Diazo-coupling reactions of cycloheptatrienols: a combined experimental and theoretical study

1995 ◽  
pp. 175 ◽  
Author(s):  
Calvin S. Q. Lew ◽  
Ting-Hua Tang ◽  
Imre G. Csizmadia ◽  
Brian Capon
Keyword(s):  
Theoretical Study ◽  
Coupling Reactions ◽  
Diazo Coupling

scholarly journals New Diazo Coupling Reactions for Visible Spectrophotometric Determination of Alfuzosin in Pharmaceutical Preparations

2007 ◽  
Vol 4 (4) ◽  
pp. 496-501 ◽  
Author(s):  
M. Vamsi Krishna ◽  
D. Gowri Sankar
Keyword(s):  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Basic Medium ◽  
Coupling Reactions ◽  
Acetyl Acetone ◽  
Diazo Coupling ◽  
Optimum Reaction ◽  
Diazonium Ion

Simple, rapid and sensitive spectrophotometric procedures were developed for the analysis of Alfuzosin hydrochloride (AFZ) in pure form as well as in pharmaceutical formulations. The methods are based on the reaction of AFZ with nitrite in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester (Method A) or ethylcyanoacetate (Method B) or acetyl acetone (method C) in basic medium to form azo dyes, showing absorption maxima at 440, 465 and 490 nm respectively. Beer’s law is obeyed in the concentration of 4-20 μg/mL of AFZ for methods A, B and 3-15 μg/mL of AFZ for method C. The molar absorptivity and sandell’s sensitivity of AFZ- ethoxyethylenemaleic ester, AFZ- ethylcyanoacetate and AFZ-acetyl acetone are1.90 × 104, 0.022; 1.93 × 104, 0.021 and 2.67 × 104L mole-1cm-1, 0.015 μg cm-2respectively. The optimum reaction conditions and other analytical parameters were evaluated. The methods were successfully applied to the determination of AFZ in pharmaceutical formulations.

ChemInform Abstract: THE ACTIVATING EFFECTS OF AMINO GROUPS IN DIAZO-COUPLING REACTIONS

1974 ◽  
Vol 5 (20) ◽  
pp. no-no
Author(s):  
YOJI HASHIDA ◽  
JUNICHI TAKENAKA ◽  
KOHJI MATSUI
Keyword(s):  
Coupling Reactions ◽  
Amino Groups ◽  
Diazo Coupling

Rapid and efficient diazotization and diazo coupling reactions on silica sulfuric acid under solvent-free conditions

2009 ◽  
Vol 81 (3) ◽  
pp. 240-244 ◽  
Author(s):  
A ZAREI ◽  
A HAJIPOUR ◽  
L KHAZDOOZ ◽  
B MIRJALILI ◽  
A NAJAFICHERMAHINI
Keyword(s):  
Sulfuric Acid ◽  
Solvent Free ◽  
Coupling Reactions ◽  
Silica Sulfuric Acid ◽  
Solvent Free Conditions ◽  
Diazo Coupling

Further studies of the diazo coupling reactions of pyrimidines

1983 ◽  
Vol 36 (8) ◽  
pp. 1659 ◽  
Author(s):  
DT Hurst
Keyword(s):  
Coupling Reactions ◽  
Methyl Substituent ◽  
Diazo Coupling ◽  
Acetyl Group ◽  
Derivatives Of

6-Arylazo derivatives of the following pyrimidines have been obtained: 2-acetamido-4,5-dihydroxy-, 4-amino-2,5-dihydroxy-, 2,4-diamino-5-hydroxy- and 4-amino-5-hydroxy-2-methyl-pyrimidine. However, some 5-substituted pyrimidines having other electron-releasing groups failed to undergo diazo coupling. 2,4-Dihydroxypyrimidin-5-yl acetate and 2-acetamido-4-hydroxypyrimidin-5-yl acetate lost the 5-acetyl group during the introduction of the arylazo group into the 6-position. However, 2-hydroxy-4,6-dimethylpyrimidin-5-yl acetate undergoes diazo coupling at the 4(6)-methyl substituent without loss of the 5-acetyl group. The mechanisms for these diazo couplings are discussed.

Sign in / Sign up

Export Citation Format

Share Document