POLYAMIDE   

          A polyamide is a polymer containing monomers of amides joined by peptide bonds. They can occur both naturally and artificially, examples being proteins, such as wool and silk, and can be made artificially through step-growth polymerization or solid-phase synthesis, examples being nylons, aramids, and sodium poly(aspartate). Polyamides are commonly used in textiles, automotives, carpet and sportswear due to their extreme durability and strength.

Classification

According to the composition of their main chain, polyamides are classified as follows:

Polyamide family	Main chain	Examples of polyamides	Examples of commercial products
Aliphatic polyamides	Aliphatic	PA 6 and PA 66	Nylon from DuPont
Polyphthalamides	Semi-aromatic	PA 6T = hexamethylenediamine + terephthalic acid	Trogamid from Evonik Industries, Amodel from Solvay
Aramides = aromatic polyamides	Aromatic	Paraphenylenediamine + terephthalic acid	Kevlar and Nomex from DuPont, Teijinconex, Twaron and Technora from Teijin, Kermel from Kermel

According to the number of repeating units' types, polyamides can be:

• homopolymers :
• PA 6 : [NH−(CH₂)₅−CO]_n made from ε-Caprolactam ;
• PA 66 : [NH−(CH₂)₆−NH−CO−(CH₂)₄−CO]_n made from hexamethylenediamine and adipic acid;
• copolymers :
• PA 6/66 : [NH-(CH₂)₆−NH−CO−(CH₂)₄−CO]_n−[NH−(CH₂)₅−CO]_m made from caprolactam, hexamethylenediamine and adipic acid ;
• PA 66/610 : [NH−(CH₂)₆−NH−CO−(CH₂)₄−CO]_n−[NH−(CH₂)₆−NH−CO−(CH₂)₈−CO]_m made from hexamethylenediamine, adipic acid and sebacic acid.

According to their crystallinity, polyamides can be:

• semi-crystalline:
• high crystallinity : PA46 et PA 66 ;
• low crystallinity : PA mXD6 made from m-xylylenediamine and adipic acid;
• amorphous : PA 6I made from hexamethylenediamine and isophthalic acid.

According to this classification, PA66, for example, is an aliphatic semi-crystalline homopolyamide.

Production from monomers

The amide link is produced from the condensation reaction of an amino group and a carboxylic acid or acid chloride group. A small molecule, usually water, or hydrogen chloride, is eliminated.

The amino group and the carboxylic acid group can be on the same monomer, or the polymer can be constituted of two different bifunctional monomers, one with two amino groups, the other with two carboxylic acid or acid chloride groups.

Amino acids can be taken as examples of single monomer (if the difference between R groups is ignored) reacting with identical molecules to form a polyamid                                                                              

The reaction of two amino acids. Many of these reactions produce long chain proteins

Aramid (pictured below) is made from two different monomers which continuously alternate to form the polymer and is an aromatic polyamide:

The reaction of 1,4-phenyl-diamine (para-phenylenediamine) and terephthaloyl chloride to produce Aramid

β-LACTAM ANTIBIOTIC

            β-Lactam antibiotics (beta-lactam antibiotics) are a broad class of antibiotics, consisting of all antibiotic agents that contains a β-lactam nucleus in their molecular structures. This includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Up until 2003, when measured by sales, more than half of all commercially available antibiotics in use were β-lactam compounds.

Bacteria often develop resistance to β-lactam antibiotics by synthesizing a β-lactamase, an enzyme that attacks the β-lactam ring. To overcome this resistance, β-lactam antibiotics are often given with β-lactamase inhibitors such as clavulanic acid.

First Meeting

1. AMINES           

    Amines are organic compounds and functional groups whose contents consist of atomic nitrogen      compounds by the couple themselves. Amino is a derivative of ammonia. Usually called the amide and has a variety of different chemicals. Which includes amino acids are acids, biogenic acids, trimethylamine, and aniline.
   
The smell of ammonia, is an old fish, urine, Rotting flesh, and all the semen is composed of amino substances.

2.  AMIDA

     Amida is a type of chemical that can have two senses. The first type is an organic functional group having a carbonyl group (C = O), which binds to a nitrogen atom (N), or a compound that contains this functional group. The second kind is a form of nitrogen anion.

 3. LACTAM

     A lactam (the noun is a portmanteau of the words lactone + amide) is a cyclic amide. Prefixes indicate how many carbon atoms (apart from the carbonyl moiety) are present in the ring: β-lactam (2 carbon atoms outside the carbonyl, 4 ring atoms in total), γ-lactam (3 and 5 total), δ-lactam (4 and 6 total). Beta β, gamma γ and delta δ are the second, third and fourth letters in the alphabetical order of the Greek alphabet, respectively.

General synthetic methods exist for the organic synthesis of lactams.

• Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement.
• Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction.
• Lactams form from cyclisation of amino acids.
• Lactams form from intramolecular attack of linear acyl derivatives from the nucleophilic abstraction reaction.
• In iodolactamization ^[1] an iminium ion reacts with an halonium ion formed in situ by reaction of an alkene with iodine.
• In iodolactamization ^[1] an iminium ion reacts with an halonium ion formed in situ by reaction of an alkene with iodine.

• Lactams form by copper catalyzed 1,3-dipolar cycloaddition of alkynes and nitrones in the Kinugasa reaction
• Diels-Alder reaction between cyclopentadiene and chlorosulfonyl isocyanate (CSI) can be utilized to obtain both β- as well as γ-lactam. At lower temp (−78 °C) β-lactam is the preferred product. At optimum temperatures, a highly useful γ-lactam known as Vince Lactam is obtained.^[2]