5.4.2 organic nitrogen compounds: amines, amides, amino acids and proteins

5.4.2 5.4.2 Organic nitrogen Organic nitrogen compounds: amines, amides, compounds: amines, amides,

amino acids and proteinsamino acids and proteins

BenzeneReactionsummary

http://en.labs.wikimedia.org/wiki/A-level_Chemistry/OCR_%28Salters%29/Reactions_of_arenes

• Burning Benzene – Smokey flame

• http://www.youtube.com/watch?v=XhRHk4zLR8A

Methoxybenzene and methylbenzene (toluene)

• Also undergo E+ subn. Do so more readily than benzene.

Phenol, C6H5OH, (carbolic acid )

Phenol, C6H5OH

• Early anesthetic (but burned the skin)• Poorly soluble (8.3 g dissolving in 100 mL )

• Does NOT behave like an aliphatic alcohol- is acidic, pKa = 10.0 (ethanol=15.9, ethanoic acid=4.75)

• Although acidic, unlike –COOH, phenol NOT will react with carbonates and hydrogencarbonates to form CO2

• Only esterifies with acid chloride (i.e. not with a carbox. Acid, RCOOH)

……RING MUCH MORE REACTIVERING MUCH MORE REACTIVETHAN BENZENETHAN BENZENE

Solubility of phenol and phenoxide anion.

Phenol in water (org solvent at bottom) >NaOH added > acidified http://www.sciencephoto.com/image/4210/530wm/A5000274-

Phenol_reactions-SPL.jpg

PhenolPhenol

withwithBrBr22(aq)(aq)

c.f. c.f. benzene!benzene!

• http://upload.wikimedia.org/wikipedia/commons/5/5c/EAS-ortho-para-meta.png

Phenol

withcolddil

HNO3

c.f. benzene!

E+ Subn in phenol

• Many (Kekule)resonance structures

http://chem-guide.blogspot.com/2010/04/electrophilic-substitution-of-phenol.html

RxRxnsns of benzene of benzene

• http://clem.mscd.edu/~wiederm/oc2chp/oc2chpphenols/phenolrxnsummary.gif

OtherReactions(N.O.S.)

- Demonstrateincreased

reactivity ofthe ring

Aspirin (synthesis #1)

• http://www.ch.ic.ac.uk/rzepa/mim/drugs/html/aspirin_text.htm

Aspirin (synthesis #2)

• http://www.ch.ic.ac.uk/rzepa/mim/drugs/html/aspirin_text.htm

Amines, amides and amino acidsAmines, amides and amino acids

• Aliphatic amines, & aromatic aminesethylamine phenylamine

a. give examples of: i. molecules that contain amine and

amide functional groupsii. amino acids

• b. describe and carry out, where appropriate (using butylamine and phenylamine), reactions to investigate the typical behaviour of primary amines. This will be limited to:

• i. characteristic smell• ii. miscibility with water as a result of hydrogen

bonding and the alkaline nature of the resulting solution• iii. formation of salts• iv. complex ion formation with copper(II) ions• v. treatment with ethanoyl chloride and

halogenoalkanes, eg making paracetamol

Making paracetamol #1

• http://www.ch.ic.ac.uk/rzepa/mim/drugs/html/paracet_text.htm (good short notes on overdose problem)

para-acetylaminophenol

Making paracetamol #2

• http://en.wikipedia.org/wiki/Paracetamol

Reduction of Nitrobenzene to phenylamime (aniline)

Diazo formation

• 1o, 2o and 3o aromatic based amines.

Video 1o amine undergoing decomposition T>10oC

Methyl orange via diazo couplingMethyl orange via diazo coupling

http://www.science.cmu.ac.th/educate/couresware_chem/203204/Arputtinan6.htm

The colourscolours of MethylMethyl OrangeOrange

• Other Azocompounds (salters chem)

< A diazo dye

Polymers

• Video of polymer – ‘bubblegum’ a.k.a. Plastics, rubber, food colouring, sucrose and dextrose – yum huh?

Nylons…

• Video 1 – intro to polymers

• Video 2 – nylon – brave? no glasses guy

• Video 3 – specific chemicals used nylon

? = addition polymer repeating unit of sodium poly(acrylate)

• Product name : SAP-Super Absorbent Polymer

• Chemical name : Sodium polyacrylate

• Monomer Molecular formula : C3H4O2

monomer Many COOH (or COONa) groups allow for widespread large amount of interaction with water molecules

Super Absorbent Polymers for Diaper

http://www.made-in-china.com

Video

Other water interacting polymers

Propeneamide

? = addition polymer repeating unit of poly(propeneamide)

• Propeneamide

•Webpage: DissolvingPolymers.mht

Dissolving Plastics

Poly(ethanol)

Polyurethane formation (isocyanate with polyol)

http://ec.gc.ca/substances/nsb/images/Polyurethane_S1.gif

PU video

Dun WORi, POLYURETHANES ARE NOT ON THE SYLLABUS !!!Dun WORi, POLYURETHANES ARE NOT ON THE SYLLABUS !!!

Condensation polymersCondensation polymers

• TeryleneTerylene is used to makefishing nets clothes (quick-dry, non-iron) cassette and video tapes

Condensation polymers: There are two main types of condensationpolymer made from carboxylic acid derivatives: polyesters and polyamides.

i) Polyesters: A well-known polyester, TeryleneTerylene, is made by heatingethane-1,2-diol with dimethylbenzene-1,4-dicarboxylate (dimethyl terepthalate):

The dimethlybenzene-1,4-dicarboxylate is obtained via the following reactionpathway:

The manufacture of ethane-1,2-diol has already been described in section 26.4.2.

Or simpler rxn (more edexcel friendly) not using the diester as

previously, but the dicarbox acid…

Kevlar

Poly(N-substituted amide)

Kevlar again.

Synthesis of Kevlar

Should be familiar with monomers and polymer requirements now.

Poly(N-substituted) amide – similar to Nylon

Amino acids.

• Naturally occurring ones are L acids (laevorotatory)

• Strecker synthesis give L and R (next slide)

R C

O

HNH3

..

R C

O

H

N

H

H

H..-

+R C

O

H

N

H

H

H..

R C

H

N

H

OH H

..-CN

R C

H

N

H

R C

H

N

H

CN

..-

OH H

R C

H

N

H

CN

H

R C

H

N

H

H

COHO

The Strecker synthesis. - Synthesis of amino acids

(1)(2)

(2)

(1)(1)

(3)(2).. ..

an imine

water

The imine

The nitrogen version of acarbonyl. C=N can replace C=O(recall 2,4-DNP reaction !!)

Like C=O's, C=N's aresusceptable to nucleophilicattack - addition - by -CN

.. ..

( +OH - ions)

The N equivalentof the alpha-hydroxynitriles. An alpha-amine nitrile

Acid hydrolysisof niriles...

An alpha-amino acid

(1)

(2)

(2)

(1)

*

The amino acids vary in their side chains (indicated in blue in the diagram).

The eight amino acids in the orange area are nonpolar and hydrophobic.

The other amino acids are polar and hydrophilic ("water loving").

The two amino acids in the magenta box are acidic ("carboxy" group in the side chain).

The three amino acids in the light light blueblue box are basic ("amine" group in the side chain).

Amino acids – Ninhydrin rxn and test

Ninhydrin rxn with amino acids.ProcedureAdd about 2 mg of the sample to 1 mL of a solution of 0.2 g of ninhydrin (1,2,3indanetrione monohydrate) in 50 mL of water. The test mixture is heated to boiling for 15-20 sec; This reaction is important not only because it is a qualitative test, but also because it is the source of the absorbing material that can be measured quantitatively by an automatic amino acid analyzer. This color reaction is also used to detect the presence and position of amino acids after paper chromatographic separation.

Positive TestA blue to blue-violet color is given by a-amino acids and constitutes a positive test. Other colors (yellow, orange, red) are negative.

ComplicationsProline, hydroxyproline, and 2-, 3-, and 4-aminobenzoic acids fail to give a blue color but produce a yellow color instead.

Ammonium salts give a positive test. Some amines, such as aniline, yield orange to red colors, which is a negative test.

Amino acids – analysis with ninhydrin

chromatography

Protein synthesis (biological)

• Video (real time)

• Video 2

• Salters Organic Toolbox

• Salters Organic Reactions.mht