M.Sc Chemistry Class Notes Of Hetero Cyclic

M.Sc. Chemistry Hetero Cyclic Lecture Notes Free Download

M.Sc Chemistry Hetero Cyclic Lecture 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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