3-Phenylpropanoic acid ethyl ester

Phenylpropanoic acid ethyl ester (ethyl hydrocinnamate)... 

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. 

Meyers and others showed that 2-oxazolines such as 295 are useful carbanionic synthons when they are converted to their a-lithio derivative. Reaction of 295 with ra-butyllithium, for example, gave 296. Addition of benzyl bromide gave the alkylated product 297, and heating that product in ethanolic sulfuric acid gave an 84% yield of the ethyl ester, ethyl 3-phenylpropanoate (298). Ketones react in a similar manner and the product is usually a conjugated acid derivative. 

An earlier version of this reaction condensed 4.18 and malonic acid to give 4.19. Refluxing 4.19 led to the monomer 4.20), which decarboxylated under the reaction conditions to give 3-amino-3-phenylpropanoic acid, 4.21. Doebner condensation with malonic acid itself sometimes leads to very poor yields of product, as seen above. An improvement in the reaction used nitro-ester 4.22 rather than malonic acid, and 4.23 [ethyl 3-(N-phenylamino)-2-nitroprop-2E-enoate] was produced in good yield. 

The condensation reaction of an imine derived from an aldehyde with ethyl bromoacetate under Reformatsky53 conditions led to a mixture of amino-esters and P-lactams. When acetaldehyde was condensed with methylamine, Schiff base 4.116 was the product A Reformatsky reaction with ethyl bromoacetate gave a mixture of the P-lactam (4.117) and the amino-ester (4.118). Acid hydrolysis and hydrogenation led to the P-amino acid N-methyl-3-aminobutanoic acid (4.119). When benz-aldehyde was the aldehyde starting material, 3-(N-methylamino)-3-phenylpropanoic acid (4.120) was the final product. ... 

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. 

In 1993, a perfluorocarbon was used as a reaction solvent for azeotropic transesterification reactions of carboxylic acid esters. One of the ultimate goals of transesterification is the use of a 1 1 ratio of ester and alcohol. Such a 1 1 transesterification was recently achieved using a fluorous version of the Otera method, which is based on tetraalkyldistannoxane. For example, octanol and ethyl 3-phenylpropionate were added to an FC-72 solution containing fluorous stannoxane [(C6Fi3CH2CH2)2SnO] 15. The mixture was then sealed and heated at 150°C for 16h. When the mixture was cooled, phase separation occurred and octyl 3-phenylpropanoate was obtained by separation and evaporation of the upper layer (Scheme 19). The lower FC-72 layer, which contained the catalyst, was used more than 20 times without any loss in catalytic activity. ... 

Table III shows the results of hydro-bromination and hydrochlorination of the ethyl trans-cinnamate inclusion complexes. No hydrochlorination was observed at various temperatures after long exposure of hydrogen chloride gas similar to the reaction of trans-cinnamic acid [14]. Addition of hydrogen bromide to the ester gave an optically active and regioselective product, ethyl R-(+)-3-bromo-3-phenyl-propanoate in 46 % e.e. from the a-cyclodextrin, or ethyl S-(-)-3-bromo-3-phenylpropanoate in 31 % e.e. from the 3-cyclodextrin inclusion complex.

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