007_C1080_Organic-Amines,Amides_CH16.pptx

AMINES AND AMIDES CHAPTER 6 H. O’BRIEN TUESDAY, SEPTEMBER 25, 2023  AMINES Amines are derivatives of ammonia, NH3, where one or more hydrogen atoms have been replaced by an organic (R) group  NAMING AMINES Com...

AMINES AND AMIDES CHAPTER 6 H. O’BRIEN TUESDAY, SEPTEMBER 25, 2023  AMINES Amines are derivatives of ammonia, NH3, where one or more hydrogen atoms have been replaced by an organic (R) group  NAMING AMINES Common Naming Alphabetically link the names of the alkyl or aromatic groups bonded to the nitrogen and attach the suffix –amine so the name is one word Use di- or tri- prefixes for identical alkyl groups  NAMING AMINES IUPAC Naming When naming amines, name the longest carbon chain Replace the –e ending with -amine The position of the amino group is given by the carbon number it is attached to The prefix N is used to identify the Nitrogen substituents  NAMING AROMATIC AMINES Aniline is the simplest aromatic amine Compounds are named as substituted anilines An italic “N” is used to indicate that an alkyl group is attached to the nitrogen and not to the ring Ex.  PHYSICAL PROPERTIES OF AMINES The N-H bond is not quite as polar as the O-H bond Primary and secondary amines can form hydrogen bonds between molecules The hydrogen bonds are not as strong as those of alcohols, so amine boiling points are somewhat lower than those of alcohols Simple, low molecular weight amines are gases at room temperature Heavier, more complex compounds are liquids or solids PHYSICAL PROPERTIES OF AMINES  PHYSICAL PROPERTIES OF AMINES Amines can hydrogen bond with water, making smaller amine molecules (less than 6 carbon atoms) usually water soluble  PHYSICAL PROPERTIES OF AMINES Low molecular weight amines have a sharp, penetrating odor similar to that of ammonia Some amines are partially responsible for the odor of decaying animal tissue  AMINE REACTIONS All amines behave as weak bases in water (similar to ammonia) Ex.  AMINE REACTIONS All amines behave as weak bases and form salts when they react with acids such as HCl Ex.  AMINE REACTIONS All amines behave as weak bases and form salts when they react with sulfuric, nitric, phosphoric, and carboxylic acids as well Ex.  NAMING AMINE SALTS Name as an amine, but change “amine” to “ammonium” and add the anion name Ex.  AMINE SALTS Amine salts can be converted back to amine form by adding a strong base The form in which amines occur in solutions is pH dependent, just as is the case for carboxylic acids AMINE REACTIONS  AMINE NEUROTRANSMITTERS Neurotransmitter – a substance that acts as a chemical bridge between nerve cells  IMPORTANT AMINE NEUROTRANSMITTERS Acetylcholine Dopamine – synthesized from the amino acid tyrosine Norepinephrine – synthesized from dopamine, may be associated with mental illness Serotonin – synthesized from the amino acid tryptophan, may be associated with mental illness  OTHER BIOLOGICALLY IMPORTANT AMINES Epinephrine (adrenaline) - more important as a hormone than a neurotransmitter - Fight-or-flight hormone, released in response to pain, anger, or fear - Increases blood glucose level for energy Amphetamines - nervous system stimulants, similar in structure to epinephrine (Abuse of amphetamines has severe detrimental effects on the body and the mind)  OTHER BIOLOGICALLY IMPORTANT AMINES Alkaloids - a class of nitrogen-containing organic compounds obtained from plants Examples include: Nicotine – found in tobacco Caffeine – found in coffee and cola drinks Quinine – used to treat malaria Opium – used to make codeine (in cough medicines), morphine (pain killer) and heroin AMINE REACTIONS > AMIDE FORMATION  AMIDE FORMATION Amines react with acid chlorides or acid anhydrides to form amides  AMIDE FORMATION The amide linkage can be thought of as separating an ammonia or amine portion and a portion derived from a carboxylic acid Note: The reaction of an amine with a carboxylic acid normally produces a salt and not an amide  AMIDE FORMATION Primary and secondary amines can form amides Tertiary amines do not react to form amides  AMIDE FORMATION Ex.  AMIDE FORMATION Ex.  POLYAMIDE FORMATION Reaction of di-acid chlorides with diamines produces polyamides that, like polyesters, are condensation polymers The repeating units in polyamides are held together by amide linkages  POLYAMIDE FORMATION Three billion pounds of nylon and related polyamides are produced annually > 60% nylon fiber for home furnishings (e.g. carpet) > ~40% textile fiber in clothing and tire cord > Minor uses: fasteners, rope, parachutes, paintbrushes, electrical parts, medical tubing, nylon sutures… Proteins are polyamides (e.g. silk and wool)  NAMING AMIDES Use the carboxylic acid’s name and drop the –ic ending (common name) or –oic ending (IUPAC name) and change to – amide Ex.  NAMING AMIDES Use N to denote alkyl groups attached to the nitrogen atom Ex.  PHYSICAL PROPERTIES OF AMIDES Hydrogen bonding between unsubstituted amides causes them to have high melting points Formamide is a liquid at room temperature All other unsubstituted amides are solids at room temperature  PHYSICAL PROPERTIES OF AMIDES Amides can form hydrogen bonds with water, making smaller amide molecules (less than 6 carbon atoms) rather water soluble  AMIDE REACTIONS Amides are neither acidic nor basic Amide hydrolysis is the reverse of amide formation; an amide is cleaved to produce a carboxylic acid and an amine or ammonia Amide hydrolysis is a central reaction in the digestion of proteins and the breakdown of proteins within cells In the body, this hydrolysis is catalyzed by enzymes  AMIDE REACTIONS The products of an amide hydrolysis depend on whether the reaction occurs in acidic or basic conditions One hydrolysis product must always be in the form of a salt Ex. AMIDES IN MEDICINE  Next Topic > Carbohydrates