M.Sc Chemistry Class Notes Of Hetero Cyclic

M.Sc. Chemistry Hetero CyclicLecture Notes Free Download

M.Sc Chemistry Hetero CyclicLecture Notes Free Download, Heterocyclic Chemistry, Pyrrole, Quinoline, Isoquinoline and Indole.

Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N.

• Quinoline (benzo[b]pyridine) is a fused heterocyclic system consisting of a benzene ring fused with pyridine cycle. It can be also considered as the heterocyclic analogue of naphthalene (1-azanaphthalene).
• Systematic IUPAC name: 1-Benzopyridine; Benzo[b]pyridine; Benzo[b]azine; Benzo[b]azabenzene.
• Other names: 1-Azanaphthalene; 1-Benzazine; Benzazine; Benzazabenzene; Benzopyridine; Quinolin; Chinoline; Chinoleine; Chinolin; Leucol; Leukol; Leucoline.
• Quinoline is a colourless liquid with an unpleasant odour and boiling point 2370C. It is miscible with water, ethanol and ether; it may be distilled by steam distillation.

• Structure of Quinoline:
• All ring atoms in Quinoline are SP2 hybridize.
• The nitrogen lone pair electrons reside in an SP2 orbital and not involved in the formation of the delocalized π molecular orbital.
• It shows aromatic properties because its π orbital contains ten electrons & satisfied the Huckel’s rule (n = 2 is 4n+2).
• The resonance of Quinoline

Synthesis of Quinoline (Skraup Synthesis)

Step I: Glycerol undergoes dehydration with sulfuric acid to give Acrolein

Step II: Aniline adds to Acrolein (1,4-addition)

Step III: Undergoes ring closure

Step IV: Oxidation of 1,2-Dihydroquinoline

Chemical properties of Quinoline

• The most typical reactions for quinoline are:
• i. Heteroatom reactions
• ii. Electrophilic and nucleophilic substitution reactions;
• iii. Oxidation and reduction.

Electrophilic and nucleophilic substitution reactions:
Electrophilic substitution reactions occur on the ring C-atoms, mainly on those of the more activated benzene moiety. Nucleophilic substitution of quinoline occurs in the electron deficient pyridine ring, as a rule in the position 2 or 4.Electrophilic substitution reactions occur in positions 5 and 8 of quinoline. Treatment of quinoline with nitrating mixture results in 5and 8-nitroquinolines. Sulphonation of quinoline produces different products depending on the reaction temperature. At 220°C quinoline8sulphonic acid is formed predominantly; At 300°C, quinoline6sulphonic acid is the sole product. When heating to 300°C quinoline8sulphonic acid is converted into quinoline6sulphonic, which is the thermodynamically favoured Sulphonation product.

• Classification – Aromatic Five-Membered
• Classification-Aromatic Six-Membered
• Reactivity of Quinoline & Isoquinoline

Furan is a heterocyclic organic compound. It consist of a five-membered aromatic ring with four carbon atoms and one oxygen. Chemical compounds containing such rings are also referred to as furans. 

Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature.

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