Today I’d like to talk about organic nitrogen compounds. I’ll be talking about nitro compounds, then I’ll move on to amines & amides, then amino acids & peptides and finally take a look at heterocyclic compounds.
I’ll start with some general info on nitro compounds. They’re usually highly explosive, especially when impure and contain more than one nitro group. Basically, the nitration process is performed with a mixture of concentrated nitric and sulfuric acid.
Through the process of nitration of methane you get nitromethane, which is an example of a nitro compound. It is commonly used as an additive in fuel to add power to engines and is twice as good as gasoline.
Another example for a nitro compound 2,4,6-Trinitrotoluene, also known as TNT, is made by putting Toluene (IUPAC Methylbenzene) through nitration three times. The most common use of TNT is as an explosive, because the gases continue spreading without the need of oxygen and because it can only be detonated by using a pressure wave from an explosion booster. The chemical equation you can see is the explosion of TNT and below that is its structure.
TNT has a detonation velocity of 6900m/s and contains 4MJ of energy per kg. When it detonates it reaches 2800°C and releases 700 liters of gas per kg.
Another important reaction of nitro compounds is the reduction.
This leads me to the next topic which is amines. Most amines are made through reduction of nitro compounds. Basically they are organic compounds that contain a nitrogen atom, are basic and were derived from ammonia, wherein one or multiple hydrogen atoms were replaced by an alkyl or aryl group. They have a sharp penetrating odor similar to ammonia and are basic. The prefix is amino- and the suffix is “-amine”.
There are four kinds of amines:
- primary, R1-NH2
- secondary, R1-NH-R2
- tertiary amines R1-N(R2)-R3
- quaternary ammonium cations N(R)4+
An example of an amine is methylamine, which is reduced nitromethane. Here you can its structure and the chemical equation of reducing nitromethane to methylamine
Another kind of amine is Hexane-1,6-diamine or hexamethylenediamine, which is used to make Polyamide-6,6, commonly known as Nylon.
Aniline, also known as aminobenzene, is less basic than aliphatic amines, is reduced nitrobenzene and one of most important amines to make dyes, rubber products and pharmaceuticals.
By substituting a hydroxyl group with an amino group in carboxyl acid you get amides. One of its properties is that it practically doesn’t have any basicity, because of the inductive effect that separates the electron pair from the nitrogen. Examples of amides are N,N-Dimethylformamide, also known as N,N-Dimethylmethanamide or DMF, an important solvent for plastic, and carbamide, commonly known as urea. Urea has a low level of basicity, due to the inability of the inductive effect to remove the electron pairs of the nitrogen atoms. It’s used as fertilizer and as an intermediate good for finished products.
As the name implies, amino acids contain an amine and a carboxylic acid functional group and they are the building blocks of proteins. Additionally, naturally occurring alpha amino acids can be generally represented by the generic formula you can see on the projector.
When classifying amino acids according to their capacity to interact with water four classes may be distinguished:
- nonpolar (hydrophobic)
- polar (hydrophilic)
A large proportion of our cells, muscles and tissue is made up of amino acids. They play an essential role in transporting and storing nutrients and healing wounds or repairing tissue. |To form protein, amino acids are linked by dehydration synthesis to form peptide bonds. The chain of amino acids is also known as a polypeptide, whereas two linked amino acids are called a dipeptide. |An example of a pentapeptide is enkephalin, which is used in the brain to dial down the pain sensitivity, its sequence is Tyr-Gly-Gly-Phe-Met. |The distinction between proteins and peptides is their size. In a sense peptides are proteins with molecular weights less than 10000.
The 20 most important amino acids are the following (The green colored amino acids are essential diet components, since they are not synthesized by the human metabolic processes):
Glycine, Alanine, Valine, Leucine, Isoleucine, Phenylalanine, Proline, Methionine, Tryptophan, which are nonpolar
Asparagine, Glutamine, Serine, Threonine, Tyrosine, which are polar
Aspartic acid and glutamic acid, which are as the name suggests acidic
And Cysteine, Lysine, Arginine and finally Histidine
Moving on to heterocyclic compounds. They are ring-shaped bonds that include many of the biochemical material essential for life. The most common heterocycles are five- or six-membered rings and contain nitrogen, oxygen and sulfur. An exception is penicillin, as it has four members. |They are commonly used found in drugs, pesticides, dyes and plastics (for example: nicotine & caffeine). |The best known five-membered rings are: Furan and Pyrrole, which are aromatic because the heteroatoms have unoccupied electron pairs that find use in delocalized electrons. |The best known six-membered rings are: Pyrimidine and purine, which are essential for the bases of nucleic acids (for example: DNA and RNA).
That was my presentation, thank you all for listening.