Chapters 20 and 24 Flashcards by Jake Brooks

Describe how primary amines are named

Root name is based on the longest chain with the NH2
Number so the amine has the lowest possible number
Add -amine suffix

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Describe how secondary amines are named differently than primary amines

The other alkyl group is treated as a substituent, with an N locant and is listed before numerical locant

N-propylamine

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Describe how tertiary amines are named differently than primary amines

The other alkyl groups are treated as substituents with N as the locant and are listed before numerical locants

N-ethyl-N-methylpropanamine

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What is the structure of aniline?

Benzenamine, phenylamine, amino benzene

NH2 directly attached to benzene ring

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What is the structure of p-toluidine?

4-methylbenzylamine

NH2 and CH3 on benzene ring, directly across from each other

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What is the structure of imidazole?

Five carbon ring, NH on top peak, N on bottom, double bonds on sides

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What is the structure of pyrrole?

Five carbon ring, NH on top peak, double bonds on sides

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How is amine basicity connected to the charge on nitrogen?

Increases with higher negative charge

conjugate base is always more basic

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How is amine basicity connected to conjugation?

Conjugated amines are worse bases

Resonance in conjugate base to distribute the negative charge from donating

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How is amine basicity connected to inductive effects?

Inductive effects decrease basicity

Remove electron density from conjugate base, stabilizing it

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How is amine basicity connected to pi-donating or pi-accepting?

Basicity decreases when acting as a pi-donor

Significant resonance form where lone pairs on nitrogen form new pi-bond with carbon

Basicity is decreased when attached to pi-acceptor or meta director (as in inductive effects)

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How is amine basicity connected to hybridization?

Lone pairs on SP hybridized nitrogens are the least basic, those on SP3 are the most basic

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How does amine basicity compare to amide basicity?

Amides are far less basic

Lots of resonance stabilization in conjugate base

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How do you make amines from ammonia? How do you control the substitution?

RX + NH3 → RNH2

Add excess RX for increased substitution

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How do you make amines from NaN3? What are the two things it can react with initially? What is the intermediate? What are the four things it can then react with?

RX (or acid chloride) + NaN3 → RN3 + Na/EtOH (or LiAlH4 or H2/Ni or NaBH4) → RNH2

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How can you convert a nitro group to an amine? What two things can it react with?

RNO2 + LiAlH4 (or H2/Ni) → RNH2

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How can you convert an amide to an amine? Give the two methods and all possible reactants. (ignore named reactions)

Amide + LiAlH4 (or H2/Ni) → RNH2

Replaces the =O with hydrogens

Amide + Very Strong Acid/Base → R2NH

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Describe the two-step process of the first stage of Gabriel synthesis

Phthalimide + KOH + RX → Phtalimide with R instead of H, called an N-substituted phthalimide

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Describe the two options for the second stage of Gabriel synthesis

N-sutstituted phalimide + NH2NH2 and EtOH/heat → RNH2

N-substituted phalimide + (1)H+/H2O/heat + (2)OH- → RNH2

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How can you create amines from nitriles (CN)? What are the two options for reactants?

RX + NaCN → RCN + (1) LiAlH4/ether (or H2/Ni) + (2) H2O → primary amine

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How can you create amines from aldehydes and ketones?

Add NH3 (1), RNH2 (2) or R2NH (3*) and source of H (such as NaBH4)

Replaces the =O with hydrogen and the reactant

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Describe the Hoffman Rearrangement

Amide + (1) Br2/NaOH + (2) H2O → RNH2

R is from the other group attached to =O (Nh2 is the other one)

Remove =O and single bond other groups to each other

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Describe the Curtius Rearrangement

Acid Chloride + (1) NaN3 + (2) heat + (3) H2O → RNH2

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Amine + Formaldehyde → ? + (1)H+ (2)NaBH3CN → ?

Imine, RN(H)CH3 (replace an H with CH3)

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Amine + HCl → ?

R3NH+ and Cl-

Primary or Secondary Amine + RX → ?

Add R, create + charge

Diisopropyl amine + n-BuLi → ?

LDA

R2NH + Acid Chloride or Ester or Acetic Anhydride or Carboxylic Acid → ?

R'C(=O)NR2

R2NH (2*) + NaNO2 (and acid) → ?

R2N-N=O

RNH2 (1*) + NaNO2 (and acid) → ?

RNN

What can RNN react with to produce alcohols, halogens (Cl, Br, I, F), and nitriles?

H2O for alcohols CuCl, CuBr, Ki, HBF4/heat CuCN

R2NH + ClSO2Ar → ? + (1)acid/base + (2)base/acid → ?

Sulfonamide R2NSO2Ar Original R2NH

What are the four parts of an amino acid?

Amino group, hydrogen, R side chain, carboxylic acid group

Describe the structure of a peptide bond, its formation, and its destruction

also called amide bond, formed between carboxylic acid and amino group during formation, water is lost and an amide functional group is formed can be broken back down to amino acids by acid and water

Describe "zwitterions" in relation to amino acids

``` At physiological (near neutral) pH, the amine group will tend to bind a protein, becoming negatively charged and the acid group will tend to donate its proton, becoming negatively charged This produces a “zwitterion” where the amino group resembles NH3+ and the carboxylic acid group resembles COO_ ```

How do you determine R/S chirality? (rectus and sinister)

Identify the chiral carbon Rank substituents by atomic number Lowest in the back, trace highest 3 Clockwise is R, counterclockwise is S

How do you determine L/D chirality? (laevus and dexter)

Place amino acid in Fischer projection with carbonyl at the top and R at the bottom If the amine is to the left and the H is to the right, it is L If the amine is to the right and the H is to the left, it is D

How can you convert a 3D configuration to a Fisher configuration?

The easiest way is guess and check Place the R on the bottom and the carboxyl on top, and guess for amine vs H Check to see if it has the correct R/S designation If so, it’s correct, you can see what side the amine is on If not, it’s incorrect, group swap amine and hydrogen

Which amino acids are L (opposed to D) and which amino acids are S (opposed to R)?

All amino acids are L All amino acids except for cystine have an S configuration **All L amino acids are S except for cystine, which is R

Describe neutral amino acids

In the zwitterion form, both the amine and the carboxylic acid are neutralized, so the amino acid is neutral unless there is an extra acid or base Amino acids with an amide on the side chain are not basic Tryptophan is neutral due to two rings Neutral amino acids can be either polar or nonpolar

Describe how to determine the polarity of neutral amino acids

more alkyl groups is less polar

What are the acidic amino acids? How can you tell?

Aspartate and Glutamate | R side chains contain carboxylic acids that are acidic enough to lose their protons

What are the basic amino acids? How can you tell?

Arginine, Lysine, and Histidine | Side chains contain amine’s whose pKa’s are high enough that they tend to bind protons

How can you make amino acids with a modified form of gabriel synthesis? You will start with potassium phthalimide and diethyl bromomalonate.

→ N-substituted phthalimide + base → Negatively Charged + 1. RBr + 2. NaOH/H2O/heat + 3. Acid/Heat → Amino Acid

How can you make amino acids using Strecker synthesis?

Aldehyde + Ammonia + HCN + (2)H2O → AA

Describe how to add and remove a Z protecting group

Benzyl chloroformate Produces a Benzyloxycarbonyl or “Z” protecting group (base catalyst) Can be removed by strong acids or hydrogenolysis with H2/Pd

Describe how to add and remove a Boc protecting group

Di-tert-butyl dicarbonate (Boc2O) Produces a “Boc” protecting group (base catalyst) Can be removed by an acid like HCl or CF3CO2H (trifluoroacetic acid)

Describe how to synthesize peptides using SOCl2

Take an amino acid and add a protecting group, then add PCl5 or SOCl2 Add another protected amino acid, producing a protected dipeptide Remove the protecting group by “deprotection” to produce the dipeptide

Describe how to synthesize peptides using (1)Et3N (2)ClCO2Et

Take an amino acid and add a protecting group, then add 1)Et3N (2)ClCO2Et Add another amino acid, producing a protected dipeptide (and CO2/EtOH) Remove the protecting group by “deprotection” to produce the dipeptide

What is the structure for alanine (Ala,A)?

methyl R group

What is the structure for glycine (Gly,G)?

hydrogen R group

What is the structure for phenylalanine (phe,F)?

CH2-Benzene ring R group

What is the structure for histidine (his, H)?

CH2-ring 5-member ring has N on the other bottom corner, double bonds up the sides, and NH on the peak

What is the structure for lysine (lys,K)?

CH2-CH2-CH2-CH2-Amine R group

What is the structure for serine (ser, S)?

CH2-OH R group

What is the structure for cysteine (cys, c)?

CH2-SH R group

What is the structure for aspartic acid (asp, D)?

CH2-carboxylic acid R group

What is the structure for glutamic acid (glu, E)?

CH2-CH2-Carboxylic acid R group

What is the structure for tyrosine (tyr, Y)?

CH2-Ph-OH R group

What is the structure for valine (val, V)?

isopropyl R group

Chapters 20 and 24 Flashcards

(60 cards)