Amines

Amine

is one of the common N-containing functional groups in organic chemistry

Amine is abundant in?

nature

Amine is a common component of

proteins, enzymes, nucleic acid, and alkaloidal drugs (N-containing active compounds)

Heterocyclic amines

• are also common in which a nitrogen is present in a ring system

• either aromatic or anti-aromatic.

Amines are derivatives of?

NH3 (ammonia)

• One H- of ammonia is replaced by a carbon group (R), yielding an amine

Alkaloids

are naturally-occurring amines

Alkaloids

plant derived constituents which contains a nitrogen molecule that has a wide variety of biological properties.

Atropine

an antispasmodic agent from Atropa belladonna

Reserpine

a tranquilizer and antiHTN agent, from Rauwolfia serpentina

quaternary ammonium salts

N atom has 4 groups attached to it and the N atom carries a positive charge

Amines are

water-soluble, forms hydrogen bonds (for 1° and 2° amines), and have a distinct putrid odor

Amines are basic by nature defined as

Kb (basicity constant).

Amines in a solution

can receive a proton from water (acting as acid).

Alkyl-substituted amines are _____ compared than aryl-substituted amines.

more basic

why is aryl-substituted amines less basic

N-atom’s lone-pair in aryl-substituted amines are delocalized and participates in p orbital overlap, making aryl-amines less basic.

Reduction of Nitrobenzene

mechanism to synthesize amines from an aromatic molecule via two-step sequence SE nitration followed by nitroreduction

2 step sequence of reduction of nitrobenzene

SE nitration followed by nitroreduction

Nitration

yields to nitrobenzene which when acted upon by a number of reducing agents will undergo nitroreduction to produce aminobenzene

Reduction of Nitriles

an amine synthesis via SN2 mechanism with RX and -CN ion, followed by reduction with strong reducing agent

Reduction of Nitriles is an amine synthesis via SN2 mechanism with

RX and -CN ion, followed by reduction with strong reducing agent

Reduction of Nitriles

always produces a 1° amine product.

The SN2 reaction (nitrile)

results in the formation of an alkyl nitrile with one additional carbon

The -CN ion can be reduced by

a strong reducing agent such as LiAlH4.

The reduction of -CN provided

-H atoms to the C-N triple bond

Reduction of Amides

is an amine synthesis via the SN Acyl mechanism with RCOOH and NH3, followed by reduction with a strong reducing agent.

Reduction of Amides

always produces a 1° amine product without an additional carbon added into the structure

Reduction of Amides

SOCl2 or DCC

used to activated the -OH in RCOOH to make a good leaving group and allow the NH3 (Nü) to undergo substitution

Reduction of Amides

can also occur on other RCOOH derivatives that can undergo SN Acylation with amines.

Acid halides and Acid anhydrides

can use NH3, 1° amines, and 2° amines to yield different amide products, which will lead to substituted amines

Alkylation via SN2 mechanism

uses RX and amines (NH3, 1° amines, 2° amines) to synthesize other amines

SN2 alkylation using azide ion (N3-) reacting with RX

• NH3 and 1○ Amine have similar reactivity, overalkylation can occur and 1○ Amine maybe difficult to form

• An azide (-N3) salt is a better reagent to create 1○ Amine since the alkyl azide is not nucleophilic, thus overalkylation is prevented

Reductive amination

is one-step synthesis reaction of amines from aldehydes and ketones reaction with NH3, 1° amines, and 2° amines in the presence of a reducing agent (NaBH4 or H2/Ni)