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Organic and biochemistry

Assistance Lecturer Amjad Amjad Jumaa

Nomenclature of the esters Reactions of the esters Introduction to an acids and bases:

acidity of aromatic and aliphatic carboxylic acids.

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Nomenclature of the esters: The names of acid derivatives are taken in simple ways from either the common name or the IUPAC name of the corresponding carboxylic acid, for the nomenclature of the esters, the –ic acid is replaced to –ate preceded by names of alcohol or phenol group. Examples

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Other examples:

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Conversion into acids. Hydrolysis.

Example:

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Problem: give a chemical equation for the hydrolysis of methyl-m-nitro benzoate in the acidic medium.

Solution:

Follow problem: write the structures and the names for the hydrolysis of the following esters in the acidic medium (H+): 1-methyl propionate 2-(p-chloro methyl benzoate) 3-ethyl formate 4-benzyl acetate 5-methyl acetate.

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Introduction to an acids and bases:Most of the attention in general chemistry is given to numerical calculations:1-PH.2-percent ionization.3-buffer problem. We are concerned with the roles that acids and bases plays as reactants, products, and catalysts in chemical reactions.

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Acidity and basicity of the some organic compounds: Acidity of aromatic and aliphatic carboxylic acids:

Acidity is determined chiefly by the difference in stability between the acid and its anion. Carboxylic acid is acid at all. The hydroxyl group (OH) in the carboxyl group (-COOH) can release a hydrogen ion in the solution (H+) to form a carboxylate anion (RCOO-) , we see both acid and a carboxylate anion are resonance hybrids.

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Stabilization by resonance is far greater for the anion than for the acid thus equilibrium is shifted in the direction of increased ionization, and Ka is increased.

Look at the following figure:

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The acidity of the carboxylic acid is thus due to the powerful resonance stabilization of its anion.