Azoles III
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Questions and Answers

What is the characteristic of 1,2-azoles?

  • Basic compounds due to the presence of oxygen
  • Contain three hetero atoms
  • Non-aromatic compounds
  • Aromatic compounds with a lone pair of electrons on nitrogen (correct)

    • What is the effect of the adjacent hetero atom on the basicity of 1,2-azoles?

  • Decreases the basicity (correct)
  • Neutralizes the basicity
  • Increases the basicity
  • Has no effect on the basicity

    • Which of the following is the most basic compound?

  • Isoxazole
  • 1,3-azoles (correct)
  • Isothiazole
  • Pyrazole

    • What is the boiling point of Isoxazole?

    <p>95°C</p> Signup and view all the answers

    What is the starting material used for the synthesis of Pyrazoles and Isoxazoles?

    <p>1,3-Dicarbonyl Compounds and Hydrazines</p> Signup and view all the answers

    How are the rings of Azoles numbered?

    <p>Start from the heteroatom with higher atomic no.</p> Signup and view all the answers

    What is the pKa value of Pyrazole?

    <p>2.5</p> Signup and view all the answers

    What is the effect of the nitrogen atom on the basicity of 1,2-azoles?

    <p>Increases the basicity due to the electron-donating effect</p> Signup and view all the answers

    What is the boiling point of Pyrazole?

    <p>186-188°C</p> Signup and view all the answers

    What is the structural composition of a pyrazole ring?

    <p>Three carbon atoms and two nitrogen atoms</p> Signup and view all the answers

    What is the source of pyrazoles in nature?

    <p>They are rare in nature</p> Signup and view all the answers

    What is the reaction involved in the synthesis of pyrazole from α,β-unsaturated aldehydes?

    <p>Dehydrogenation</p> Signup and view all the answers

    What is the characteristic of pyrazole in nonpolar solvents like benzene?

    <p>It forms dimers and trimers</p> Signup and view all the answers

    What is the type of nitrogen atom present in pyrazole?

    <p>Both pyrrole type and pyridine type</p> Signup and view all the answers

    What is the characteristic of pyrazole as an amphoteric compound?

    <p>It can react with both acids and bases</p> Signup and view all the answers

    What is the industrial method of pyrazole synthesis involving diazoalkans?

    <p>Interaction with acetylene</p> Signup and view all the answers

    What is the novel pyrazole synthesis method involving 1,3-dinitroalkanes?

    <p>Heterocycle formation</p> Signup and view all the answers

    What is the smell of pyrazole?

    <p>Weak pyridine smell</p> Signup and view all the answers

    What is the functional group of the dicarbonyl component in pyrazole synthesis?

    <p>Ester</p> Signup and view all the answers

    What is the classification of pyrazoles in terms of their occurrence in nature?

    <p>Alkaloids</p> Signup and view all the answers

    What is the method of forming heterocyclic rings from 1,3-dinitroalkanes?

    <p>Heterocycle formation</p> Signup and view all the answers

    What is the solubility of pyrazole in nonpolar solvents like benzene?

    <p>Forms dimers and trimers</p> Signup and view all the answers

    What is the characteristic of pyrazole with regard to its acidity and basicity?

    <p>Amphoteric</p> Signup and view all the answers

    Which of the following 1,2-azoles has the lowest boiling point?

    <p>Isoxazole</p> Signup and view all the answers

    What is the reason for the difference in basicity between 1,2-azoles and 1,3-azoles?

    <p>Due to the electron-withdrawing effect of the adjacent hetero atom</p> Signup and view all the answers

    What is the characteristic of the 1,2-azoles in terms of aromaticity?

    <p>They are fully aromatic</p> Signup and view all the answers

    What is the most widely used method for the synthesis of pyrazoles and isoxazoles?

    <p>From 1,3-dicarbonyl compounds and hydrazines or hydroxylamines</p> Signup and view all the answers

    What is the significance of the lone pair of electrons on the nitrogen atom in 1,2-azoles?

    <p>It contributes to the basicity of the compound</p> Signup and view all the answers

    What is the characteristic of the nitrogen atom present in pyrazole?

    <p>Both pyrrole type and pyridine type</p> Signup and view all the answers

    What is the effect of intermolecular hydrogen bonds in nonpolar solvents like benzene?

    <p>Forms dimers and trimers</p> Signup and view all the answers

    What is the classification of pyrazoles in terms of their pharmacological effects?

    <p>Alkaloids</p> Signup and view all the answers

    What is the characteristic of pyrazole in terms of its solubility?

    <p>Soluble in water, ethanol, and ether</p> Signup and view all the answers

    What is the reaction involved in the synthesis of pyrazole from 1,3-dicarbonyl compounds?

    <p>Reaction with hydrazine, alkylhydrazine, or arylhydrazine</p> Signup and view all the answers

    Which of the following is a characteristic of 1,2-azoles?

    <p>They have a lone pair of electrons on the nitrogen atom</p> Signup and view all the answers

    What is the effect of the adjacent hetero atom on the basicity of 1,2-azoles?

    <p>It decreases the basicity of 1,2-azoles</p> Signup and view all the answers

    Why are 1,3-azoles more basic than 1,2-azoles?

    <p>Due to the electron-withdrawing effect of the adjacent hetero atom</p> Signup and view all the answers

    What is the most widely used method for the synthesis of pyrazoles and isoxazoles?

    <p>Synthesis from 1,3-Dicarbonyl Compounds and Hydrazines or Hydroxylamines</p> Signup and view all the answers

    How are the rings of Azoles numbered?

    <p>Starting from the heteroatom with the higher atomic number</p> Signup and view all the answers

    What is the role of hydrazine in the synthesis of pyrazole?

    <p>As a reactant to form the 5-membered ring</p> Signup and view all the answers

    What is the reason for pyrazole's solubility in water, ethanol, and ether?

    <p>Due to the formation of intermolecular hydrogen bonds</p> Signup and view all the answers

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