40 Questions
What is the characteristic of 1,2-azoles?
Aromatic compounds with a lone pair of electrons on nitrogen
What is the effect of the adjacent hetero atom on the basicity of 1,2-azoles?
Decreases the basicity
Which of the following is the most basic compound?
1,3-azoles
What is the boiling point of Isoxazole?
95°C
What is the starting material used for the synthesis of Pyrazoles and Isoxazoles?
1,3-Dicarbonyl Compounds and Hydrazines
How are the rings of Azoles numbered?
Start from the heteroatom with higher atomic no.
What is the pKa value of Pyrazole?
2.5
What is the effect of the nitrogen atom on the basicity of 1,2-azoles?
Increases the basicity due to the electron-donating effect
What is the boiling point of Pyrazole?
186-188°C
What is the structural composition of a pyrazole ring?
Three carbon atoms and two nitrogen atoms
What is the source of pyrazoles in nature?
They are rare in nature
What is the reaction involved in the synthesis of pyrazole from α,β-unsaturated aldehydes?
Dehydrogenation
What is the characteristic of pyrazole in nonpolar solvents like benzene?
It forms dimers and trimers
What is the type of nitrogen atom present in pyrazole?
Both pyrrole type and pyridine type
What is the characteristic of pyrazole as an amphoteric compound?
It can react with both acids and bases
What is the industrial method of pyrazole synthesis involving diazoalkans?
Interaction with acetylene
What is the novel pyrazole synthesis method involving 1,3-dinitroalkanes?
Heterocycle formation
What is the smell of pyrazole?
Weak pyridine smell
What is the functional group of the dicarbonyl component in pyrazole synthesis?
Ester
What is the classification of pyrazoles in terms of their occurrence in nature?
Alkaloids
What is the method of forming heterocyclic rings from 1,3-dinitroalkanes?
Heterocycle formation
What is the solubility of pyrazole in nonpolar solvents like benzene?
Forms dimers and trimers
What is the characteristic of pyrazole with regard to its acidity and basicity?
Amphoteric
Which of the following 1,2-azoles has the lowest boiling point?
Isoxazole
What is the reason for the difference in basicity between 1,2-azoles and 1,3-azoles?
Due to the electron-withdrawing effect of the adjacent hetero atom
What is the characteristic of the 1,2-azoles in terms of aromaticity?
They are fully aromatic
What is the most widely used method for the synthesis of pyrazoles and isoxazoles?
From 1,3-dicarbonyl compounds and hydrazines or hydroxylamines
What is the significance of the lone pair of electrons on the nitrogen atom in 1,2-azoles?
It contributes to the basicity of the compound
What is the characteristic of the nitrogen atom present in pyrazole?
Both pyrrole type and pyridine type
What is the effect of intermolecular hydrogen bonds in nonpolar solvents like benzene?
Forms dimers and trimers
What is the classification of pyrazoles in terms of their pharmacological effects?
Alkaloids
What is the characteristic of pyrazole in terms of its solubility?
Soluble in water, ethanol, and ether
What is the reaction involved in the synthesis of pyrazole from 1,3-dicarbonyl compounds?
Reaction with hydrazine, alkylhydrazine, or arylhydrazine
Which of the following is a characteristic of 1,2-azoles?
They have a lone pair of electrons on the nitrogen atom
What is the effect of the adjacent hetero atom on the basicity of 1,2-azoles?
It decreases the basicity of 1,2-azoles
Why are 1,3-azoles more basic than 1,2-azoles?
Due to the electron-withdrawing effect of the adjacent hetero atom
What is the most widely used method for the synthesis of pyrazoles and isoxazoles?
Synthesis from 1,3-Dicarbonyl Compounds and Hydrazines or Hydroxylamines
How are the rings of Azoles numbered?
Starting from the heteroatom with the higher atomic number
What is the role of hydrazine in the synthesis of pyrazole?
As a reactant to form the 5-membered ring
What is the reason for pyrazole's solubility in water, ethanol, and ether?
Due to the formation of intermolecular hydrogen bonds
Test your knowledge of heterocyclic compounds with this quiz on azoles, including their general features, physical properties, synthesis methods, and chemical reactions. Covers pyrazole and its reduced forms, as well as industrial and novel synthesis methods.
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