondary hydroxyl group of the glycol is esterified exclusively. Both enantiomers of the reagent are readily accessible since both (R)- and (5)-hydroxyphenylacelic acid (mandelic acids) arc industrial products. 

Cohare and co-workers reported that aristolactam BU (22) was prepared, following Kupchen s method, by Perkin condensation of 6-bromo-3,4-di-methoxy phenyl acetic acid (119) and o-nitrobenzaldehyde (120) (Scheme 14). The 2-bromo-4,5-dimethoxy-2 -nitro-ds-stilbene-a-carboxylic acid (121) was obtained. The nitro group of 121 was reduced with ferrous sulfate and ammonium hydroxide, and the resulting 2-bromo-4,5-dimethoxy-2 -amino-cw-stilbene-a-carboxylic acid (122) without purification was submitted to the Pschorr phenanthrene synthesis to yield l-bromo-3,4-dimethoxyphen-anthrene-lO-carboxylic acid (123). The phenanthrylamine 124 was prepared from 123 via a Schmidt reaction, and, by treatment with n-butyllithium and CO2, 124, afforded 22 (42). 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

In an earlier investigation by the author (1), polymeric ketones, (II), were prepared at ambient temperature by acid dehydration of a-phenyl acetic acid using phosphorus pentoxide and methane sulfonic acid as illustrated in Eq. (1). Aromatic polyketones formed from this process are provided in Table 2. 

TABLE 2. Selected Aromatic Polyketones Prepared by Dehydration of a-Phenyl Acetic Acid Using Phosphorus Pentoxide and Methane Sulfonic Acid"... 

Treatment of the dibromides with sodium ethoxide gives 2-bromo-methyl-2,3-dihydrobenzofurans (170) o- (2,3-dibromopropyl)phenyl acetate (188, X = OAc, R = H) gives 2-bromomethyl-2,3-dihydro-benzofuran (170, R = R1 = H).447 The following substituted 2-bromo-methyl-2,3-dihydrobenzofurans have been prepared by this method ... 

Boc-m-Ampa-OH (56) has been prepared by Curtius rearrangement of the monoester of m-phenylenediacetic acid 54 (Scheme 17).It can probably also be obtained more rapidly through the m-bromomethyl precursor as described for the o- and p-isomers. A detailed description of the preparation of [5-(l-aminoethyl)-2-(cyclohexylmethoxy)phenyl]acetic acid methyl ester 57 has been given.175 ... 

Diphenylbuta-l,3-diene (Section Expt 6.141) is prepared by a variant of the general method in which cinnamaldehyde is similarly condensed with phenyl-acetic acid. 

Diethyl 2-phenylmalonate is prepared by a mixed Claisen condensation between ethyl phenyl-acetate and diethyl carbonate. 

The membrane structures and their preparation described above are just two examples. There are many variations of the basic preparation procedure resulting in slightly different products. Instead of styrene, often substituted styrenes such as methylstyrene or phenyl-acetate are used instead of divinylbenzene monomers such as divinylacetylene or butadiene are used. 

In June 1992, we reasoned that the preparation of methyl tropate via the reaction of formaldehyde with methyl phenyl acetate may provide a low-cost intermediate capable of being reduced to PPD. The preparation of ethyl tropate via this route was already published.5 However, the German workers found that formation of ethyl 2-phenylacrylate was substantial. In addition, no ongoing reduction of methyl tropate to PPD was described (Scheme 2). 

Ozonolysis of vinylpyrazine in methanol at — 30° furnishes pyrazine aldehyde in 73% yield.196 Vinylpyrazine undergoes a variety of addition reactions and pyrazylethyl derivatives of amines, ketones, ethyl phenyl acetate, phenylacetonitrile, and acetamide have been obtained.197-199 2-(2-Pyrazylethyl)cyclohexanone (42) has been prepared both by the condensation of vinylpyrazine with cyclohexanone in the presence of sodium metal and by interaction of vinylpyrazine with the pyrrolidine enamine of cyclohexanone followed by hydrolysis.200... 

When 2-methoxycycloalkyl phenyl telluriums, prepared from cycloalkenes and phenyl tellurium trichloride in methanol, are treated with 3-chloroperoxybenzoic acid, the elimination of the phenyltelluro group is accompanied by ring-contraction and formation of the dimethyl acetals of formylcycloalkanes2 3. 

The acid chloride was prepared from (+)-a-methoxy-a-(trif1uoro-methyl)phenyl acetic acid which was used as obtained from Aldrich Chemical Company, Inc. 

To obtain the best lipase-catalyzed amidation resolution, the lipase operational conditions, i.e., additives, lipase preparations, acyl donors, and solvents, were further evaluated. When molecular sieve 4 A was added to control the water content in the enzymatic resolution, decompositions of aminonitrile intermediates were observed. Among a range of lipases, the resolution process by lipase PS-C I provided the highest conversion of amide products. Phenyl acetate 37 was chosen as acyl donor because its reaction led to marginal by-reactions. Thus, the lipase-catalyzed amidation resolution of the dynamic aminonitrile systems in the presence of zinc bromide as heterogeneous catalyst was performed by lipase PS-C I and phenyl acetate as acyl donor in dry toluene at 0 °C. 

The incorporation of a phenyl ring as part of an extended carbon tether [(C) , n — 2] requires the preparation of the homologous [2-[(E)-phenyl-diazenyl]phenyl]acetic acid 89 or its methyl ester 90 (Scheme 22), which in a subsequent step has to be transformed into l-diazo-3-[2-[(E)-phenyldia-zenyl]phenyl]acetone. 

General Discussion. Aldol-type condensation of the magnesium enolate of (R)-(+)-phenyl (p-toluenesulfinyl)acetate, prepared with f-butylmagnesium bromide, with the aldehyde precursor of maytansine afforded, after desulfurization with Aluminum Amalgam, the desired 4,5-unsaturated 3-(5)-hydroxy ester in high yield and high diastereoselectivity (eq 3). ... 

Phenylethyl alcohol is prepared by reduction of ethyl phenyl-acetate with sodium in absolute alcohol by hydrogenation of phenylacetaldehyde in the presence of a nickel catalyst or by addition of ethylene oxide or ethylene chlorohydrin to phenylmagnesium bromide, followed by hydrolysis. Phenylethyl alcohol also occurs naturally in a number of essential oils, especially rose oil. 

The phenyl acetate biosensor is not of great commercial importance, but it illustrates a novel use of antibodies as chemical recognition agents. In principle, catalytic antibodies may be raised for any reactions for which stable transition state analogues may be prepared. 

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