The Wittig reaction is valuable reaction. It has unique properties that allows for a carbon=carbon double bond to form from where a C=O double bond used to be located. Creating additional C=C double bonds is valuable due to its use in synthesis. The Wittig reaction will allow the synthesis of Stilbene (E and Z) from a Benzaldehyde (Ketcha, 141). One purpose of a Wittig reaction is the formation of alkenes from aldehydes or ketones employing a carbo-phosphorous ylide, which is stabilized vie resonance to allow for the carbon bonded to phosphorus to be deprotonate from by a base (Ketcha, 142).
The principal product in this case is R-Nuc. In such reactions, the nucleophile is usually electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. An example of Nucleophilic substitution is the hydrolysis of an alkyl bromide, R-Br, under basic conditions, where the attacking nucleophile is the base OH− and the leaving group is Br−. R-Br + OH− → R-OH + Br− Nucleophilic substitution reactions are commonplace in organic chemistry, and they can be broadly categorized as taking place at a carbon of a saturated aliphatic compound carbon or (less often) at an aromatic or other
The next step is nucleophilic attack by the deprotonated cysteine's anionic sulfur on the substrate carbonyl carbon. In this step, a fragment of the substrate is released with an amine terminus, the histidine residue in the protease is restored to its deprotonated form, and a thioester intermediate linking the new carboxy-terminus of the substrate to the cysteine thiol is formed. Therefore, they are also sometimes referred to as thiol proteases. The thioester bond is subsequently hydrolyzed to generate a carboxylic acid moiety on the remaining substrate fragment, while regenerating the free enzyme. 3.Mechanism of threonine protease Threonine proteases use the secondary alcohol of their N-terminal threonine as a nucleophile to perform catalysis.
During the separation, the component in sample will interact with the adsorbent material within the pores of the stationary phase. This will cause the different flow rates for the different components and leading to the separation of the components as they released from the column. The HPLC is worked basically on the high pressure pump. The separation of HPLC can be based on the polarity, electrical charges and the molecular size. But it is more highly based on the polarity of the compound.
These control the release rate of the drug from the patches. These are prepared by dispersing the drug in polymeric base solution. There are some polymers used in preparation of Transdermal patches: Natural polymers: such as, cellulose derivatives, Zein, Gelatin, Shellac, Waxes, Proteins, Gums and their derivatives, Natural rubber, Starch etc. Synthetic Elastomers: e.g. polybutadiene, hydrin rubber, polyisobutylene, silicon rubber, nitrile, acrylonitrile, neoprene, butyl rubber etc.
Instead of using a simple benzene derivative as a reactant, the substrate being used is ferrocene, which consists of a central iron atom bounded or sandwiched between two cyclopentadienyl rings. This synthesis also involves greener reagents. As stated above, aluminum chloride is often used as a strong Lewis acid catalyst to start the reaction. However, it is corrosive and can give off considerable quantities of acidic and toxic wastes. Since ferrocene is highly reactive (due to its two cyclopentadienyl rings), AlCl3 can be replaced with a more benign catalyst, phosphoric acid.
It can be defined as a group of organic chemicals and have been used to hinder the process of oxidative degradation of food products, fats and oils and polymers. Antioxidant can be defined as forms of molecules that help to maintain the body’s chemical reactions. They assist in preventing excessive activity of free radical molecules. Free radicals are molecules that are very reactive;
With the presence of NAD+, malate will then be transported into cytosol and will be converted back into oxaloacetate. The conversion will then reduces NAD+ into NADH and H+. The conversion from oxaloacetate into malate serve to move NAD+ from mitochondria into cytosol which is important in gluconeogenesis to proceed. In conclusion of this reaction, pyruvate carboxylase enzyme catalyzes the conversion of pyruvate into oxaloacetate in TCA cycle. But oxaloacetate needed to be converted into malate first before it can exit the mitochondria.
Polymerase Chain reaction (PCR) Principle: PCR is a process which involves taking a DNA template and amplifying distinct regions of it in vitro. To conduct PCR you need the DNA sample, DNA primers( two because one is forward and one is a reverse primer), Deoxynucleoside triphosphate bases(dNTP), DNA (Taq) polymerase, a buffer and some cations (mg2+). The reaction is carried out in a thermal cycler which fluctuates the temperature to allow progression of the amplification. Procedure: Initially the double helix is separated by breaking the hydrogen bonds using heat, leaving the bases exposed. This is called denaturation and it occurs at approximately 960C.
Chlorides of group || cations contain (Cadmium chloride, Mercuric chloride, Copper chloride and Bismuth chloride). 1- Mercuric chloride HgCl2:- It's poisonous odorless white crystalline solid, very toxic compound, and it's slightly volatile at ordinary temperatures. Parent acid and base: Hydrochloric acid HCl + Hg(OH) 2 Uses:- *Antiseptic and disinfectant in insecticides, preservatives, and batteries. *Antibacterial. * Obsolete substance.