ester to amide and esterification

the reaction involves

a neutral good nucleophile (amine) and a poor inital leaving group (-OR group)

acid derivatives reactivity ( most to least)

acid chlorides > anhydrides > esters ~ carboxylic acid > amides.

since esters and acids are similar reactivity and its acid catalyzed how does the reaction proceed

The reaction proceeds through equalibrium

what does ester to carboxylic acid in a acidic enviornmetn involve

ROH and H+

ester to acid

reactants = ester, H2O or ROH, H+ (acid catalyzed)

products = carboxylic acid and alcohol

acid to ester

reactants = carboxylic acid, alcohol, H+ (acid catalyzed); products = ester and water

trans esterification

Reactants: an ester + an alcohol.

Products:

• a new ester (where the original ester’s R group is replaced by the alcohol’s R group), and

• a new alcohol (made from the part that was taken off the original ester).

All the 3 reaction of esters and carboxylic acids are all

• cataxyzed by H+

• reversible

• all follow the same mechanism

amide to ester

• Acid promoted

• the reaction goes uphill

  • the ester is less stablethan the amide

  • results in a less favorable reaction

amide to ester

reactants- amide, (reacts with alcohol and in strong acidic conditions)

product- ester ( the NH2 is replaced by OR group from the alcohol) and ammonia (NH3).

what drives the reaction forward for amide to ester reactions

acid promoted reaction protonates the amine making it a better leaving group.

Does the acid catalyst shift the equilibrium?

No! Catalysts speed up reactions but do not shift equilibrium.

What can shift the equilibrium toward ester formation?

The environment

Acid Amide to Carboxylic

is acid promoted

the reaction is identicia to amide to ester

reactants

• amide

• strong acid

product

• carboxylic acid (NH2 is replaced by OH)

• amine