N-Benzoyl-L-phenylalanine

The nature of the hydrogen bonding in polymorphs of AT-benzoyl-D,L-phen-ylalanine and N-benzoyl-L-phenylalanine has been investigated by solid state 13C NMR [137]. 

The multiple resonances observed for the carbon of the carboxylic acid group in N-benzoyl-L-phenylalanine were shown to be related to different types of hydrogen bonding. These results are in good agreement with earlier studies using... 

Figure 10.19 Comparison of calculated (lines) and experimental (symbols) band profiles. Left N-benzoyl-L-phenylalanine on Resolvosil-BSA-7 (isotherms in Figures 3.12). Right N-benzoyl-D-phenylalanine, same conditions. Mobile phase 0.1 M buffer aqueous solution (pH 6.8) with 7% 1-propanol (v/v). L = 15 cm d = 4 mm F = 1 mL/min N = 700 sample sizes 1, 0.494 ftmol 2 0,989 jimol 3 1.48 ftmol. Bi-Langmuir isotherm selective site ui = 20.1, qs i = 0.556 mmol/L nonselective site ai = 7.09, qg 2 = 217 mmol/L. (Inset) Band profiles calculated from the Langmuir model (see Figure 3.12). S. Jacobson, S. Golshan-Shirazi and G. Guiochon, AIChE /., 37 (1991) 836 (Fig. 2). Reproduced by permission of the American Institute of Chemical Engineers. 1991, AIChE. All rights reserved.

Figure 18.6 pH dependence of the apparent equilibrium constant for the synthesis of N-benzoyl-L-phenylalanine ethyl ester in water and in a biphasic system consisting of chloroform and 5% (v/v) water (redrawn from Martinek et al., 1980, 1981b)... 

P.J. Chu, M.J. Potrzebowski, A.L Scott, Y. Gao, Conformational studies of N-benzoyl-L-phenylalanine by combined rotation and multiple-pulse spectroscopy proton nuclear magnetic resonance, J. Am. Chem. Soc. 112 (1990) 881—883. 

Conversion of N-benzoyl-L-phenylalanine into L-phenylalanine Hydroxylation... 

Figure 17.19 Rates of hydrolysis of two families of esters by a hydrolase, chymotrypsin. The esters of N-acetyl-L-phenylalanine exhibit very similar rates because the process in each case is limited by the same enzyme deacylation reaction (Zerner et al., 1964). The esters of N-benzoyl glycine exhibit rates varying by more than a factor of 3 because their hydrolyses are mostly limited by the initial enzyme acylation step (Epand and Wilson, 1963).

The aqueous filtrate from the acylase hydrolysis described above was acidified to pH 2.4 with 1M HC1. The crystals were isolated (2.91 g) and recrystallized from boiling EtOAc (500 mL) to give N-acetyl-4-benzoyl-D-phenylalanine(d-76) yield 2.72g (87%) mp 186.5-187°C [a]D25 -49.0 0.8 (c 1.05, EtOH). Reaction with Ac20 converted a small aliquot of 4-benzoyl-L-phenylalanine (l-3) into /V-acetyl-4-benzoyl-L-phenylalanine (l-76) mp 187-188 °C [a]D25 +50.9 0.8 (c 0.98, EtOH). 

A phenylalanine ester, N-benzoyl-0-[N benzoyl - L -phenylalanyl]-L- phenylalaninol (13), was also isolated from this same extract [56]. Silica gel fractions 10 and 11 were further resolved by HPLC as described for the penitrems. Fraction 21 of this separation was chromatographed by normal phase HPLC (Rainin cyanopropyl semipreparative, 5% isopropanol/hexane, flushed with 25% isopropanol/hexane). Fraction 4 yielded phenylalaninol. 

Trypsin, chymotrypsin, and cathepsin C (all from bovine), and the synthetic substrates glycyl-L-phenylalanine p-naphtylamide (GPNA), 4-phenylazo benzyloxy-car-bonyl-pro-leu-gly-pro-D-arg (PZ-peptide), N-benzoyl-L-tyrosine ethyl ester (BTEE), and Na-benzoyl-DL-arginine p-nitroanilide (BAPNA), were purchased from Sigma Chemical Co (St. Louis, MO). Fresh bluefish (Pomatomus saltatrix) and sheephead samples were purchased from a local fish market (Waldman Plus, Montreal, PQ) and kept in iCe until ready for use. 

Ci8Hi9NOi, N-Benzoyl-L-tyrosine ethyl ester, 38B, 500 Cl 8 2il2N2O5, 3,5-Iodo-L-thyronine N-methylacetamide, 38B, 500 C18H22N2OSS, Glycyl-L-phenylalanine p-toluenesulphonate, 38B, 499 Cl8H2 5N3O4, N-Benzyloxycarbonyl-a-aminoisobutyryl-L-prolyl methyl-amide, 45B, 525... 

N-Benzoyl-Lalanine methyl ester is in turn about eight times more reactive than is its D enantiomer). The open-chain compounds may not bind to the enzyme in the same manner, however, as does the locked substrate. The conformation around the amido bond of the open-chain compounds, for example, can be transoid rather than cisoid (81). In addition, if equatorial 24 is considered to be the reactive conformer for both the Dand L enantiomers, and if the alanine methyl group is attracted to the hydrophobic aromatic binding subsite, then structures 34 and 38 would result. The L enantiomer of N-benzoyl-phenylalanine methyl ester 38 in this representation has approximately the same conformation as equatorial L-24. But attraction of the methyl of the D enantiomer to the location occupied by the methyl group of the L enantiomer causes the carbomethoxy group to move from the position it occupies in D-24. 

Lipase-catalyzed enantiomer-differentiating hydrolysis of racemic phenyl benzyl oxazolin-2-one in aqueous solution in combination with an uncatalyzed in situ racemization of the unchanged enantiomer of the heterocyclic system, with two different lipases, gives access to d- and L-N-benzoyl-phenylalanine 9 and ent-9, respectively. Enantiomer-differentiating alcoholysis and in situ racemization in organic solvents in the presence or absence of added water under the catalysis of lipase can in some cases furnish amino acid derivatives (10-18) with good selectivities and yields. 

A soln. of excess glycine ethyl ester hydrochloride in 1 N NaOH and phosphate buffer, pH 7.8, added to a soln. of benzoyl-DL-phenylalanine glycolic ester in alcohol and 1 N NaOH, the pH brought to 8.15, amorphous enzyme from ground pancreas added, and allowed to stand 2 hrs. at 20° benzoyl-L-phenylalanyl-glycine ether ester. Y 70.6% based on L-antipode. F. e. s. M. M. Botvinik et al., aC. 31, 3234 (1961) G. A. 57, 3560b. 

However, one uniquely constrained substrate, 3-methoxycarbonyl-2-dibenzazocine-l-one, was synthesized in 1968 by Belleau and Chevalier from diphenic anhydride (106). This 2,2 -bridged biphenyl compound is a constrained analogue of N-benzoyl phenylalanine methyl ester (BPME). 

JV-Acetyl-n-phenylalanine derivatives, 25° (23). l JV-Benzoyl-u-arginine derivatives, 25° (24). 

Amino-acid analogs DL-a-Amino-n-octanoate, D-a-aminophenylacetate, p-amino-DL-phenylalanine, M-benzoyl-DL-leucine, L-a-hydroxyisocaproate, a-ketoisocaproate, N-methyl-DL-leucine [747]... 

---