Organic Functional Groups Lecture 5 to End PDF

ORGANIC FUNCTIONAL GROUPS Dr Graeme Kay Academic Strategic Lead – Chemical Sciences 01224 262548 [email protected] Lecture 5  ALKYNES nes are hydrocarbons that contain a C-C triple bond. A triple bond consis ond and two ∏ bonds. pounds with triple bonds at t...

ORGANIC FUNCTIONAL GROUPS Dr Graeme Kay Academic Strategic Lead – Chemical Sciences 01224 262548 [email protected] Lecture 5  ALKYNES nes are hydrocarbons that contain a C-C triple bond. A triple bond consis ond and two ∏ bonds. pounds with triple bonds at the end of a molecule are called terminal alk erminal –Ch groups are called acetylenic hydrogens. OH 1-pentyn-3-ol nal Alkynes are acidic, and the end hydrogen can be removed as a proton RONG bases (e.g. organolithiums, Grignard reagents) to form metal acety lkynides. are strong nucleophiles and bases, and are protonated in the presence o and acids. Preparation of Alkynes ydrohalogenation of vicinal or geminal-dihalides is a particul ul method for the preparation of alkynes  ALKYNES ome common reactions of Alkynes:  Introduction to Polymers Dr Graeme Kay Academic Strategic Lead – Chemical Sciences 01224 262548 [email protected]  New Subject – Introduction to Polymer Chemistry olymers are substances that consist of very large molecules alled MACROMOLECULES, that are made up of many repeatin ubunits. These subunits are called MONOMERS. he reactions that join together these subunits are called OLYMERISATIONS. olymers can be natural or man-made. ood book – Morrison and Boyd, 6th Ed, Chpt 31, pp1077. lymerisation e process of joining of many small molecules to form very ge molecules. lymers are formed in two general ways: Chain-reaction polymerisation. Step-reaction polymerisation. hain-reaction polymerisation. efinition: A chain reaction in which the growth of a polymer hain proceeds exclusively by reaction(s) between monomer(s nd reactive site(s) on the polymer chain with regeneration of e reactive site(s) at the end of each growth step. H2C CH2 RADICAL + H2C CH2 RADICAL CH2CH2 RADICAL CH2CH2CH2 ETC.... ep-reaction polymerisation. en the term ‘addition polymerisation’ is used interchangeabl ype of polymerisation mechanism in which bi-functional multifunctional monomers react to form first dimers, trimers en longer oligomers. ee-Radical Vinyl polymerisation (Chain reaction). ually require a small amount of initiator. nCH2 CH CH2CHCH2CHCH2CHCH2CH Cl Cl Cl Cl Cl Vinyl monomer Polymer Poly vinyl chloride (PVC)  --> Polystyrene styrene --> ?? N acrylonitrile olymerisation e a mixture of two (or more) monomers is allowed to undergo merisation – a copolymer. A polymer that contains two (or more) kinds o omeric units in the same molecule. H3C CH2 CH3 initiator CH2 + O O O CH3 O styrene methyl methacrylate POLYSTYRENE(CO-METHYL METHACRYLATE) p-reaction polymerisation. ontrast to chain-reaction polymerisation, the reaction here d depend on chain-carrying free radicals. Instead, the steps a ependent to each other – they involve more than one functio up in the monomer. example: Polyamides  cture and properties of macromolecules size of polymers have little effect on chemical properties reactivity. It is their PHYSICAL properties that differ from aller, ordinary molecules. These differences have an impact o rmaceutical processes. cture and properties of macromolecules tallinity y crystalline materials tend to be formed/arranged in a regular, symmetrical way g rise to a geometric pattern that is repeated over and over. neral, a high mwt polymer does not exist entirely in a crystalline form – this come ts size and its difficulty to move about and arrange itself in the regular patterns ed for crystallinity. In reality, polymers form solids with regions of crystallinity allites) imbedded in an amorphous material – we classify polymers by their EE OF CRYSTALLINITY. info: //www.youtube.com/watch?v=9yVywEMutSY //pslc.ws/macrog/crystal.htm Crystallinity and polymer structure From: https://pslc.ws/macrog/crystal.htm A polymer's molecular structure strongly affects crystallinity. If it's regular and orderly, highly symmetrical, it will pack into crystals more easily. In a way, the molecules want to get next to each other in crystalline domains. If the molecular structure is not highly regular and symmetrical, it won't. Let's take a look at polystyrene in it's various forms to help us understand how this works. There are two kinds of polystyrene. There is atactic polystyrene, and there is syndiotactic polystyrene. The former is totally amorphous and the lymers in Pharmacy s topic is further developed in semester 2. ditionally, polymers were used as tablet binders, holding the excipients together. e modern pharmaceutical dosage forms use polymers for drug protection, e masking, controlled release of a given drug, targeted delivery and to increase g bioavailability – these are just some of the advances.. harmaceutical Application: example 1 llulose-based polymers are extensively used in armaceutical dosage forms – it is worth noting at cellulose is not soluble in water. ethyl cellulose, CMC and hydroxypropyl- ethyl cellulose are the most common used. ese can be used as coatings for sustained release plications, emulsion stabilisers or tablet atings (hydroxypropyl/ethyl variants are ater soluble) ceutical Application: example 2 tic polymers in drug delivery. rs based on acrylic or methacrylic acids have extensive applications in drug deliv e used to protect the drug or control the drugs release. They are classified as: c and neutral. mple, cationic polymers are used as pH-dependant drug delivery platforms to pr e drugs, to mask unpleasant tastes and dour, to protect the API from moisture a improve drug storage. example: Eudragit E 100 Polymers in Pharmacy Taken from: Martin’s Physical Pharmacy and Pharmaceutical Sciences. 6th Ed. Pg. 509. Polymers in Pharmacy Taken from: Martin’s Physical Pharmacy and Pharmaceutical Sciences. 6th Ed. Pg. 509.  Introduction to Sulfa drugs Dr Graeme Kay Academic Strategic Lead – Chemical Sciences 01224 262548 [email protected]  Sulphonamides – Sulfa antibacterial class 1930’s it was discovered that the dye Prontosil had antibacterial properties (in v O NH2 S O N N H2N NH2 prontosil wever, when it was tested in vitro, it had no antibacterial property………..  Sulphonamides was discovered that Prontosil degraded in vivo to give the metabolite below: O NH2 S O NH2 O S N N O H2N H2N NH2  Sulfonamides 4-Amino-N-Substituted-Benzene-sulfonamide O H2N S NHR O Mechanism of Action Sulfonamides interfere with folic acid synthesis by preventing addition of para-aminobenzoic acid (PABA) into the folic acid molecule through competing for the enzyme dihydropteroate synthetase. https://slideplayer.com/slide/8244287/  Structure Activity Relationship (SAR) essed online 15/10/2019: https://www.slideshare.net/sakshisaxena9256/sakshi-saxena-bsbt-518-p1  Structure Activity Relationship (SAR) Accessed online 15/10/2019: https://slideplayer.com/slide/9647711/  Acidity O O H H H2N S N H2N S N H O CH 3 O O Which is the stronger acid?  Clinically active agents Look up the structures of these molecules. Accessed online 15/10/2019: https://doctorlib.info/pharmacology/basic-clinical- pharmacology-13/46.html Useful materials and web sources: https://slideplayer.com/slide/8244287/ https://www.sciencedirect.com/topics/neuroscience/su lfonamides https://www.youtube.com/watch?v=7CHX_c4Xu3c