pentylamine or pentanamine cyclohexylamine or cyclohexanamine

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1 omenclature - Amines: 1. Simple 1º Amines like simple ethers (no other functional groups), can simply name the alkyl group and end with the suffix -amine. Alternatively, you may remove the final e from the alkane and just add -amine. 2 pentylamine or pentanamine 2 cyclohexylamine or cyclohexanamine 2. For simple symmetrical 2º or 3º amines, add di- or tri- to the prefixes: diethylamine 3. For simple asymmetrical 2º or 3º amines, the largest alkyl group is considered the parent alkyl group and the other group(s) is/are considered -substituents ( because the substituent is on nitrogen): -methylpentylamine or -methylpentanamine 4. Complex amines have similar rules to alcohols and are considered complex because there are other functional groups in the molecule. In terms of priorities, the amine group is below that of the alcohol, and above alkenes and alkynes. If the amine group is not the highest priority functional group than the amine group becomes a substituent (prefix) and is named as an amino group. 2 6-amino-4-nonanol 2 3-amino-2-hydroxyhexanal [Side otes about Amines: Properties of Amines: itrogen is the fourth most abundant element Biologically active amines: itrogen groups are commonly found in natural products

2 ephedrine amphetamine epinephrine (decongestant) (stimulant) (adrenaline) Alkaloids are amine compounds that are naturally derived from plant sources. otice the similarity in structures. Taking a known drug, with known capabilities, and changing the structure in subtle ways to either mimic or increase the activity of the drug, without causing negative side effects, are typically how new drug therapies are developed. Generally, amines have a characteristic bad smell. For example, trimethylamine is partially responsible for the smell of fish while cadaverine (1,5-pentanediamine) and putrescine (1,4-butanediamine) have appalling odors (these compounds are formed during the decomposition of proteins). Amines are less polar than alcohols (lower electronegativity of nitrogen versus oxygen). nly amines with four carbons or less are generally water-soluble because the compound is still more polar than non-polar. Amines have mid-range MP/BP compared to alcohols and alkanes/alkenes. Amines are more polar (electronegative!) than alkanes or alkenes resulting in higher melting and boiling points (dipole-dipole forces, -bonding) but less polar than alcohols so the melting/boiling point is therefore lower than that of a similar alcohol. The nitrogen -bond is less strong than that of oxygen. (Why?) C 3 C 2 C 3 C 3 C 2 2 C 3 C 2 BP=-42ºC BP=16.6ºC BP=78.3ºC Acid-Base chemistry of amines: Amines are electron-rich and are considered to be basic and nucleophilic compounds. Being less electronegative, the lone pair on itrogen is more reactive than that on oxygen. They react with acids to form salts and they react with electrophiles in bond-forming reactions. [End Side otes on Amines]

3 Formation of Imines and Enamines: 3, , , Imine or Enamine? a. 3, + b. (C 3 ) 2, + c. 2 C 3, + eutral nitrogen nucleophiles are stronger than neutral oxygen nucleophiles. Amines can react with ketones and aldehydes without the acid catalyst needed for oxygen nucleophiles, but as you will see in the mechanisms, the reactions cannot complete the transformations to an imine or enamine without a proton source being present. The p is more important in these reactions too much acid and the amine (uc) is protonated (and destroyed): Forward Mechanism: Imine Formation 3 + 2

4 3 everse Mechanism: Conversion of an Imine to back to an Aldehyde or Ketone Forward Mechanism: Formation of Enamines

5 everse Mechanism: eversal of Enamine back to Aldehyde or Ketone eductive Amination: Conversion of a ketone or aldehyde to an amine (via an imine or iminium ion), followed by reduction with hydrogen gas with a i catalyst or ab 4 : /i or ab 4 Can use 3, 1º amines or even 2º amines to build a variety of amine-containing compounds. Product? ab 4 Product? 2 2 /i