Preparation and Characterization by Alkaline Methanolysis of 5,5-Diethyl-4-(tetraacetyl-β-D-glucosyloxy)-2,6(1,5)-pyrimidinedione1

1953 ◽  
Vol 75 (8) ◽  
pp. 1881-1883 ◽  
Author(s):  
Jack A. Snyder ◽  
Karl Paul Link
Keyword(s):  
Alkaline Methanolysis

scholarly journals Alkaline methanolysis of lipid extracts extends shotgun lipidomics analyses to the low-abundance regime of cellular sphingolipids

2007 ◽  
Vol 371 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Xuntian Jiang ◽  
Hua Cheng ◽  
Kui Yang ◽  
Richard W. Gross ◽  
Xianlin Han
Keyword(s):  
Shotgun Lipidomics ◽  
Alkaline Methanolysis

Biliprotein in adult icteric serum--demonstrated by extension of the alkaline methanolysis procedure.

1982 ◽  
Vol 28 (12) ◽  
pp. 2398-2404 ◽  
Author(s):  
T W Wu ◽  
S S Sullivan
Keyword(s):  
Total Bilirubin ◽  
Unconjugated Bilirubin ◽  
Clinical Implications ◽  
Protein Pellet ◽  
Analytical Recovery ◽  
Alkaline Methanolysis

Abstract We confirmed that the alkaline methanolysis procedure of Blanckaert (Biochem. J. 185: 115-128, 1980) converts the sugar conjugates of bilirubin (Bc) into their corresponding methyl and dimethyl esters, which can be extracted into chloroform along with underivatized unconjugated bilirubin (Bu). By this procedure, we accounted for Bu nearly quantitatively, but only 76-83% of total Bc. By pretreating samples containing Bu and (or) Bc with a caffeine/benzoate reagent, we improved the analytical recovery of Bc to 85-93% without affecting the Bu. When the method (+ caffeine/benzoate) was applied to adult icteric serum, a variable fraction (20-75%) of the original total bilirubin (based on diazo reactivity) remained with the protein pellet, which is routinely discarded in the original methanolysis procedure. In this pellet we demonstrated the occurrence of a strongly protein-bonded bilirubin fraction (biliprotein) similar to the recently described "delta" fraction (Clin. Chem. 28: 629-637, 1982). The analytical and clinical implications of our findings are discussed.

Serum and Bile Bilirubin Pigments in the Differential Diagnosis of Crigler-Najjar Disease

PEDIATRICS ◽  
1994 ◽  
Vol 94 (4) ◽  
pp. 553-556 ◽  
Author(s):  
FIRMINO F. RUBALTELLI ◽  
ANTONELLA NOVELLO ◽  
LUCIA ZANCAN ◽  
MARIA TERESA VILEI ◽  
MAURIZIO MURACA
Keyword(s):  
High Serum ◽  
Unconjugated Bilirubin ◽  
Bile Pigment ◽  
Bile Pigments ◽  
Pigment Composition ◽  
Bilirubin Concentration ◽  
Before And After ◽  
Alkaline Methanolysis ◽  
Bile Samples

Objective. To differentiate between Crigler-Najjar (CN) disease types 1 and 2. Design. The patterns of serum bilirubins, bile pigment composition, and phenobarbital response were studied. Patients. Three infants, affected by high serum unconjugated bilirubin concentrations, previously classified as type 1 CN. Methods. Serum and bile bilirubin pigment composition, both before and after phenobarbital (PB) treatment, were determined by alkaline methanolysis and high-pressure liquid chromatography. PB was given for at least 3 weeks by oral administration (5 mg/kg bw per day). Results. No diconjugated bilirubin was found either before or after PB treatment in the serum of the three studied infants. In two patients traces of monoconjugated bilirubin were detected before PB therapy, and the ratio of conjugated/total bilirubin (percent) was increased by the PB response. In the third patient, traces of monoconjugated bilirubin appeared only after PB administration. However, the serum unconjugated bilirubin concentration decreased significantly only in the second patient, following the second cycle of PB treatment, leading to the diagnosis of type 2 CN. The analysis of the methyl ester derivatives of bile pigments was also performed on bile samples obtained in two patients by Entero-Test (R) both before and after PB treatment. An absolute increment in monoesterified bilirubin concentration was found after PB administration, although the percent concentration increased in one case and decreased in the other. No diesterified bilirubin was detected in the bile samples. Conclusions. The present results show that in types 1 and 2 CN disease it is possible to detect traces of monconjugated but not diconjugated bilirubin both in serum and in bile. Whereas PB treatment is effective in slightly increasing the serum monoconjugated bilirubin concentration even in type 1 CN disease, the diagnosis of type 1 or 2 is based on finding a substantial decrease of serum unconjugated bilirubin following PB administration.

Subfractionation of serum bilirubins by alkaline methanolysis and thin-layer chromatography

1990 ◽  
Vol 11 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Andreas Sieg ◽  
Rainer König ◽  
Dieter Ullrich ◽  
Johan Fevery
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Alkaline Methanolysis ◽  
Layer Chromatography

Alkaline Methanolysis of Theobromine β-D-Glucoside Tetraacetate

1949 ◽  
Vol 71 (11) ◽  
pp. 3743-3746 ◽  
Author(s):  
Clinton E. Ballou ◽  
Karl Paul. Link
Keyword(s):  
Alkaline Methanolysis

ChemInform Abstract: ALKALINE METHANOLYSIS OF 1,1,1-TRICHLORO-2-HYDROXY-4-ALKANONES

1976 ◽  
Vol 7 (43) ◽  
pp. no-no
Author(s):  
E. KIEHLMANN ◽  
J. I. WELLS ◽  
W. REEVE
Keyword(s):  
Alkaline Methanolysis

Novel Rearrangement During Alkaline Hydrolysis of 1,1,1-Trichloro-2-alken-4-ones

1972 ◽  
Vol 50 (16) ◽  
pp. 2561-2567 ◽  
Author(s):  
Eberhard Kiehlmann ◽  
B. C. Menon ◽  
J. I. Wells
Keyword(s):  
Methyl Ester ◽  
Potassium Hydroxide ◽  
Potassium Salt ◽  
Dienoic Acid ◽  
Equimolar Amount ◽  
Hydrogen Atoms ◽  
Alkaline Methanolysis ◽  
Pentadienoic Acid ◽  
Hydrolysis Of ◽  
Fold Excess

The action of a five-fold excess of potassium hydroxide in methanol on 1,1,1-trichloro-2-penten-4-one (1), 1,1,1-trichloro-6-methyl-2-hepten-4-one (5), and 1,1,1-trichloro-6,6-dimethyl-2-hepten-4-one (9) gives rise to the potassium salt of 5-chloro-2,4-pentadienoic acid (2), the potassium salt and methyl ester of 5-chloro-6-methyl-2,4-heptadienoic acid (7), and the methyl ester of 5-chloro-6,6-dimethyl-2,4-heptadienoic acid (10), respectively.When the same reaction is performed with an equimolar amount of base, 1 is converted into methyl 5-chloro-2,4-pentadienoate (3) as well as 1,1,1-trichloro-2-methoxy-4-pentanone (4); the latter compound (4) is shown to be a true intermediate in the formation of 3.Neither 1,1,1-trichloro-5-methyl-2-hexen-4-one (11) nor 1,1,1-trichloro-5-ethyl-2-hepten-4-one (14) yields the expected dienoic acid or ester when treated with an equimolar amount of potassium hydroxide. Instead, alkaline methanolysis of 11 leads to the formation of a mixture of 1,1,1-trichloro-2-methoxy-5-methyl-4-hexanone (12) and 1,1-dichloro-2,5-dimethoxy-5-methyl-4-hexanone (13), whereas 14 gives predominantly 1,1,1-trichloro-2-methoxy-5-ethyl-4-heptanone (15) and traces of 1,1-dichloro-2,5-dimethoxy-5-ethyl-4-heptanone (16).On the basis of these observations, a mechanism is proposed for the formation of 2, 7, and 10 which requires the presence of two geminal α-hydrogen atoms in the olefinic starting material.

Extraction of mycobacterial mycolic acids and other long-chain compounds by an alkaline methanolysis procedure

1984 ◽  
Vol 2 (5) ◽  
pp. 243-249 ◽  
Author(s):  
D.E. Minnikin ◽  
S.M. Minnikin ◽  
A.G. O'Donnell ◽  
M. Goodfellow
Keyword(s):  
Mycolic Acids ◽  
Alkaline Methanolysis ◽  
Chain Compounds ◽  
Long Chain

Presence in normal human urine of a hypotensive and platelet-activating phospholipid

1983 ◽  
Vol 244 (6) ◽  
pp. F706-F711 ◽  
Author(s):  
M. Sanchez-Crespo ◽  
P. Inarrea ◽  
V. Alvarez ◽  
F. Alonso ◽  
J. Egido ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Human Urine ◽  
Lupus Erythematosus ◽  
General Structure ◽  
Lipid Fraction ◽  
Platelet Activating Factor ◽  
Chromatographic Behavior ◽  
Hypotensive Activity ◽  
Alkaline Methanolysis ◽  
Normal Human

Urine from normotensive volunteers and patients with systemic lupus erythematosus glomerulonephropathy was sequentially concentrated by negative-pressure ultrafiltration, dialyzed against distilled water, and extracted into the chloroform phase of a mixture of organic solvents(chloroform:methanol:water, 1:1:0.9 vol/vol). The lipid fraction was further purified by thin-layer chromatography on silica gel plates using neutral, acidic, and basic mixtures of organic solvents and it was then tested for its ability to induce the release of [3H]serotonin from rabbit platelets. All of the samples contained a platelet-activating moiety similar to a synthetic platelet-activating factor (PAF-acether) on the basis of its chromatographic behavior, resistance to the pretreatment of platelets by 10(-6) M indomethacin, and loss of activity by alkaline methanolysis or treatment by phospholipases A2, C, and D. Cross-densensitization experiments between synthetic PAF-acether and the urine factor showed that both compounds act on platelets through the activation of the same putative receptor. Further, the urine factor induced hypotension when intra-arterially injected in normotensive rats, and this activity was also abrogated by alkaline methanolysis. In summary, these data provide evidence of the presence in normal human urine and, probably, of the release by the kidney of a lipid factor with platelet-activating and hypotensive activity whose general structure seems to be alkyl-acyl-glyceryl-phosphorylcholine and, therefore, is similar to the structure of the inflammatory mediator PAF-acether and the antihypertensive polar renomedullary lipid.

scholarly journals Further studies of the chemical composition of the lipopolysaccharide of Pseudomonas aeruginosa

1972 ◽  
Vol 126 (2) ◽  
pp. 395-407 ◽  
Author(s):  
I. R. Chester ◽  
G. W. Gray ◽  
S. G. Wilkinson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Large Scale ◽  
Lipid A ◽  
Thiobarbituric Acid ◽  
Molar Ratio ◽  
Positive Component ◽  
Qualitative And Quantitative ◽  
Alkaline Methanolysis ◽  
Molecular Weight Fractions ◽  
High Voltage Electrophoresis

1. Qualitative and quantitative analytical results for the lipopolysaccharide from acetone-dried cells of Pseudomonas aeruginosa (N.C.T.C. 1999) are presented and possible contamination of the material with nucleic acid was further examined. 2. Additional sugars detected (only in large-scale hydrolysates) were mannose and arabinose; traces of spermidine and putrescine were also found. 3. The heptose component is l-glycero-d-mannoheptose. 4. The thiobarbituric acid-positive component is a 3-deoxy-2-octulonic acid, of which only 35–40% links lipid A to the polysaccharide. This linkage is not broken by hydrolysis with acetic acid up to 0.08m. 5. Liberation of lipid A required hydrolysis with 0.1m-hydrochloric acid, which substantially degraded the polysaccharide moiety. 6. Fractions obtained from the degraded polysaccharide by high-voltage electrophoresis were examined; in these, the alanine/galactosamine molar ratio is approx. 1. 7. Hydrazinolysis of whole lipopolysaccharide showed that at least 40% of the alanine is in amide linkage, possibly with galactosamine. 8. Lipid A, solubilized by alkaline methanolysis was fractionated; most of the phosphorus of the higher-molecular-weight fractions was released as Pi by a phosphomonoesterase. 9. Hydrazinolysis of lipid A destroyed approx. 80% of the glucosamine, and glycosidically linked glucosamine oligosaccharides could not be isolated.

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