Rings Pyridne quinoline and isoquinoline Pyridne Pyridine is a water miscible liquid b p 115 oC with an unpleasant odour An Excelent polar solvent A base ID: 377303
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Slide1
Heterocyclic Rings Pyridne, quinoline and isoquinolineSlide2
PyridnePyridine is a water -miscible liquid, b. p. 115 oC with an unpleasant odourAn Excelent polar solvent, A base (
pka
= 5.23
)Pyrrole is less basic than pyridine becuase the lone pair of electrons in pyrrole is part of the aromatic ring, while that in pyridine is free.Slide3Slide4
1) The Hantzsch Synthesis1,3-dicarbonyl compound + ammonia + aldehydeSlide5Slide6
2) Reaction of Ammonia + 1,5-diketoneSlide7
3) Diels-Alder ReactionSlide8Slide9Slide10Slide11
4) Kroehnke SynthesisSlide12
Chemistry of PyridineSlide13Slide14
Electrophilic SubstitutionPyridine is million times less reactive than benzeneNitration (less than 5%, Chlorination in moderate yield, Bromination in a good yield)3-position is usually attacked preferablySlide15Slide16
ChiChibabin Reaction (Nucleophilic Substitution) Slide17
Quinoline and IsoquinolineSlide18
Quinoline Skraup SynthesisSlide19
Combes SynthesisSlide20
Isoquinoline Synthesis, Bischler-NapierlaskiSlide21
Pictet-Spengler SynthesisSlide22
Pomeranz-Fritsch SynthysisSlide23
Chemistry of Quinoline and Isoquinoline Nucleophilic Substitution (ChiChibabin Reaction)Slide24Slide25Slide26
Electrophilic SubstitutionOccurs at the 5- or 8-positions, or bothSlide27
Quinoline N-Oxides can be nitrated at the 4-position or photoisomerize as follows