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Preparation Of Ketones From Nitriles

Chapter 16: Aldehydes And Ketones (carbonyl Compounds)

Chapter 16: Aldehydes And Ketones (carbonyl Compounds)

The Carbonyl Double Bond Both the carbon and oxygen atoms are hybridized sp2, so the system is planar. The three oxygen sp2 AO’s are involved as follows: The two unshared electorn pairs of oxygen occupy two of these AO’s, and the third is involved in sigma bond formation to the carbonyl carbon. The three sp2 AO’s on the carbonyl carbon are involved as follows: One of them is involved in sigma bonding to one of the oxygen sp2 AO’s, and the other two are involved in bonding to the R substituents. The 2pz AO’s on oxygen and the carbonyl carbon are involved in pi overlap, forming a pi bond. The pi BMO, formed by positive overlap of the 2p orbitals, has a larger concentration of electron density on oxygen than carbon, because the electrons in this orbital are drawn to the more electronegative atom, where they are more highly stabilized. This result is reversed in the vacant antibonding MO. As a consequence of the distribution in the BMO, the pi bond (as is the case also with the sigma bond) is highly polar, with the negative end of the dipole on oxygen and the positive end on carbon. We will see that this polarity, which is absent in a carbon-carbon pi bond, has the effect of strongly stabilizing the C=O moiety. Resonance Treatment of the Carbonyl Pi Bond 1.Note that the ionic structure (the one on the right side) has one less covalent bond, but this latter is replaced with an ionic bond (electrostatic bond). 2.This structure is a relatively “good” one, therefore, and contributes extensively to the resonance hybrid, making this bond much more thermodynamically stable than the C=C pi bond, for which the corresponding ionic structure is much less favorable (negative charge is less stable on carbon than on oxygen). 3.The carbonyl carbon therefore has extensive car Continue reading >>

Synthesis Of Nitriles

Synthesis Of Nitriles

Name Reactions Recent Literature The Schmidt reaction of aldehydes with NaN3 furnishes the corresponding nitriles in near quantitative yields in the presence of TfOH and tolerates various electron-withdrawing and electron-donating substituents. Formanilides, common side products, are not observed. The reaction is easily scalable, high yielding, and nearly instantaneous. B. V. Rokade, J. R. Prabhu, J. Org. Chem., 2012, 77, 5364-5370. Participation of 'activated DMSO' in the one-pot transformation of aldehydes to nitriles allows the generation of a wide range of aromatic, heterocyclic, and aliphatic nitriles with water as the only byproduct. A straightforward and practical procedure is demonstrated on a multigram scale. J. K. Augustine, A. Bombrun, R. N. Atta, Synlett, 2011, 2223-2227. A deep eutectic mixture of choline chloride and urea (1:2) is an efficient and ecofriendly catalyst for the one-pot synthesis of nitriles from aldehydes under solvent-free conditions under both conventional and microwave irradiation. Nitriles were obtained in good to excellent yields. U. B. Patil, S. S. Shendage, J. M. Nagarkar, Synthesis, 2013, 45, 3295-3299. In the presence of a catalytic amount of 4-AcNH-TEMPO, NaNO2, and HNO3, benzaldehydes underwent condensation with NH4OAc and a subsequent aerobic oxidation to produce nitriles selectively under O2. Aerobic oxidative conversion of a primary alcohol is also achieved. J.-H. Noh, J. Kim, J. Org. Chem., 2015, 80, 11624-11628. A copper-promoted C≡N triple bond cleavage of coordinated cyanide anion under a dioxygen atmosphere enables a nitrogen transfer to various aldehydes via a single electron-transfer process. This protocol provides a new cleavage pattern for the cyanide ion and maybe a more useful synthetic pathway to nitriles from ald Continue reading >>

Making Nitriles From Halogenoalkanes

Making Nitriles From Halogenoalkanes

MAKING NITRILES This page looks at various ways of making nitriles - from halogenoalkanes (haloalkanes or alkyl halides), from amides, and from aldehydes and ketones. It pulls together information from pages dealing with each of these kinds of compounds The halogenoalkane is heated under reflux with a solution of sodium or potassium cyanide in ethanol. The halogen is replaced by a -CN group and a nitrile is produced. Heating under reflux means heating with a condenser placed vertically in the flask to prevent loss of volatile substances from the mixture. The solvent is important. If water is present you tend to get substitution by -OH instead of -CN. Note: A solution of potassium cyanide in water is quite alkaline, and contains significant amounts of hydroxide ions. These react with the halogenoalkane. This reaction is discussed on the page about the reactions between halogenoalkanes and hydroxide ions. Use the BACK button on your browser to return to this page if you choose to follow this link. For example, using 1-bromopropane as a typical halogenoalkane: You could write the full equation rather than the ionic one, but it slightly obscures what's going on: The bromine (or other halogen) in the halogenoalkane is simply replaced by a -CN group - hence a substitution reaction. In this example, butanenitrile is formed. Note: If you want the mechanisms for these reactions (which differ depending on exactly what sort of halogenoalkane you are talking about), you can find them by following this link. Use the BACK button on your browser to return to this page if you choose to follow this link. Making a nitrile by this method is a useful way of increasing the length of a carbon chain. Having made the nitrile, the -CN group can easily be modified to make other things - as you w Continue reading >>

01 Apra Nickel For A Ketone

01 Apra Nickel For A Ketone

Direct Synthesis of Arylketones by Nickel-Catalyzed Addition of Arylboronic Acids to Nitriles Ketones from boronic acids and nitriles One of the first contracts we carried out in GalChimia was the preparation of a ketone present as impurity in a process for an API. The synthesis relied in the addition of an organomagnesium compound to a nitrile. The nitrile was commercially available, but the organomagnesium compound had to be prepared from the corresponding bromide, magnesium turnings and iodine or 1,2-dibromethane as promotor. A modern version of this reaction can be seen in this paper by Cheng et al. (National Tsing Hua UniVersity, Taiwan). Their studies follow the trail of other metal mediated protocols for the addition of boronic acids to nitriles, but in this case using a first-row transition metal: Nickel. The use of different bidentante Ni complexes and a Lewis acid allows the succesful addition of different boronic acids to the nitriles. In a typical protocol, a sealed tube containing Ni(dppe)Cl2 (10 mol%), ZnCl2 (150 mol%) and boronic acid (200 mol%) is purged and then the nitrile, H2O (100 mol%) and 1,4-dioxane were sequentially added to the system and the reaction heated at 80 °C for 8 h. Two striking points about the protocol are the introduction of water to enhance the yield, something not expected when using ZnCl2, and the absence of base; no base is necessary for the transmetalation of arylboronic acid to the nickel center. The protocol is efficient and gives good yields. Since the reaction system uses 1,4-dioxane as solvent, microwave heating should not be specially effective here, but the presence of water and the zinc salt could change that, so it is worth giving it a try. No examples of heterocycles are given, so there is room for more work. Org. Le Continue reading >>

Conversion To Ketones Using Grignard Reagents

Conversion To Ketones Using Grignard Reagents

Grignard reagents can attack the electophillic carbon in a nitrile to form an imine salt. This salt can then be hydrolyzed to become a ketone. Mechanism 1) Nucleophilic Attack by the Grignard Reagent 2) Protonation 3) Protonation 4) Nucleophilic attack by water 5) Proton Transfer 6) Leaving group removal 7) Deprotonation Continue reading >>

Preparation Of Ketones From Nitriles And Phosphoranes

Preparation Of Ketones From Nitriles And Phosphoranes

Abstract The preparation of a ketone from a phosphorane and a nitrile is described. The workup conditions are mild, and the yields are high. The unreacted starting materials can easily be recovered. Continue reading >>

Synthesis Of Ketones By Palladium-catalysed Desulfitative Reaction Of Arylsulfinic Acids With Nitriles

Synthesis Of Ketones By Palladium-catalysed Desulfitative Reaction Of Arylsulfinic Acids With Nitriles

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Nitrile

Nitrile

This article is about the group of organic compounds. For the synthetic rubber product, see Nitrile rubber. The structure of a nitrile: the functional group is highlighted blue. A nitrile is any organic compound that has a −C≡N functional group.[1] The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons. Inorganic compounds containing the −C≡N group are not called nitriles, but cyanides instead.[2] Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic. Structure and basic properties[edit] The N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond.[3] Nitriles are polar, as indicated by high dipole moments. As liquids, they have high dielectric constants, often in the 30s. History[edit] The first compound of the homolog row of nitriles, the nitrile of formic acid, hydrogen cyanide was first synthesized by C. W. Scheele in 1782.[4][5] In 1811 J. L. Gay-Lussac was able to prepare the very toxic and volatile pure acid.[6] The nitrile of benzoic acids was first prepared by Friedrich Wöhler and Justus von Liebig, but due to minimal yield of the synthesis neither physical nor chemical properties were determined nor a structure suggested. Théophile-Jules Pelouze synthesized propionitrile in 18 Continue reading >>

Stephen Aldehyde Synthesis

Stephen Aldehyde Synthesis

Not to be confused with Stevens rearrangement. Stephen aldehyde synthesis, a named reaction in chemistry, was invented by Henry Stephen (OBE/MBE). This reaction involves the preparation of aldehydes (R-CHO) from nitriles (R-CN) using tin(II) chloride (SnCl2), hydrochloric acid (HCl) and quenching the resulting iminium salt ([R-CH=NH2]+Cl−) with water (H2O).[1][2] During the synthesis, ammonium chloride is also produced. Mechanism[edit] The following scheme shows the reaction mechanism: Stephen aldehyde synthesis: Reaction mechanism By addition of hydrogen chloride the used nitrile (1) reacts to its corresponding salt (2). It is believed that this salt is reduced by a single electron transfer by the tin(II) chloride (3a and 3b).[3] The resulting salt (4) precipitates after some time as aldimine tin chloride (5). Hydrolysis of 5 produces a amide (6) from which an aldehyde (7) is formed. Substitutes that increase the electron density promote the formation of the aldimin-tin chloride adduct. By electron withdrawing substituents, the formation of amide chloride is facilitated.[4] In the past, the reaction was carried out by precipitating the aldimine-tin chloride, washing it with ether and then hydrolyzing it. However, it has been found that this step is unnecessary and the aldimine tin chloride can be hydrolysed directly in the solution.[5] This reaction is more efficient when aromatic nitriles are used instead of aliphatic ones. However, even for some aromatic nitriles (e. g. 2-formylbenzoic acid ethyl ester) the yield can be low.[5] Sonn-Müller method[edit] In the Sonn-Müller method[6][7] the intermediate iminium salt is obtained from reaction of an amide PhCONHPh with phosphorus pentachloride. See also[edit] Amide reduction Nitrile reduction Pinner reaction – a sim Continue reading >>

Synthesis Of Ketones

Synthesis Of Ketones

Like aldehydes, ketones can be prepared in a number of ways. The following sections detail some of the more common preparation methods: the oxidation of secondary alcohols, the hydration of alkynes, the ozonolysis of alkenes, Friedel‐Crafts acylation, the use of lithium dialkylcuprates, and the use of a Grignard reagent. The oxidation of secondary alcohols to ketones may be carried out using strong oxidizing agents, because further oxidation of a ketone occurs with great difficulty. Normal oxidizing agents include potassium dichromate (K 2Cr 2O 7) and chromic acid (H 2CrO 4). The conversion of 2‐propanol to 2‐propanone illustrates the oxidation of a secondary alcohol. The addition of water to an alkyne leads to the formation of an unstable vinyl alcohol. These unstable materials undergo keto‐enol tautomerization to form ketones. The hydration of propyne forms 2‐propanone, as the following figure illustrates. When one or both alkene carbons contain two alkyl groups, ozonolysis generates one or two ketones. The ozonolysis of 1,2‐dimethyl propene produces both 2‐propanone (a ketone) and ethanal (an aldehyde). Friedel‐Crafts acylations are used to prepare aromatic ketones. The preparation of acetophenone from benzene and acetyl chloride is a typical Friedel‐Crafts acylation. The addition of a lithium dialkylcuprate (Gilman reagent) to an acyl chloride at low temperatures produces a ketone. This method produces a good yield of acetophenone. Hydrolysis of the salt formed by reacting a Grignard reagent with a nitrile produces good ketone yields. For example, you can prepare acetone by reacting the Grignard reagent methyl magnesium bromide (CH 3MgBr) with methyl nitrile (CH 3C&tbond;N). Continue reading >>

Insertions Of Ketones And Nitriles Into Organorhodium(i) Complexes And B-hydrocarbyl Eliminations From Rhodium(i) Alkoxo And Iminyl Complexes.

Insertions Of Ketones And Nitriles Into Organorhodium(i) Complexes And B-hydrocarbyl Eliminations From Rhodium(i) Alkoxo And Iminyl Complexes.

Organometallics 2008, 27, 4749-4757. A series of tris(triethylphosphine)-ligated organorhodium(I) complexes were prepared, and their reactions with electron-poor arylnitriles and diarylketones were studied. [(PEt3)3Rh(Ar)] (Ar = phenyl (1a) or o-anisyl (1e)) reacted with an excess of electron-poor arylnitriles Ar′C≡N (Ar′ = p-CF3C6H4 or 3,5-bis(CF3)C6H3) to form Rh(I) iminyl complexes {(PEt3)3Rh[N═C(Ar)(Ar′)]} (2h−j). In contrast, 3,5-bis(CF3)C6H3CN did not insert into the M−C bond of the arylrhodium(I) complexes [(PEt3)3Rh(Ar)] (Ar = p-CF3C6H4 (1f) or 3,5-bis(CF3)C6H3 (1g)), containing more electron-poor aryl groups. The kinetic data for nitrile insertions were most consistent with a pathway involving initial ligand dissociation, followed by a classic migratory insertion. The iminyl complexes 2i−j decomposed at higher temperatures via β-aryl eliminations with selective migration of the more electron-poor aryl group 3,5-bis(CF3)C6H3 to form 1g and the corresponding nitriles. Migratory aptitudes of various aryl groups were assessed by studying β-aryl eliminations from a variety of iminyl complexes. Kinetic data for these β-aryl eliminations were most consistent with initial phosphine dissociation and carbon−carbon bond cleavage of the resulting 14-electron intermediate. Insertions of diarylketones Ar(Ar′)C═O (Ar = 3,5-bis(CF3)C6H3, Ar′ = Ph or 3,5-bis(CF3)C6H3)) into 1a also occurred, although the resulting Rh(I) alkoxides {(PEt3)2Rh[OC(Ph)(Ar)(Ar′)]} (3f−g) were not stable under the reaction conditions and could not be directly identified. Instead, a mixture of {(PEt3)3Rh[3,5-bis(CF3)C6H3]} (1g) and the ketone Ph(Ar′)C═O (Ar′ = Ph or 3,5-bis(CF3)C6H3)) were detected as the major products, indicating that decomposition of alkoxides 3f Continue reading >>

A2 Organic Reactions / Reagents & Conditions

A2 Organic Reactions / Reagents & Conditions

1. GRIGNARD REAGENTS · Preparation: i. HALOALKANE + Mg → GRIGNARD · Reagents and Conditions: 1) Heat under reflux 2) Dry Ether 3) Single Crystal of Iodine catalyst if needed · Reactions: i. GRIGNARD + CO2(cold/solid) → (+1C)CARBOXYLIC ACID + MgBrCl (+1C = the addition of one Carbon molecule to the chain) ii. GRIGNARD + METHANAL → (+1C) 1º ALCOHOL + MgBrCl iii. GRIGNARD + Other ALDEHYDES → (+1C) 2º ALCOHOL +MgBrCl iv. GRIGNARD + KETONE → (+1C)3º ALCOHOL + MgBrCl · Reagents and Conditions: 1) Dry Reagents 2) With HCl 2. CARBOXYLIC ACIDS · Preparation: i. 1º ALCOHOLS + 2[O] → CARBOXYLIC ACID + WATER · Reagents and Conditions: 1) Heat under Reflux 2) Potassium Dichromate / H2SO4 ii. Hydrolysis of Nitriles NITRILE + 2H2O + HCl → CARBOXYLIC ACID + NH4Cl · Reagents and Conditions: 1) Heat under reflux 2) With dilute HCl · Reactions: i. CARBOXYLIC ACID + NaOH → CARBOXYLATE SALT + H2O ii. CARBOXYLIC ACID + Na2CO3/NaHCO3 → CARBOXYLATE SALT + H2O + CO2 iii. CARBOXYLIC ACID + ALCOHOL ↔ ESTER + H2O · Reagents and Conditions: 1) Warmed under reflux 2) With concentrated H2SO4 iv. CARBOXYLIC ACID + PCl5 → ACID CHLORIDE + POCl3 + HCl · Reagents and Conditions: 1) Dry / room temperature v. CARBOXYLIC ACID + 4[H] → ALCOHOL + H2O · Reagents and Conditions: 1) LiAlH4 in dry ether 2) With HCl 3. ACID CHLORIDES: · Preparation: i. CARBOXYLIC ACID + PCl5 → ACID CHLORIDE + HCl + POCl3 · Reactions: i. ACID CHLORIDE + H2O → CARBOXYLIC ACID + HCl ii. ACID CHLORIDE + ALCOHOL → ESTER + HCl iii. ACID CHLORIDE + (concentrated)AMMONIA → AMIDE + NH4Cl iv. ACID CHLORIDE + AMINE → SUBSTITUTED AMIDE + HCl 4. ESTERS: · Preparation: i. CAR Continue reading >>

Chapter 20: Carboxylic Acid Derivatives. Nucleophilic Acyl Substitution

Chapter 20: Carboxylic Acid Derivatives. Nucleophilic Acyl Substitution

Summary | Reactions of Acyl Halides | Reactions of Acid Anhydrides | Reactions of Esters | Reactions of Amides | Reactions of Nitriles | Reactions of Nitriles Chapter 20: Carboxylic Acid Derivatives. Nucleophilic Acyl Substitution Reaction type: Nucleophilic Addition Overview Nitriles typically undergo nucleophilic addition to give products that often undergo a further reaction. The chemistry of the nitrile functional group, CºN, is very similar to that of the carbonyl, C=O of aldehydes and ketones. Compare the two schemes: versus However, it is convenient to describe nitriles as carboxylic acid derivatives because: the oxidation state of the C is the same as that of the carboxylic acid derivatives. hydrolysis produces the carboxylic acid Like the carbonyl containing compounds, nitriles react with nucleophiles via two scenarios: Strong nucleophiles (anionic) add directly to the CºN to form an intermediate imine salt that protonates (and often reacts further) on work-up with dilute acid. Examples of such nucleophilic systems are : RMgX, RLi, RCºCM, LiAlH4 Weaker nucleophiles (neutral) require that the CºN be activated prior to attack of the Nu. This can be done using a acid catalyst which protonates on the Lewis basic N and makes the system more electrophilic. Examples of such nucleophilic systems are : H2O, ROH The protonation of a nitrile gives a structure that can be redrawn in another resonance form that reveals the electrophilic character of the C since it is a carbocation. Hydrolysis of Nitriles Reaction type: Nucleophilic Addition then Nucleophilic Acyl Substitution Summary Nitriles, RCºN, can be hydrolyzed to carboxylic acids, RCO2H via the amide, RCONH2. Reagents : Strong acid (e.g. H2SO4) or strong base (e.g. NaOH) / heat. Related Reactions MECHANISM OF TH Continue reading >>

An Improved Synthesis Of 5-halopyrimidines: Reaction Of Α-halo Ketones With Nitriles

An Improved Synthesis Of 5-halopyrimidines: Reaction Of Α-halo Ketones With Nitriles

© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.A. García Martínez* , A. Herrera Fernández, Dolores Molero Vilchez, M. Hanack, L. R. Subramanian Continue reading >>

Preparation Of Nitriles From Cyanogen And Ketones

Preparation Of Nitriles From Cyanogen And Ketones

Unite States Patent PREPARATION OF NITRILES FROM CYANOGEN AND KETONES William L. Fierce, Crystal Lake, and Walter J. Sandner, Carpentersville, Ill., assignors to The Pure Oil Company, Chicago, 111., a corporation of Ohio No Drawing. Application May 14, 1957 Serial No. 658,976 15 Claims. (Cl. 260-465) This invention relates to new and useful improvements in methods for preparing organic nitriles and more particularly to a method of preparing aliphatic and aromatic nitriles by reaction of cyanogen and ketones at elevated temperatures. It is, therefore, one object of this invention to provide an improved method for preparing aliphatic and aromatic nitriles. Another object of this invention is to provide a method of preparing a variety of aliphatic and aromatic nitriles from ketones. A feature of this invention is the provision of a process for preparing aliphatic and aromatic nitriles by the high temperature reaction of cyanogen and a ketone. Another feature of this invention is the provision of a process for preparing aliphatic and aromatic nitriles, such as acetonitrile, propionitrile, acrylonitrile, and benzonitrile by the high temperature reaction of cyanogen and lower alkyl and aryl ketones at a temperature above the decomposition point of the ketone. Other objects and features of this invention will become apparent from time to time throughout the specification and claims as hereinafter related. This invention comprises a process in which a ketone and cyanogen are reacted at a temperature in the range from 500 to 1000 C. Within this range of temperature aliphatic and aromatic ketones decompose readily to produce free radicals and carbon monoxide, with the free radicals reacting rapidly with cyanogen to produce aliphatic and aromatic nitriles as the principal reaction

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