569. Amino-acids and peptides. Part IV. Alkaline hydrolysis of α-acetylalanine (2-amino-4-oxopentanoic acid), N-glycyl-α-acetylalanine, and related compounds

1963 ◽  
Vol 0 (0) ◽  
pp. 3100-3105 ◽  
Author(s):  
C. H. Hassall ◽  
D. I. John ◽  
T. G. Martin ◽  
J. A. Schofield
2013 ◽  
Vol 53 (2) ◽  
pp. 121 ◽  
Author(s):  
Carlos Álvarez ◽  
Manuel Rendueles ◽  
Mario Díaz

Alkaline hydrolysis of proteins recovered from slaughterhouse blood is a method to obtain profitable peptides and free amino acids for animal feed, besides decreasing the waste produced by this industry. The current trend to use enzymatic hydrolysis may need reconsidering due to its high cost in materials and the need for control processes that are both complex and expensive. The use of caustic soda (NaOH), which is a low-cost product, to obtain useful peptides from porcine haemoglobin is studied in this paper. Concentrations of 6 M NaOH at 50°C for 24 h afforded an 80% peptide recovery yield with an average peptide size of 13 kDa. Product obtained at 24 h was composed of soluble haemoglobin (7%), peptides larger than 10 kDa (63%), peptides between 6 and 10 kDa (16%), peptides between 1 and 6 kDa (1%), free amino acids (4%) and non-soluble compounds (8%). A kinetic model was subsequently developed. It is proposed that neutralising the alkaline product using acid products allows the processing of a higher amount of protein while employing the same amounts of reagents, although this topic requires further research.


1960 ◽  
Vol 67 (4) ◽  
pp. 319-332
Author(s):  
J. G. Campbell

SynopsisEvidence is presented that, in fowls, as in a number of mammals, intravenously administered sodium bromosulphthalein is excreted by the liver into the bile in several forms. These metabolites are not glucuronides, esters or sulphates, and in the fowl do not have the chromatographic mobilities or other characteristics of any of the amino acids described as conjugating with BSP in mammals. In all, three forms of BSP are detectable in fowl bile after administration of the dye, one, with the highest Rf. is unchanged BSP, the others are associated with ninhydrin positive material, and have lower Rf. values. Conjugation has been studied in young chickens and in adults, and the effects of sex hormones, cortisone and liver damage have been assessed. It is shown that a proportion of the injected BSP may be retained for some time in the liver as a colourless form, so that only prolonged alkaline hydrolysis of liver extract and homogenate results in its liberation as a detectable coloured form. The significance of this, and the effect of sex hormones in influencing the amount of conjugation and thus possibly affecting the rate of liver clearance of BSP is discussed, and evidence is presented that there exists an apparent inverse relationship between the amount of œstrogen as assessed by BSP liver-clearance test and the relative proportions of the two BSP conjugates in the bile. Also direct relationship may exist between the amount of œstrogen and the proportion of colourless BSP found in the liver.


1984 ◽  
Vol 49 (11) ◽  
pp. 2520-2530 ◽  
Author(s):  
Václav Bártl ◽  
Karel Šindelář ◽  
Vladimír Valenta ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
...  

Reactions of 2-chloro- and 2-methyl-6,11-dihydrodibenzo[b,e]thiepin-11-ol with 2-bromoethanol in the presence of sulfuric acid in boiling benzene afforded the 2-bromoethyl ethers VIa and VIb which were transformed by substitution reactions with 1-methylpiperazine, 1-(2-hydroxyethyl)-piperazine and 1-(ethoxycarbonyl)piperazine to the title compounds. Alkaline hydrolysis of the carbamate IVa gave the secondary amine IIIa. Treatment of the bromo ether VIa with 4-(4-chloro-3-trifluoromethylphenyl)piperidin-4-ol resulted in the piperidine derivative VIIa. Substitution reaction of 11-chloro-6,11-dihydrodibenzo[b,e]thiepin with 1-(2-methoxyethyl)piperazine and 1-(2-ethoxyethyl)piperazine led to the amino ethers VIII and IX. Reaction of 11-chloro-11-phenyl-6,11-dihydrodibenzo[b,e]thiepin with 2-dimethylaminoethanethiol in dimethylformamide at 90°C gave a mixture of two isomeric bases which was separated to the expected sulfide X and the base XII, resulting evidently after the rearrangement of the primary carbocation. A similar reaction of 3-dimethylaminopropanethiol afforded a single product of structure XI. Out of the compounds prepared, the ether VIII was found most interesting: it is little toxic and has significant antireserpine activity in two tests (is considered a potential antidepressant). The ethers Iab, Iab, IIIa and VIIa did not reveal the expected neuroleptic activity.


1951 ◽  
Vol 29 (9) ◽  
pp. 731-733 ◽  
Author(s):  
S. Epstein ◽  
C. A. Winkler

Measurements of the rates of alkaline hydrolysis of cyclotrimethylenetrinitramine (RDX) and cyclotetramethylenetetranitramine (HMX) in aqueous acetone show these two reactions to involve consecutive steps, the first of which is second order and rate controlling. Activation energies were estimated as 14 and 25 kcal. respectively. By establishing calibration curves, and controlling temperature, alkali concentration relative to concentration of explosive, and reaction time, the differential hydrolysis permits analysis of the HMX content of RDX(B) with an error of approximately ±0.2% HMX.


1994 ◽  
Vol 59 (5) ◽  
pp. 1126-1136 ◽  
Author(s):  
Vladimír Valenta ◽  
Jiří Urban ◽  
Jan Taimr ◽  
Zdeněk Polívka

4-(Aminomethyl)-1-benzyl-2-oxopyrrolidine (VI) was transformed by treatment with (4-benzhydrylpiperazin-1-yl)carbonyl chlorides IIIb - IIId and with (4-methylpiperazin-1-yl)carbonyl chloride (IIIa) to the carboxamides IVa - IVd. Heating of 1-(ethoxycarbonylmethyl)-2,4-dioxopyrrolidine (XIX) in acetonitrile in the presence of water afforded XVIIIa. Treatment with ammonia led to the diamide XVIIIc, while alkaline hydrolysis of XVIIIa gave the dicarboxylic acid XVIIIb. 4-(Aminomethyl)-1-(4-methylthiobenzyl)-2-oxopyrrolidine (XII) was prepared by the reaction of 4-(methylthio)benzylamine with itaconic acid and the following sequence of reactions starting from the obtained carboxylic acid VII including esterification, reduction and treatment the obtained alcohol IX with thionyl chloride, synthesis of phthalimido derivative XI and hydrazinolysis. Amine XII added to 4-chlorophenyl isocyanate formed XIII. The compounds prepared were tested for nootropic activity.


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