Phenyl butanoate

Some workers avoid delay. Pai)adium-on-carbon was used effectively for the reductive amination of ethyl 2-oxo-4-phenyl butanoate with L-alanyl-L-proline in a synthesis of the antihyperlensive, enalapril maleate. SchifTs base formation and reduction were carried out in a single step as Schiff bases of a-amino acids and esters are known to be susceptible to racemization. To a solution of 4,54 g ethyl 2-oxO 4-phenylbutanoate and 1.86 g L-alanyl-L-proline was added 16 g 4A molecular sieve and 1.0 g 10% Pd-on-C The mixture was hydrogenated for 15 hr at room temperature and 40 psig H2. Excess a-keto ester was required as reduction to the a-hydroxy ester was a serious side reaction. The yield was 77% with a diastereomeric ratio of 62 38 (SSS RSS)((55). 

Asymmetric hydroalkoxycarbonylation of a-methylstyrene is also examined, leading to 3-phenyl-butanoic acid, the //< r///< /-product. The highest ee is at best 60% for this substrate.When an allylic alcohol is treated with a chiral Pd complex under GO, cyclohydrocarbonylation takes place to give the corresponding 7-butyrolactone in an asymmetric manner (Equation (6)). Similarly, chiral -lactones and other lactams can also be synthesized. 

Amino-3-(4-hydroxy-2,6-dimethyl phenyl (butanoic acid (25C) from 24C yield 90% mp... 

A similar unsuccessful attempt to perform a Claisen rearrangement on benzyl vinyl ether 7 resulted in a highly successful 1,3-benzyl shift to afford ethyl 3.3-dilluoro-2-oxo-4-phenyl-butanoate (8) in 82% yield.10... 

Exercise 20-25 A first step in unravelling the mechanism of the metabolism of fatty acids was made in 1904 by F. Knoop, who found that dogs metabolized 4-phenyl-butanoic acid to phenylethanoic acid and 3-phenylpropionic acid to benzoic acid. What does this pattern of results indicate about the mechanism of degradation of fatty acids Give your reasoning. 

Exercise 26-40 Explain why p for ionization of benzoic acids is larger than p for phenylethanoic acids. Estimate a value ofp for the ionization of substituted 4-phenyl-butanoic acids. Why should we expect the value of p for alkaline hydrolysis of ethyl benzoates to be larger than for acid ionization and to have the same sign ... 

Phenyl acetate Phenyl propanoate Phenyl butanoate Diphenyl oxalate Phenyl salicylate (salol)... 

The photoinitiation activity of poly(ABP)/DMA and IBP/DMA, as compared with that found for poly(ABP) and IBP alone, clearly confirms that the presence of amine activates both the systems. 4-[4-(7V,V-dimethylamino)phenyl] butanoate of 4-hydroxy benzophenone (DMABP), the low-molecular-weight structural model of poly(ABP-co-DMAS), having benzophenone and tertiary amine functions in the same molecule, is foimd [18,22,53] to display an intermediate activity with respect to those observed for poly(ABP)/DMA and poly(ABP-co-DMAS) systems (Table 11). 

Asymmetric induction in ring closure reactions of central chiral ferrocene derivatives has been reported. Moderate diastereoselectivity was found in the ring closure of the enantiomeric 4-ferrocenyl-2-methyl-2-phenyl-butanoic acids by treatment with trifluoroacetic anhydride (Fig. 4-211) [10]. The diastereoisomeric ketones could be separated by chromatography. A higher induction was observed in an asymmetric Pictet — Spengler type cyclization of a reactive imine formed from enantiomerically pure 2-ferrocenyl-2-propylamine and formaldehyde, as only one isomer of the product was detected (Fig. 4-21 g) [135, 136]. 

Iactone. The observed low frequency is probably caused by hydrogen bonding of the lactone carbonyl with the imino proton of the hydrazone residue on C2, as shown by NMR spectroscopy. The same low frequency band also appeared in the spectra of the bis(arylhydrazones) of other analogues (42,46) such as the phenyl analogue of DHA [4-phenyl-butano-1,4-lactone 2,3-bis(phenylhydrazone)], which cannot form a 1,5-lactone. Finally, the lactone ring size was also deduced from its chemical reactions (24). 

Phenyl-1,3-butadiene W-Phenylbutanamide Phenylbutanedioicacid, (t) l-Phenyl-I.S-biitanedione Phenyl butanoate... 

Problem 15.51. Write the equation for the saponification of phenyl butanoate by NaOH. Ans. 

Thus, the two names are phenyl butyrate (common name) and phenyl butanoate (lUPAC name). 

At first we tried to address the problem with Moreau s method of kinetic resolution which has been applied with great success to compounds of central chirality (ref. 18). To our knowledge this technique has not yet been used for compounds with axial chirality. To be on safe ground, we had to calibrate the effects first with compounds of similar structure and known absolute configuration. We selected 2,2 -dihydroxy-1,1 -binaphthyl (31) as an example and reacted it in the usual way with an excess of racemic 2-phenyl butanoic anhydride in the presence of pyridine. The optical excess in the remaining anhydride was determined by means of the gas chromatographic variant of Brooks and Gilbert (ref. 19) (Scheme 6). 

Another of the arylalanines, L-tryptophan, was used at the same laboratories [81] for the synthesis of novel benzazepines (56) as dual inhibitors of ACE and thromboxane synthase (Scheme 5.25). Ozonolysis of 7V-acetyl l-tryptophan to effect scission of the indole ring followed by 7V-protection gave the 4-keto acid (57) as a cyclization precursor. Downstream transformations included diastereoselective reduction of the ketone functionality and reductive alkylation of the amine substituent with ethyl 2-oxo-4-phenyl-butanoate. 

COMBINE comparative binding energy analysis AHPBA 3(S)-amino-2(S)-hydroxyl-4-phenyl butanoic acid... 

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