Introduction:- In organic chemistry the substitution reactions is the most important reactions, especially Nucleophilic aromatic substitution reactions where nucleophile attacks positive charge or partially positive charge As it does so, it replaces a weaker nucleophile which then becomes a leaving group. The remaining positive or partially positive atom becomes an electrophile. The general form of the reaction is: Nuc: + R-LG → R-Nuc + LG: The electron pair (:) from the nucleophile (Nuc :) attacks the substrate (R-LG) forming a new covalent bond Nuc-R-LG.
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).
This reaction was able to happen during designated lab time due to the fact that a phenol was used. Phenols or more reactive than unsubstitued benzene rings due to the presence of the alcohol on the benzene ring. The alcohol is considered an activating group due to the oxygen’s ability to donate its lone pairs into the benzene ring thus giving it more electrons and thus making it more nucleophilic and more likely to react with the introduced electrophilic species. As aforementioned, there are various products formed in this reaction the two major products formed though are the ortho and para products. It is debatable which product is more prominent due to steric reasons and the capability of each product to conduct in hydrogen bonding.
Carbohydrates (starch)are broken down in the oral cavity by saliva amylose. They are made up of 3 elements, carbon (C), hydrogen(H) and oxygen(O) and can be found together in three different forms. Either as a monosaccharide, disaccharide or a polysaccharide they are differentiated by the number of rings in their chemical compound. There chemical formation is C6,H12,O6 and due to their bond angles between the carbons, tend to form a pentose of hexoses, stable ring structure. Each carbon atom is then numbered 1-6 and depending on the orientation of the OH group in carbon 1 will decipher weather the monosaccharide is either an a or b
Because of limitless industrial importance of PUs, hence need to study diisocyanate chemistry briefly and understand the properties and their reactivity. Mainly the isocynates are highly reactive and allow to forming urethane groups without any by-products formation. This isocyanates contains two or more –NCO functional groups for one molecule is called as diisocyanes or polyisocyanate respectively. The industrial important monoisocyanate compound is methyl isocyanate (MIC), majorly used to manufacturing of pesticides but this isocyanate is extremely hazardous which is responsible to Bhopal disaster, in 1984. All diisocyanate are liquids or solids in the nature and highly reactive, it undergo reaction across the double bond C
In the synthesized Friedel-Craft acylation reaction mechanism, anisole (methoxybenzene) is the nucleophile. The double bond on the nucleophile attacks the electrophile acetyl. The acetyl compound is then bound to the anisole in the para position, which created the product p-methoxyacetophenone. Since anisole is an activator (electron donor), the acetyl could have bound in either the ortho or para position (or in the meta position, but it is not as likely). However, the reason that acetyl was not bound in the ortho position was because the para position demonstrated the least amount of steric hindrance.
The agent used was called tetramethyl-p-phenylendiamine. When reduced the agent was clear but when oxidized it turned deep purple to a blackish color. This agent (Cytochrome C Oxidase) was the electron donor. This test did not distinguish whether the organism is oxidative or if it fermented.
Due to its poisonous nature, it is capable of killing cells and as a result, they body has mechanisms in place to break down hydrogen peroxide into non harmful constituents of water and oxygen. The body's cells are able to break down the hydrogen peroxide with the help of biological catalysts or enzymes. Enzymes speed up this break down into harmless entities otherwise the reaction would occur to slowly and may destroy cells in the balance. (Biology Corner
Bio-diesel production yields undesirable by-products for example methanol and glycerin. These by-products are removed so that the bio-diesel is suitable for use. Fractional distillation is used in the essential oil, flavor and fragrance industry. Raw essential oils are extracted from different plants such as mint, clove and tee tree for example. These raw oils contains impurities that have a bad flavour or odor.
This is beneficial for reactivity because the nitrogen in -NH2 in aniline is able to delocalize the positive charge of a carbocation by donating its electrons to the carbon during the transition state when aniline is brominated. The next strongest substituent would be -OH in phenol, followed by -OCH3 in anisole. This is because the three hydrogens on the carbon make the carbon slightly electronegative, slightly pulling away the electrons surrounding the oxygen directly attached to the benzene ring. The least reactive substituent would be -NHCOCH3 in acetanilide because the highly electronegative oxygen pulls away electrons from the nitrogen directly attached to the benzene ring, making the nitrogen less willing to stabilize the carbocation in the transition state in an electrophilic aromatic substitution reaction. Since all of the substituents are orth, para-directos, bromine in a bromination reaction would be substituted at either the 2 carbon, 4 carbon, 2 and 4 carbon, 2 and 6 carbon, or 2, 4, and 6 carbon.
It is also responsible for the bactericidal activity of isoniazid. Isoniazid has inhibitory effect on mycolic acid synthesis and seems to be its main purpose. Evidence suggests that after treatment with isoniazid, there is a lack of fatty acids on mycobacterium cell wall. Also inh A enzyme acts as molecular target for isoniazid inhibition. This enzyme plays a role in prolongation of the fatty acids that contribute to mycolic acid synthesis.
The lungs and kidneys work hand in hand because the lungs adjust the acid concentration quickly while the kidneys reabsorb or produce bicarbonate. What the lung and the kidney are doing for each other is termed compensation. Protein buffering is used in both intracellular and extracellular buffering. Proteins are considered negative buffers and pair well with hydrogen.