Benzyl ethers of methyl α-D-glucopyranoside

1980 ◽  
Vol 45 (7) ◽  
pp. 1959-1963 ◽  
Author(s):  
Dušan Joniak ◽  
Božena Košíková ◽  
Ludmila Kosáková
Keyword(s):  
Kinetic Study ◽  
Spectrophotometric Determination ◽  
Reductive Cleavage ◽  
Ether Bond ◽  
Benzyl Ethers ◽  
Acid Catalyzed ◽  
Model Substances ◽  
Hydrolysis Of

Methyl 4-O-(3-methoxy-4-hydroxybenzyl) and methyl 4-O-(3,5-dimethoxy-4-hydroxybenzyl)-α-D-glucopyranoside and their 6-O-isomers were prepared as model substances for the ether lignin-saccharide bond by reductive cleavage of corresponding 4,6-O-benzylidene derivatives. Kinetic study of acid-catalyzed hydrolysis of the compounds prepared was carried out by spectrophotometric determination of the benzyl alcoholic groups set free, after their reaction with quinonemonochloroimide, and it showed the low stability of the p-hydroxybenzyl ether bond.

DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules

1980 ◽  
Vol 63 (5) ◽  
pp. 1049-1051
Author(s):  
Juan A Squella ◽  
Luis J Nunez-Vergara ◽  
Maximo Aros
Keyword(s):  
Absorption Band ◽  
Spectrophotometric Determination ◽  
Degradation Product ◽  
Uv Absorption ◽  
Acidic Hydrolysis ◽  
Average Recovery ◽  
Polarographic Wave ◽  
Spectrophotometric Methods ◽  
Hydrolysis Of

Abstract Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at –0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively

Spectrophotometric Determination of Carbaryl in Grains

1982 ◽  
Vol 65 (1) ◽  
pp. 32-34
Author(s):  
Kalapanda M Appaiah ◽  
Rasamsetti Ramakrishna ◽  
Kadari R Subbarao ◽  
Omprakash Kapur
Keyword(s):  
Spectrophotometric Determination ◽  
Absorption Maximum ◽  
Potassium Hydroxide ◽  
Oxidizing Agent ◽  
Spectrophotometric Measurement ◽  
The Relationship ◽  
Hydrolysis Of

Abstract A method has been developed for determining carbaryl (1-naphthyl N-methyl carbamate) in grains, based on hydrolysis of carbaryl with methanolic potassium hydroxide to 1-naphthol, reaction with 4-aminophenazone in the presence of alkaline oxidizing agent, and spectrophotometric measurement at the absorption maximum at 475 nm. The relationship between absorbance and concentration is linear in the range of 0.5-20 μg/mL. The method can be applied to levels as low as 0.3 ppm carbaryl in grains.

scholarly journals Structure Determination of Two New Monocillin I Derivatives

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Jixun Zhan ◽  
E. M. Kithsiri Wijeratne ◽  
A. A. Leslie Gunatilaka
Keyword(s):  
Double Bond ◽  
Acid Solution ◽  
Beauveria Bassiana ◽  
Structure Determination ◽  
Spectroscopic Data ◽  
Enzymatic Process ◽  
Acid Catalyzed ◽  
Hydrolysis Of

Biotransformation of monocillin I (1) by Beauveria bassiana ATCC 7159 was investigated. Two new derivatives 2 and 3 were isolated and identified on the basis of the spectroscopic data. Compounds 2 and 3 are synthesized by hydration at 10,11-double bond and hydrolysis of 14,15-epoxide, respectively. The R configuration of 11-OH in 2 was established by the modified 2-methoxy-2-trifluoromethylphenylacetic acid (MTPA) method. The conversion of 1 to 2 and 3 was reconstituted in an acid solution, indicating that the formation of 2 and 3 is an acid-catalyzed instead of an enzymatic process.

Synthesis and Acid-Catalyzed Hydrolysis of Some 3-(4-Methoxyphenyl)propyl Glucuronates

2000 ◽  
Vol 65 (10) ◽  
pp. 1609-1618 ◽  
Author(s):  
Monika Poláková ◽  
Dušan Joniak ◽  
Miloslav Ďuriš
Keyword(s):  
Acid Hydrolysis ◽  
Acid Catalyzed ◽  
Model Substances ◽  
Hydrolysis Of

3-(4-Methoxyphenyl)propyl D-glucuronate, 3-(4-methoxyphenyl)propyl methyl 4-O-methyl-α-Dglucopyranosiduronate, 3-(4-methoxyphenyl)propyl 1,2,3,4-tetra-O-acetyl-α-D-glucopyranuronate and 3-(4-methoxyphenyl)propyl 1,2-(S):3,5-di-O-benzylidene-α-D-glucofuranuronate were prepared as a model substances for the ester lignin-saccharide bonds. Rates of acid-catalyzed hydrolysis of the prepared compounds in 1 M HCl in acetonitrile-water 3 : 1 at 20 °C have been measured by LC-DAD analysis and it showed the low stability of the ester bonds towards acid hydrolysis.

Spectrophotometric Determination of Decamethrin and Its Residues in Insecticidal Formulations and in Water

1994 ◽  
Vol 77 (3) ◽  
pp. 748-751 ◽  
Author(s):  
R V Prabhakara Raju ◽  
R Raghava Naidu
Keyword(s):  
Spectrophotometric Determination ◽  
Hydrolysis Product ◽  
Spectrophotometric Methods ◽  
Alkaline Conditions ◽  
The Relationship ◽  
Hydrolysis Of

Abstract Three spectrophotometric methods were developed for the microdetermination of decamethrin in insecticidal formulations and in water. The methods are based on the hydrolysis of decamethrin with methanolic KOH to 3-phenoxybenzaldehyde; condensation of the hydrolysis product with 2,4- dinitrophenylhydrazine (2,4-DNPH), 4-nitrophenylhydrazine (4-NPH), or 2,4,6-trinitrophenylhydrazine (2,4,6-TNPH) under alkaline conditions; and measurement of the condensates at the absorption maxima of 444,535, and 480 nm, respectively. The relationship between absorbance and concentration was linear in the ranges of 0.1–5.0 μg/mL, 0.5–7.0 μg/mL and 0.1–5.5 μg/mL for 2,4-DNPH, 4-NPH, and 2,4,6-TNPH, respectively. The methods are sufficiently sensitive and can be used to detect decamethrin at concentrations as low as 0.1 μg/mL.

Spectrophotometric Determination of Diphenylamine, Pyrrole, and Indole - A Kinetic Study

1990 ◽  
Vol 23 (6) ◽  
pp. 1139-1157 ◽  
Author(s):  
Anees Ahmad ◽  
Mohsin Qureshi ◽  
Iftekhar Ahmad Khan ◽  
Khwaja Zuber Alam
Keyword(s):  
Kinetic Study ◽  
Spectrophotometric Determination
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