CHEM 233 Lecture Notes - Lecture 1: Leaving Group, Phosphorus Tribromide, Triethylamine
Document Summary
Biological examples of acylphosphates and thioesters: reaction is enzyme catalyzed, doesn"t happen without an enzyme, each enzyme is reaction-specific, can only bind with specific molecules. Is part of atp: a carboxylate does a nucleophilic attack on the phosphate, where the p-o bond is broken to liberate adp. Acyl phosphates are converted to thioesters and amides: rsh attacks acyl phosphate, or amine attacks acyl phosphate. Acyl phosphates are good acylating agents: like milder versions of acyl anhydrides. Glutamate can convert to glutamine: with atp and nh3 reagents, carboxylate attacks atp, then becomes an acyl phosphate, the acyl phosphate gets attacked by nh3 to become an amide. Challenges to peptide synthesis: carboxylic acids and amides are kinetically inert and the only reaction that occurs is an acid- base reaction. In order to form an amide bond, a dehydration event is required: to do the reaction, we need a way of creating the synthetic equivalent of an acyl phosphate or thioester.
