Heterocyclic Chemistry Flashcards
which is the least reactive: pyrrole, furan or thiophene?
thiophene
how is thiophene similar to benzene?
the 3p orbital has poor overlapping
what is formed in the reaction of furan with bromine and other solvents?
polybrominated ring
what is formed when furan is reacted with MeOH (methanol)
no bromine is added to the ring, instead we the MeO binds.
what is the length of a C-S bond equal to?
approximately equal to the length of 2 C-C bonds
what is an indole made of?
a pyrrole ring and a benzene ring
In an electrophilic reaction, where do electrophiles bind in indoles compared to pyrroles?
in indoles, electrophiles bind to the 3-position but in pyrroles they bind to the 2-position
what are the steps to create an indole from a ketone and hydrazine?
- condensation reaction
- elimination of water (dehydration)
- proton transfer followed by nucleophilic attack
- acid induced elimination of ammonia
what is formed from an acetal hydrolysis reaction?
aldehyde and alcohol
what is a bicyclic heterocycle (aka a quinolone)?
pyridine and benzene fused together
why does pyridine prefer electrophilic reactions but the bicyclic heterocycle prefers electrophilic substitution?
the nitrogen on the pyridine makes the ring less electron dense. This in turn makes it prone to nucleophilic attacks.
-bicyclic heterocycles prefer electrophilic substitution as the nitrogen on pyridine has less of an effect on the electron density of the benzene ring
what is uric acid used for?
to excrete excess nitrogen
what causes gout?
when crystalline uric acid is deposited in joints
how is puric acid made?
- purines from DNA (G and A) are degraded into xanthine.
- this then gets oxidised to uric acid
what enzyme is used to create uric acid from xanthine?
xanthine oxidase
