Lactam & Lactone Mine Lecture.pdf

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Dr. Sadia Iqbal Lecturer DCOP, DUHS

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At the end of lecture student will be able to  Define and classify functional groups  Explain their    

Method of preparation, Chemical properties Physical properties Uses

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Alcohol Phenols Carboxylic acids Anilines Diazonium salts Amide Imide Amines Aldehyde & Ketone Lactone

Lactam

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[From

Lact ( one ) + am ( ide )]

H O N

NH 

A lactam is cyclic amide O



Any of a group of cyclic amides characterized by the –NHCO- group, derived from aminocarboxylic acids by the intra-molecular elimination of water from the amino and carboxylic groups.

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 Lactam (lactone + amide)  β-lactam (2 carbon atoms outside the carbonyl, 4 ring atoms in total)  γ-lactam (3 and 5)  δ-lactam (4 and 6)  ε-Lactam (7 ring atoms)

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 To name, add the word lactam to the IUPAC acid name or replace the -ic acid of common name with -olactam.

IUPAC name: 3-aminopropanoic acid lactam Common name: β-propiolactam

6-aminohexanoic acid lactam ε-caprolactam

4-amino-2-methylpentanoic acid lactam α-methyl-ɣ-valerolactam

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 From amide by iodolactamization  A method for iodocyclization of an amide nitrogen onto a carbon- carbon double bond.  As an example, conversion of 5-hexenamide to its N,O-bis(trimethylsilyl) derivative followed by treatment with a solution of iodine and aqueous sodium sulfite quench gave the iodolactam in 64% overall yield.

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 From amide by iodolactamization

5-hexenamide

N,O-bis(trimethylsilyl) derivative

iodolactam

Trifluoromethanesulfonate, also known by the trivial name triflate, is a functional group with the formula CF3SO3−. The triflate group is often represented by −OTf

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 From Ketone (Schmidt Reaction) Lactams form from cyclic ketone and hydrazoic acid (HN3)

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 From Amino Carboxylic acid

IUPAC name: Common name:

4-aminobutanoic acid ɣ-aminobutyric acid

4-aminobutanoic acid lactam ɣ-butyrolactam

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 Reduction (With Lithium alumuinum hydride) H3C H3C

1 LiAlH4, ether O N

2H2O

H

LACTAM

4-amino-4-methylpentanoic acid lactam ɣ-methyl-ɣ-valerolactam

H3C H3C

H H N H

a cylic amine

pyrrolidine

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 Hydrolysis

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 Amoxicillin

 Cephalexin

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 Carbapenems

 Cephalosporins

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Alcohol Phenols Carboxylic acids Anilines Diazonium salts Amide Imide Amines Aldehyde & Ketone Lactam

Lactone

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 Lactone is a cyclic ester which can be seen as the condensation product of an alcohol group (-OH) and a carboxylic acid group (-COOH) in the same molecule.  It is characterized by a closed ring consisting of two or more C atoms and a single Oxygen atom, with a ketone group (=O) in one of C adjacent to the Oxygen.

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 Reaction of —OH and —COOH on same molecule produces a cyclic ester called lactone.  To name, add the word lactone to the IUPAC acid name or replace the -ic acid of common name with -olactone.

IUPAC name: 5-hydroxypentanoic acid lactone Common name: ɣ-valerolactone

5-pentanolide

4-hydroxy-2-methylpentanoic acid lactone α-methyl-ɣ-valerolactone

2-methyl-4-pentanolide

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 Water-soluble,  Slightly soluble in ethanol  Not soluble in ether

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 Hydrolysis Heating a lactone with a base (sodium hydroxide) will hydrolyse the lactone to its parent compound, the straight chained bifunctional compound.

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 Reduction Lactones can be reduced to diols using lithium aluminum hydride in dry ether. The reduction reaction will first break the ester bond of the lactone, and then reduce the carboxylic acid group (-COOH) to the alcohol group (-OH).

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 Aminolysis Lactones also react with ethanolic ammonia, which will first break the ester bond and then react with the acidic -COOH group, because of the basic properties of ammonia, to form a difunctional group, i.e. alcohol and amide.

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 Regulation of acidity and color in food  Support of antioxidants and preservatives  Lactones contribute significantly to the flavor of fruit, and of unfermented and fermented dairy products, and are therefore used as flavors and fragrances.  Polycaprolactone is an important plastic.

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• Organic chemistry, 4th ed, by Brown Foote Iverson • Organic chemistry, 5th ed, by John McMarry • Organic chemistry, 2nd ed, by Paula Yurkanis Bruice • Wilson and GISVOLD’S Text book of organic medicinal and pharmaceutical chemistry, 11th ed, John, H. Block, John M. Beals, Jr • Organic chemistry, vol 1, 6th ed, by IL Finar