Propionic acid 638 Subject

Propiolactone is subject to attack by enolate ions to give propionic acid derivatives of ketones. It may likewise react with nucleophilic enamines to give carboxyethylation according to the reactions. The morpholide is easily hydrolyzed to the corresponding acid. 

To obtain a better understanding of the reaction mechanism, some compounds that are considered to he intermediates were subjected to the reaction. Various reaction courses can be considered as illustrated in Fig. 21. Path A a-Methyltropic acid is oxidized to a-phenyl-a-methylmalonic acid. Then, the malonate is converted to optically active a-phenylpropionate hy arylmalonate decarboxylase. In order to confirm this assumption, incubation of the malonic acid with Rhodococcus sp. was carried out. The result obtained was the total recovery of the substrate, indicating that no decarboxylase is present in this bacterium. Path B a-Methyltropic acid is converted to racemic a-phenylpropionic acid, which is deracemized to optically active propionic acid. To examine the possibility of this route, racemic a-phenylpropionic acid was subjected to the reaction to observe... 

Coumarin (7.88) is a well-known 6-lactone (six-membered ring) of natural origin found in various preparations such as some tobaccos, alcoholic beverages, and cosmetics. Besides reactions of oxidation, reduction, and conjugation, coumarin is also subject to lactone hydration in vivo and in the presence of microsomes [170-174], The resulting metabolites include ortho-coumaric acid (7.89) formed directly from coumarin, 3-(2-hydroxyphenyl)-propionic acid (7.91) formed following reduction of coumarin to dihydrocou-... 

In a more detailed study, the same esterase P. fluorescens) was again subjected to mutagenesis using the same mutator strain, but also by saturation mutagenesis at selected positions 133a). In addition to 3-phenylbutyric acid ethyl ester (27), 3-bromo-2-methyl-propionic acid methyl ester rac-31) was chosen for the hydrolytic kinetic resolution, with the WT PFE showing an E factor of 12 in favor of the (5)-32. 

Lactose is readily fermented by lactic acid bacteria, especially Lactococcus spp. and Lactobacillus spp., to lactic acid, and by some species of yeast, e.g. Kluyveromyces spp., to ethanol (Figure 2.27). Lactic acid may be used as a food acidulant, as a component in the manufacture of plastics, or converted to ammonium lactate as a source of nitrogen for animal nutrition. It can be converted to propionic acid, which has many food applications, by Propionibacterium spp. Potable ethanol is being produced commercially from lactose in whey or UF permeate. The ethanol may also be used for industrial purposes or as a fuel but is probably not cost-competitive with ethanol produced by fermentation of sucrose or chemically. The ethanol may also be oxidized to acetic acid. The mother liquor remaining from the production of lactic acid or ethanol may be subjected to anaerobic digestion with the production of methane (CH4) for use as a fuel several such plants are in commercial use. 

R = H) was observed with acetic acid. However, with propionic acid both isomers (414 and 415 R = Me) were formed in approximately equal amounts. It therefore appears that an initial acylation a to the carbonyl group, leading to the diketone, is followed by a second attack, the site of which is subject to subtle preferences (Scheme 137). 

Because the E. coli HMS174/PHA exhibited good growth in the presence of propionate and also had a high yield of P(HB-HV) accumulation in flask fermentation, E. coli HMS174/PHA was subjected to a fed-batch culture in which the cells were fed by glucose and propionic acid. The A6QQ... 

The diethyl 2-[3-bis(methoxycarbonyl)methyl-4-nitrophenyl]-2-methylmalonate obtained above,(4.13 g, 9.71 mmol) was dissolved in acetic acid (40 ml). To the solution were added water (16 ml) and concentrated sulfuric acid (4 ml), and the resulting mixture was heated for 15 hours under reflux. The acetic acid was distilled off under reduced pressure. The residue was concentrated under reduced pressure after addition of toluene. The precipitated crystals were collected by filtration and washed with water to give 2.06 g of the desired compound as a pale brown crystalline product. The filtrate and washing were combined and subjected to extraction using ethyl acetate. The ethyl acetate portion was washed successively with water and an aqueous saturated sodium chloride solution, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to leave 0.32 g of 2-(3-carboxymethyl-4-nitrophenyl)propionic acid as a yellow crystalline product. The total amount was 2.38 g (yield 96.8%). 

Dalapon is a member of the propionic acid group. Compounds in this class are water-soluble and relatively stable. They are subject to hydrolysis, but the rate is slow at lower temperatures. Also, they are sorbed to an appreciable extent on soils having high organic content, and a few of them remain active for several seasons. 

Finally, stereochemical or simply chemical considerations have led several authors to postulate the formation of a p-lactone whenever they have had to deal with a reaction involving ammonia or an amine in aqueous or alooholic solution and a P-halo aoid. Some of the older literature on this subject has been discussed by Darapsky and others, > notably the formation of 3-phenylhydracrylamidu by t-hc reaction of ammoDium hydxosidc with 3-bromo-3-phenyl-propionic acid ... 

This prompted us to develop a novel regioselective nitrosation procedure for resorcinol monoethers, e.g. for monobenzyl resorcinol, as starting material (Fig. (11)). Solid sodium nitrite in anhydrous propionic acid as solvent was an effective system for the completely regioselective nitrosation of the subject compounds. High yields of pure 2-nitroso products were obtained. Attack at the 4-position becomes only competitive in the presence of water in the solvent. Absence of water was ensured by addition of one percent of propionic anhydride. The excellent regioselectivity observed is obviously related to the presence of nitrosyl... 

If the antibody is immobilised on Sepharose , the supernatant containing the free, radioactive peptide can be separated easily and assayed in a gamma counter. With a standard curve drawn for known amounts of peptide subjected to assay under exactly the same conditions, unknown amounts of peptide can be determined by interpolation on the standard curve. There are two potential problems with this type of radioimmunoassay. First, the peptide to be assayed perhaps does not contain Tyr. If it contains His, however, this may suffice since His can be iodinated, especially by an enzymic procedure described below. Alternatively, the peptide is allowed to react with the Bolton and Hunter reagent (Bolton and Hunter, 1973), prepared by iodina-tion of the ester of 3-(4 -hydroxyphenyl)propionic acid and /V-hydroxysuccinimide. Any free amino group can be acylated by this reagent. Secondly, reaction of a peptide with Nal and chloramine-T can cause oxidation of Met, Cys and even Tyr residues, which can interfere with complexation of the iodinated peptide with antibodies raised to the un-iodinated peptide. An alternative method (Holohan et al., 1973) of iodination uses lactoperoxidase in the presence of H202. As pointed out above, this procedure is applicable to the iodination of His residues. This method avoids modification of the side-chains of Met, Cys and Tyr. 

The condensation, using heterogeneous catalysts, of methyl esters of acetic or propionic acids with formaldehyde to form methyl acrylate or methyl methacrylate has been the subject of a number of recent patents. Thus, lead acetate on silica 145), manganese dioxide on silica (146), and Ba-, Ca-, Sr-, and Mg- Decalso derivatives (147) have been effective catalysts for this reaction. 

Analysis of endogenous IAA. The extracts of cells with methanol were subjected to solvent fractionation using methylene chloride to give methylene chloride soluble acidic fractions. The fractions were purified by HPLC on an ODS column and finally by HPLC on a Nucleosil 5N(CH3>2 column with a fluorescent detector. Quantification was made by using an internal standard of indole-3-propionic acid which was added before purification. The results are shown in Figure 7. 

A recent publication described preparation of dendrimers from functional aliphatic polyesters that are based on 2,2-bis(hydroxymethyl)propionic acid [249]. A, Al -dicyclohexylcarbodiimide was used as the coupling agent in a double-stage convergent approach that reduced the number of synthetic and Uquid chromatographic steps required in the preparations and purifications. The hydroxyl functional dendrimers were then subjected to a variety of surface modifications by reactions with different acid chlorides [249]. 

Fig. 2. Western blot analysis of protein bound to immunoabsorbant columns. PyBHK EF-2 preparations containing cellular ADP-ribosyltransferase activity were chromatographed on Sepharose 4B coupled to Pseudomonas toxin A antibody or pyBHK ADP-ribosyltransferase antibody. After washing unbound material from the resin with PBS, the bound protein was eluted from the columns with 1 M propionic acid, concentrated under vacuum and subjected to electrophoresis on a 7.5% SDS-polyacrylamide slab gel. In addition. Pseudomonas toxin A standards were subjected to electrophoresis on the gel. Following electroblotting of the proteins from the ge) to a nitrocellulose sheet, the sheet was sectioned and reacted with Pseudomonas toxin A antibody (A-Q or with pyBHK ADP-ribosyltransferase antibody iP-F). Pseudomonas toxin A (A) protein from Pseudomonas toxin A antibody coupled immunoabsorbant B) protein from pyBHK ADP-ribosyltransferase antibody coupled immunoabsorbant (C, D) protein from Pseudomonas toxin A antibody-coupled immunoabsorbant (i ) Pseudomonas toxin A F). The numbers represent Mj. X 10" of the mol.wt. standards...

It is well known that spatially-hindered phenols have antioxidant properties [3, 4]. Therefore, the test subjects used were preparations that are spatially-hindered phenols potassium phenosan (2,6-ditert-butyl-4-hy-droxyphenyl-propionic acid potassium salt) and anphen sodium (1-N-(acetylamido) -1 - (3,5-di-tert-butyl-4-hydroxybenzyl)-methyl-malonate). 

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