The document discusses various types of molecular rearrangement reactions. It begins by defining rearrangement reactions as those where the atoms or groups in a molecule reshuffle to form a structural isomer of the original substance. Rearrangements are then classified as intermolecular or intramolecular. Several examples of nucleophilic rearrangements are provided, including carbonium ion rearrangements like the pinacol-pinacolone, Wagner-Meerwein, and benzillic acid rearrangements. Nitrogen deficiency rearrangements like the Schmidt, Curtius, Hoffmann, Beckmann, and Lossen rearrangements are also briefly described. The mechanisms and features of several important rearrangements are discussed in more detail.
This document summarizes various types of rearrangement reactions in organic chemistry. It describes 15 categories of rearrangements including rearrangements to electron deficient carbons, nitrogens, and oxygens. For each category, 1-2 specific rearrangements are explained in more detail, including their mechanisms. Rearrangements discussed include the Wagner-Meerwein, Pinacol, Benzilic acid, Hofmann, Curtius, Lossen, Beckmann, Baeyer-Villiger, Stevens, Sommelet-Hauser, Wittig, Favorskii, Benzidine, Fries, and Claisen rearrangements. The document was prepared by a student as part of their coursework to provide an overview of
The document discusses different types of substitution reactions including nucleophilic substitution, electrophilic substitution, and free radical substitution. It provides details on the mechanisms, kinetics, stereochemistry and factors affecting the rate of nucleophilic substitution reactions SN1 and SN2. SN1 follows a unimolecular mechanism involving a carbocation intermediate while SN2 follows a bimolecular mechanism with a single concerted transition state. The document also discusses electrophilic aromatic substitution reactions and addition and elimination reactions of alkenes and alkynes.
There are five types of skeletal rearrangements: electron deficient, electron rich, radical, rearrangements on aromatic rings, and sigmatropic rearrangements. Molecular rearrangements involve the migration of a group from one atom to another within the same molecule. Examples include the Wagner-Meerwein rearrangement, pinacol-pinacolone rearrangement, and Cope rearrangement. Rearrangements are driven by stability of the carbocation intermediate or relief of ring strain.
FREE RADICALS , CARBENES AND NITRENES.pptxtenzinpalmo3
This document discusses free radicals, carbenes, and nitrenes. It defines each type of species, describes their characteristics such as electronic structure and stability. The document outlines different types for each species and methods for their formation and synthetic applications. Free radicals form through bond homolysis and vary in stability based on alkyl substituents. Carbenes are divalent carbon species that exist as singlet or triplet forms with different hybridizations. Nitrenes are analogous to carbenes but with nitrogen and vary in stability and spin state. Examples of formation and trapping methods are provided along with sample synthetic reactions for each reactive intermediate.
The Claisen rearrangement is a thermal rearrangement reaction discovered by Rainer Ludwig Claisen in which the allyl group of a phenolic allyl ether migrates ortho to the phenol group. Key characteristics of the Claisen rearrangement are the inversion of the migrating allyl carbon and the intramolecular, unimolecular nature of the reaction. The mechanism involves a cyclic transition state that allows for migration to the ortho position, or para if both ortho positions are blocked.
E1 &E2 mechanism, sandmeyer and benzyne mechanismlsk1976
The document discusses the Sandmeyer reaction, which is a type of radical-nucleophilic aromatic substitution reaction that replaces an amino group on an aromatic ring with different substituents. During the reaction, the amino group is converted to a diazonium salt that can then be transformed into various functional groups using a catalyst. It also describes the reaction of halobenzenes with potassium amide in liquid ammonia to yield aniline, which proceeds through an elimination-addition mechanism involving the elimination of an alpha hydrogen and addition of an amide anion to form an intermediate benzyne structure.
SMILES REARRANGEMENT [REACTION AND MECHANISM]Shikha Popali
The Smiles rearrangement is an intramolecular aromatic nucleophilic substitution reaction. It involves the migration of a substituent X from one carbon of an aromatic ring to another, with an aromatic substituent Y acting as the nucleophile. A specific example provided is the migration of an SO2Ar group to the ortho position of an ArO- nucleophile, activated by an adjacent nitro group. The X group is usually S, SO, or SO2, while the Y nucleophile is typically the conjugate base of OH, NH2, NHR or SH, though even CH2 has been used.
This document summarizes various types of rearrangement reactions in organic chemistry. It describes 15 categories of rearrangements including rearrangements to electron deficient carbons, nitrogens, and oxygens. For each category, 1-2 specific rearrangements are explained in more detail, including their mechanisms. Rearrangements discussed include the Wagner-Meerwein, Pinacol, Benzilic acid, Hofmann, Curtius, Lossen, Beckmann, Baeyer-Villiger, Stevens, Sommelet-Hauser, Wittig, Favorskii, Benzidine, Fries, and Claisen rearrangements. The document was prepared by a student as part of their coursework to provide an overview of
The document discusses different types of substitution reactions including nucleophilic substitution, electrophilic substitution, and free radical substitution. It provides details on the mechanisms, kinetics, stereochemistry and factors affecting the rate of nucleophilic substitution reactions SN1 and SN2. SN1 follows a unimolecular mechanism involving a carbocation intermediate while SN2 follows a bimolecular mechanism with a single concerted transition state. The document also discusses electrophilic aromatic substitution reactions and addition and elimination reactions of alkenes and alkynes.
There are five types of skeletal rearrangements: electron deficient, electron rich, radical, rearrangements on aromatic rings, and sigmatropic rearrangements. Molecular rearrangements involve the migration of a group from one atom to another within the same molecule. Examples include the Wagner-Meerwein rearrangement, pinacol-pinacolone rearrangement, and Cope rearrangement. Rearrangements are driven by stability of the carbocation intermediate or relief of ring strain.
FREE RADICALS , CARBENES AND NITRENES.pptxtenzinpalmo3
This document discusses free radicals, carbenes, and nitrenes. It defines each type of species, describes their characteristics such as electronic structure and stability. The document outlines different types for each species and methods for their formation and synthetic applications. Free radicals form through bond homolysis and vary in stability based on alkyl substituents. Carbenes are divalent carbon species that exist as singlet or triplet forms with different hybridizations. Nitrenes are analogous to carbenes but with nitrogen and vary in stability and spin state. Examples of formation and trapping methods are provided along with sample synthetic reactions for each reactive intermediate.
The Claisen rearrangement is a thermal rearrangement reaction discovered by Rainer Ludwig Claisen in which the allyl group of a phenolic allyl ether migrates ortho to the phenol group. Key characteristics of the Claisen rearrangement are the inversion of the migrating allyl carbon and the intramolecular, unimolecular nature of the reaction. The mechanism involves a cyclic transition state that allows for migration to the ortho position, or para if both ortho positions are blocked.
E1 &E2 mechanism, sandmeyer and benzyne mechanismlsk1976
The document discusses the Sandmeyer reaction, which is a type of radical-nucleophilic aromatic substitution reaction that replaces an amino group on an aromatic ring with different substituents. During the reaction, the amino group is converted to a diazonium salt that can then be transformed into various functional groups using a catalyst. It also describes the reaction of halobenzenes with potassium amide in liquid ammonia to yield aniline, which proceeds through an elimination-addition mechanism involving the elimination of an alpha hydrogen and addition of an amide anion to form an intermediate benzyne structure.
SMILES REARRANGEMENT [REACTION AND MECHANISM]Shikha Popali
The Smiles rearrangement is an intramolecular aromatic nucleophilic substitution reaction. It involves the migration of a substituent X from one carbon of an aromatic ring to another, with an aromatic substituent Y acting as the nucleophile. A specific example provided is the migration of an SO2Ar group to the ortho position of an ArO- nucleophile, activated by an adjacent nitro group. The X group is usually S, SO, or SO2, while the Y nucleophile is typically the conjugate base of OH, NH2, NHR or SH, though even CH2 has been used.
Retrosynthes analysis and disconnection approach ProttayDutta1
Retrosynthetic analysis is a technique used to plan organic syntheses by working backwards from the target molecule. It involves mentally deconstructing the target molecule through sequential disconnections and functional group transformations until commercially available starting materials are reached. Each disconnection produces synthons, which are idealized fragments that represent possible reaction precursors. Common types of disconnections include C-X, C-C, and carbonyl bonds. The goal of retrosynthesis is to simplify the target structure and design multiple possible synthesis routes leading from simple starting materials to the target. It helps chemists discover efficient syntheses by considering the reactivity, selectivity, and availability of materials at each step.
The Favorskii rearrangement is a rearrangement of cyclopropanones and α-halo ketones that leads to carboxylic acids or their derivatives. It involves the formation of an enolate away from the halogen that cyclizes to a cyclopropanone intermediate, which is then attacked by a nucleophile like hydroxide or an alkoxide base to yield an acid, ester, or amide through ring contraction. The reaction is useful for preparing carboxylic acids, esters, and amides.
Retrosynthetic analysis, definition, importance, disconnection approach, one group two group disconnection logical and illogical disconnection approach compounds containing two nitrogen atom retrosynthetic analysis of camphor, cartisone, reserpine
The document discusses the Diels-Alder reaction, which is a [4+2] cycloaddition reaction between a conjugated diene and a dienophile to form a six-membered ring. The reaction is initiated by heat and proceeds through a concerted mechanism. The reaction is stereospecific and favors the endo product. It has many applications including the synthesis of steroids, aromatic compounds, flame retardants, and pesticides.
This document summarizes several organic rearrangement reactions: the Cope rearrangement, Claisen rearrangement, and Curtius rearrangement. The Cope rearrangement involves the [3,3]-sigmatropic rearrangement of 1,5-dienes. The Claisen rearrangement is a carbon-carbon bond forming reaction that rearranges allyl vinyl ethers to γ,δ-unsaturated carbonyls. The Curtius rearrangement converts carboxylic acids to isocyanates through an acid azide intermediate. Mechanisms are provided for each reaction.
Wilkinson's catalyst, also known as chloridotris(triphenylphosphane)rhodium(I), is a coordination complex of rhodium with the formula RhCl(PPh3)3. It is a red-brown solid that is soluble in hydrocarbon solvents and used widely as a catalyst for hydrogenation of alkenes. Wilkinson's catalyst is obtained by treating rhodium(III) chloride hydrate with excess triphenylphosphine, which acts as a reducing agent to reduce rhodium from Rh(III) to Rh(I). It adopts a slightly distorted square planar structure and undergoes fast dynamic exchange processes in solution.
The document discusses pericyclic reactions and the Woodward-Hoffmann rules for predicting their stereochemistry. It begins by defining pericyclic reactions as concerted reactions where bonds are formed or broken in a cyclic transition state. It then provides examples of different types of pericyclic reactions, including electrocyclizations, cycloadditions, and sigmatropic rearrangements. The Woodward-Hoffmann theory is explained, showing how it can be used to predict whether a reaction will proceed with antarafacial conrotation or suprafacial disrotation based on whether the reaction is thermally or photochemically induced. Specific examples like cyclobutene formation and the Diels-Alder reaction are analyzed in
This document discusses the Shapiro reaction, which was discovered by Robert H. Shapiro in 1967. The reaction involves converting aryl sulfonyl hydrazones of aldehydes and ketones into olefins using alkyl lithium reagents, grignard reagents, or alkali metal amides at -78°C. The reaction mechanism proceeds through deprotonation, elimination, and loss of nitrogen to form alkenyl intermediates. The Shapiro reaction has been used in the total synthesis of natural products like phytocassane D and in the formation of ring B in the Nicolaou Taxol total synthesis.
The document summarizes the pinacol-pinacolone rearrangement, which involves the conversion of a vicinal diol to a ketone or aldehyde in the presence of an acid. It was first described by German chemist William Rudolph Fittig in 1860. A key example is the conversion of pinacol to pinacolone using sulfuric acid. The reaction proceeds through protonation, dehydration, rearrangement, and dehydrogenation steps. The migratory aptitude is influenced by electronic effects and stability of the carbocation intermediate. The rearrangement has applications in synthesizing carbonyl compounds, cyclic ketones, spiro-compounds, and supports ring expansions and contractions.
Nitrenes are nitrogen analogues of carbenes that contain no charge and are highly reactive and electrophilic. They exist in both singlet and triplet states, with the triplet state being more stable due to the presence of unpaired electrons. Nitrenes can be generated from acyl and alkyl azides, from sulphinylamine, or through insertion reactions. Important reactions involving nitrenes include the Beckmann rearrangement, Hofmann bromamide reaction, Curtius rearrangement, Lossen rearrangement, and Schmidt rearrangement.
The Birch reduction is a reaction where aromatic compounds undergo partial reduction to unconjugated cyclohexadiene compounds in the presence of alkali metals like sodium or lithium in liquid ammonia. The solvated electrons from the reaction of the metal with liquid ammonia give the solution an intense blue color. The mechanism begins with single electron transfer from the metal to the aromatic ring, forming a radical anion. Regioselectivity in the reduction depends on whether substituents on the aromatic ring are electron donating groups or electron withdrawing groups. The Birch reduction can selectively reduce the less electron-rich ring in bicyclic aromatic compounds.
The Mannich reaction involves the condensation of an enolizable carbonyl compound, an aldehyde such as formaldehyde, and an amine to form a β-amino carbonyl compound known as a Mannich base. The reaction proceeds via the initial addition of the amine to the aldehyde to form an iminium ion intermediate, which then reacts with the enol form of the carbonyl compound to eliminate a proton and form the Mannich base product. While versatile building blocks in organic synthesis, the Mannich reaction has limitations in terms of substrate scope and control of regio- and stereoselectivity. Examples of applications include the synthesis of tropinone, a precursor of atropine, as well
The document discusses the Michael addition reaction, which involves the nucleophilic addition of a carbanion to an α,β-unsaturated carbonyl compound. It provides the definition, mechanism, examples including the synthesis of warfarin, and applications such as asymmetric Michael reactions. The mechanism involves deprotonation of the carbonyl compound by a base to form an enolate ion, which adds to the Michael acceptor to form a new carbon-carbon bond via 1,4-addition.
Selenium dioxide (SeO2) and Raney nickel are both useful reagents in organic synthesis. SeO2 can be used to oxidize alkenes to allylic alcohols or carbonyls. It also oxidizes carbonyls to 1,2-dicarbonyls and internal alkynes to 1,2-dicarbonyls. Raney nickel catalyzes hydrogenation of aromatics and reduction of carbonyl groups by cleaving C-S bonds. Both reagents have applications in functional group transformations.
Synthetic Reagents & Applications in Organic ChemistryAjay Kumar
This document discusses 12 synthetic reagents and their applications in organic chemistry. It describes the preparation, structure, and common uses of each reagent which include aluminium isopropoxide, N-bromosuccinimide, diazomethane, dicyclohexyl-carbodimide, Wilkinson reagent, Wittig reagent, osmium tetroxide, titanium chloride, diazopropane, diethyl azodicarboxylate, triphenylphosphine, and benzotriazol-1-yloxy)tris(dimethyl-amino)phosphonium hexafluorophosphate. These reagents are used for transformations like oxidation, reduction, bromination,
The Paternò-Büchi reaction involves the photochemical reaction between a carbonyl compound and an alkene to form an oxetane ring. This reaction was first reported in 1909 by Paternò and Chieffi. Several mechanisms are possible, including those involving a diradical intermediate or photoinduced electron transfer. The reaction shows regioselectivity, site selectivity, and stereoselectivity that depend on factors such as the solvent, substituents on the carbonyl compound or alkene, and temperature. The Paternò-Büchi reaction has been used to synthesize various natural products and allows formation of oxetane rings, which are present in several biologically active compounds.
The document discusses various types of selectivity in organic reactions including:
- Stereo selectivity which controls the stereochemistry of products
- Regioselectivity which controls the site of reaction
- Chemoselectivity which controls reaction of one functional group in the presence of others
Examples and explanations are provided for each type of selectivity with mechanisms and factors that influence the outcome. Guidelines for solving problems of chemoselectivity involving protecting groups and derivatives that can react only once are also outlined.
Molecular Rearrangements of Organic Reactions ppsOMPRAKASH1973
This PPT is usefull for aspirants of JEE-IIT, CSIR-NET and UPSC exams in CHEMISTRY section. It is also usefull for grduates and Post graduates students of Indian Universities.
The document discusses various types of molecular rearrangement reactions. It describes rearrangements that involve the migration of groups between molecules (intermolecular) or within the same molecule (intramolecular). Examples of nucleophilic rearrangements that involve the migration of groups to electron-deficient carbons, nitrogen, or oxygen atoms are provided, including the Pinacole-Pinacolone, Wagner-Meerwein, Benzilic acid, and Schmidt rearrangements. Mechanisms and features of these important rearrangement reactions are also outlined.
02. Chemistry Common Name Reactions for Students.pdfsdmitragotri
The document discusses several name reactions including the Stobbe condensation, Oppenauer oxidation, Meerwein-Ponndorf-Verley reduction, Reformatsky reaction, Wagner-Meerwein rearrangement, Hofmann rearrangement, and Wittig reaction. It provides the mechanisms and applications of each reaction. It also discusses the nature of carbonyl groups and several other organic chemistry concepts.
Retrosynthes analysis and disconnection approach ProttayDutta1
Retrosynthetic analysis is a technique used to plan organic syntheses by working backwards from the target molecule. It involves mentally deconstructing the target molecule through sequential disconnections and functional group transformations until commercially available starting materials are reached. Each disconnection produces synthons, which are idealized fragments that represent possible reaction precursors. Common types of disconnections include C-X, C-C, and carbonyl bonds. The goal of retrosynthesis is to simplify the target structure and design multiple possible synthesis routes leading from simple starting materials to the target. It helps chemists discover efficient syntheses by considering the reactivity, selectivity, and availability of materials at each step.
The Favorskii rearrangement is a rearrangement of cyclopropanones and α-halo ketones that leads to carboxylic acids or their derivatives. It involves the formation of an enolate away from the halogen that cyclizes to a cyclopropanone intermediate, which is then attacked by a nucleophile like hydroxide or an alkoxide base to yield an acid, ester, or amide through ring contraction. The reaction is useful for preparing carboxylic acids, esters, and amides.
Retrosynthetic analysis, definition, importance, disconnection approach, one group two group disconnection logical and illogical disconnection approach compounds containing two nitrogen atom retrosynthetic analysis of camphor, cartisone, reserpine
The document discusses the Diels-Alder reaction, which is a [4+2] cycloaddition reaction between a conjugated diene and a dienophile to form a six-membered ring. The reaction is initiated by heat and proceeds through a concerted mechanism. The reaction is stereospecific and favors the endo product. It has many applications including the synthesis of steroids, aromatic compounds, flame retardants, and pesticides.
This document summarizes several organic rearrangement reactions: the Cope rearrangement, Claisen rearrangement, and Curtius rearrangement. The Cope rearrangement involves the [3,3]-sigmatropic rearrangement of 1,5-dienes. The Claisen rearrangement is a carbon-carbon bond forming reaction that rearranges allyl vinyl ethers to γ,δ-unsaturated carbonyls. The Curtius rearrangement converts carboxylic acids to isocyanates through an acid azide intermediate. Mechanisms are provided for each reaction.
Wilkinson's catalyst, also known as chloridotris(triphenylphosphane)rhodium(I), is a coordination complex of rhodium with the formula RhCl(PPh3)3. It is a red-brown solid that is soluble in hydrocarbon solvents and used widely as a catalyst for hydrogenation of alkenes. Wilkinson's catalyst is obtained by treating rhodium(III) chloride hydrate with excess triphenylphosphine, which acts as a reducing agent to reduce rhodium from Rh(III) to Rh(I). It adopts a slightly distorted square planar structure and undergoes fast dynamic exchange processes in solution.
The document discusses pericyclic reactions and the Woodward-Hoffmann rules for predicting their stereochemistry. It begins by defining pericyclic reactions as concerted reactions where bonds are formed or broken in a cyclic transition state. It then provides examples of different types of pericyclic reactions, including electrocyclizations, cycloadditions, and sigmatropic rearrangements. The Woodward-Hoffmann theory is explained, showing how it can be used to predict whether a reaction will proceed with antarafacial conrotation or suprafacial disrotation based on whether the reaction is thermally or photochemically induced. Specific examples like cyclobutene formation and the Diels-Alder reaction are analyzed in
This document discusses the Shapiro reaction, which was discovered by Robert H. Shapiro in 1967. The reaction involves converting aryl sulfonyl hydrazones of aldehydes and ketones into olefins using alkyl lithium reagents, grignard reagents, or alkali metal amides at -78°C. The reaction mechanism proceeds through deprotonation, elimination, and loss of nitrogen to form alkenyl intermediates. The Shapiro reaction has been used in the total synthesis of natural products like phytocassane D and in the formation of ring B in the Nicolaou Taxol total synthesis.
The document summarizes the pinacol-pinacolone rearrangement, which involves the conversion of a vicinal diol to a ketone or aldehyde in the presence of an acid. It was first described by German chemist William Rudolph Fittig in 1860. A key example is the conversion of pinacol to pinacolone using sulfuric acid. The reaction proceeds through protonation, dehydration, rearrangement, and dehydrogenation steps. The migratory aptitude is influenced by electronic effects and stability of the carbocation intermediate. The rearrangement has applications in synthesizing carbonyl compounds, cyclic ketones, spiro-compounds, and supports ring expansions and contractions.
Nitrenes are nitrogen analogues of carbenes that contain no charge and are highly reactive and electrophilic. They exist in both singlet and triplet states, with the triplet state being more stable due to the presence of unpaired electrons. Nitrenes can be generated from acyl and alkyl azides, from sulphinylamine, or through insertion reactions. Important reactions involving nitrenes include the Beckmann rearrangement, Hofmann bromamide reaction, Curtius rearrangement, Lossen rearrangement, and Schmidt rearrangement.
The Birch reduction is a reaction where aromatic compounds undergo partial reduction to unconjugated cyclohexadiene compounds in the presence of alkali metals like sodium or lithium in liquid ammonia. The solvated electrons from the reaction of the metal with liquid ammonia give the solution an intense blue color. The mechanism begins with single electron transfer from the metal to the aromatic ring, forming a radical anion. Regioselectivity in the reduction depends on whether substituents on the aromatic ring are electron donating groups or electron withdrawing groups. The Birch reduction can selectively reduce the less electron-rich ring in bicyclic aromatic compounds.
The Mannich reaction involves the condensation of an enolizable carbonyl compound, an aldehyde such as formaldehyde, and an amine to form a β-amino carbonyl compound known as a Mannich base. The reaction proceeds via the initial addition of the amine to the aldehyde to form an iminium ion intermediate, which then reacts with the enol form of the carbonyl compound to eliminate a proton and form the Mannich base product. While versatile building blocks in organic synthesis, the Mannich reaction has limitations in terms of substrate scope and control of regio- and stereoselectivity. Examples of applications include the synthesis of tropinone, a precursor of atropine, as well
The document discusses the Michael addition reaction, which involves the nucleophilic addition of a carbanion to an α,β-unsaturated carbonyl compound. It provides the definition, mechanism, examples including the synthesis of warfarin, and applications such as asymmetric Michael reactions. The mechanism involves deprotonation of the carbonyl compound by a base to form an enolate ion, which adds to the Michael acceptor to form a new carbon-carbon bond via 1,4-addition.
Selenium dioxide (SeO2) and Raney nickel are both useful reagents in organic synthesis. SeO2 can be used to oxidize alkenes to allylic alcohols or carbonyls. It also oxidizes carbonyls to 1,2-dicarbonyls and internal alkynes to 1,2-dicarbonyls. Raney nickel catalyzes hydrogenation of aromatics and reduction of carbonyl groups by cleaving C-S bonds. Both reagents have applications in functional group transformations.
Synthetic Reagents & Applications in Organic ChemistryAjay Kumar
This document discusses 12 synthetic reagents and their applications in organic chemistry. It describes the preparation, structure, and common uses of each reagent which include aluminium isopropoxide, N-bromosuccinimide, diazomethane, dicyclohexyl-carbodimide, Wilkinson reagent, Wittig reagent, osmium tetroxide, titanium chloride, diazopropane, diethyl azodicarboxylate, triphenylphosphine, and benzotriazol-1-yloxy)tris(dimethyl-amino)phosphonium hexafluorophosphate. These reagents are used for transformations like oxidation, reduction, bromination,
The Paternò-Büchi reaction involves the photochemical reaction between a carbonyl compound and an alkene to form an oxetane ring. This reaction was first reported in 1909 by Paternò and Chieffi. Several mechanisms are possible, including those involving a diradical intermediate or photoinduced electron transfer. The reaction shows regioselectivity, site selectivity, and stereoselectivity that depend on factors such as the solvent, substituents on the carbonyl compound or alkene, and temperature. The Paternò-Büchi reaction has been used to synthesize various natural products and allows formation of oxetane rings, which are present in several biologically active compounds.
The document discusses various types of selectivity in organic reactions including:
- Stereo selectivity which controls the stereochemistry of products
- Regioselectivity which controls the site of reaction
- Chemoselectivity which controls reaction of one functional group in the presence of others
Examples and explanations are provided for each type of selectivity with mechanisms and factors that influence the outcome. Guidelines for solving problems of chemoselectivity involving protecting groups and derivatives that can react only once are also outlined.
Molecular Rearrangements of Organic Reactions ppsOMPRAKASH1973
This PPT is usefull for aspirants of JEE-IIT, CSIR-NET and UPSC exams in CHEMISTRY section. It is also usefull for grduates and Post graduates students of Indian Universities.
The document discusses various types of molecular rearrangement reactions. It describes rearrangements that involve the migration of groups between molecules (intermolecular) or within the same molecule (intramolecular). Examples of nucleophilic rearrangements that involve the migration of groups to electron-deficient carbons, nitrogen, or oxygen atoms are provided, including the Pinacole-Pinacolone, Wagner-Meerwein, Benzilic acid, and Schmidt rearrangements. Mechanisms and features of these important rearrangement reactions are also outlined.
02. Chemistry Common Name Reactions for Students.pdfsdmitragotri
The document discusses several name reactions including the Stobbe condensation, Oppenauer oxidation, Meerwein-Ponndorf-Verley reduction, Reformatsky reaction, Wagner-Meerwein rearrangement, Hofmann rearrangement, and Wittig reaction. It provides the mechanisms and applications of each reaction. It also discusses the nature of carbonyl groups and several other organic chemistry concepts.
The Wagner-Meerwein rearrangement is an organic reaction that converts an alcohol to an olefin using an acid catalyst. It involves the formation of a carbocation intermediate followed by a 1,2-shift of a group to form a more stable carbocation. This is then deprotonated to form the olefin product. It can be used to rearrange highly branched compounds and reduce ring strain in cyclic compounds. Examples include the rearrangement of neopentyl alcohols and bicyclic terpene derivatives.
This document provides an overview of 9 organic reactions: 1) Metal hydride reduction using NaBH4 and LiAlH4, 2) Clemmensen reduction, 3) Birch reduction, 4) Wolff-Kishner reaction, 5) Oppenauer oxidation, 6) Dakin reaction, 7) Beckmann rearrangement, 8) Schmidt rearrangement, and 9) Claisen-Schmidt condensation. For each reaction, it discusses the reaction mechanism, modifications, and applications in organic synthesis and drug development. The document serves as a reference for graduate students and researchers on important carbonyl reactions and their uses in pharmaceutical chemistry.
1) A new reaction is reported that uses ethylene-1,2-diamines or o-phenylenediamines, aromatic aldehydes, and TMSCN to provide a straightforward route to synthesize 2-aminopyrazines and 2-aminoquinoxalines.
2) DBU is found to be a superior promoter of this reaction, accelerating the rate and providing good yields. The reaction involves desilylation, Strecker reaction, amidine-forming cyclization, and dehydrogenative aromatization in a tandem sequence.
3) The reaction scope is investigated and found to work for a variety of aromatic aldehydes containing electron-withdrawing and electron
The Chichibabin reaction is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction: The direct amination of pyridine with sodium amide takes place in liquid ammonia
The document discusses coumarins, which are naturally occurring compounds with diverse pharmacological properties. Coumarins are found in many plant species and have a wide range of biological activities. Some examples mentioned include uses as anticoagulants, antimicrobials, anti-inflammatories, and more. Common coumarin derivatives discussed include warfarin and various synthetic routes for producing coumarins are also summarized such as the Perkin reaction and Pechmann condensation.
content:-
1. Introduction
2. Fermentation pathway
3. Production of some other foods & industrial chemical by use of fermentation
4. Energetics of fermentation
5. Summary
Ketones are organic compounds that contain a carbonyl functional group (C=O). Ketones can be prepared through oxidation of secondary alcohols, hydration of alkynes, ozonolysis of alkenes, Friedel-Crafts acylation, and use of Grignard reagents. Ketones undergo reactions such as reduction to alcohols, nucleophilic addition, reactions with Grignard reagents, and addition of derivatives of ammonia. Some pharmaceutical drugs contain ketone groups, such as antibiotics, drugs that interfere with tumor growth, and pain medications.
Molecular rearrangement reactions- Dr. Alka Tangri.pdfRaviansMotivations
This document discusses several types of rearrangement reactions in organic chemistry. It defines rearrangement reactions as reactions where a chemical unit such as an atom, ion, or group of atoms migrates within or between molecules of the same species to form a new product. The document discusses intramolecular and intermolecular rearrangements, and provides examples of anionotropic rearrangements like the pinacol rearrangement and cationotropic rearrangements like the Fries rearrangement. It also provides detailed mechanisms and applications of the pinacol rearrangement and Hoffman rearrangement.
This document summarizes a case study of a child with metabolic acidosis following sepsis and 20% body surface area burns. It applies the Fencl-Stewart approach to analyze the acid-base disturbance. This involves measuring the standard base excess, sodium-chloride effect, albumin effect, and calculating the unmeasured ion effect. In this case, the unmeasured ion effect of -21.5 mEq/L suggests lactic acidosis as the cause. Bicarbonate therapy is not recommended due to risks of worsening tissue hypoxia and intracellular acidosis. The appropriate treatment is to correct hypoalbuminemia, hypernatremia, and the underlying cause of lactic acidosis through improving oxygen delivery and
The document summarizes the pinacol-pinacolone rearrangement, which involves the conversion of a vicinal diol to a ketone or aldehyde in the presence of an acid. It was first described by German chemist William Rudolph Fittig in 1860. A key example is the conversion of pinacol to pinacolone using sulfuric acid. The reaction proceeds through protonation, dehydration, rearrangement, and dehydrogenation steps. The migratory aptitude is influenced by electronic effects and stability of the carbocation intermediate. The rearrangement has applications in synthesizing carbonyl compounds, cyclic ketones, spiro-compounds, and supports ring expansions.
1) The document summarizes key concepts about ketones and aldehydes from an organic chemistry textbook chapter, including their structures, nomenclature, physical properties, reactions, and industrial uses.
2) Methods of synthesizing ketones and aldehydes are discussed, including oxidation of alcohols, Friedel-Crafts acylation, and reactions of nitriles, acid chlorides, and carboxylic acids.
3) Common reactions of ketones and aldehydes described include nucleophilic addition, hydration, imine and acetal formation, reductions, and oxidations.
1) The document summarizes key concepts about ketones and aldehydes from an organic chemistry textbook chapter, including their structures, nomenclature, physical properties, reactions, and industrial uses.
2) Methods of synthesizing ketones and aldehydes are discussed, including oxidation of alcohols, Friedel-Crafts acylation, and reactions of dithianes, carboxylic acids, nitriles, and acid chlorides.
3) Reactions of ketones and aldehydes include nucleophilic addition, hydration, cyanohydrin formation, imine formation, acetal formation, and reductions using sodium borohydride, lithium aluminum hydride
1) The document summarizes key concepts about ketones and aldehydes from an organic chemistry textbook chapter, including their structures, nomenclature, physical properties, reactions, and industrial uses.
2) Methods of synthesizing ketones and aldehydes are discussed, including oxidation of alcohols, Friedel-Crafts acylation, and reactions of nitriles, acid chlorides, and carboxylic acids.
3) Common reactions of ketones and aldehydes described include nucleophilic addition, hydration, imine and acetal formation, reductions, and oxidations.
Organic Chemistry Name Reaction with mechanisms 140TusharRanjanNath
140 name reactions in brief. Its mechanisms and advantages and disadvantages. All structures were made by individuals without pasting from other sources.
The document summarizes the pinacol-pinacolone rearrangement reaction mechanism. It involves the protonation of a glycol, loss of water to form a resonance-stabilized carbocation, migration of a methyl or alkyl group, and deprotonation to form a ketone product. Key features include:
- Migration is faster when the migrating group is on the opposite side of the leaving group.
- Rearrangement is easier in trans configurations than cis.
- Phenyl groups migrate more readily than alkyl groups due to increased stabilization through delocalization.
- Steric effects can inhibit migration, as seen with o-substituted phenyl groups.
Here are the answers:
a)
i) K (2-methyl-1-propanol):
CH3
|
CH3-C-CH2-CH2-OH
|
CH3
L (2-methyl-2-propanol):
CH3
|
CH3-C-CH(OH)-CH3
ii) K can be prepared by reacting propanone with methylmagnesium bromide, a Grignard reagent:
CH3COCH3 + CH3MgBr → CH3C(OCH3)(CH3) → CH3C(OH)(CH3)CH3 + MgBr
iii) M
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Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
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Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
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ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
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Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
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I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
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Slides from:
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3. REARRANGEMENT REACTION
The reactions which proceed by a rearrangement or
reshuffling of the atoms groups in the molecule to
produce a structural isomer of the original
substance are called Rearrangement reactions.
Most are migrations from an atom to an adjacent
one (called 1,2-shifts),but some are over longer
distances.
10/15/2019 3
4. Classification :
Intermolecular rearrangement :
Reactions which involve migration of group between two
molecules.
In which the migration group gets completely detached and is later on
reattached are called intermolecular rearrangements.
Eg :Aromatic rearrangements
Intra molecular rearrangement :
Reactions which involve rearrangement with in the same molecule
Those rearrangements in which the migration group is never fully
detached from the system
Eg: Nucleophillic rearrangement
Electrophillic rearrangement
Free radical rearrangement
10/15/2019 4
6. NUCLEOPHILLIC REARRANGAMENT :
Migrating group migrating towards electro defficient atoms.
ELECTROPHILIC REARRANGEMENT:
migrating group migrates towards electron rich centre.
FREE-RADICAL REARRANGEMENT:
those reactions in which migrating group moves to a free-radical centre.
AROMATIC REARRANGEMENT:
Migrating towards aromatic nucleus.
10/15/2019 6
7. NUCLEOPHILIC REARRANGEMENT
Migrating group migrates from a carbon atom to an adjacent electron
deficient atom which is generally C, N, O.
rearrangement to electron deficient CARBON atom(carbonium ion
rearrangement)
Eg: Pinacole-pinacolone rearrangement
Wagner-meerwein rearrangement
Benzilic acid rearrangement
rearrangement to electron deficient NITROGEN atom
E.g.: Schmidt rearrangement.
Hofmann rearrangement
rearrangement to electron deficient OXYGEN atom
E.g.: Baeyer villager reaction
Cumene hydroperoxide rearrangement
10/15/2019 7
8. CARBONIUM ION REARRANGEMENT:
In this case electron deficient atom is carbon the
intermediate is known as carbonium ion rearrangement.
And the reaction of this class is known as carbonium ion
Rearrangement.
with change in c-skeleton with out change in skeleton
E.g.; Pinacole-pinacolone rearrangement E.g.: allycyclic rearrangement
Wagner-meerwein rearrangement
Benzilic acid rearrangement
Wolf rearrangement
10/15/2019 8
9. PINACOLE-PINACOLONE REARRANGEMENTS
The conversion of pinacols(1,2-glycols) to ketones or aldehydes means
of acids is known as pinacol rearrangements.
MECHANISM :
The reaction involves four steps:-
1. protonation of hydroxyl group
2. Loss of water to form a carbocation
3. 1,2-shift of :H, :R or : Ar to form a more stable cation
4. Loss of H+ to form the final product
CH3
CC
OH
CH3H3C
CH3
OH
2,3-DIMETHYL-2,3-BUTANEDIOL
(PINACOL)
CH3
CC
O
CH3H3C
CH3
METHYL t-BUTYL KETONE
(PINACOLONE)
H2SO4
10/15/2019 9
11. FEATURES OF PINACOLE REARRANGEMENT:
1).Stability of carbonium ion:
when there is a choice as which hydroxyl group will be
preferentially removed i.e.,when two oh groups are different
then that oh group will be removed which produces the more
stable cation
C6H5 C
OH
C6H5
C CH3
CH3
OH
C6H5 C
OH
C6H5
C CH3
CH3
C6H5 C
C6H5
C CH3
CH3
OH
C6H5
C6H5
C CH3
OCH3
3,3-diphenylbutan-2-one
2-methyl-1,1-diphenylpropane-1,2-diol
less stable
more stable
alkyl migration
H
-H2O
H
-H2O
-H+
10/15/2019 11
12. 2).MIGRATORY APTITUDE:
When each of the carbon atoms of the glycol as an aryl and alkyl group, the more Nucleophilic (potentially
electron-rich) aryl group preferentially migrates.
C6H5
CC
OH
CH3H3C
C6H5
OH
CC CH3H3C
C6H5
OC6H5
migration of
phenyl group
2,3-diphenylbutane-2,3-diol 3,3-diphenylbutan-2-one
When the migratory competition is between two aryl groups, then the one
which Is better nucleophile (more powerful electron donor towards carbon)
migrates Preferentially.
TOL
CC
OH
C6H5C6H5
TOL
OH
CC
TOL
C6H5C6H5
TOL
O
10/15/2019 12
13. 3) INTRA MOLECULAR MIGRATION:
The migrating group migrates with in the molecule, that is it
never becomes free from the rest of the molecule as it retains
its configuration in the product.
4) TRANS MIGRATION:
The migrating group migrates to the opposite side of the
leaving group which has important consequences in alicyclic
system
10/15/2019 13
14. CH3 - C = CH2 CH3 - C - CH2Cl CH3- C -CH2OH
CH3 - C - C =O
CH3
CH3 CH3
CH3 H
H
Cl2
Moist
Ag2O
H
Dimethyyl acetaldehyde
(Isobutaraldehyde)
Cl OH
Isobutylene
APPLICATIONS:
1.SYNTHESIS OF CARBONYL COMPOUNDS FROM ALKENES
Isobutyraldehyde may prepared on large scale from isobutylene
10/15/2019 14
15. O
EtONa
CH3NO2
H NaNO2+HCl
5c
-N2
O
-H
HO CH2NO2 HO CH2NH2
HO
CH2 - N N HO CH2
2.RING EXPANSION OF CYCLIC KETONES
Cylohexanone can be converted to cycloheptanone in good yield
cycloheptanone
10/15/2019 15
16. Ph Ph
OHOH
O Ph
Ph
-H
O
O
OH OH
H
7,8-Diphenylacenaphthene
7-Oxo-8,8-diphenylacenaphthene
Cyclopentanone
pinacol
1.Mg,ether
2.H2Oa
2
1.
3.KETONES FROM CYCLIC DIOLS
Pinacol rearrangement has been employed to prepare ketones which are otherwise
Inaccessible to synthesis
10/15/2019 16
18. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 18
1) A hydroxide anion attacks one of
the ketone groups.( nucleophilic addition ).
2) Alkyl group attack on the second carbonyl group in
a concerted step with reversion of the hydroxyl group
back to the carbonyl group.
3) This sequence resembles a nucleophilic acyl
substitution.
19. The reaction is a representative of 1,2-rearrangements. These
rearrangements usually have migrating carbocations but this
reaction is unusual because it involves a migrating carbanion.
A hydroxide anion attacks one of the ketone groups in
1 in a nucleophilic addition to the hydroxyl anion
2. The next step requires a bond rotation to conformer
3 which places the migrating group R in position for attack on
the second carbonyl group in a concerted step with reversion of
the hydroxyl group back to the carbonyl group.
10/15/2019 19
The carboxylic acid in intermediate 4 is less basic than
the hydroxyl anion and therefore proton transfer takes
place to intermediate 5 which can be protonated in
acidic workup to the final α-hydroxy–carboxylic acid 6.
20. Migrations to Electron-Deficient Carbons
Wagner-Meerwein Rearrangements
1,2-Shifts of migrating groups to empty orbitals in carbo-
cations or toward partially empty orbitals in developing
carbocations are the most common rearrangements of
organic molecules. Especially, migration of hydrogen atom
or alkyl or aryl groups in carbocations are called “Wagner-
Meerwein Rearrangements”
21. Wagner Meerwein : Tert-amyl & Neo- pentyl
comp.
alcohol, halide
Highly branched : Sub, Add, elim. i.e. Dehydration,
dehydrohalogenation
H2
CC
CH3
H3C
CH3
H+
OH C
H
CH3C
CH3
CH3
2-methylbut-2-ene
2,2-dimethylpropan-1-ol
H3C C
H
C CH3
CH3
CH3 Cl
ZnCl2
3-chloro-2,2-dimethylbutane
H3C C
H
C CH3
CH3
Cl CH3
2-chloro-2,3-dimethylbutane
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 21
22. Mechanism: 1) Formation of Carbonium ion by protonation
2) Rearrangement of Carbonium ion
3) Migration of Nucleophiles
4) Deprotonation
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 22
24. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 24
Wolff : α-diazoketones upon treatment with silver oxide and water gives carboxylic acid
C
N
N
H
O
Diazoacetophenone
Ag2O,H2O
-N2
C
OH
O
Phenyl acetic acid
C
N
N
H
O
Diazoacetophenone
C
N
N
H
O
-N2
C
H
O
-keto carbene
O
Oxirene
C
H
O
-keto carbene
C
O
H
Ketene
OH
C
O
H
OH
Mechanism
25. Migration to N+
N
O
R
X
- X
O C N R
Isocynate
X = Br Hoffmann
X = Curtius& Scmidt
X = OCOR Lossen
X = OH Beckmann
N N
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 25
26. Curtius :Acyl azide to isocynate to amine
O C N R
Isocynate
Acyl azide
O
N3R
Heat
-N2
O C N R
Isocynate
O
NR N N
O
NR N N
O
NR
+ N2
Mechanism
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 26
27. Hoffmann :Amide to amine with one carbon less
O
NH2R
+ NaOBr
Amide
Sodium hypobromite
NaOH + Br2
R NH2 + 2NaBr + Na2CO3 + H2O
Amine with 1C less
O C N R
Isocynate
O
NH2R Br Br
O
N
H
R
Br
NaOH
O
NR
Br
O
NR
Hydrolysis
R NH2 + CO2
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 27
28. Lossen: Decomposition of Hydroxamic acid
to primary amine by using base.
O
N
H
R OH
OH-
R NH2
+ CO2
Hydroxamic acid Primary amine
O
N
H
R O
Hydroxamic acid derivative
Ar
O
KOH
O
NR O Ar
O
O Ar
O
O
NR
CO N R
Isocynate
R NH2
Primary amine
H2O
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 28
Mechanism
29. Beckmann:Oxime to amide
R'
NR
OH
Oxime
R R'
O
H2N OH
Ketone
Hydroxyl amine
H+
R
H
N
O
R'
Amide
H2SO4, H3PO2,P2O5,SOCl2,PCl5
C
R'
N
R OH
H+
C
R'
N
R OH2
-H2O
C
R'
N
R
C N
R
R'
H2O
C N
R
R'
OH
C NH
R
R'O
-H+
Mechanism
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 29
30. Features: 1) Trans migration, Stereospescific
2) Acyl derivative of oxime
3) Rate of reaction depends upon ionization rate of acyl derivative
4) The migrating “C” retains configuration.
5) Breaking of C-C and Formation of C-N bond occurs synchronously
6) Not intramolecular reaction, Carbonium ion forms and then attack
of hydroxyl ion. i.e complete loss of oxime “O”
10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 30
C N
Ph
Ph
OH
P
Cl
Cl
Cl Cl
Cl
Phosphoruspentachloride
C N
O
P
Cl
Cl
Cl
Cl
-OPCl4
C N
Ph
H2O
C N
HO
-H
H
C NH
O
31. SCHMIDT REARRANGEMENT
Carboxylic acids react with hydrazoic acid in presence of concentrated
sulphuric acid to give amine directly, the reaction is known as Schmidt
reaction.
RCOOH+N3H H2SO4 R-NH2 +CO2+ N2
Schmidt reaction also occurs between ketones or
aldehydes and hydrazoic acid.
RCHO
ALDEHYDE
HN3
H2SO4
RCN
CYANIDE
RNH.CHO
N-formyl derivative of
amine
RCONHR N2
H2SO4
N3HR2COR
ketones amides
Ketones Substituted amides
Aldehydes Nitriles & N-formyl derivatives
10/15/2019 31
32. Mechanism:
Mechanism involves following steps:
1.elimination of nitrogen.
2.formation of intermediate.
3.intermediate undergo rearrangement to form isocyanate.
4.hydrolysis of isocyanate to form amine & co2
Transformation occurs more rapidly with out heating
with sterically hindered acids(mesitoic acid)
10/15/2019 32
34. The reaction with acids i.e.benzoic acid,which require heating for the removal
of nitrogen from acid azide proceed as below
C
OH
R
O
H2SO4
H+
R C
O
OH2
R C
O
H2O
10/15/2019 34
35. REACTION WITH KETONES:
R
C
R
O
H+
R R
C
HO
N3H
R C
OH
R
NH N N
H2O
R
C
R
N N N
N2
R
C
R
N
C
NR
R
H2O
H2O+
C
NR
R H+
C
O
R
NHR
KETONE
AMIDE
10/15/2019 35
36. MECHANISM FOR ALDEHYDES:
H
C
O
R
H+
H
C
R
HO
N3H
H C
OH
R
NH N N
H2O
H C R
N N N
N2
IF R MOVES
H C R
N
H C
NR
H2O
H C
O
NHR
FORMYL DERIVATIVE OF PRIMARY AMINE
aldehyde
10/15/2019 36
37. IF ‘H’ MOVES:
H
C
N N N
R
N2
H
C
R
N
C R
NH
R C N
CYANIDES
H+
10/15/2019 37
38. APPLICATIONS:
PREPARATION OF AMINES:
Primary amines are obtained in good yield directly from acids.
a)
b)
C6H5CH2COOH N3H
H2SO4
CHCL3
C6H5CH2NH2 N2 CO2
phenyl acetic acid benzyl amine
O
HO
p-toluic acid
CH3 N3H H2N
p-toluidine
H2SO4 NH2
10/15/2019 38
39. PREPARATION OF AMINOACIDS:
H3C CO C
H
R
COOC2H5
alkyl aceto ester
N3H
H2SO4
CH3CO NH C
H
R
COO
acidic hydrolysis
H2N C
H
R
COOH
+ CH3COOH
ACITIC ACID
+ C2H5OH
ETHYL
ALCOHOL
C2H5
10/15/2019 39
40. • PREPARATION OF LACTONES:
• Cyclic ketones react to give lactones
+ N3H
H2SO4
O H
C
NH
O
Cyclohexanone caprolactam
10/15/2019 40
41. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 41
Rearrangements to electron deficient oxygen atom
Bayer Villager oxidation: Oxidation of ketone to ester in
presence of peracid
C
O
R'R
Ketone
+ C
O
OR
O
H
Peracid
C
O
OR
R'
Ester
C
O
C2H5H3C
Acetone
+ C
O
OH3C
O
H
Peracetic acid
C
O
OH3C
C2H5
Ethyl ethanoate
O
cyclohexanone
O
O
O
H
Perbenzoic acid
O
O
oxepan-2-one
(Caprolactone)
42. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 42
Oxidizing agent :
Peroxytrifluroacetic acid , Permonosulphuric acid (Caro’s acid),
Perbenzoic acid, Peracetic acid , BF3-H2O2
Mechanism
C
O
R R'
H+
C
OH
R R'O
Ph O
O
R
C
R'
OH
O
O
Ph
O
CR
OH
OR'
Carbonium
CR
OH
OR'
Oxonium
- H
O
OR
R'
Migratory aptitude:
Tert-alkyl> Sec-alkyl, aryl, benzyl> pri-alkyl> methyl
43. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 43
Condensed cyclic ketone, migration of lesser aptitude group
takes place and forms abnormal lactones'
H3C
CH3
O
30
10
H3C
CH3
O30
10
H3C
CH3
O
30
10
O
O
94%6%
+
Apocamphor
Lactone lactone
RCOOOH
Why?
Due to steric interaction Bulky per acid molecule
attacks carbonyl group from the side
apposite to bridge. Migration of bridge ‘C’ forms
twisted boat, if 10 ‘C’ forms Chair form
44. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 44
Dakin oxidation :
The replacement of aldehyde group of o/p- hydroxyl or
o-amino Benzaldehyde by hydroxyl group
in presence of alkaline hydrogen peroxide
H
OH/NH2
O
o-hydroxy/amino benzalldehyde
Alkaline
H2O2
OH
OH/NH2
Catechol/o-aminophenol
Note: This is only for aromatic Aldehyde /Ketone
having o/p –OH/NH2
45. 10/15/2019 R.D.Amrutkar SPH Pharmacy,Malegaon 45
H
OH/NH2
O
o-hydroxy/amino benzalldehyde
Alkaline
CH
OH/NH2
Catechol/o-aminophenol
O
O
H
O
O
O
H
- OH
C
H
OH/NH2
O
O
OH/NH2
O
- HCOOH
OH/NH2
OH
CHO
OH
OCH3
H2O2
-vanillin
OH
OH
OCH3
Pyrogallol
46. Reactions & Reagents By O.P.Agarwal Published by Krishna
Prakashan Media, Pg.No. 514 to537.
Advanced organic chemistry by Jerry march,4th Edition,
Published By John Willey & Sons Pvt.Ltd. Pg. No. 1051 to1157
Reactions and rearrangements by S N Sanyal, 4th Edition
Published By Bharati Bhawan, Pg. No.158 to 172
Adavanced organic chemistry by Bhal and Bhal , Published
By Chand & Company Ltd. Pg. No. 98
Reactions and reagents By G.R.Chatwal Published by
Himalaya publishing house, Pg. No.702 to717 &731 to 732.
REFERENCES
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