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Preparation Of Ketones From Nitriles

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 >>

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 >>

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 >>

Grignard Reaction Grignard Reagents

Grignard Reaction Grignard Reagents

The Grignard Reaction is the addition of an organomagnesium halide (Grignard reagent) to a ketone or aldehyde, to form a tertiary or secondary alcohol, respectively. The reaction with formaldehyde leads to a primary alcohol. Grignard Reagents are also used in the following important reactions: The addition of an excess of a Grignard reagent to an ester or lactone gives a tertiary alcohol in which two alkyl groups are the same, and the addition of a Grignard reagent to a nitrile produces an unsymmetrical ketone via a metalloimine intermediate. (Some more reactions are depicted below) Mechanism of the Grignard Reaction While the reaction is generally thought to proceed through a nucleophilic addition mechanism, sterically hindered substrates may react according to an SET (single electron transfer) mechanism: The Grignard reagent can act as base, with deprotonation yielding an enolate intermediate. After work up, the starting ketone is recovered. A reduction can also take place, in which a hydride is delivered from the β-carbon of the Grignard reagent to the carbonyl carbon via a cyclic six-membered transition state. With carboxylic acid chlorides: Esters are less reactive than the intermediate ketones, therefore the reaction is only suitable for synthesis of tertiary alcohols using an excess of Grignard Reagent: With nitriles: With CO2 (by adding dry ice to the reaction mixture): With oxiranes: Recent Literature Highly Enantioselective Desymmetrization of Anhydrides by Carbon Nucleophiles: Reaction of Grignard Reagents in the Presence of (-)-Sparteine R. Shintani, G. C. Fu, Angew. Chem. Int. Ed., 2002, 41, 1057-1059. Added-Metal-Free Catalytic Nucleophilic Addition of Grignard Reagents to Ketones H. Zong, H. Huang, J. Liu, G. Bian, L. Song, J. Org. Chem., 2012, 77, 4645- 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 >>

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 >>

Efficient And Scalable Synthesis Of Ketones Via Nucleophilic Grignard Addition To Nitriles Using Continuous Flow Chemistry

Efficient And Scalable Synthesis Of Ketones Via Nucleophilic Grignard Addition To Nitriles Using Continuous Flow Chemistry

In the present Letter we report the development of efficient continuous flow chemistry conditions for the scalable preparation of ketones. This transformation is achieved via nucleophilic addition of Grignard reagents to the corresponding nitriles and imine hydrolysis by means of in-series plug flow reactors. Graphical abstract 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

-unsaturated Esters, Ketones And Nitriles Using Microwave And Solvent-free Conditions

-unsaturated Esters, Ketones And Nitriles Using Microwave And Solvent-free Conditions

ARTICLE Synthesis of b-phenylchalcogeno-a, b Eder J. LenardãoI, *; Márcio S. SilvaI; Samuel R. MendesI; Francisco de AzambujaI; Raquel G. JacobI; Paulo César Silva dos SantosII; Gelson PerinI, * IInstituto de Química e Geociências, Universidade Federal de Pelotas, CP 354, 96010-900 Pelotas-RS, Brazil IIDepartamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria-RS, Brazil ABSTRACT A simple, clean and efficient solvent-free protocol was developed for hydrochalcogenation of alkynes containing a Michael acceptor (ester, ketone and nitrile) with phenylchalcogenolate anions generated in situ from the respective diphenyl dichalcogenide (Se, Te, S), using alumina supported sodium borohydride. This efficient and improved method is general and furnishes the respective (Z)-b-phenylchalcogeno-a,b-unsaturated esters, ketones and nitriles, in good yield and higher selectivity, compared with those that use organic solvent and inert atmosphere. The use of microwave (MW) irradiation facilitates the procedure and accelerates the reaction. Keywords: microwave irradiation, solvent-free reaction, b-phenylchalcogeno esters, b-phenylchalcogeno ketones, b-phenylchalcogeno nitriles RESUMO Um método simples e eficiente foi desenvolvido para a hidrocalcogenação de alquinos contendo um aceptor de Michael (éster, cetona e nitrila) com ânions fenilcalcogenolatos gerados in situ a partir do respectivo dicalcogeneto de difenila (Se, Te, S), usando hidreto de boro e sódio suportado em alumina e meio livre de solvente. Este método é geral e permite a obtenção de ésteres, cetonas e nitrilas (Z)-b-fenilcalcogeno-a,b-insaturados, com rendimentos e seletividade comparados aos obtidos quando se utiliza solvente orgânico e atmosfera inerte. O uso de irradiação de m 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 >>

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 >>

Grignard Reagent

Grignard Reagent

This is a wiki on Grignard Reagents, their preparatory steps, and their uses. This wiki is for all-information-Grignard. Grignard reagents are useful compounds in metalorganics that can be used to produce a wide range of alcohols; however they are very difficult to prepare. The typical preparation of Grignards is shown in figure 1: In Figure 1, a Grignard is prepared by reacting a halogenated compound with either lithium or magnesium in ether. can be aliphatic or aromatic and is a halogen like chlorine, bromine, of iodine. Difficulty of Grignard Reagents Grignards are difficult to prepare because they easily react with the common molecules of life, as shown in Figure 2: As shown in Figure 2, Grignards will become when reacted with carbon dioxide, or will become the original compound () used to prepared the Grignard if in the pressence of . Take special care to note the middle path for it details the typical use of a Grignard; the addition of groups (aromatic or aliphatic) to form complex alcohols. Grignards can be reacted with aldehydes or ketones to form or alcohols; respectively. The key is that Grignards love attacking carbonyl groups (). Mechanism of a Grignard Attack on a Carbonyl group Grignards attack carbonyls to form alkoxides. Note that the alkoxide must be protonated to obtain the desired alcohol. Nucleophilic Addition Unto Epoxides Grignards possess the ability to attack epoxide compounds; however, these reagents are selective of which carbon in an epoxide ring they will attack. Take note the the Grignard in the image above attacked the least substituted carbon in the epoxide ring, which opened up the epoxide ring to form a alkoxide. After protonation, the desired alcohol was produced. Attack on Nitriles Grignards further possess the property to form ketones 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 Using Various Methods

Preparation Of Ketones Using Various Methods

Preparation of ketones: Ketones are the organic compound containing carbonyl groups (C=O). The general formula for a ketone is R(C=O)R’, where R and R’ can be alkyl or aryl groups. They are classified into two categories by their substituents: symmetrical ketones (when two identical groups are attached to the carbonyl group) and asymmetrical ketones (when two different groups are appended to the carbonyl group). Many methods exist for the preparation of ketones at industrial scale and in laboratories. Standard methods include oxidation of alcohol, hydrocarbons, etc. Some general methods for the preparation of ketones are explained below: Preparation of ketones from acyl chlorides: Acyl chlorides upon treatment with Grignard reagent and a metal halide, yields ketones. For example: when cadmium chloride is reacted with the Grignard reagent, dialkyl cadmium is formed. Dialkylcadmium thus formed is further reacted with acyl chlorides to form ketones. Preparation of ketones from nitriles: Treatment of nitriles with Grignard reagent upon further hydrolysis yields ketones. Preparation of ketones from benzenes or substituted benzenes: Electrophilic aromatic substitution of a benzene ring with acid chlorides in the presence of a Lewis acid such as AlCl3 results in the formation of ketones. This reaction is popularly known as Friedel Craft’s acylation reaction. Preparation of ketones by dehydrogenation of alcohols: Dehydrogenation of alcohol is a reaction in which two hydrogen molecules are removed from an alcohol molecule upon oxidation. During oxidation of alcohol both C-O and O-H bonds are broken for the formation of C=O bonds. Secondary alcohols in the presence of strong oxidizing agents undergo dehydrogenation to produce ketones. For example: when vapours of secondary Continue reading >>

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