N-Benzoyl-P-alanine

Filter off the crude product, wash the filter-cake with about 60 ml of chilled water. The yield of crude N-benzoyl-P-alanine (mp 131-133°C) is approximately 20.2 g. 

T Recrystallization. Recrystallize 20 g of the crude product from 350 ml of boiling water. About 1 g of decolourising charcoal may be added, if the solution has a pale-yellowish colouration. The yield of pure N-benzoyl-P-alanine (mp 132-132.5°C) is 18.2 g. 

Figure 3.33 Effect of temperature on adsorption isotherms, (a) Adsorption of p-cresol on ODS silica. Column dimensions 1.2 x 50 mm. Temperature 1, 25°C 2, 40°C 3, 60°C. Reproduced with permission from J. Jacobson, J. Frmz and Cs. Horvath, ]. Chromatogr., 316 (1984) 53 (Fig. 9). (b) Adsorption of N-Benzoyl-D-alanine on immobilized bovine serum albumin. Reproduced with permission from S. Jacobson and G. Guiochon, J. Chromatogr., 522 (1992) 23 (Fig. 2).

Acetylbenzene. See Acetophenone Acetyl benzoyl. See 1-Phenyl-1,2-propanedione N-Acetyl-N-butyl-P-alanine, ethyl ester. See Ethyl butylacetylaminopropionate Acetyl butyl citrate. See Acetyl tributyl citrate 2-Acetyl-5-t-butyl-4,6-dinitroxylene. See Musk ketone... 

Figure 4.22 Experimental concentration profiles in the column effluent for adsorption isotherm determination by binary frontal analysis. (Left) Bottom trace solid line, experimental UV profile dotted line reconstructed profile of 3-phenylpropanol (P) dashed line reconstructed profile of 2-phenylethanol (E). Arrows 1-5 indicate the time when the eluent sample was taken for on-line analysis. Top trace On-line analysis of the sampled eluent. Reproduced with permission from J. Zhu, A. Katti and G. Guiochon, J. Chromatogr. 552 (1991) 71 (Fig. 1). (Right) Examples of one-step binary frontal analyses for the determination of the competitive isotherms of N-benzoyl-D,L-alanine. Injection of large volumes (5 mL) of solutions of increasing concentrations of racemic mixture. Reproduced with permission from S.C. Jacobson, A. Felinger and G. Guiochon, Biotechnol. Progr., 8 (1992) 533 (Fig. 1), 1992 American Chemical Society.

Figure 4.2S Competitive isotherms of phenol and p-cresol on an octadecylsilica. In these two figures, the top isotherm is the single solute isotherm. Isotherms denoted A, B, and C correspond to solutions with 1 3,1 1, and 3 1 mole ratios of phenol and p-cresol, respectively, (a) Competitive isotherms of p-cresol. (b) Competitive isotherms of phenol. Reproduced with permission from J. Jacobson, J. Frenz and Cs. Horvdth, Ind. Eng. Chem. (Res.), 26 (1987) 43 (Fig. 4), 1987 American Chemical Society, (c) Competitive isotherms of N-benzoyl D- (o) and L-alanine v>) in the racemic mixture single component isotherms of N-benzoyl D- (+) and L-alanine (A). Reproduced with permission from S.C. Jacobson, A. Felinger and G. Guiockon, Biotechnol. Progr., 8 (1992) 533 (Fig. 2), 1992 American Chemical Society.

As an example, we show in Figure 4.25 the competitive isotherms of the mixture of p-cresol (Figure 4.25a) and phenol (Figure 4.25b) on octadecyl silica [14], and those of N-benzoyl-D- and L-alanine on BSA immobilized on silica [29]. The isotherms in Figure 4.25 were measured by binary frontal analysis (Section 4.2.1). 

Figure 11.20 Comparison of calculated (solid line) and experimental (s5nnbols) individual band profiles. Mixtures of N-benzoyl-L-(l) and D-(2)-alanine on a Resolvosil-BSA-7 column. Mobile phase 10 mM buffer aqueous solution (pH 6.7) with 3% 1-propanol (v/v) at Fn = 1 mL/min. L = 15 cm, d = 4 mm N = 700 plates. Binary competitive Langmuir isotherm selective site ai i = 14.16, fli p = 35.09, qs,i,L - 0.0019 mol/L, = 0.0020 mol/L nonselective site 2 = 4.41, = 0.01995 mol/L. (Left) Racemic mixture, sample sizes 0.26...

L-a-Alanine. See L-Alanine P-Alanine, N-acetyl-N-butyl-, ethyl ester. See Ethyl butylacetylaminopropionate P-Alanine, N-(2-aminoethyl)-N-[2-(2-carboxyethoxy) ethyl]-, N-coco acyl derive., 2,2 -iminobisethanol salts. See DEA-cocoamphodipropionate D-Alanine, N-benzoyl-N-(3-chloro-4-fluorophenyl)-, isopropyl ester. See Flamprop-m-isopropyl... 

Benzoyl chloride, methoxy- Benzoyl chloride, 4-methoxy-. See p-Anisoyl chloride Benzoyl chloride, 3-nitro- Benzoyl chloride, m-nitro-. See m-Nitrobenzoyl chloride N-Benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine 1-methylethyl ester. SeeFlamprop-isopropyl... 

Methyl benzoyl chloride p-M ethyl benzoyl chloride. See p-Toluoyl chloride Methyl N-benzoyl-N-(3-chloro-4-fluorophenyl) alaninate Methyl N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alaninate Methyl 2-(benzoyl (3-chloro-4-fluorophenyl) amino) propionate. See Flamprop-methyl Methylbenzoylformate. See Methyl phenylglyoxalate 4-Methyl benzyl acetate CAS 2216-45-7 EINECS/ELINCS 218-689-3 Synonyms p-M ethyl benzyl acetate Empirical C10H12O2... 

But the formation of azlactones as intermediates cannot explain all the observations made in this field. Thus it has been mentioned already that ketene racemizes AT-methyltryptophan. Carter and Stevens (1940) state that certain acyl derivatives of ir-proline and W-methyl-n-phenyl-alanine are rapidly racemized by the action of acetic anhydride in glacial acetic acid. In the same paper it is also reported that the addition of various azlactones to a solution of benzoyl-p-methoxyphenylalanine in acetic acid produces fairly rapid racemization of the acyl derivative. An azlactone can obviously not be formed from a compound such as proline, and there is no evidence that structures such as XLIII exist and even if they exist, there is no apparent reason why they should be so easily racemized. There is a possibility of the transient formation of a dipolar structure such as XLV, which is analogous to the formula proposed for sydnones (Baker and Ollis, 1946). But a more likely explanation is that both ketene and acetic anhydride can form mixed anhydrides with acylamino acids, which can then rearrange to form azlactones and acetic acid. Reference has already been made to the action of ketene on carboxylic acids to produce mixed anhydrides and similar reactions have been observed with acetic anhydride. The marked racemization of such structures is partly explained by the strongly electronegative character of the anhydride group. Such an explanation is supported by the findings... 

Several p-amino acids occur naturally as free metabolites in metabolic pathways or as key intermediates in biosynthetic products. p-Alanine is the simplest p-amino acid that appears in pantothenic acid, a precursor of the coenzyme A. Further examples are (2R,3S)-N-benzoyl-3-phenylisoserine derived from (R)-p-phenylalanine, a compound in the antitumor agent paclitaxel from Taxus brevifolia [89], or as building blocks for p-lactam antibiotics [90] and in jasplakinolide, an antifungal compound [91] (Scheme 29.12). 

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