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For the textbook, chapter, and section you specified we found
1 Videos
13 Assessment Questions
164 Molecular Structures
16 Journal Articles
27 Other Resources
Videos: 1 results
Amines and Aniline  
pH of aqueous ammonia, cyclohexylamine, and aniline, iodination of aniline, oxidation of aniline with benzoyl peroxide, the nitrous acid test, diazo coupling, reaction of luminol and light sticks are demonstrated.
Amines / Ammonium Compounds
Assessment Questions: First 3 results
Enamines (6 Variations)
A collection of 6 assessment questions about Enamines
Aldehydes / Ketones |
Amines / Ammonium Compounds |
Synthesis
Organic : FunctionalGroups (18 Variations)
The structure for niacin (one of the B-vitamins) is shown below. Which of the following functional groups is present in niacin?

Alcohols |
Aldehydes / Ketones |
Carboxylic Acids |
Esters |
Amines / Ammonium Compounds
Nomenclature (1 Variations)
A collection of 1 assessment questions about Nomenclature
Aldehydes / Ketones |
Nomenclature / Units / Symbols |
Amines / Ammonium Compounds |
Carboxylic Acids
View all 13 results
Molecular Structures: First 3 results
1-aminodecane C10H23N

3D Structure

Link to PubChem

Amines / Ammonium Compounds

azepane C6H13N

3D Structure

Link to PubChem

Amines / Ammonium Compounds |
Heterocycles

dimethylamine C2H7N

3D Structure

Link to PubChem

Amines / Ammonium Compounds

View all 164 results
Journal Articles: First 3 results.
Pedagogies:
Percy Julian, Robert Robinson, and the Identity of Eserethole  Addison Ault
The Nova production Percy JulianForgotten Genius, which included the very public disagreement over the identity of "eserethole," the key intermediate for the synthesis of the alkaloid physostigmine, left three important chemical questions unanswered.
Ault, Addison. J. Chem. Educ. 2008, 85, 1524.
Constitutional Isomers |
Enantiomers |
Natural Products |
Stereochemistry |
Synthesis
Synthesis and NMR Spectral Analysis of Amine Heterocycles: The Effect of Asymmetry on the 1H and 13C NMR Spectra of N,O-Acetals  Shahrokh Saba, James A. Ciaccio, Jennifer Espinal, and Courtney E. Aman
Describe an undergraduate organic laboratory experiment in which students prepare two N,O-acetals that differ only in a single ring substituent that introduces asymmetry, giving each compound a distinct 1H and 13C NMR spectral pattern that must be explained by students.
Saba, Shahrokh; Ciaccio, James A.; Espinal, Jennifer; Aman, Courtney E. J. Chem. Educ. 2007, 84, 1011.
Amines / Ammonium Compounds |
Chirality / Optical Activity |
Green Chemistry |
Heterocycles |
NMR Spectroscopy |
Stereochemistry |
Synthesis
Using "Basic Principles" To Understand Complex Science: Nicotine Smoke Chemistry and Literature Analogies  Jeffrey I. Seeman
The HendersonHasselbalch equation calculates the equilibrium distribution of 50:50 for nicotine in its nonprotonated (free base form), relative to its monoprotonated form, at pH of 8 in dilute aqueous solution. This ratio has then been used in the literature to predict the effect of ammonia compounds in tobacco and in smoke on nicotine pyrolysis and smoke chemistry. Experiments demonstrate that neither the thermal chemistry of tobacco alkaloids nor the transfer of nicotine from tobacco to smoke can be explained by the position of the nonprotonated versus monoprotonated form equilibrium in aqueous extracts of tobacco. The high thermal stability of nicotine in air allows nicotine salts to be converted to nonprotonated nicotine and volatilize during heating prior to any substantial decomposition of the nicotine moiety. In contrast, cocaine hydrochloride is thermally unstable and will rapidly decompose upon heating; cocaine hydrochloride must first be converted to its nonprotonated form prior to heating and volatilization.
Seeman, Jeffrey I. J. Chem. Educ. 2005, 82, 1577.
Acids / Bases |
Applications of Chemistry |
Calorimetry / Thermochemistry |
Heterocycles |
pH |
Natural Products |
Gases
View all 16 articles
Other Resources: First 3 results
Molecular Models of Resveratrol  William F. Coleman
The featured molecules this month are from the paper "Resveratrol Photoisomerization: An Integrative Guided-Inquiry Experiment" by Bernard, Gernigon, and Britz-McKibbin exploring trans to cis photoisomerization in resveratrol. Examination of Figure 1 in that paper, where the hydrogen atoms have been omitted, might lead one to conclude that the structures are relatively straightforward. These isomers provide students an excellent opportunity to test their ability to take a two-dimensional representation and envision the three-dimensional structure of the molecule and to consider the competing factors that might lead to the three-dimensional structures being non-planar. The two-dimensional models focus attention on the possibility of extended pi-electron delocalization. Addition of the hydrogen atoms clearly suggests that delocalization will compete with non-bonded H-H repulsions in the cis isomer. Further examination of the trans isomer shows that such non-bonded interactions are, in what one might call a first-order approximation, like those in biphenyl interactions that lead biphenyl to be non-planar in both the gas phase and in a variety of solvents. The backbone of the trans isomer of resveratrol, trans-stilbene, has been the subject of a number of theoretical and experimental investigations (1, 2). In general, Hartree-Fock calculations predict a non-planar geometry for this molecule while Density Functional Calculations, using the same basis sets, predict an essentially planar structure. Spectroscopic evidence supports a temperature-dependent structure for trans-stilbene with the molecule being planar at low temperature and non-planar at high temperatures. Our calculations on trans-resveratrol produce similar results. Hartree-Fock calculations using the 6-31G** (6- 31G(d,p)) basis set predict a dihedral angle of approximately 24 degrees between each ring and the central carbon-carbon double bond. This result is consistent with the reported value of 23 degrees using the 6-31G* basis set. We also find that DFT calculations using the B3LYP functional and the 6- 31G** basis set, lead to a planar configuration. We include several versions of trans-stilbene and trans-resveratrol in the molecule collection so that students can explore these structural questions in more detail. For each molecule, structures obtained from PM3, HF(6-31G**), and DFT(B3LYP/6-31G**) calculations are included, as well as planar and non-planar structures of biphenyl. Measurement of the various bond and torsion angles using Jmol will help students develop a sense of the distance dependence of the non-bonded interactions and their importance in determining the actual structure. They might also wish to consider what additional degree(s) of freedom resveratrol and stilbene have that biphenyl does not, allowing the trans-form of the former molecules to remain planar under certain conditions, while minimizing the effect of the non-bonded repulsions.
Plant Chemistry |
Natural Products
Molecular Models of Lycopene and Other Carotenoids  William F. Coleman
Over the past decade or so the phrase emerging research suggests has entered the argot of advertising, and that phrase has been applied to this month's Featured Molecule, lycopene, particularly with regard to potential health benefits of tomatoes. The paper by Jie Zhu, Mingjie Zhang, and Qingwei Liu (1) describes an extraction and purification of lycopene from tomato paste using an emulsion rather than the traditional solvent-based extraction. Lycopene is a member of the family of molecules called carotenoids, the most familiar of which is beta-carotene. This family of natural products includes more than 500 members that have been isolated and whose structures have been determined. Professor Hanspeter Pfander's research group at the University of Bern maintains a Web site with a significant amount of information on carotenoid structure, synthesis, and activity (2). Structurally one can think of carotenoids as consisting of three segments, a relatively rigid conjugated central portion with end groups. The end groups are, in general, flexible with respect to rotation about the bond connecting them to the central portion. For example, in beta-carotene, the dependence of total energy on the dihedral angle shown in Figure 1, displays a very broad range of essentially isoenergetic conformations (Figure 2). The energies shown in Figure 2 were calculated at the PM3 level using Hyperchem 7.5 (3). Calculations at the HF/631-G(d,p) level, with many fewer data points, show a similar trend. Many of the health benefits derived from various carotenoids are attributed to their antioxidant activities. Carotenoids react with singlet-oxygen in a physical, diffusion-controlled, quenching process that results in ground state triplet-oxygen and, following a non-radiative relaxation, ground state carotenoid. Of the various carotenoids that have been studied, lycopene and beta-carotene show the greatest quenching rate constants (4). The carotenoids provide us with countless explorations by students and teachers looking for connections between fundamental chemical concepts and real-world applications. Structure, reactivity, chemical synthesis, biosynthesis, and stereochemistry are just a few of the concepts involved in understanding the manifest important roles that these molecules play.
Plant Chemistry |
Natural Products
Molecular Models of Annatto Seed Components  William F. Coleman
In January 2008 the focus of this column was on the plant pigments lycopene and beta-carotene (1). Our attention this month returns to two papers discussing the pigments in annatto seeds (Figure 1), including direct precursors to lycopene. The paper by Teixeira, Dur�n, and Guterres describes the extraction and encapsulation of annatto seed components (2). The McCullagh and Ramos paper describes the separation of the pigment bixin from these seeds by TLC and column chromatography (3). These molecules could form the basis of interesting exercises across the chemistry curriculum. In courses designed for non-majors, students could choose a molecule from the table and search the literature for both scientific and non-scientific sources. Are the claims made in the latter sources regarding the health benefits of these molecules consistent with the scientific data? That discussion could be expanded to the more general question of how one tests the validity of statements made in what are essentially advertisements. Are any of these precursor molecules to lycopene considered to have anticancer properties (4)? In introductory or general chemistry courses, students could explore the various bond lengths and bond angles in the molecules to see whether they are consistent with their expectations based on simple bonding models. In introductory, organic, or biochemistry classes, the thermodynamics of hydrogenation and dehydrogenation could be examined. This might make an interesting alternative to the oft-discussed Haber Process. What conditions would one propose for a dehydrogenation process? Why are dehydrogenation reactions important? What enzymes catalyze the various dehydrogenation steps from phytoene to lycopene? These molecules could also be used in a variety of computational exercises in introductory and physical chemistry courses. Hartree�Fock calculations on a molecule such as phytoene may prove time-consuming depending on the nature of the computing system available. A good place to begin would be to perform semi-empirical calculations on the various molecules. Do the optimized structures match experimental results or the results of larger calculations? Does the HOMO�LUMO gap correlate with the observed electronic absorption spectra? Which is more important in determining the difference in absorption between phytoene and phytofluene, the total number of double bonds or the number of bonds in the region of conjugation? Of course the aspect of these molecules that is most likely to capture student attention is their color, and they provide nice examples of the origin of color, the relationship between color observed and color absorbed, and, in upper level courses, the more detailed relationships of the energies of the ground and excited states.
Plant Chemistry |
Natural Products
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