Block Five Flashcards
What is the order of reactiveness of carboxylic acid derivatives?
Acyl chloride > Acid anhydrides > Esters > Amides > Carboxylic acids
When are amines basic?
When they have no charge
How does pKa relate to the basicity of an amine?
The higher the pKa for the conjugate acid, the higher the basicity of the amine
Do electron withdrawing groups increase or decrease basicity?
Decrease
Why do mixtures form when alkyl halides undergo substitution reactions with excess NH3?
The amines continue to react forming primary, tertiary and quaternary amines
How are aromatic amines formed from a benzene ring with NO2 attached?
Fe/H+ and OH-
Ch3Br
Which four functional groups can be reduced by LiAlH4 and H3O+ to form primary amines?
Oximes, imines, nitriles, and primary amides
What do the reagenst NaOEt and EtOH cause?
Condensation if the reactant has an alpha proton
When a tertiary amide reacts with LiAlH4 and H3O+ what forms?
A tertiary amine
Why can tertiary amines not react with acyl chlorides to form amides like secondary and primary amines?
HCl cannot be formed as a byproduct so the reaction does not occur
What are the two ways to form a primary amide with ammonia?
Acid chloride and acid anhydride
How are tertiary amides formed?
Secondary amines with acid chloride
Which reagents are required to convert an aryl amide into and aryl amine?
70% aq H2SO4
OH-
What are the functional groups of amino acids?
Amine and carboxylic acid around a stereogenic centre
What is the overall charge of an amino acid in acidic solution?
+1
When is an amino acid in zwitterion form?
In neutral solution
What is the function of protected derivatives?
Ensure that the NH2 of glycine and the COOH of alanine so that they cannot react and only the desired dipeptide will form
Why is DCC necessary in the reaction of Gly and Ala?
It enhances the reactivity of the carboxylic acid forming an active ester
What is the angle about an amide bond?
Planar at 180 degrees
Are anti parallel or parallel Beta Sheets more stable?
Anti-parallel
Is a chain of fewer than fifty amino acid bonds a peptide or a protein?
Peptide
What is the process of enzymes lowering the activation energy for reactions?
Enzyme + Substrate = Enzyme + Product
What occurs when a carbonyl compound with an alpha proton is reacted with either an acid or a strong base?
An enol or enolate is formed
Which reagents are required to convert a ketone to an alcohol?
NaBH4 or LiAlH4
H3O+
What reagent is needed to convert an alcohol to a ketone?
H2CrO4
What causes the formation of a cyclic compound via a peptide bond?
Heat
