DOCSLIB.ORG

Packet 2, 2325

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Packet 2, 2325 Organic Chemistry II CHEM 2325 Packet #2 1. Predict the 1H NMR spectra for isopropyl butyrate. O O There are a number of things that should be considered when trying to predict a 1H NMR spectrum for a given compound. 1) Determine the number of symmetrically different hydrogen positions. This will represent the number of different signals expected. In isopropyl butyrate there are 5 different types of hydrogens. 2 4 H H O H CH3 H3C O CH3 H H 1 3 5 two methyl groups are symmetrically equivalent 2) Need to predict downfield shift for each signal. This prediction is based entirely on how much electron density is around the hydrogen in question. Need to be able to predict the amount of shift for typically functional groups. adjacent to ester beta to carbonyl isopropyl bonding ~1.6 ppm ~5 ppm H H O H CH3 H3C O CH3 H H terminal methyl terminal methyl gamma to carbonyl beta to ester ~0.9 ppm ~1.2 ppm alpha to carbonyl ~2.2 ppm 3) The amount each signal is split is due to the number of magnetically active hydrogens are present on the adjacent carbons. This follows the N+1 rule, where the splitting observed is N+1 the number of hydrogens causing the splitting. 5 adjacent H's, 6 adjacent H's, therefore hextet therefore heptet H H O H CH3 H3C O CH3 H H 2 adjacent H's, 1 adjacent H, therefore triplet therefore doublet 2 adjacent H's, therefore triplet 4) The intensity of each signal (and thus the integral for each signal) is due to the number of hydrogens causing the signal These predictions allows one to either predict a 1H NMR or assign positions in a given 1H NMR. Actual spectrum: 2. Predict the position of the downfield shift in a 1H NMR for the following functional groups: alkyl halides typically low 3 ppm allylic hydrogens low 2 ppm α-carbonyl hydrogens low 2 ppm aromatic hydrogens 7-8 ppm aldehyde 9-10 ppm ethers mid 3 ppm esters low to mid 4 ppm alkyl hydrogens 1-2 ppm terminal methyl groups below 1 ppm vinylic hydrogens 5-6 ppm Effects are cumulative. If a given hydrogen is adjacent to a carbonyl and geminal to a halogen, then the downfield shift will be between 4-5 ppm. b. Predict changes in downfield shift with the following substituents on a monosubstituted benzene ring. Explain the relative downfield shift for each, and explain the physical basis for the relative shift. O NO2 CH3 OCH3 While an unsubstituted benzene has only one signal and a downfield shift of low 7 ppm, adding substituents will affect the amount of downfield shift. Electron withdrawing substituents will cause the signal to be further downfield, while an electron donating substituent will cause the signal to be more upfield. In these compounds, nitro group is the most electron withdrawing and thus will have the furthest downfield shift. The acetyl group is also electron withdrawing. The methoxy substituent is the most electron donating and thus will have the furthest upfield aromatic signals for these compounds (one signal is at 6.88 ppm). The methyl group is also electron donating, but not as much as the methoxy group. 1 3. Below are shown H NMRs for five isomers (C4H10O1). Indicate the proper structure for each spectrum. The relative integration is shown in each spectrum. 9 OH 1 6 2 ! "! HO 1 1 3 1 3 OH 1 2 2 signals, 4 total 3 2 1 HO 3 O 2 2 3 .
Load more

Recommended publications
  • Chapter 21 the Chemistry of Carboxylic Acid Derivatives
    Instructor Supplemental Solutions to Problems © 2010 Roberts and Company Publishers Chapter 21 The Chemistry of Carboxylic Acid Derivatives Solutions to In-Text Problems 21.1 (b) (d) (e) (h) 21.2 (a) butanenitrile (common: butyronitrile) (c) isopentyl 3-methylbutanoate (common: isoamyl isovalerate) The isoamyl group is the same as an isopentyl or 3-methylbutyl group: (d) N,N-dimethylbenzamide 21.3 The E and Z conformations of N-acetylproline: 21.5 As shown by the data above the problem, a carboxylic acid has a higher boiling point than an ester because it can both donate and accept hydrogen bonds within its liquid state; hydrogen bonding does not occur in the ester. Consequently, pentanoic acid (valeric acid) has a higher boiling point than methyl butanoate. Here are the actual data: INSTRUCTOR SUPPLEMENTAL SOLUTIONS TO PROBLEMS • CHAPTER 21 2 21.7 (a) The carbonyl absorption of the ester occurs at higher frequency, and only the carboxylic acid has the characteristic strong, broad O—H stretching absorption in 2400–3600 cm–1 region. (d) In N-methylpropanamide, the N-methyl group is a doublet at about d 3. N-Ethylacetamide has no doublet resonances. In N-methylpropanamide, the a-protons are a quartet near d 2.5. In N-ethylacetamide, the a- protons are a singlet at d 2. The NMR spectrum of N-methylpropanamide has no singlets. 21.9 (a) The first ester is more basic because its conjugate acid is stabilized not only by resonance interaction with the ester oxygen, but also by resonance interaction with the double bond; that is, the conjugate acid of the first ester has one more important resonance structure than the conjugate acid of the second.
    [Show full text]
  • Metabolic-Hydroxy and Carboxy Functionalization of Alkyl Moieties in Drug Molecules: Prediction of Structure Influence and Pharmacologic Activity
    molecules Review Metabolic-Hydroxy and Carboxy Functionalization of Alkyl Moieties in Drug Molecules: Prediction of Structure Influence and Pharmacologic Activity Babiker M. El-Haj 1,* and Samrein B.M. Ahmed 2 1 Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, University of Science and Technology of Fujairah, Fufairah 00971, UAE 2 College of Medicine, Sharjah Institute for Medical Research, University of Sharjah, Sharjah 00971, UAE; [email protected] * Correspondence: [email protected] Received: 6 February 2020; Accepted: 7 April 2020; Published: 22 April 2020 Abstract: Alkyl moieties—open chain or cyclic, linear, or branched—are common in drug molecules. The hydrophobicity of alkyl moieties in drug molecules is modified by metabolic hydroxy functionalization via free-radical intermediates to give primary, secondary, or tertiary alcohols depending on the class of the substrate carbon. The hydroxymethyl groups resulting from the functionalization of methyl groups are mostly oxidized further to carboxyl groups to give carboxy metabolites. As observed from the surveyed cases in this review, hydroxy functionalization leads to loss, attenuation, or retention of pharmacologic activity with respect to the parent drug. On the other hand, carboxy functionalization leads to a loss of activity with the exception of only a few cases in which activity is retained. The exceptions are those groups in which the carboxy functionalization occurs at a position distant from a well-defined primary pharmacophore. Some hydroxy metabolites, which are equiactive with their parent drugs, have been developed into ester prodrugs while carboxy metabolites, which are equiactive to their parent drugs, have been developed into drugs as per se.
    [Show full text]
  • Methyl Substitution Effects on the Proton Chemical Shifts in Benzene *
    Methyl Substitution Effects on the Proton Chemical Shifts in Benzene * G. S. REDDY E. I. du Pont de Nemours & Company, Inc. Explosives Department, Eastern Laboratory, Gibbstown, New Jersey, U.S.A. (Z. Naturforschg. 21 a, 609—615 [1966] ; received 16 December 1965) Methyl substitution effects on aromatic and methyl proton chemical shifts in several mono-, di-, and trimethyl benzenes are studied. A new method for obtaining the changes in the ring proton chemical shifts from those of methyl proton shifts at the corresponding positions is used. The extra jr-electron densities in toluene are calculated using the already known relation between the jr-elec- tron densities and the proton shifts in aromatic systems. An inverse relationship is obtained between the ionization potentials and the total methyl effects on the chemical shifts in this series of com- pounds as one would expect. Dipole moment of toluene is calculated, and a reasonably good agree- ment is found between the experimentally observed and the calculated dipole moment. Several efforts have been made from time to Considerable work has also been done in estimat- time to study the substitution effects on chemical ing ir-electron densities from chemical shift meas- shifts and coupling constants. One of the earliest urements in unsaturated systems. This study in- attempts in this line are those of CAVANAUGH and volves extension of the substitution effects and also DAILEY 1 who tried to study the effect of multiple estimating jr-electron densities in methyl benzenes. methyl substitution in methane. They encountered Eight mono-, di-, and trimethyl substituted benzenes negative shifts contrary to expectations based on have been studied, and a new technique has been inductive and hyperconjugative effects of the methyl deployed to obtain the methyl substitution effects group which eventually was attributed to the an- on the chemical shifts of ring protons from proton isotropy effect of the added C — C bonds 2-7.
    [Show full text]
  • Chapter 13 Reactions of Arenes Electrophilic Aromatic Substitution
    CH. 13 Chapter 13 Reactions of Arenes Electrophilic Aromatic Substitution Electrophiles add to aromatic rings in a fashion somewhat similar to the addition of electrophiles to alkenes. Recall: R3 R4 E Y E Y C C + E Y R1 C C R4 R1 C C R4 − R2 R1 δ+ δ R2 R3 R2 R3 In aromatic rings, however, we see substitution of one of the benzene ring hydrogens for an electrophile. H E + E Y + Y H δ+ δ− The mechanism is the same regardless of the electrophile. It involves two steps: (1) Addition of the electrophile to form a high-energy carbocation. (2) Elimination of the proton to restore the aromatic ring system. H H H H slow E Y + Y step 1 + E δ+ δ− high energy arenium ion H H step 2 fast E E + Y + Y H The first step is the slow step since the aromaticity of the benzene ring system is destroyed on formation of the arenium ion intermediate. This is a high energy species but it is stabilized by resonance with the remaining two double bonds. The second step is very fast since it restores the aromatic stabilization. 1 CH. 13 H H H H H H E E E There are five electrophilic aromatic substitution reactions that we will study. (1) Nitration H NO2 H2SO4 + HNO3 (2) Sulfonation H SO3H + H2SO4 (3) Halogenation with bromine or chlorine H X FeX3 X = Br, Cl + X2 (4) Friedel-Crafts Alkylation H R AlX + RX 3 (5) Friedel-Crafts Acylation O H O C AlX3 R + Cl C R 2 CH.
    [Show full text]
  • SYNTHESIS and PROPERTIES of SOME ARALKYL Hymoperoxides
    SYNTHESIS AND PROPERTIES OF SOME ARALKYL HYmOPEROXIDES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By ARLO d / bCGGS, B.S., M.S. The Ohio State University 1954 Approved by: Department of Chemistry ACKNOWLEDGEMENT The author wishes to express sincere appreciation to Professor Cecil E. Boord for his advice and counsel during this investigation* Thanks also are due Dr. Kenneth W*. Greenlee for his continual interest and guidance and his cooperation in ex­ tending the facilities of the American Petroleum Institute Research Project 4-5* The financial support of this work by the Firestone Tire and Rubber Company is gratefully acknowledged* ii TABLE OF CONTENTS Page I. INTRODUCTION................................ 1 II. LITERATURE S URVEY ............... 2 III. STATEMENT OF THE PROBLEM.................... 10 IV. DISCUS5IŒ ........................... 11 A. Methods of Preparing Hydroperoxides .... 12 1. Preparation of hydroperoxides from alcohols ............. 12 a. a-methylbenzyl hydroperoxide ...... 12 b. benzyl hydroperoxide .......... l6 c. cinnamyl and a-phenylallyl hydroperoxides 17 d. 1,2,3,4-tetrahydro-l-naphthyl hydro­ peroxide ............ 22 e. a-indanyl hydroperoxide ........ 23 f. 0-, m- and p-methylbenzyl hydroperoxides 24 g. m- and p-methoxybenzyl hydroperoxides. 28 h. 1,1-diphenylmethyl hydroperoxide .... 31 i. 1,2-diphenylethyl hydroperoxide .... 32 j. 1-a-naphthyl- and l-J3-naphthylethyl hydroperoxides ........ 33 k. 1-styrylethyl hydroperoxide 35 1. 4-a-dimethylbenzyl and 4-methoxy-a- methylbenzyl hydroperoxides ...... 36 m. a-ethylbenzyl and a-ethyl-p-methylbenzyl hydroperoxides ....... ........ 36 n. a-n-propylbenzyl and a-isopropylbenzyl hydroperoxides .................... 37 0. a-2,5“trimethylbenzyl hydroperoxide .
    [Show full text]
  • One-Pot Syntheses of Irida-Polycyclic Aromatic Hydrocarbons† Cite This: Chem
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue One-pot syntheses of irida-polycyclic aromatic hydrocarbons† Cite this: Chem. Sci.,2019,10, 10894 a a a b a All publication charges for this article Yu Xuan Hu,‡ Jing Zhang,‡ Xiaoyan Wang, Zhengyu Lu, Fangfang Zhang, have been paid for by the Royal Society Xiaofei Yang,a Zhihua Ma,a Jun Yin, *a Haiping Xia b and Sheng Hua Liu *a of Chemistry Metalla-analogues of polycyclic aromatic hydrocarbons (PAHs) have captivated chemists with their fascinating structures and unique electronic properties. To date, metallabenzene, metallanaphthalene and metallaanthracene have been reported. Metalla-analogues with more complicated fused rings have rarely been reported. Herein, we have successfully synthesized a series of new iridafluoranthenes and fused-ring iridafluoranthenes ranging from pentacyclic to heptacyclic metallaaromatic hydrocarbons in Received 6th August 2019 high yields under mild reaction conditions for the first time. Their photophysical and redox properties Accepted 12th October 2019 were also explored using UV-vis spectroscopy and electrochemistry combined with TD-DFT DOI: 10.1039/c9sc03914g calculations. The present work may offer an important guideline for the design and construction of new rsc.li/chemical-science polycyclic metallaaromatic hydrocarbons and metalla-nanographenes. Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Introduction carbeneiridium compound by using an intramolecular C–H activation reaction.6b In 2018, they further developed irida- Polycyclic aromatic hydrocarbons (PAHs), as important compo- phenanthrene, iridanaphthalene and iridaanthracene from nents in the eld of organic chemistry, have attracted a signi- their corresponding methoxy(alkenyl)carbeneiridium inter- * cant amount of attention due to their wide range of applications mediates via reactions of [IrCp Cl(NCMe) (PMe3)]PF6 with 8 in organic light-emitting diodes,1 eld-effect transistors2 and diarylpropargyl alcohols.
    [Show full text]
  • Fatty Acid Biosynthesis
    BI/CH 422/622 ANABOLISM OUTLINE: Photosynthesis Carbon Assimilation – Calvin Cycle Carbohydrate Biosynthesis in Animals Gluconeogenesis Glycogen Synthesis Pentose-Phosphate Pathway Regulation of Carbohydrate Metabolism Anaplerotic reactions Biosynthesis of Fatty Acids and Lipids Fatty Acids contrasts Diversification of fatty acids location & transport Eicosanoids Synthesis Prostaglandins and Thromboxane acetyl-CoA carboxylase Triacylglycerides fatty acid synthase ACP priming Membrane lipids 4 steps Glycerophospholipids Control of fatty acid metabolism Sphingolipids Isoprene lipids: Cholesterol ANABOLISM II: Biosynthesis of Fatty Acids & Lipids 1 ANABOLISM II: Biosynthesis of Fatty Acids & Lipids 1. Biosynthesis of fatty acids 2. Regulation of fatty acid degradation and synthesis 3. Assembly of fatty acids into triacylglycerol and phospholipids 4. Metabolism of isoprenes a. Ketone bodies and Isoprene biosynthesis b. Isoprene polymerization i. Cholesterol ii. Steroids & other molecules iii. Regulation iv. Role of cholesterol in human disease ANABOLISM II: Biosynthesis of Fatty Acids & Lipids Lipid Fat Biosynthesis Catabolism Fatty Acid Fatty Acid Degradation Synthesis Ketone body Isoprene Utilization Biosynthesis 2 Catabolism Fatty Acid Biosynthesis Anabolism • Contrast with Sugars – Lipids have have hydro-carbons not carbo-hydrates – more reduced=more energy – Long-term storage vs short-term storage – Lipids are essential for structure in ALL organisms: membrane phospholipids • Catabolism of fatty acids –produces acetyl-CoA –produces reducing
    [Show full text]
  • Functional Groups Kimberly Hatch Harrison
    Functional Groups Kimberly Hatch Harrison Functional groups are those small chemical species you see hanging off the outside of a molecule. Just a handful of these functional groups de- termine most of the chemical reactions that happen between biological molecules. If you memorize the chemical behavior of these functional groups, you’ll be able to predict what kinds of reactions biological molecules can do. You can’t open a lock with a screwdriver–the shape of a screwdriver is quite different from a key, which means it has a dif- ferent function. "Form determines function" is something you’ll hear over and over in biochemistry, and that’s because it’s true. The over- all 3-dimensional shape of a molecule allows it to fit into another molecule, like how a key fits into a lock. But not all keys are the same. You have to look closely at the teeth of a key to see which lock it can open. Similarly, you need to look at the details of the outside of a molecule to understand what kinds of chemical interactions it can do with other molecules. How the carbon skeleton of a biological molecule is folded up de- termines its general 3D shape. So that’s one level of understanding– this molecule looks like a key, this one looks like a lock, etc. But then you must look closer, at the surface details, to understand exactly which key, exactly what kind of lock. When you examine the outside of a biological molecule, you can identify which functional groups are standing out on its surface, like little flags.
    [Show full text]
  • Detection of Phenethylamine, Amphetamine, and Tryptamine Imine By-Products from an Acetone Extraction
    Detection of Phenethylamine, Amphetamine, and Tryptamine Imine By-Products from an Acetone Extraction Mary A. Yohannan* and Arthur Berrier U.S. Department of Justice Drug Enforcement Administration Special Testing and Research Laboratory 22624 Dulles Summit Court Dulles, VA 20166 [email: mary.a.yohannan -at- usdoj.gov] ABSTRACT: The formation of imine by-products from phenethylamines, amphetamines, and tryptamines upon an acetone extraction is presented. These imine by-products were characterized using GC/MSD and exhibited preferential cleavage at the α-carbon of the alkyl chain. Further characterization of the imine by-products of phenethylamine and tryptamine was done using IR and NMR. KEYWORDS: phenethylamine, tryptamine, imine, acetone, schiff base, drug chemistry, forensic chemistry In most forensic laboratories, the solvents used to extract at the α-carbon on the alkyl chain. In addition to GC/MS, the drugs are chosen based upon their solubility properties and their imines formed from phenethylamine base and tryptamine base ability to not interact with the drug. In fact, there are very few were characterized by Fourier transform-infrared spectroscopy publications where a solvent used to extract a drug reacts with (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. the drug and forms by-products [1-3]. This laboratory recently discovered that an additional Experimental component was formed when acetone was used to extract a Solvents, Chemicals, and Materials sample containing a known tryptamine. Analysis by gas Acetone was ACS/HPLC grade from Burdick and Jackson chromatography/mass spectroscopy (GC/MS) of the acetone Laboratories (Muskegon, MI). Phenethylamine base and extract yielded an extra peak in the total ion chromatogram that tryptamine base were obtained from Sigma-Aldrich Chemicals was approximately half the abundance of the known tryptamine (Milwaukee, WI).
    [Show full text]
  • Ganic Compounds
    6-1 SECTION 6 NOMENCLATURE AND STRUCTURE OF ORGANIC COMPOUNDS Many organic compounds have common names which have arisen historically, or have been given to them when the compound has been isolated from a natural product or first synthesised. As there are so many organic compounds chemists have developed rules for naming a compound systematically, so that it structure can be deduced from its name. This section introduces this systematic nomenclature, and the ways the structure of organic compounds can be depicted more simply than by full Lewis structures. The language is based on Latin, Greek and German in addition to English, so a classical education is beneficial for chemists! Greek and Latin prefixes play an important role in nomenclature: Greek Latin ½ hemi semi 1 mono uni 1½ sesqui 2 di bi 3 tri ter 4 tetra quadri 5 penta quinque 6 hexa sexi 7 hepta septi 8 octa octo 9 ennea nona 10 deca deci Organic compounds: Compounds containing the element carbon [e.g. methane, butanol]. (CO, CO2 and carbonates are classified as inorganic.) See page 1-4. Special characteristics of many organic compounds are chains or rings of carbon atoms bonded together, which provides the basis for naming, and the presence of many carbon- hydrogen bonds. The valency of carbon in organic compounds is 4. Hydrocarbons: Compounds containing only the elements C and H. Straight chain hydrocarbons are named according to the number of carbon atoms: CH4, methane; C2H6 or H3C-CH3, ethane; C3H8 or H3C-CH2-CH3, propane; C4H10 or H3C-CH2- CH2-CH3, butane; C5H12 or CH3CH2CH2CH2CH3, pentane; C6H14 or CH3(CH2)4CH3, hexane; C7H16, heptane; C8H18, octane; C9H20, nonane; C10H22, CH3(CH2)8CH3, decane.
    [Show full text]
  • Reactions of Aromatic Compounds Just Like an Alkene, Benzene Has Clouds of  Electrons Above and Below Its Sigma Bond Framework
    Reactions of Aromatic Compounds Just like an alkene, benzene has clouds of electrons above and below its sigma bond framework. Although the electrons are in a stable aromatic system, they are still available for reaction with strong electrophiles. This generates a carbocation which is resonance stabilized (but not aromatic). This cation is called a sigma complex because the electrophile is joined to the benzene ring through a new sigma bond. The sigma complex (also called an arenium ion) is not aromatic since it contains an sp3 carbon (which disrupts the required loop of p orbitals). Ch17 Reactions of Aromatic Compounds (landscape).docx Page1 The loss of aromaticity required to form the sigma complex explains the highly endothermic nature of the first step. (That is why we require strong electrophiles for reaction). The sigma complex wishes to regain its aromaticity, and it may do so by either a reversal of the first step (i.e. regenerate the starting material) or by loss of the proton on the sp3 carbon (leading to a substitution product). When a reaction proceeds this way, it is electrophilic aromatic substitution. There are a wide variety of electrophiles that can be introduced into a benzene ring in this way, and so electrophilic aromatic substitution is a very important method for the synthesis of substituted aromatic compounds. Ch17 Reactions of Aromatic Compounds (landscape).docx Page2 Bromination of Benzene Bromination follows the same general mechanism for the electrophilic aromatic substitution (EAS). Bromine itself is not electrophilic enough to react with benzene. But the addition of a strong Lewis acid (electron pair acceptor), such as FeBr3, catalyses the reaction, and leads to the substitution product.
    [Show full text]
  • Comparative Responses of Rice (Oryza Sativa) Straw to Urea Supplementation and Urea Treatment
    COMPARATIVE RESPONSES OF RICE (ORYZA SATIVA) STRAW TO UREA SUPPLEMENTATION AND UREA TREATMENT M. N. A. Kumar1, K. Sundareshan, E. G. Jagannath S. R. Sampath and P. T. Doyle2 Southern Regional Station, National Dairy Research Institute, Bangalore - 560030, India Summary Twenty five 75% Holstein Friesian cross bred bullocks fed rice straw (Oryza saliva) of long form, were fed with the following five treatments. 1. Rice straw, untreated (RS) 2. RS + water (1:1), stored for 24 hours (WRS) 3. RS (100 kg) + urea solution (4 kg urea/100 litre water) and dried (USRS) 4. RS (100 kg) + urea solution (as in 3) stored in wet condition for 24 hours (UWRS) 5. RS (100 kg) + urea solution (as in 3) stored in pit for 21 days (UTRS). Potential digestibility of treatments of RS was evaluated by monitoring (in vitro) Simulating Rumen like Fermentation (SRLF). The results indicated that Dry Matter Intake (DMI), digestibility of nutrients, N utilization were of the order UTRS > UWRS > USRS > WRS and RS (p < 0.05 to P < 0.01). SRLF index was high (255.84) for UTRS and least (145.58) for USRS. It was interm­ ediary (199.66) for UWRS. The acetyl content (AC) of UTRS with higher hemicellulose (HCE) dig­ estibility (80.8%) was low compared to UWRS, USRS, RS and WRS. The acetate content was of the order UTRS < UWRS < USRS < WRS and RS thereby indicating that reduction in acetyl con­ tent was an index of positive response of urea-treatment of RS. In addition, the ratio of HCE/AC in faeces of UTRS was 0.87 as against the ratios (2.26-2.48) observed in other treatments recording reduction jn AC due to urea-treatinent.
    [Show full text]