Carboxylic Acids and Reduction/Oxidation Carboxylic

Carboxylic Acids and Reduction/Oxidation • Addition of H (or “H-”) Reduction 2 • Loss of O2 or O carboxylic aldehyde alcohol alkane acid (or ketone) • Loss of H 2 Oxidation • Addition of O2 or O + Neither oxidation nor reduction: Addition or loss of H , H2O, or HX Carboxylic acids are the most oxidized functional group of carbon. Carboxylic Acids via Oxidation Chromate oxidation of primary alcohols: unavoidably Na2Cr2O7 H2SO4 aldehyde carboxylic alcohol acid Oxidation of aldehydes with Tollens’ reagent: 1. Ag2O, NH3 2. H O+ 3 Selective for aldehydes; will not oxidize alcohols. aldehyde carboxylic acid Carboxylic Acids via Oxidation Oxidative cleavage of alkynes: 1. O3 2. H2O internal alkyne Oxidation of benzylic carbons: KMnO4 Purifying Carboxylic Acids by Acid-Base Extraction Acidic and basic organic molecules can be separated from other substances by manipulating their protonation state and solubility. Let’s say we run a reaction. Na2Cr2O7 + unreacted H2SO4 + Na+ 3+ We want this… + Cr(H2O)6 + organic + HSO - …but not these. side products 4 How do we isolate our desired product from the other materials, without using distillation or chromatography? Acid-Base Extraction Step 1: Remove inorganics from organics via differential solubility. a separatory (sept) funnel - Na+ HSO4 Cr(H O) 3+ H2O 2 6 CHCl3 + organic side densities: products (H2O) = 1 g/mL (CHCl3) = 1.48 g/mL A large density difference ensures the two liquids separate completely and quickly. (Much faster than, say, oil and water.) Step 2: Add basic water to deprotonate carboxylic acid, and transfer it to the aqueous phase. - Na+ HSO4 3+ discard Cr(H2O)6 H2O layer + organic + organic side side products products add discard NaOH/ H2O CHCl3 layer + organic side products Step 3: Re-acidify carboxylate to return it to organic solution. Remove solvent in vacuo to yield pure acid. add HCl/ H2O, fresh CHCl3 discard H2O layer remove solvent in rotary evaporator Chemistry student, removing solvent in a “rotovap” Nucleophilic Addition to Carbonyls Heteroatom electron donors add reversibly to C=O groups. Equilibrium driven + to the left by entropy. Also true for Cl , HS , NH3 nucleophiles. Hydrogen anions (“hydride”) and carbon anions add irreversibly to C=O groups. + Reaction driven to the right by instability of - - charge on H , RCH2 . +.

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Aldehydes and Ketones
12 Aldehydes and Ketones Ethanol from alcoholic beverages is first metabolized to acetaldehyde before being broken down further in the body. The reactivity of the carbonyl group of acetaldehyde allows it to bind to proteins in the body, the products of which lead to tissue damage and organ disease. Inset: A model of acetaldehyde. (Novastock/ Stock Connection/Glow Images) KEY QUESTIONS 12.1 What Are Aldehydes and Ketones? 12.8 What Is Keto–Enol Tautomerism? 12.2 How Are Aldehydes and Ketones Named? 12.9 How Are Aldehydes and Ketones Oxidized? 12.3 What Are the Physical Properties of Aldehydes 12.10 How Are Aldehydes and Ketones Reduced? and Ketones? 12.4 What Is the Most Common Reaction Theme of HOW TO Aldehydes and Ketones? 12.1 How to Predict the Product of a Grignard Reaction 12.5 What Are Grignard Reagents, and How Do They 12.2 How to Determine the Reactants Used to React with Aldehydes and Ketones? Synthesize a Hemiacetal or Acetal 12.6 What Are Hemiacetals and Acetals? 12.7 How Do Aldehydes and Ketones React with CHEMICAL CONNECTIONS Ammonia and Amines? 12A A Green Synthesis of Adipic Acid IN THIS AND several of the following chapters, we study the physical and chemical properties of compounds containing the carbonyl group, C O. Because this group is the functional group of aldehydes, ketones, and carboxylic acids and their derivatives, it is one of the most important functional groups in organic chemistry and in the chemistry of biological systems. The chemical properties of the carbonyl group are straightforward, and an understanding of its characteristic reaction themes leads very quickly to an understanding of a wide variety of organic reactions.
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Aldehydes and Ketones Are Simple Organic Compounds Containing a Carbonyl Group
Aldehydes and Ketones are simple organic compounds containing a carbonyl group. Carbonyl group contains carbon- oxygen double bond. These organic compounds are simple because the carbon atom presents in the carbonyl group lack reactive groups such as OH or Cl. By Dr. Sayed Hasan Mehdi Assistant Professor Department of Chemistry Shia P.G. College, Lucknow Dr. S.Hasan Mehdi 6/13/2020 This is to bring to kind notice that the matter of this e- content is for the B.Sc. IV semester students. It has been taken from the following sources. The students are advised to follow these books as well. •A TEXTBOOK OF ORGANIC CHEMISTRY by Arun Bahl & B.S. Bahl, S. Chand & Company Ltd. Publication. •Graduate Organic Chemistry by M. K. Jain and S.C. Sharma, Vishal Publishing Co. •Pradeep’s Organic Chemistry Vol II by R. N. Dhawan, Pradeep Publication, Jalandhar. Dr. S.Hasan Mehdi 6/13/2020 An aldehyde is one of the classes of carbonyl group- containing alkyl group on one end and hydrogen on the other end. The R and Ar denote alkyl or aryl member respectively. In the condensed form, the aldehyde is written as –CHO. Dr. S.Hasan Mehdi 6/13/2020 Dr. S.Hasan Mehdi 6/13/2020 1. From Alcohols: a. By oxidation of Alcohols: Aldehydes and ketones can be prepared by the controlled oxidation of primary and secondary alcohols using an acidified solution of potassium dichromate or permanganate. Primary alcohol produces aldehydesRef. Last slide. O K Cr O RCH2OH + [O] 2 2 7 + R C H H 10 Alcohol Aldehyde O CH3CH2OH+ [O] K2Cr2O7 + CH3 C H H Ethyl Alcohol Acetaldehyde The aldehydes formed in the above reaction are very easily oxidised to carboxylc acids if allowed to remain in the reaction mixture.
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Nucleophilic Aromatic Substitution
NUCLEOPHILIC AROMATIC SUBSTITUTION Ms. Prerana Sanas M.Pharm (Pharmceutical Chemistry) Asst.Professor, NCRD’s Sterling Institute of Pharmacy Nerul Navi Mumbai Nucleophilic aromatic substitution results in the substitution of a halogen X on a benzene ring by a nucleophile (:Nu– ). Aryl halides undergo a limited number of substitution reactions with strong nucleophiles. NAS occurs by two mechanisms i) Bimoleccular displacement (Addition –Elimination) ii) Benzyne Formation( Elimination –Addition) 7/5/2019 Ms.Prerana Sanas 2 Bimolecular displacement (Addition – Elimination) Aryl halides with strong electron-withdrawing groups (such as NO2) on the ortho or para positions react with nucleophiles to afford substitution products. For example, treatment of p-chloronitrobenzene with hydroxide (– OH) affords p-nitrophenol by replacement of Cl by OH. Nucleophilic aromatic substitution occurs with a variety of strong nucleophiles, including – OH, – OR, – NH2, – SR, and in some cases, neutral nucleophiles such as NH3 and RNH2 . 7/5/2019 Ms.Prerana Sanas 3 Mechanism…… The mechanism of these reactions has two steps: Step i) Addition of the nucleophile (:Nu– ) forms a resonance-stabilized carbanion with a new C – Nu bond—three resonance structures can be drawn. • Step [1] is rate-determining since the aromaticity of the benzene ring is lost. In Step ii) loss of the leaving group re-forms the aromatic ring. This step is fast because the aromaticity of the benzene ring is restored. 7/5/2019 Ms.Prerana Sanas 4 Factors affecting Bimolecular displacement Increasing the number of electron-withdrawing groups increases the reactivity of the aryl halide. Electron-withdrawing groups stabilize the intermediate carbanion, and by the Hammond postulate, lower the energy of the transition state that forms it.
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Chapter 14 – Aldehydes and Ketones
Chapter 14 – Aldehydes and Ketones 14.1 Structures and Physical Properties of Aldehydes and Ketones Ketones and aldehydes are related in that they each possess a C=O (carbonyl) group. They differ in that the carbonyl carbon in ketones is bound to two carbon atoms (RCOR’), while that in aldehydes is bound to at least one hydrogen (H2CO and RCHO). Thus aldehydes always place the carbonyl group on a terminal (end) carbon, while the carbonyl group in ketones is always internal. Some common examples include (common name in parentheses): O O H HH methanal (formaldehyde) trans-3-phenyl-2-propenal (cinnamaldehyde) preservative oil of cinnamon O O propanone (acetone) 3-methylcyclopentadecanone (muscone) nail polish remover a component of one type of musk oil Simple aldehydes (e.g. formaldehyde) typically have an unpleasant, irritating odor. Aldehydes adjacent to a string of double bonds (e.g. 3-phenyl-2-propenal) frequently have pleasant odors. Other examples include the primary flavoring agents in oil of bitter almond (Ph- CHO) and vanilla (C6H3(OH)(OCH3)(CHO)). As your book says, simple ketones have distinctive odors (similar to acetone) that are typically not unpleasant in low doses. Like aldehydes, placing a collection of double bonds adjacent to a ketone carbonyl generally makes the substance more fragrant. The primary flavoring agent in oil of caraway is just a such a ketone. 2 O oil of carraway Because the C=O group is polar, small aldehydes and ketones enjoy significant water solubility. They are also quite soluble in typical organic solvents. 14.2 Naming Aldehydes and Ketones Aldehydes The IUPAC names for aldehydes are obtained by using rules similar to those we’ve seen for other functional groups (e.g.
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Lecture 5 Diastereoselective Addition Into Carbonyl Compounds
Lecture 5 Diastereoselective Addition into Carbonyl Compounds Containing α-Stereogenic Centres Learning outcomes: by the end of this lecture, and after answering the associated problems, you will be able to: 1. use the Felkin-Anh T.S. to predict the stereochemical outcome of reactions carried out on carbonyl compounds that possess an α-stereogenic centre; 2. rationalise the preferential adoption of a Felkin-Anh T.S. in nucleophilic addition reactions on steric and stereoelectronic grounds; 3. understand how the presence of an α-electron-withdrawing substituent affects the Felkin-Anh T.S.; 4. use the Felkin-Anh T.S. to prepare 1,2-syn diols from α-alkoxy ketones; 5. use the Cram chelation model to prepare 1,2-anti diols from α-alkoxy ketones. Stereoselective Addition of Nucleophiles into Ketones and Aldehydes containing α- Stereogenic Centres The addition of a nucleophile into a chiral ketone or aldehyde provides diastereoisomers. When the stereogenic centres in the substrate are close to the reacting carbonyl group (e.g. 1,2-disposed), then it is often possible to exploit this stereochemical information to control the stereoselectivity of the addition reaction. This method for controlling the stereochemical outcome of a reaction is known as substrate control. A number of models have been developed for predicting the stereochemical outcome of this type of reaction. Felkin-Anh Model Consider a carbonyl compound containing an α-stereogenic centre in which the three substituents at the α-site are well differentiated in size: O HO Nu Nu OH RL Nu RL RL R R R S M S M S RM R R R R R RS = small substituent RM = medium-sized substituent RL = large substituent Of the two diastereoisomeric alcohol addition products, one will be formed to a greater extent than the other.
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APPENDIX G Acid Dissociation Constants
harxxxxx_App-G.qxd 3/8/10 1:34 PM Page AP11 APPENDIX G Acid Dissociation Constants §␮ ϭ 0.1 M 0 ؍ (Ionic strength (␮ † ‡ † Name Structure* pKa Ka pKa ϫ Ϫ5 Acetic acid CH3CO2H 4.756 1.75 10 4.56 (ethanoic acid) N ϩ H3 ϫ Ϫ3 Alanine CHCH3 2.344 (CO2H) 4.53 10 2.33 ϫ Ϫ10 9.868 (NH3) 1.36 10 9.71 CO2H ϩ Ϫ5 Aminobenzene NH3 4.601 2.51 ϫ 10 4.64 (aniline) ϪO SNϩ Ϫ4 4-Aminobenzenesulfonic acid 3 H3 3.232 5.86 ϫ 10 3.01 (sulfanilic acid) ϩ NH3 ϫ Ϫ3 2-Aminobenzoic acid 2.08 (CO2H) 8.3 10 2.01 ϫ Ϫ5 (anthranilic acid) 4.96 (NH3) 1.10 10 4.78 CO2H ϩ 2-Aminoethanethiol HSCH2CH2NH3 —— 8.21 (SH) (2-mercaptoethylamine) —— 10.73 (NH3) ϩ ϫ Ϫ10 2-Aminoethanol HOCH2CH2NH3 9.498 3.18 10 9.52 (ethanolamine) O H ϫ Ϫ5 4.70 (NH3) (20°) 2.0 10 4.74 2-Aminophenol Ϫ 9.97 (OH) (20°) 1.05 ϫ 10 10 9.87 ϩ NH3 ϩ ϫ Ϫ10 Ammonia NH4 9.245 5.69 10 9.26 N ϩ H3 N ϩ H2 ϫ Ϫ2 1.823 (CO2H) 1.50 10 2.03 CHCH CH CH NHC ϫ Ϫ9 Arginine 2 2 2 8.991 (NH3) 1.02 10 9.00 NH —— (NH2) —— (12.1) CO2H 2 O Ϫ 2.24 5.8 ϫ 10 3 2.15 Ϫ Arsenic acid HO As OH 6.96 1.10 ϫ 10 7 6.65 Ϫ (hydrogen arsenate) (11.50) 3.2 ϫ 10 12 (11.18) OH ϫ Ϫ10 Arsenious acid As(OH)3 9.29 5.1 10 9.14 (hydrogen arsenite) N ϩ O H3 Asparagine CHCH2CNH2 —— —— 2.16 (CO2H) —— —— 8.73 (NH3) CO2H *Each acid is written in its protonated form.
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Nomenclature of Carboxylic Acids • Select the Longest Carbon Chain Containing the Carboxyl Group
Chapter 5 Carboxylic Acids and Esters Carboxylic Acids • Carboxylic acids are weak organic acids which Chapter 5 contain the carboxyl group (RCO2H): Carboxylic Acids and Esters O C O H O RCOOH RCO2H Chapter Objectives: O condensed ways of • Learn to recognize the carboxylic acid, ester, and related functional groups. RCOH writing the carboxyl • Learn the IUPAC system for naming carboxylic acids and esters. group a carboxylic acid C H • Learn the important physical properties of the carboxylic acids and esters. • Learn the major chemical reaction of carboxylic acids and esters, and learn how to O predict the products of ester synthesis and hydrolysis reactions. the carboxyl group • Learn some of the important properties of condensation polymers, especially the polyesters. Mr. Kevin A. Boudreaux • The tart flavor of sour-tasting foods is often caused Angelo State University CHEM 2353 Fundamentals of Organic Chemistry by the presence of carboxylic acids. Organic and Biochemistry for Today (Seager & Slabaugh) www.angelo.edu/faculty/kboudrea 2 Nomenclature of Carboxylic Acids • Select the longest carbon chain containing the carboxyl group. The -e ending of the parent alkane name is replaced by the suffix -oic acid. • The carboxyl carbon is always numbered “1” but the number is not included in the name. • Name the substituents attached to the chain in the Nomenclature of usual way. • Aromatic carboxylic acids (i.e., with a CO2H Carboxylic Acids directly connected to a benzene ring) are named after the parent compound, benzoic acid. O C OH 3
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Optimisation Du Métabolisme Énergétique Du Soufre Chez La Bactérie Hyperthermophile Aquifex Aeolicus
Aix-Marseille Université Ecole Doctorale des Sciences de la Vie et de la Santé Thèse de Doctorat d’Université Mention Microbiologie Clément AUSSIGNARGUES Optimisation du métabolisme énergétique du soufre chez la bactérie hyperthermophile Aquifex aeolicus Soutenue le 17 Décembre 2012 devant le jury: Pr. Frédéric BARRAS Dr. Laurent COURNAC Dr. Bruno FRANZETTI Dr. Marie-Thérèse GIUDICI-ORTICONI Dr. Anne GODFROY Dr. Marianne ILBERT Laboratoire de Bioénergétique et Ingénierie des Protéines Centre National de la Recherche Scientifique Aix-Marseille Université Ecole Doctorale des Sciences de la Vie et de la Santé Thèse de Doctorat d’Université Mention Microbiologie Clément AUSSIGNARGUES Optimisation du métabolisme énergétique du soufre chez la bactérie hyperthermophile Aquifex aeolicus Soutenue le 17 Décembre 2012 devant le jury: Pr. Frédéric BARRAS Dr. Laurent COURNAC Dr. Bruno FRANZETTI Dr. Marie-Thérèse GIUDICI-ORTICONI Dr. Anne GODFROY Dr. Marianne ILBERT Laboratoire de Bioénergétique et Ingénierie des Protéines Centre National de la Recherche Scientifique Sommaire Sommaire Introduction 2 Chapitre I- Métabolismes énergétiques du soufre 4 I) Le soufre, un élément essentiel aux multiples facettes 6 II) Le soufre utilisé comme composé énergétique 9 A) Oxydation des composés du soufre 10 1. Oxydation du sulfure d’hydrogène H2S 10 a) La Sulfure Quinone Oxydoréductase (SQR) 10 b) La flavocytochrome c sulfure déshydrogénase (FCSD) 13 2- 2. Oxydation du thiosulfate (S2O3 ) 14 a) Thiosulfate : accepteur oxydoréductase (TAOR) 14 b) Le système Sox 16 2- 3. Oxydation du sulfite (SO3 ) 20 a) Sulfite : accepteur oxydoréductase (SAOR) 21 b) Voie de l’APS 23 4. Oxydation du soufre stocké dans les globules 26 B) La réduction du soufre : soufre/polysulfure réductase 29 C) Un cas particulier : la dismutation du soufre (SOR) 33 1.
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Aldehydes Can React with Alcohols to Form Hemiacetals
340 14 . Nucleophilic substitution at C=O with loss of carbonyl oxygen You have, in fact, already met some reactions in which the carbonyl oxygen atom can be lost, but you probably didn’t notice at the time. The equilibrium between an aldehyde or ketone and its hydrate (p. 000) is one such reaction. O HO OH H2O + R1 R2 R1 R2 When the hydrate reverts to starting materials, either of its two oxygen atoms must leave: one OPh came from the water and one from the carbonyl group, so 50% of the time the oxygen atom that belonged to the carbonyl group will be lost. Usually, this is of no consequence, but it can be useful. O For example, in 1968 some chemists studying the reactions that take place inside mass spectrometers needed to label the carbonyl oxygen atom of this ketone with the isotope 18 O. 16 18 By stirring the ‘normal’ O compound with a large excess of isotopically labelled water, H 2 O, for a few hours in the presence of a drop of acid they were able to make the required labelled com- í In Chapter 13 we saw this way of pound. Without the acid catalyst, the exchange is very slow. Acid catalysis speeds the reaction up by making a reaction go faster by raising making the carbonyl group more electrophilic so that equilibrium is reached more quickly. The the energy of the starting material. We 18 also saw that the position of an equilibrium is controlled by mass action— O is in large excess.
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Ketenes 25/01/2014 Part 1
Baran Group Meeting Hai Dao Ketenes 25/01/2014 Part 1. Introduction Ph Ph n H Pr3N C A brief history Cl C Ph + nPr NHCl Ph O 3 1828: Synthesis of urea = the starting point of modern organic chemistry. O 1901: Wedekind's proposal for the formation of ketene equivalent (confirmed by Staudinger 1911) Wedekind's proposal (1901) 1902: Wolff rearrangement, Wolff, L. Liebigs Ann. Chem. 1902, 325, 129. 2 Wolff adopt a ketene structure in 1912. R 2 hν R R2 1905: First synthesis and characterization of a ketene: in an efford to synthesize radical 2, 1 ROH R C Staudinger has synthesized diphenylketene 3, Staudinger, H. et al., Chem. Ber. 1905, 1735. N2 1 RO CH or Δ C R C R1 1907-8: synthesis and dicussion about structure of the parent ketene, Wilsmore, O O J. Am. Chem. Soc. 1907, 1938; Wilsmore and Stewart Chem. Ber. 1908, 1025; Staudinger and Wolff rearrangement (1902) O Klever Chem. Ber. 1908, 1516. Ph Ph Cl Zn Ph O hot Pt wire Zn Br Cl Cl CH CH2 Ph C C vs. C Br C Ph Ph HO O O O O O O O 1 3 (isolated) 2 Wilsmore's synthesis and proposal (1907-8) Staudinger's synthesis and proposal (1908) wanted to make Staudinger's discovery (1905) Latest books: ketene (Tidwell, 1995), ketene II (Tidwell, 2006), Science of Synthesis, Vol. 23 (2006); Latest review: new direactions in ketene chemistry: the land of opportunity (Tidwell et al., Eur. J. Org. Chem. 2012, 1081). Search for ketenes, Google gave 406,000 (vs.
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Ester Synthesis Lab (Student Handout)
Name: ________________________ Lab Partner: ____________________ Date: __________________________ Class Period: ____________________ Ester Synthesis Lab (Student Handout) Lab Report Components: The following must be included in your lab book in order to receive full credit. 1. Purpose 2. Hypothesis 3. Procedure 4. Observation/Data Table 5. Results 6. Mechanism (In class) 7. Conclusion Introduction The compounds you will be making are also naturally occurring compounds; the chemical structure of these compounds is already known from other investigations. Esters are organic molecules of the general form: where R1 and R2 are any carbon chain. Esters are unique in that they often have strong, pleasant odors. As such, they are often used in fragrances, and many artificial flavorings are in fact esters. Esters are produced by the reaction between alcohols and carboxylic acids. For example, reacting ethanol with acetic acid to give ethyl acetate is shown below. + → + In the case of ethyl acetate, R1 is a CH3 group and R2 is a CH3CH2 group. Naming esters systematically requires naming the functional groups on both sides of the bridging oxygen. In the example above, the right side of the ester as shown is a CH3CH2 1 group, or ethyl group. The left side is CH3C=O, or acetate. The name of the ester is therefore ethyl acetate. Deriving the names of the side from the carboxylic acid merely requires replacing the suffix –ic with –ate. Materials • Alcohol • Carboxylic Acid o 1 o A o 2 o B o 3 o C o 4 Observation Parameters: • Record the combination of carboxylic acid and alcohol • Observe each reactant • Observe each product Procedure 1.
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In This Handout, All of Our Functional Groups Are Presented As Condensed Line Formulas, 2D and 3D Formulas and with Nomenclature Prefixes and Suffixes (If Present)
In this handout, all of our functional groups are presented as condensed line formulas, 2D and 3D formulas and with nomenclature prefixes and suffixes (if present). Organic names are built on a foundation of alkanes, alkenes and alkynes. Those examples are presented first and you need to know those rules. The strategies can be found in Chapter 4 of our textbook (alkanes: pages 93-98, cycloalkanes 102-104, alkenes: pages 104-110, alkynes: pages 112-113 and combinations of all of them 113-115). After introducing examples of alkanes, alkenes, alkynes and combinations of them, the functional groups are presented in order of priority. A few nomenclature examples are provided for each of the functional groups. Examples of the various functional groups are presented on pages 115-135 in the textbook. Two overview pages are on pages 136-137. Some functional groups have a suffix name when they are the highest priority functional group and a prefix name when they are not the highest priority group, and these are added to the skeletal names with identifying numbers and stereochemistry terms (E and Z for alkenes, R and S for chiral centers and cis and trans for rings). Several low priority functional groups only have a prefix name. A few additional special patterns are shown on pages 98-102. The only way to learn this topic is practice (over and over). The best practice approach is to actually write out the names (on an extra piece of paper or on a white board, and then do it again). The same functional groups are used throughout the entire course.
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