Ethyl 2-phenylpropanoate

Copper(Il) complexes 18a-f of methyl or ethyl 3-oxobutanoate la, 2-bromo-3 oxobutanoate lb, 2-(anilinocarbonyl)-3-oxobutanoate Ic, 3-oxo-3- rfienylpro-panoate Id, 2-bromo-3-oxo-3-phenylpropanoate le, or 3-aniHno-2-benzoyl-3-oxopropanoate If were reacted with phenylhydrazine hydrochloride and sodium ( )... 

In the other extreme, ethyl 3-oxohexanoate 75 required fusion with 3-pyridyl-hydrazide 73a or 3-hydrazinocarbonyl-pyridine-l-oxide 73b at 120°C in order to give the corresponding pyrazol-3-ones 76a,b (92AF1350) (Scheme 22). Depending on the reaction conditions, the reaction of ethyl 3-oxo-3-phenylpropanoate 77 and cyanomethylhydrazide 78 gave different products. Thus, fusion at 140°C gave pyrazol-3-one 79 and N,A -bis(cyanoacetyl)hydrazine 80, while heating in ethanol... 

A series of 2-(4-chlorophenoxy)-3-oxoalkanoate were reduced by baker s yeast, and Kluyveromyces marxianus. Yeast reduction of ethyl 2-(4-chlorophenoxy)-3-oxo-3-phenylpropanoate (R=Ph) afforded enantiomerically pure ethyl 2R, 3S)-2-(4-chlorophenoxy)-3-hydroxy-3-phenylpropanoate out of the four possible stereoisomers in >99% de [29h]. Although baker s yeast reduction of butanoate (R = CFl3) was not selective (92% de), the use of K. marxianus afforded (2R, 3S)-isomer selectively [29i]. The products are intermediates for potential peroxisome prolifera-tor-activated receptor isoform a-agonists (Figure 8.39a). 

Methyl 2-methylbenzoate Methyl 3-methylbenzoate Methyl 4-methylbenzoate Phenyl acetate Benzyl acetate Methyl phenylacetate Ethyl phenylacetate Methyl 3-phenylpropanoate Ethyl 3-phenylpropanoate Methyl 4-phenylbutanoate Dimethyl phthalate Benzonitrile... 

In ethyl 3-keto-2-oximino-3-phenylpropanoate catalytic hydrogenation over palladium on carbon reduced both the keto and oximino group, giving a 74% yield of ethyl ester of -phenylserine (ethyl 2-amino-3-hydroxy-3-phenylpropionate). The reduction is stereospecific and only the erythro dia-stereomer was obtained, probably via a cyclic intermediate 11097]. Similarly, hydrogenation over Raney nickel at 25-30° and 1-3 atm converted ethyl a-oximimoacetoacetate quantitatively to ethyl 2-amino-3-hydroxybutanoate [45]. 

The assignment of (/ )-2,3-dihydro-2-phenylfuran rests on Jones oxidation which furnished (ft)-dihydro-5-phenyl-2(3//)-furanone [(/ )-24]80. The configuration of the corresponding S-enantiomer (obtained by yeast reduction of 4-oxo-4-phenylbutanoic acid) was established by correlation with ethyl (S)-3-hydroxy-3-phenylpropanoate (of known configuration, obtained itself by a baker s yeast reduction) by a sequence featuring an Arndt -Eistert homologization as the key step (see also p 403)19. 

Immobilisation of an Acetobacter aceti strain in calcium alginate resulted in improvement of the operational stability, substrate tolerance and specific activity of the cells and 23 g phenylacetic acid was produced within 9 days of fed-batch cultivation in an airlift bioreactor [133]. Lyophilised mycelia of Aspergillus oryzae and Rhizopus oryzae have been shown to efficiently catalyse ester formation with phenylacetic acid and phenylpropanoic acid and different short-chain alkanols in organic solvent media owing to their carboxylesterase activities [134, 135] (Scheme 23.8). For instance, in n-heptane with 35 mM acid and 70 mM alcohol, the formation of ethyl acetate and propylphenyl acetate was less effective (60 and 65% conversion yield) than if alcohols with increased chain lengths were used (1-butanol 85%, 3-methyl-l-butanol 86%, 1-pentanol 91%, 1-hexanol 100%). This effect was explained by a higher chemical affinity of the longer-chain alcohols, which are more hydrophobic, to the solvent. 

The reaction mixture was partitioned between diethyl ether (60 mL) and water (30 mL). The organic layer was washed with water (2 x 30mL), brine (30mL), and dried over MgS04. After concentration on a rotary evaporator, the oily residue was distilled using a Kugelrohr apparatus (120°/0.07 mbar) to yield 5.35 g (92 %) of (S)-ethyl 3-hydroxy-3-phenylpropanoate with 98 % ee. 

Another resonance-stabilized intramolecular phosphonium salt (11), the addition product of ethyl 2-cyanocinnamate with triethyl phosphonate, yields after irradiation in cyclohexane solution ethyl 2-cyano-3-diethoxyphosphinyl-3-phenylpropanoate (12) and ethylene (13) (equation 7)35. The structure of 12 was confirmed by IR spectra and an independent synthesis from corresponding reactants. 

For a-bromo ketones and related compounds, enhancement of the enantioselectivities has been achieved by the addition of simple Lewis acids (e.g., BF3, Cp2TiCl2, or magnesium salts, which presumably form Lewis acid-Lewis base complexes with the carbonyl functions of the substrates).2627 The stereochemical effect of some Lewis acid additives on the reduction of a racemic a-bromo ester, namely ethyl 2-bromo-2-phenylpropanoate, is summarized in Scheme 27.2. 

Certain of the monoalkylated ethyl phenylacetates have been further alkylated with alkyl and aralkyl halides to produce the corresponding disubstituted phenylacetic esters.8 Ethyl 2-phenyl-propanoate has been alkylated by methyl iodide to give pure ethyl 2-methyl-2-phenylpropanoate in 81% yield. Similarly, the alkylations of ethyl 2-phenylhexanoate with methyl iodide, w-butyl bromide, and benzyl chloride gave the corresponding pure dialkylated products in 73%, 92%, and 72% yields, respectively. 

Cognate preparations. Phenylpropynoic acid. Place a solution of 88 g (84 ml, 0.5 mol) of ethyl cinnamate (Expt 6.137) in 50 ml of carbon tetrachloride in a 500-ml round-bottomed flask. Immerse the flask in ice and add 80 g (25.5 ml, 0.5 mol) of bromine from a separatory funnel slowly with frequent shaking. The halogen will disappear rapidly at first, but more slowly towards the end of the reaction no hydrogen bromide is evolved and the time of the addition is about 20-25 minutes. Allow the mixture to stand for 1 hour, pour the solution into a large evaporating dish and permit the excess of bromine and the carbon tetrachloride to evaporate spontaneously in the fume cupboard. The crude ethyl 2,3-dibromo-3-phenylpropanoate will remain as a solid cake this... 

Oxazolidine 130 is a masked aldimine bearing a chiral N-(2-hydroxy-l-phenyl)ethyl moiety and is readily available from (R)-phenylglycinol. Mannich reaction of 130 with Reformatsky reagent of ethyl bromodifluoroacetate produces difluorolactam 131 in high diastereoselectivity, which is then transformed to enantio-enriched (S)-3-amino-2,2-difluoro-3-phenylpropanoic acid 133 (see Scheme 9.28) [55]. 

The storage stability of other lipases has been also analysed. For instance, the storage stability of PsL in hydrophobic ILs for a period of 20 days at room temperature, measured with the variation of the transesteriiication activity of this enzyme during transesterification of ethyl 3-phenylpropanoate with different alcohols, resulted in an increased yield of 62-98% in [bmim fNTfj ] and 45-98% in [bmim ] [PFg ], respectively, depending on the nature of alcohol used in the tiansesterifica-tion reaction. In these ionic liquids, the operational stability was also measured and found that the P.yL-IL mixture was recycled live times without any decrease in the transesterification activity [13]. 

Aromatic esters have been synthetised in ionic liquids. In this context, the lipase-catalysed acylation of 2-hydroxymethyl-l,4-benzodioxane with vinyl acetate was carried out in two ionic liquids, [bmim+][PFg ] and [bmim+][BF ] [14], They found better or comparable conversion in these unconventional media than in conventional organic solvents. Another interesting example of aromatic ester biosynthesis in ILs was reported by Vidyaa and Chadhaa [13]. These authors carried out the transesteii-fication of ethyl 3-phenylpropanoate with 11 alcohols catalysed by in [bmim ] [PFg ], [bmim "][BF "] and [bmim+llNTf "] as reaction media. 

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