1. Define Heterocyle as it applies to organic molecules. ANS >>> Cyclic
molecules in which one or mroe carbon atoms are replaced by heteratoms -
elements other than carbon or hydrogen.
2. What are two main sub-groups of heterocyclic compounds? ANS >>>
Aliphatic and Aromatic
3. Explain why pyridine is soluble in water. ANS >>> First - the ability of
pyridine to accept Hydrogen bonding interactions from water molecules due to
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, the lone pair of electrons in the nitrogen atom. In addition, the electronegative
nitrogen creates a relatively strong dipole moment in the pyridine molecule, thus
making pyridine a polar compound overall.
4. Is pyridine more likely to act as an acid or base? Explain. ANS >>>
Pyridine, like all amines, is a weak base. Amines use the lone pair on the
nitrogen atom to accept protons and thus act as bases.
5. Name the two main classes of reactions that the pyridine molecule will
undergo - ANS >>> EAS - Electrophilic Aromatic Substitution
NAS - Nucleophilic Aromatic Substitution
6. Heterocyclic six-membered rings with two or more N atoms present as a
part of the ring system are known as what type of heterocycles? ANS >>>
Azines
7. Why are pyrimidines the most biologically important members of the di-
azene family of molecules? ANS >>> Derivatives of pyrimidines are important
bases in the nucleic acids DNA and RNA , namely cytosine, thymine and uracil.
8. Name the most important five-membered heterocyclic compounds con-
taining a single heteroatom substitution and state which element is the het-
eroatom in each. ANS >>> Furan (Oxygen based)
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molecules in which one or mroe carbon atoms are replaced by heteratoms -
elements other than carbon or hydrogen.
2. What are two main sub-groups of heterocyclic compounds? ANS >>>
Aliphatic and Aromatic
3. Explain why pyridine is soluble in water. ANS >>> First - the ability of
pyridine to accept Hydrogen bonding interactions from water molecules due to
https://www.stuvia.com/en-us/user/techgrades
, the lone pair of electrons in the nitrogen atom. In addition, the electronegative
nitrogen creates a relatively strong dipole moment in the pyridine molecule, thus
making pyridine a polar compound overall.
4. Is pyridine more likely to act as an acid or base? Explain. ANS >>>
Pyridine, like all amines, is a weak base. Amines use the lone pair on the
nitrogen atom to accept protons and thus act as bases.
5. Name the two main classes of reactions that the pyridine molecule will
undergo - ANS >>> EAS - Electrophilic Aromatic Substitution
NAS - Nucleophilic Aromatic Substitution
6. Heterocyclic six-membered rings with two or more N atoms present as a
part of the ring system are known as what type of heterocycles? ANS >>>
Azines
7. Why are pyrimidines the most biologically important members of the di-
azene family of molecules? ANS >>> Derivatives of pyrimidines are important
bases in the nucleic acids DNA and RNA , namely cytosine, thymine and uracil.
8. Name the most important five-membered heterocyclic compounds con-
taining a single heteroatom substitution and state which element is the het-
eroatom in each. ANS >>> Furan (Oxygen based)
https://www.stuvia.com/en-us/user/techgrades
