Total Synthesis Of Cp Compounds Essays (578 words) - Total Synthesis

Total Synthesis Of Cp Compounds Man's fascination with the many uses that can be found with the exploitation of natural substances has been demonstrated time and again throughout history, but the stage was set at the turn of the century for organic chemists to begin to focus on utilizing natural compounds for the benefit of medicinal and industrial uses. The discoveries of penicillin, aspirin, and other naturally occurring useful compounds in the earlier parts of the century set the stage for the utilization and exploitation of biologically active compounds as a molecular science. However, there are limits as to how much we can do with what nature provides us. This puts the role of the synthetic organic chemist at the forefront of synthetic compound synthesis technology. KC Nicolaou is one such leader. The main goal of Nicolaou's lab is the complete synthesis of naturally occurring compounds, along with solid phase chemistry, molecular design, combinatorial synthesis, and biological investigations; some of the results of Nicolaou's work include: the total synthesis of the anticancer agent Toxol, the marine neurotoxins brevetoxins A and B, the anititumor agents epothilones A and B, eleutherobin and sarcodictyins, the antibiotic vancomycin, the cholesterol-lowering CP-molecules, the immunosuppressant agent sanglifehrin A, the antibiotic everninomicin, and a number of bisorbicillinoids such as trichodimerol, bisorbicillinol, and bisorbibutenolide. Another example of Dr. Nicolaou's work is a paper published in Chemistry International entitled The Absolute Configuration and Asymmetric Total Synthesis of the CP Molecules (co-authored by Jae-Kyu Jung, Won Hyung Yoon, Yun He, Yong-Li Zhong, and Phil Baran.) In this paper, Nicolaou and his associates describe how their goal was both the total synthesis of these CP compounds (achieved in 1999) along with the determination of their absolute configurations; methods used in initial attempts to determine absolute configuration at different carbons included X-ray crystallography and NMR. Nicolaou set about synthesizing this compound by thinking through possible reactions that he might use to begin to build the carbon skeleton needed for this molecule. His team decided on a type-II intramolecular Diels-Alder reaction as the key step to generation of the core skeleton. The Diels-Alder reaction utilizes a dienophile in order to form new carbon-carbon bonds in a single step, in this case to form multiple ring structures. However, Nicolaou ran into trouble when several reagent-based enantioselective approaches with the precursor failed to yield appreciable levels of the desired product. After much study of this problem, Nicolaou's team came to the conclusion that a Lewis acid catalyst would be their best shot at inducing the asymmetry needed for this particular absolute configuration. After several more reaction steps, the team had two diastereomeric diols in a racemic mixture that were then converted to enantiomeric aldehydes with TBAF and NaIO4 - induced oxidative cleavage. After conversion to the indoline, the synthetic compound was compared to the naturally derived compound using NMR, TLC, and IR spectroscopy. However, the optical rotation of the synthetic compound was opposite in magnitude to the naturally derived CP molecule; the synthetic compound was verified as the enantiomer of the naturally occurring compound circular dichroism spectroscopy, and thus, the absolute configuration was verified. This paper parallels Nicolaou's research goals by showing how this team determined the absolute configuration of a complex compound they synthesized from a much simpler molecule (glycidol). It also shows the importance of techniques used to determine structure and content of complex molecules, such as NMR and IR spectroscopy. Science

Free Essays on Biotechnology

S. After listening to my speech, the audience will know 3 ways that biotechnology will help/hurt the future of society. Introduction: Have you every received a vaccination from a doctor to prevent the flu? If so, it probably came in the form of a shot that the doctor inserted into your arm and injected you with. This situation may be your worst fear if you are afraid of needles. Have you ever imagined the possibility of receiving the same flu vaccination by eating a carrot or a piece of chicken? Don’t be alarmed, this possibility is closer than you think with the advancement of biotechnology in food products today. Body: I. Biotechnology has the reputation of being very new and high tech. A. In fact, it is possibly the oldest-technology known to man B. One example would be penicillin, produced by growing mold and extracting the Penicillium C. It is the same with genetic engineering; domestic pets or farm animals. Selective breeding over many centuries (different animals) II. So, if biotechnology has been around so long, why all the fuss now? The reason is that we can now do so much more. A. Now we have gene therapy, enables doctors to change the genes in our own cells (no more disease or mutations) B. But most people don’t want to be the first person to receive this gene therapy so transgenic mice have been made to carry the diseases so doctors can study them C. Now we have a way, thanks to biotechnology, that we can study these diseases and mutations and can make new discoveries and treatments for millions of people. III. Commercial production of genetically modified crops A. Some of the genetically modified crops being grown in the U.S. include: corn, soybeans, canola, squash and papaya B. One of the benefits of these crops is that it can substantially increase productivity in the developing world by making it possible to grow crops in areas that cannot currently sustain them. (grown in a d... Free Essays on Biotechnology Free Essays on Biotechnology S. After listening to my speech, the audience will know 3 ways that biotechnology will help/hurt the future of society. Introduction: Have you every received a vaccination from a doctor to prevent the flu? If so, it probably came in the form of a shot that the doctor inserted into your arm and injected you with. This situation may be your worst fear if you are afraid of needles. Have you ever imagined the possibility of receiving the same flu vaccination by eating a carrot or a piece of chicken? Don’t be alarmed, this possibility is closer than you think with the advancement of biotechnology in food products today. Body: I. Biotechnology has the reputation of being very new and high tech. A. In fact, it is possibly the oldest-technology known to man B. One example would be penicillin, produced by growing mold and extracting the Penicillium C. It is the same with genetic engineering; domestic pets or farm animals. Selective breeding over many centuries (different animals) II. So, if biotechnology has been around so long, why all the fuss now? The reason is that we can now do so much more. A. Now we have gene therapy, enables doctors to change the genes in our own cells (no more disease or mutations) B. But most people don’t want to be the first person to receive this gene therapy so transgenic mice have been made to carry the diseases so doctors can study them C. Now we have a way, thanks to biotechnology, that we can study these diseases and mutations and can make new discoveries and treatments for millions of people. III. Commercial production of genetically modified crops A. Some of the genetically modified crops being grown in the U.S. include: corn, soybeans, canola, squash and papaya B. One of the benefits of these crops is that it can substantially increase productivity in the developing world by making it possible to grow crops in areas that cannot currently sustain them. (grown in a d... Free Essays on Biotechnology Biotechnology Continuing through the twenty-first century, technology is expanding and to all aspects of life for the purpose of fixing worldwide problems to making our life’s much easier. In the past few years, a new branch of technology has opened up, called Biotechnology. Biotechnology combines agriculture and science to improve crops. Methods such as Genetics are used to modify crops and animals. Those in the Biotechnology work field say that this new devolvement in science may in the future change agriculture. So what is the purpose of Biotechnology? It’s to solve nationwide as well as worldwide agriculture problems to make farming more efficient and profitable. Farmers each year lose millions to crop damage from droughts, pest, and poor soil conditions. Biotechnology is not just to make farmers money, but to also put an end to hunger and slow down the growth of disease spread through affected crops. Agriculture plays a major role in our lifestyle. It is the key for our survival. Without food, we simply can not live. Today crops have been successfully genetically engineered and grown today. Crops such as corn are now grown to be immune to deaseses. The bacteria that once could destroy an entire field of corn, does absolutely nothing to the new crops. With the use of this new technology, pesticides are no longer needed. For instance, soybeans can be genetically altered to grow containing its own pesticide. Also the threat of pesticides entering drinking water is reduced, as the need of the chemicals are no longer needed. Areas with harsh soil conditions that couldn’t support the growth of crops are now able to grow crops. A crop can be changed to live with less water, and survive in warmer temperatures. Countries such as India, where a major medical condition such as blindness is fixed, by changing the genes of rice crops so that it can prevent blindness. Although I did not mention all the benefits of biotechnology, more...

The effectiveness of Chemical Compounds in Brassica vegetables in the Essay

The effectiveness of Chemical Compounds in Brassica vegetables in the Prevention of Colorectal Cancer - Essay Example The chemical compounds in vegetables known to treat and prevent cancer include phytochemicals, isoprenoids and pigments (Govind & Madhuri, 2011). Vegetable pigments in particular – flavonoids, carotenoids and anthocyanins – are the main chemical components of Brassica vegetables, the group of vegetables known to significantly prevent the occurrence of one of the deadliest cancers in the body – colorectal cancer (Cartea et al. 251). In fact, according to the Centers for Disease Control and Prevention, colorectal cancer is the second leading cancer killer in the United States, after lung cancer and preceding breast cancer (â€Å"Colorectal Cancer,† 2011). The antioxidant properties of various chemicals called flavonoids in Brassica vegetables prevent colon cancer as well as other forms of cancer, thus there is a need to take a closer look at these chemicals. Chemicals in Brassica Vegetables and their Benefits in Colorectal Cancer Prevention The over 3,500 sp ecies of Brassica or cruciferous vegetables include those from the family Brassicaceae or Cruciferae – kale, cabbage, broccoli, cauliflower, Brussels sprouts, Chinese cabbage, turnip, oilseed, and mustard (Cartea et al., 2011). These vegetables contain a number of chemicals such as vitamins, fiber, soluble sugars, minerals, carotenoids, glucosinolates, minerals and most of all, phenolic compounds (Cartea et al., 2011). Additionally, folic acid and selenium may also be present (Kumar & Andy, 2011). It is, however, the phenolics that account for the anti-cancer properties of Brassica vegetables (Cartea et al., 2011). There are around 8,000 naturally-occurring phenolic compounds with at least one aromatic ring and one or more hydroxyl groups attached to it (Cartea et al., 2011). Among the most widespread of the phenolics are the flavonoids, which contain 15 carbons with two aromatic rings connected by a three-carbon bridge (Cartea et al., 2011). The flavonoids act as scavengers of free radicals and inhibit hydrolytic and oxidative enzymes (Kumar & Andy, 2011). The free radicals eliminated by flavonoids include hydroxyl radicals, superoxide anion radicals and lipid peroxy radicals (Kumar & Andy, 2011). These radicals rob the body of the oxygen needed to promote a cancer-free internal environment. Moreover, flavonoids are also anti-inflammatory (Kumar & Andy, 2011). Flavonoids reduce the number of immobilized leucocytes that result from injury to the tissues during a disease, which then leads to decrease in total serum complement – a mechanism associated with a reduction in inflammation of the tissue (Nijveldt et al., 2001). The most widespread type of flavonoids are the flavonols and it is this particular subtype that is particularly the anti-cancer components of Brassica vegetables (Cartea, et al., 2011). The most common of the flavonols are quercetin and kaempferol, which are richest in amount in the leaves (Cartea et al., 2011). More specifically, quercetin, which is also found in French bean and red and yellow piyaz, has been known for its anticarcinogenic properties (Govind & Madhuri, 2011). Figure 1. Quercetin (http://www.3dchem.com/molecules.asp?ID=445) Figure 2. Kaempferol (http://upload.wikimedia.org/wikipedia/commons/1/1c/Kaempferol.png) Among the Brassica vegetables, it is red cabbage that has the highest antioxidant content and this is closely followed by green cabbage, mustard

Personal Goal Essay Example | Topics and Well Written Essays - 1250 words

Personal Goal - Essay Example I am just beginning my professional career. The reason to choose this field of profession was that it offers a chance to gain a never ending knowledge of a particular field of study, whether the knowledge comes from the student or any other source. The future of being an Educator is great as it provides ways to get involved in the field of study directly, a direct interaction with the students helps to gain awareness about the perspective of the young generation and how the future of the world is going to change according to their mindsets. In addition to that, being an educator provides a never-ending professional development and opportunity to learn. This is so because there is always going to be potential of development and research in different fields of education. Emergence of new skills and concepts allow educators to grow and development professionally parallel to acting as an expert in their own field. The career of an educator comes with apparent challenges. A decade ago edu cation was not considered a professional job but today teachers are required to prepare themselves before entering a class. Similarly in coming 4 to 5 years, the level of studies would enhance and a simple explanation won’t be enough to clear the doubts of students. A teacher has to face such challenges and give a logical reasoning and prove his point of view with examples to convince the students. The greatest strength of being a teacher is his knowledge, being a specialized teacher in the field of economics particularly is a benefit in itself. Development is needed in every profession, but specifically for an educator, knowledge of new advancements and discoveries are a must for satisfying and teaching the students. To be a successful educator, communication and interpersonal skills are necessary so that everything is easily understood by all students. Secondly there is a constant need for increasing one’s knowledge and skills with constant revisions in order to teac h effectively. Where as in the coming year I need to enhance few areas to participate and develop professionally. Firstly an educator has to continue his studies, in my case a professional master’s degree in my field of study, secondly adopting the latest way of teaching i.e. through presentations and multi-media and lastly to prepare oneself before a particular lecture. All these areas need development to enhance my current skills and ensure a healthy career as an educator. In addition to that, changing requirements of the students and continuously transforming structure of education system in different parts of the world requires teachers and educators to be more attentive to changes that are being taking place in their field of study. Nowadays, students expect teachers to not only be experts in their given fields but multidisciplinary, furthermore provide them with emotional and professional guidance with a level of individual attention to needs. Hence, a teacher is expect ed to be a mentor along with being an instructor. Furthermore, participation of all kind of students i.e. different ethnic groups, socio-economic classes and disable students, in main education system has introduced further complexities in the education system that has redefined the role of educators.  

Love Essay Example for Free

Love Essay When I think about the concept of love, my thoughts are uncertain. When I think about the word love, the four letters arranged in a random pattern, nothing is simpler. Clearly, a distinct difference lies between a word and what it represents. The importance of the word love lies in the power it has over people. When asking someone what love means, not one person has a solid answer to the question. The word love is so abstract, as to which why I adore the word â€Å"Love. † While growing older, we have used the word love in many contexts. The word love can be referred to as a variety of different feelings and attitudes, ranging from just common pleasure I loved that meal to an intense interpersonal attraction I love my boyfriend. The word love can be used in numerous ways and with endless feeling. In certain situations, the word love is such an expression that sometimes ones relationship might even depend on it. For example, If for a long time someone has not said â€Å"I love you† to a loved one, they might think something is wrong. The word â€Å"love† is a word that makes one wonder how much power one word could have. Love does not have just one meaning, but rather many different definitions. It is a word used in many different contexts, with many different levels of feelings that are unexplainable. Love is a word that is universal in every language of the world. Everyone knows of it or has used the word. Although we know of it, no person has an actual definition of it. The uncertainty of this word makes me realize how powerful the word is, even though we still seem to know what someone is trying to say. Everyone uses the word love, but never took a minute to think about its meaning. I adore this word and will always think about as the future generations use the word love in ambiguity.

Self-Esteem and Self-Concept :: Self Image Self Perception Essays

In today’s age and the growing trend in American society of â€Å"what’s hot and what’s not†, is having a huge impact on young children’s self-concept and self-esteem. Self-concept â€Å"refers to the beliefs, attitudes, knowledge, and ideas people have about themselves,† whereas self-esteem is â€Å"a personal judgment of worthiness that indicates the extent to which the individual believes himself to be capable, significant, successful, and worthy (392).†   Ã‚  Ã‚  Ã‚  Ã‚  My interest on this subject was peaked after spending the evening with my five year-old cousin, Sami, last week. We were sitting and eating dinner when she said, â€Å"Cali, I am fat and ugly.† Well, I almost fell out of my chair. At the age of five, she was already cutting herself down. â€Å"Research shows that physical appearance is the strongest correlate of global self-worth in childhood and adolescence (398).†   Ã‚  Ã‚  Ã‚  Ã‚  However, our textbook explains that children around my cousin’s age have a hard time defining their sense of self. They tend to describe their physical characteristics, areas of interest, family life, etc (394). Nowhere in the text does it say that a child her age should be viewing herself in terms of physical attractiveness. Adolescence and high school students are more apt to make judgments of themselves, not children in kindergarten.   Ã‚  Ã‚  Ã‚  Ã‚  I feel that television, magazines, books and the internet make our youth have a lower self-esteem because they feel they are not as good looking as the characters on their favorite television show. My cousin watches Nickelodeon and even on children’s shows it seems there are no ugly or fat children. The actresses look older than I do because of all the make-up and their choice of clothing. What does that say to our youth? â€Å"Most American girls receive consistent and clear messages that beauty is defined in terms of being ‘slim and trim’ (398).†   Ã‚  Ã‚  Ã‚  Ã‚  In the classroom, self-concept and self-esteem have a huge impact on how well a child does in school. When I was in elementary school and especially high school, I would classify myself as being a good language arts student, but a poor Math and Science student. In elementary school there isn’t as much competition between students, therefore I didn’t feel the need to comment on my strengths and weaknesses. Like the author says, â€Å"and older student’s self-concept may be further broken down according to success in individual subject areas, such as reading, mathematics, or science (394).† In elementary school, all of the subjects could be incorporated into one lesson, while in high school the students switch classes and concentrate on a certain subject per period.

Cortes Conquers the Aztecs: Spanish Conquest or Indian Civil War Essay

The Spanish conquests of Montezuma and the Aztecs were both a Spanish conquest as well as an Indian civil war. The thing that ties them both together is the Conquistador Hernan Cortes. You could argue for both sides as to which played a more significant part in the fall of the Aztecs, however, I feel they both played an equal role in the defeat of the Aztecs and the fall of Tenochititlan to the Spaniards. When Cortes first came to Mexico, he did not know the language spoken by the Indian tribes. He was fortunate enough to have two interpreters; Aguilar, a shipwrecked Spaniard who had learned the Maya language, and Malinche. Malinche was a young maiden â€Å"given† to Cortes as an offering. Between her and Aguilar, Cortes was able to become familiar with the way the Aztecs lived, thought, and fought. He used this tactic to aid in expedition and to guard against any attacks. By far, one of the biggest downfalls of Montezuma and the Aztecs was the role of the God Quetzalcoatl. The majority of the Aztecs’ lives and beliefs was centered on their Gods. One of their biggest beliefs was of the God Quetzalcoatl, the feathered serpent. Montezuma believed that Cortes was the human version of Quetzalcoatl. The legend of Quetzalcoatl depicted a bearded, white God who looked similar to Cortes. Quetzalcoatl was prominent during the Toltec rule and had supposedly left the valley because he was unhappy with the way things were. The Aztecs believed he was expected to return and bring back good times and good fortune. Cortes took advantage of their beliefs and immersed himself into the Aztecs lives. Against the advice of his royal family, Montezuma welcomed Cortes and the Spaniards with open arms. They wanted Montezuma to kill the foreigners. The Aztecs tried giving the Spaniards gold and other riches to get them to leave their city. This only fueled their desire and ambitions for more, and they refused to leave. The more they gave, the more the Spaniards wanted. Cortes made Montezuma a prisoner of his own city, which led to an uprising by the Aztecs known as â€Å"La Noche Triste†, or The Sad Night. Many lives were lost on both sides. Many other factors contributed to Cortes’ victory over the Aztecs. His soldiers had far more superior weapons and they had horses. The Aztecs were very afraid of the horses because they had never seen anything like them before. Disease also played a huge part in the defeat of the Aztecs. The Spanish brought ailments that the Aztecs had no immunities for. Three-fourths died from either violence or diseases such as small-pox and the measles in just the first century of the conquests. The Aztecs’ tactics of war were quite different from those of the Spaniards, and this was also a point in the Spaniards’ favor. The Spaniards fought to kill. The Aztecs did not. The Aztecs fought to capture and get prisoners so they could later use them as human sacrifices to their Gods. In fact, Cortes himself was captured several times but was re-captured by his men and rescued. The most important factor by far in the defeat of the Aztecs by Cortes, according to some historians, is the help he received from the other suppressed Indian tribes in the area. This is why I believe one could view this as not only a Spanish conquest, but also as an Indian civil war. These other Indian tribes chose to help Cortes fight because they felt they would benefit greatly from the defeat of the Aztecs. They were tired of living under the Aztecs’ rule and saw Cortes as a type of hero, or liberator. They were more than happy to help wage a war against the Aztecs if it meant they could have better lives. After many deaths on both sides, The Aztec capitol fell in August of 1521. After capturing Tenochititlan, the Spaniards destroyed the city and on top of it built was is now present day Mexico City. I believe the preceding statements support my argument that the most important factors in the demise of Montezuma and the Aztecs were from the equal combination of having to deal with a Spanish conquest and an Indian civil war. Sources: Vigil, James Diego From Indians to Chicano Internet site, Then Again Info World History Chronology Project; www.thenagaininfo Matthew, Roy T. and F. DeWitt Platt Western Humanities Sullivan, Richard E., Dennis Sherman and John B. Harrison A Short history of Western Civilization Wood, Michael A Legacy- The Search for Ancient Cultures