9. Nitrogen and Phosphorous groups Flashcards
Describe mechanism for Gabriel synthesis
1) N-phthalamidomalonic ester (Thad) = deprotonated by base
2) N-phthalamidomalonic ester (Thad) = alkylated; phthalamide acts as nuc —> attacks alkyl halide (this whole alkylation thing is a nuc substitution)
3) alkylated product = hydrolyzed by H3O+ –> amino group and 2 CA at each end forms
4) in heat, one of the CA comes off –> alpha amino acid
DEHYDRATION DOES NOT OCCUR IN THIS SYNTHESIS. DOESNT RESULT IN OPTICALLY ACTIVE SOLN EITHER
Describe mechanism for Strecker synthesis
1) ald/ket + ammonia in presence of H+ –> imine + H2O
2) imine + KCN in presence of H+ –> alpha amino nitrile
3) alpha amino nitrile + H3O+ –> alpha amino acid
DEHYDRATION DOES NOT OCCUR IN THIS SYNTHESIS. DOESNT RESULT IN OPTICALLY ACTICE SOLN EITHER
Why does H3PO4- make a good buffer?
b/c it has 3 H to get rid off –> their pKas = across the entire pH scale
What are the R groups of negatively charged amino acids vs positively charged amino acids?
R groups = CA vs R groups = amines
Amides can be reduced to amines via? Amides can be hydrolyzed to? Describe mechanism for amide hydrolysis
LAH. Hydrolyzed to CA + amine
1) Carbonyl O = protonated —> =OH at top
2) water attacks carbonyl C of amide —> -OH at top, water at bottom
3) amino group steals H from water
4) -OH at top doubles bonds with C —> kicks out amino group, =OH at top again
5) =OH = deprotonated —> CA + amino group
3 ways to make amides
CA + amine
Anhydride + amine
Ester + amine
Amines are basic b/c…
Their e- donating functional groups
Pyrophosphate
P2O7 4-; denoted as PPi; ester dimer of phosphate in DNA
Organic phosphates vs inorganic phosphates
Nucleotides like ATP and GTP vs phosphate groups like HPO42- and H2PO4-; denoted as Pi
Which phosphoric acid ion predominates? Know which ones are in acidic and basic forms
H3PO4 = acidic; H2PO4- = predominates, also mildly acidic; HPO4- = weakly basic; PO43- = most basic
When 2 triphosphates bond (as they do in DNA synthesis), what molec is released?
Pyrophosphate is released when a phosphodiester bond is created in DNA synthesis
Schiff base
C=N, where C is bonded to 2 other R groups and N is bonded to another R group that isn’t H; subclass of imines; formed by carbonyl group from ald/ket + PRIMARY amine, formation depends on nuc attack of amine onto ald/ket
Where does transamination occur?
in most cells
What are heterocyclic amines?
Benzene ring w/ an N in the structure
