Synthesis of a Potential Enzyme Inhibitor

Synthesis of a Potential Enzyme Inhibitor Delaram Salehifard Aim Synthesis and characterisation of Benzocaine. Introduction The Fischer esterification of 4-amino benzoic acid is catalysed by an acid is fully reversible. Method: 3g of 4-aminobenzoic acid was weighed out and placed into a dry 100cm3 round bottom flask (ensuring no residues are left inside the joint). 20 cm3 of methylated spirits was measured out and added to the 4-aminobenzoic acid in the round bottom flask. 3 cm3 of concentrated Sulfuric acid was measured out and added to the round bottom flask mixture (ensuring no residues are left on the joint), a condenser was fit onto the round bottom flask and the mixture was gently swirled. Using a heating mantle, the mixture was heated and upon boiling; refluxed for 30 minutes. At the end of reflux, the heat source was removed and the mixture was allowed to cool to room temperature. Upon cooling, the mixture was gently stirred using a glass stirring rod and Sodium hydroxide solution (20%) was slowly added to the mixture until a neutral pH was attained. The mixture was allowed to stand for 5 minutes before the contents were poured into a beaker containing approximately 70 cm3 of ice, the reaction vessels was rinsed with distilled water and the washings were transferred into the beaker to reach an approximate volume of 150cm3. The product was filtered using a Buchner funnel (washed with some cold water) ensuring that the moisture is completely sucked out. The product was then transferred onto a watch glass and dried in an oven at a temperature no greater than 60oC. The dry mass was then noted and the product submitted for analysis. Steps1-10 were repeated using Isopropyl alcohol instead of Methylated spirits and the melting point for the product was attained. Mechanism of action Step one portrays the protonation of the carbonyl oxygen on 4-aminobenzoic acid where the Sulphuric acid acts as the H+ donor (the regeneration of this proton would establish the Sulphuric acid as a catalyst). This proton transfer results in a delocalisation of positive charge which gives rise to the presence of the three resonance structures portrayed in â€Å"step 1- resonance†. Of these three structures, the middle structure (where the positive charge is localised onto the carbon atom) allows for the esterification to proceed as its partial positive charge allows Nucleophilic attack by the Oxygen atom on Methanol; as seen in step two. Following this nucleophilic attack, a protonation and de-protonation occurs (which has a net effect of proton transfer) thus leading to the formation of a water molecule on the carbon atom which cleaves off in the hydrolysis in step 3. This hydrolysis results in a delocalisation of positive charge which gives rise to the presence of the three resonance structures portrayed in â€Å"step 4- resonance†. Of these structures, the middle structure where the positive charge is localised onto the carbon atom allows for a de-protonation to occur as the Hydrogen atom donates its electrons to the positive carbon thus neutralising the carbon and forming a double bond. This de-protonation also results in the regeneration of the Sulphuric acid proton which protonated the reactant in step 1 thus establishing Results Week one percentage yield: Mass of reactant: 3g Mass of product obtained: 2.38g RMM reactant: 137 RMM product: 165 Reactant/product moles: 0.022 Theoretical yield= 3.62g % Yield = (Actual yield / theoretical yield) * 100 = 65.75% Week two percentage yield: Mass of reactant: 3g Mass of product obtained: 2.79g RMM reactant: 137 RMM product: 179 Reactant/product moles: 0.022 Theoretical yield= 3.92 % Yield = (Actual yield / theoretical yield) * 100 = 71.18% Melting point: Experimental product 1MP: 85.9-88.4oC Literature product 1MP: 88-90oC Experimental product 2 MP: 83.5-84.1oC Literature product 2 MP: 84oC H NMR 4-amino benzoic acid Benzocaine 13CNMR 4-amino benzoic acid Benzocaine DEPT-135 4-amino benzoic acid Benzocaine Analysis The melting points for both products were average reading from three attempts and are reasonably within the literature range. This can be attributed to accurate measurements, clean utensils (thus avoiding impurities) and sufficient drying. At roughly 66% and 71% the percentage yields for products one and two respectively are reasonably low. This may be due to a number of problems such as, incomplete transfer of reactant into the reaction vessel, not transferring all of the reaction vessel washings for filtering, incorrect filtering technique where some product was allowed to pass through instead of being retained e.g. filtering too fast or incomplete transfer of the product from the filter paper after filtration. With reference to the HNMR tables, I have deduced corresponding H atom based on integration, splitting and chemical shift. The chemical shift of an atom depends on the extent of shielding it has, for example a H atom attached to an Oxygen (e.g. H atom number 6 on 4-amino benzoic acid) has less shielding due to the Oxygen atoms’ electronegativity whereas a H atom attached to a C atom has more shielding as carbon is not electronegative and in the case of H atoms number 2 and 3, they are also surrounded by other atoms which give them some shielding. I found locating H atoms 2 and 3 particularly tricky as their quintet splitting pattern and integration of 3 where very misleading however their chemical shift reaffirmed their identity as it is relatively to the left thus indicating a fair amount of shielding. With reference to the 13CNMR tables I was able to deduce the corresponding Carbon atoms based on two properties, chemical shift and peak height. The chemical shift (in accordance to the level of shielding/position of the C atoms) allowed me to locate peaks for carbonyl carbons (Carbon number 7 in both reactant and product) and more shielded carbon aand the height/integration of the peaks which corresponds to the number hydrogen atoms attached to the C atom in question. With reference to the DEPT-135 tables I was able to distinguish the difference between the C atoms in accordance with the different number of H attached to each C atom. This technique portrays CH and CH3 atoms as positively phased and CH2 atoms negatively phased. For atoms with the same phasing, I used the chemical shift ( as with 13 CNMR ) to distinguish between the C atoms in question. In this esterification, the product was maintained in a pH of 7-8. This was done in order to prevent a nucleophilic attack from hydroxide ions which would hydrolyse the product which and reverse the esterification thus converting the product back into the reactant. Rf values can be used to deduce the polarity of a molecule, where a low Rf value can indicate a polar molecule. This is based on how the molecule interacts with the mobile and stationary phases. For example; a low Rf value is a result of the molecule interacting with the polar stationary phase/silica and not travelling very far up the plate allowing us to deduce that its polar. Based on this theory and the fact that polarity increases with RMM; a larger molecule would be more polar and thus have a lower Rf. I would therefore predict that Isopropyl 4-Aminobenzoate would have a lower Rf value than Benzocaine due to its larger RMM making it more polar than Benzocaine. References UNCP. (2014). CNMR spectroscopy. Available: http://www2.uncp.edu/home/mcclurem/courses/chm550/nmr_lec4.pdf. Last accessed 06/03/2014.Chemspider. (2014).4-Aminobenzoic acid.Available: http://www.chemspider.com/953. Last accessed 06/03/2014. Chemspider. (2014).benzocaine.Available: http://www.chemspider.com/Chemical-Structure.13854242.html?rid=752b9fda-5ccb-49f3-bf93-47ceb79356b4. Last accessed 06/03/2014. Jim Clark. (2002).THE MECHANISM FOR THE ACID CATALYSED HYDROLYSIS OF ESTERS.Available: http://www.chemguide.co.uk/physical/catalysis/hydrolyse.html#top. Last accessed 06/03/2014. Chemspider. (2014).4 aminobenzoic acid.Available: http://www.chemspider.com/953. Last accessed 06/03/2014. Chemspider. (2014).Isopropyl 4-Aminobenzoate.Available: http://www.chemspider.com/Chemical-Structure.78903.html. Last accessed 07/03/2014.

Theme of Feminism in The Women Who Walked into Doors

The Women Who Walked Into Doors The Feminist lens allows us to view a piece of literature from a different perspective. It applies the perspective of feminism to a certain piece of literature. There are a large number of feminism literary theories and all with a different angle of viewing the literature. Some theories look at the way words and symbols in the book are gendered. Other theories show the difference of writing between male and female authors.Many theories also focus on stereotypes and inequalities of women's ights and how they are symbolized in a book. Basically the feminist lens helps you analyze a book based on the philosophies and views of modern day feminism the any piece of literature. The Women Who Walked into Doors is a book about a woman named Paula and her struggle against her abusive husband that spent the 17 years of their marriage beating and abusing her. I am pretty sure that everyone who has read this book agrees that it is really a feminist novel with Roddy Doyle, the author, really trying to explore the life a woman's mind under abuse.The first signs of feminism come early in the book. Paula seems to be attracted to a guy named Charlo Spencer who is considered to be a â€Å"ride†, a term used to define an attracting looking person. We see the idea that women are into â€Å"bad boys† demonstrated by Paula when she falls for Charlo. She states how he looks sexy with his cigarette, a leather jacket, and blue denim Jeans. This was a typical description of a â€Å"bad boy' in the 90's. She also stated that he had a criminal record as if it were a good thing and rather attractive.As the novel progresses a lot of feminist theories are presented such as the audacity is young women in the 90's and even in current times. Paula is a risk taker and likes to explore around and not really afraid of consequences. This again touches on the feminist theory that women tend to be irrational decision makers in their late teenage hood. A p erfect example from the book is when Paula ignored her father's view on Charlo when he made it obvious he hated Charlo and said he is a criminal.However later in the novel as she grows older she realizes her father was right and only trying to protect her. This again supports the idea that during a stage of their life, women tend to make stupid decisions that they will regret later on in life. After Paula gets married to Charlo and the abuse and beatings start Roddy Doyle really starts to push some strong feminist theories through. One of the most important being the reliance that a woman has towards a man and really takes this idea to its peaks.This is portrayed by Paula throughout most of the novel, even though Charlo beats, rapes, and abuses her she still says she loves him and she can't leave him. For the sake of her own safety and well being she was not willing to let go of the man who she loved yet who abused her. This is supposed to show how women are dependent on men and bei ng beat by a man is better than not having one. Finally he most important theory being presented I believe is the imbalance of power between men and women and the breaking point ot a woman's tolerance towards abusive behavior.Throughout their marriage Paula has been powerless by not being able to make any choices or have any say in how things are done, because if she were to speak up she would likely get beaten by Charlo. This shows the imbalance in power and inequality in women's rights in the 90's when this book was written. Also even if Paula wanted to leave Charlo she did not have the power to on her own. However the idea presented is that women behave only like this is the problem is etween husband and wife, in the novel, when Charlo looks at Nicola, his oldest daughter, in a dirty way as if he wants to harm her is when Paula's breaking point is reached.She takes a frying pan and beats him down in the kitchen then kicks him out of the house for good. This brings us to the idea that when women's will not stand up for themselves but when their children are targeted they do the unthinkable to protect them. The fact that this book was written by a male author is really impressive for how he constructed the book from a females perspective and make it so effective in sending its messages and impacting on the reader.

Analysis Of Compania De Minas Buenaventura S.a Essay

Compaà ±ia de Minas Buenaventura S.A.A. is the leading Peruvian mining company and one of the largest owners of mining rights among precious metals in Peru. Founded in 1953, Buenaventura has focused on mining processing, development, and exploration of gold, silver, coal, lead, molybdenum, and zinc. Some highlights of the company [1]: †¢ Owns two growing underground gold mines, as well as the world’s 4th largest silver mine. †¢ Possesses an aggressive and proven exploration program. †¢ Own a 43.65% stake in Yanacocha, Latin America’s largest gold mine and the most profitable in the world. †¢ Producer of the best geological information in Peru. †¢ Seeks to expand its reserves production and earnings. †¢ Listed on Lima Stock Exchange (BUE.LM) since 1971 and on The New York Stock Exchange (NYSE: BVN) since 1996. Buenaventura’s Code of Business Conduct and Ethics is oriented to the Board of Directors of the company. It set some important aspects and basic behaviors that all members of the company must follow. The document is divided into 5 parts [2]. 1. Purpose, where it is established the main goal of the document. 2. Administration / Applicability / Violations, where it is established the scope and disciplinary actions of the document. 3. Policy Guidelines, part of the document where the Board of Directors set the main policies guidelines that will set the standards for conducting the company business. 4. Reporting Illegal or Unethical Behavior, where the Board of Directors

`` Ode Imitations Of Immortality `` By William Wordsworth

William Wordsworth once defined poetry as being â€Å"a spontaneous overflow of powerful feelings recollected in tranquility.† In his poem, â€Å"Ode: Imitations of Immortality,† Wordsworth expresses his powerful feelings about the natural world and his struggle to understand why humanity has failed to recognize the value of nature. He is saddened by the fact that time has stripped away much of natures glory, depriving him of the wild spontaneity he once exhibited as a youth. Wordsworth uses the symbolism of the child to represent the state of being closer to the glory of nature. From childhood to adulthood, Wordsworth reflects on the impermanent nature of time as the chaotic and creative forces that influence the human existential condition. In the third stanza, the speaker introduces the theme of time to the reader through the motif of the drum. The speaker is melancholy as he states, â€Å"While the young lambs bound as to the tabors sound, to me alone came a though t of grief.† The tabor refers to a drum, which shows that the speaker of the poem is connecting the young lamb to the pulse of time. This represents the struggle of man versus time as the imagery creates an odd sense of duality. The young lamb leaping to the beat of time provides a sense of comfort through the innocence of the springtime youth, but the image also foreshadows the inevitable changing of the seasons and the coming of age. 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