scholarly journals A New Generation of Glycoconjugated Azo Dyes Based on Aminosugars

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Lorenzo Guazzelli ◽  
Giorgio Catelani ◽  
Felicia D’Andrea
Keyword(s):  
Acid Hydrolysis ◽  
Azo Dyes ◽  
Azo Dye ◽  
Protecting Groups ◽  
Third Generation ◽  
Sugar Moiety ◽  
The Third ◽  
New Generation ◽  
Monoazo Dyes ◽  
Hydrolysis Of

The third generation of glycoconjugated azo dyes (GADs) was prepared linking monoazo dyes to 6-amino-6-deoxy-d-galactose or 6′amino-6′-deoxylactose through mixed amido-ester connections. The complementary conjugation reactions were studied using the succinyl derivative of either the acetal protected aminosugar or the azo dye. Target “naturalized” GADs were obtained after acid hydrolysis of the acetal protecting groups present on the sugar moiety.

Selective acid hydrolysis of 2,4,6-trimethylbenzyl esters and its application in peptide synthesis

1966 ◽  
Vol 19 (8) ◽  
pp. 1511 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Acid Hydrolysis ◽  
Peptide Synthesis ◽  
Trifluoroacetic Acid ◽  
Ester Group ◽  
Protecting Groups ◽  
Alkaline Conditions ◽  
Hydrolysis Of

Experiments with various N-acylamino acid 2,4,6-trimethylbenzyl esters have shown that the ester group is cleaved selectively by cold trifluoroacetic acid without affecting benzyloxycarbonyl, formyl, or phthaloyl amino-protecting groups present. The possible value of this selective behaviour in peptide syntheses where the use of alkaline conditions would be detrimental is illustrated by the synthesis of certain dipeptide derivatives.

Determination of Unconjugated and Total N-Acetyl-p-aminophenol (NAPA) in Urine and Serum

1967 ◽  
Vol 13 (3) ◽  
pp. 215-219 ◽  
Author(s):  
Karel P M Heirwegh ◽  
Johan Fevery
Keyword(s):  
Liver Disease ◽  
Acid Hydrolysis ◽  
Azo Dye ◽  
Acidic Medium ◽  
Diazonium Salt ◽  
Accurate Method ◽  
Total N ◽  
Hydrolysis Of ◽  
Urine And Serum

Abstract A sensitive and accurate method is described for the determination of N-acetyl-p-aminophenol (NAPA) and its metabolites in urine and serum. In strongly acidic medium, p-aminophenol (PAP) resulting from differential extraction and acid hydrolysis of total NAPA and unconjugated NAPA, is diazotized and the diazonium salt coupled with N-(1-naphthyl)ethylenediamine (NED) in the presence of ethanol. The blue azo dye formed is determined spectrophotometrically. Application to liver disease is briefly reported.

Preparation of enantiomeric and racemic 2,3,4,5-tetrahydroxypentyl derivatives of adenine, cytosine and uracil

1982 ◽  
Vol 47 (10) ◽  
pp. 2786-2805 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Catalytic Hydrogenation ◽  
Protecting Groups ◽  
Sodium Salts ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Subsequent Acid

1-(Adenin-9-yl)-1-deoxy-DL-ribitol (III), -D-arabitol (IXa), -L-arabitol (XIVa), -DL-xylitol (XXIVa), 1-(cytosin-L-yl)-1-deoxy-D-arabitol (IXb), -L-arabitol (XIVb), 1-(uracil-1-yl)-1-deoxy-D-arabitol (IXc), -L-arabitol (XIVc) and -DL-xylitol (XXIVb) were prepared by reaction of 1-O-p-toluenesulfonyl-2,3:4,5-di-O-isopropylidenealditols Ib, VIIb, XIIb and XXIIb with sodium salts of adenine, N4-benzoylcytosine or 4-methoxy-2-pyrimidone followed by removal of the protecting groups. Condensation of the mentioned sodium salts with methyl 5-O-p-toluenesulfonyl-2,3-O-isopropylidene-β-D-ribofuranoside (IV) with subsequent acid hydrolysis and reduction with sodium borohydride afforded 1-(adenin-9-yl)-1-deoxy-L-ribitol (VIa) and 1-(cytosin-1-yl)-1-deoxy-L-ribitol (VIb). 1-(Adenin-9-yl)-1-deoxy-L-lyxitol (XVII), -L-lyxitol (XVIII) and -2-O-methyl-D-lyxitol (XXI) were prepared analogously. Acid hydrolysis of 5-(adenin-9-yl)-5-deoxy-4-O-benzyl-1,2-O-isopropylidene-α-D-xylofuranose (XXVa), followed by reduction with sodium borohydride and catalytic hydrogenation, gave 1-(adenin-9-yl)-1-deoxy-L-xylitol (XXVIb).

The Third Generation of Guerrilla Warfare

Asian Survey ◽  
1968 ◽  
Vol 8 (6) ◽  
pp. 435-447 ◽  
Author(s):  
Chalmers Johnson
Keyword(s):  
Guerrilla Warfare ◽  
Third Generation ◽  
The Third

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

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