CHEM 2332H Lecture Notes - Phenyl Group, Ethel Page, Acid Dissociation Constant
15 Jul 2014
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*condensations & alpha-substitution of carbonyl compounds (ch 22) Ch 22 problems in notes, problem set due monday. Making tripeptides tripeptide: 1 lysine + 2 phenyl alanine. Very tough to remove need very strong base, water, high t for nucleophilic substitutionbut not good for working w/ amino acids. Very stable --> challenging to do nucleophilic acyl substitution. This h is very acidic very stable to nucleophilic substitution very unstable in base: can use piperdine (weak amine base) this is up for losing co2. Very thermodynamically favorable: you get conjugation, lose a small molecule. boc tbu-carbamate, solid, made through anhydride harder to do as e2 b/c protons are not as acidic as fmoc, so do e1 instead. Boc = stable to base, not stable to acid. Benzyl isn"t stable to hydrogenation for carbamate or for ether turns into toluene. Orthogonal: rxn conditions can be @ 90 degrees to each other.
