Since the foundations of stereochemistry were first considered by Louis Pasteur in 1848 and its importance highlighted when he famously said that the universe is chiral (L'Univers est dissymétrique 1) this sub-discipline of chemistry has evolved into an integral area of research in understanding a drug molecules pharmacological effect. The important role of stereochemistry in API (Active Pharmaceutical Ingredient) drug design is reflected in the international regulations and guidelines which address this topic. The FDA has guidelines in place calling for absolute stereochemistry of a molecule to be known for compounds with chiral centred molecules 3. ICH guidelines Q6A 3.3.1 (d) outlines tests and stereochemical aspects that must be considered …show more content…
Isomers are molecules which have an identical atomic composition but differ in their spatial or bonding arrangements 5. Isomers can be further divided up into constitutional (structural) isomers and stereoisomers (spatial isomers) 3. An example of structural isomers are ethanol and dimethyl ether. Both these chemicals have the molecular formula C2H6O but differ in their chemical structures. Ethanol has the chemical structure CH3¬CH2OH while dimethyl ether has the chemical structure CH3OCH3. These two compounds have completely different physical and chemical properties and are therefore easily identified and separated 6. Another example of structural isomers are catechol, resorcinol and hydroquinone which all have the same molecular formula C6H6O2 but different bonding arrangement of their atoms5. Stereoisomers are of importance in API synthesis because they are not as readily identifiable as structural isomers and therefore require a more in depth analysis of the drug molecule or substance. Stereoisomers can be further subdivided into two different categories; configurational isomers which includes geometric isomers and optical isomers, and conformational …show more content…
The symbol ‘E’ is derived from the German word ‘entgegen’ which means ‘opposite’ 8. If the two groups with the higher priorities are on the same side of the double bond, then it is the (Z)- isomer. The symbol ‘Z’ is derived from the German word ‘zusammen’ which means ‘together’ 8. Tamoxifen and doxepin are some examples of pharmaceutical compounds where the geometry of the atoms or groups around its carbon-carbon double bond impact its pharmacological activity. Tamoxifen is an estrogen antagonist used in the treatment of breast cancer 9. The activities of its isomers are completely opposite to each other. The (Z)- isomer of Tamoxifen acts as an estrogen antagonist (binds to the receptor without activating it), while the (E)- isomer of Tamoxifen acts as an estrogen agonist (can fully bind to its receptor and activate it) 9. The mixture of (E) and (Z) isomers in the Tamoxifen racemate may have reduced efficacy due to the binding of the (Z)- isomer to the receptors and blocking binding sites for the (E)-
The purpose of this experiment is to determine the absolute configuration of an unknown chiral secondary alcohol using the competing enantioselective conversion (CEC) method. This method uses both R- and S- enantiomers of a chiral acyl-transfer catalyst called homobenzotetramisole (HBTM), in separate parallel reactions, and thin layer chromatography to identify the stereochemistry of the secondary alcohol, whether it be an R- or S- enantiomer. Quantitative analysis was performed using a program called ImageJ after the appropriate picture was taken of the stained TLC plate. The molecular structure of the unknown alcohol was identified using 1H NMR spectroscopy by matching the hydrogens to the corresponding peak.
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
Antiarrhythmic agents are used to suppress abnormal rhythms of the heart. Many attempts have been made to classify antiarrhythmic agents. There is a problem from the fact that many of the antiarrhythmic agents have multiple actions, making any classification accurate. Betapace (sotalol) comes in tablets and solution for oral a...
The isomerization procedure was done in order to create dimethyl fumarate from dimethyl maleate. Dimethyl maleate and dimethyl fumarate are cis and trans isomers, respectively. This procedure was done via a free radical mechanism using bromine. The analysis of carvones reaction was done in order to identify the smell and optical rotation of the carvone samples that were provided. The odor was determined by smelling the compound and the optical rotation was determined using a polarimeter.
...e 3. Both letters A and B within the structure of trans-9-(2-phenylethenyl) anthracene, that make up the alkene, have a chemical shift between 5-6 ppm and both produce doublets because it has 1 adjacent hydrogen and according to the N + 1 rule that states the number of hydrogens in the adjacent carbon plus 1 provides the splitting pattern and the number of peaks in the split signal, which in this case is a doublet.1 Letters C and D that consist of the aromatic rings, both are multiplets, and have a chemical shift between 7-8 ppm. 1H NMR could be used to differentiate between cis and trans isomers of the product due to J-coupling. When this occurs, trans coupling will be between 11 and 19 Hz and cis coupling will be between 5 and 14 Hz, showing that cis has a slightly lowered coupling constant than trans, and therefore have their respective positions in a product. 2
This news article addresses the issue of the mass amount of kids in jail and who is most likely to be in jail. In this article, the author uses many key statistics of the amount of colored kids and teens in jail. In the beginning, the article starts with the amount of kids in jail then proceeds to tell us the percentage of colored kids versus the percentage of non colored kids in jail. Next, it focuses on the amount and increase of people that have been incarcerated just in the past few years and why they have most likely been sentenced. Lastly, the author then states what actions have been taken to stop this and mentions the committees that have formed to help those who have been targeted by this issue. The intended audience is parents who
Ostrove, N. M. (2004). Statement of Nancy M. Ostrove, Ph.D., Deputy Director, Division of Drug.
The Similarity Analysis Module in Spartan’14 was used the calculate the similarity score for each of the benzodiazepines compared to the benzodiazepine active site on the chloride receptor. Of the benzodiazepines studied, it was found that lorazepam has the best fit for the active site because it had the highest similarity score compared to the pharmacophore and the lowest number of collisions with the wall of the active site. AutoDock Vina was also used to calculate the binding affinity of each benzodiazepine with the active site on the chloride receptor. It was found that diazepam, lorazepam and midazolam all have the lowest binding affinity of -9.8 kcal/mol and therefore are more likely to bind to the active site. Combining these results
As we discussed above that pharmacokinetic and pharmacodynamics can be seen as two sides of the same coin in order to gain better understanding of their efficacy and safety profiles.” Generally it is possible to make fairly robust predictions of the pharmacokinetic profile in man using in vitro systems and preclinical pharmacokinetic studies. A previously published survey on the causes of failure in drug development indicated that inappropriate pharmacokinetics were a major cause such as; factors as low bioavailability due to high extraction or poor absorption characteristics, short elimination half-life leading to short duration of action and excessive variability due to genetic or environmental factors. This observation has led to an increased emphasis on pharmacokinetic input to the drug discovery process throughout the pharmaceutical industry. However, it is important to realise that this may only permit the rejection of compounds to b...
...degree of intermolecular association. By adjusting the formulation or the chemical moieties of the drug delivery system, the moment and the location of the release of the drug may be controlled (You e.a. 2010).
Stoichiometry is a chemical branch that studies amounts of substances that are involved in reactions. Stoichiometry will help you to find out how much of the mixture you will need, or how much you started with. The calculations of a stoichiometry problem depends on a balanced chemical equations. The factors of the balanced equations signifies the molar ratio (the number of moles of each reactant needed to form a certain numbers of moles of each product) of the reactants and products taking part in the reaction. From the atomic and molecular point of view the stoichiometry in a chemical reaction is very simple. For example, one mole of oxygen reacts with two moles of hydrogen,
Molecular pharmacology deals with the biochemical and biophysical characteristics of interactions between molecules of different substances and those of the cell. In other words, it is molecular biology applied to pharmacologic and toxicologic questions. The methods of molecular pharmacology include precise mathematical, physical, chemical and molecular biological techniques to understand how cells respond to hormones or pharmacologic agents, and how chemical structure correlates with biological activity of various
Chemistry has lots of charming facts; one such is hetero cyclic compounds. Heterocyclic compounds are organic compounds that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen as the heteroatom. The ring may be aromatic or non-aromatic. Every first step of life starts with hetero-cyclic compounds. Every man's potential to think, intelligence, behavior, character depends on his gene. The basic skeleton of the genetic material (DNA) is made up of heterocyclic compound like adenine, guanine, cytosine and thymine. Thus knowing about heterocyclic compound and its application is part of venturing human life. The different pharmacological activity of the different hetero cyclic compounds ring , from a last related to this moiety and screened them for their different pharmacological activities to get a molecule which have good pharmacological activity and lesser side effect. These pharmacological activities of new hetero cyclic derivatives this hetero cyclic has shown its importance as antibacterial, antifungal, anti-inflammatory, hypoglycemic, antidepressant, anti-malarial, analgesic, anticancer
Photochemistry is the study of chemical reactions resulting from the exposure of light radiations. Light supplies the required energy to take place the photochemical reactions. The visible and UV radiations are mainly used in photochemical reactions. Many important processes in our daily life involve photochemistry. The best example is photosynthesis, in which most plants utilize the sunlight to convert carbon dioxide and water into glucose and release oxygen as a side product.