bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Halogen‐Metal Interconversion Reaction with Organolithium Compounds
Authors: Jones Reuben G. , Gilman Henry 
Published: March 2011

Abstract
The reaction of an organic halide with an organometallic compound in which the metal and the halogen atoms exchange laces is known as the halogen‐metal interconversion reaction. Numerous studies have established the fact that the halogen‐lithium interconversion is a general and widely applicable reaction. Many organic halides do not react satisfactorily with metallic lithium to form RLi compounds or with metallic magnesium to form Grignard reagents. However, the desired organolithium compound often can be obtained by a halogen‐metal Interconversion reaction. The halogen‐metal interconversion greatly extends the utility of organolithium and Grignard‐type reactions.
The Preparation of Thiazoles
Authors: Wiley Richard H. , England D. C. , Behr Lyell C. 
Published: March 2011

AbstractThiazoles have become increasingly important in pharmaceutical, biochemical and technical fields. Commercially important compounds that contain the thiazole ring are the mercaptothiazoles, which are valuable as rubber accelerators, and for penicillins and thiamin, for example. Certain thiazole derivatives show great promise as intermediates in the synthesis of amino acids. This chapter summarizes information on the methods of preparation of the thiazoles, but is restricted to those in which the thiazole ring is not part of a condensed system.
Reductions by Lithium Aluminum Hydride
Authors: Brown Weldon G. 
Published: March 2011

AbstractLithium aluminum hydride is a useful and convenient reagent for the selective reduction of various polar functional groups. It is used in diethyl ether solution, less commonly in higher boiling ethers, following the conventional procedures for syntheses employing the Grignard reagents, which the hydride closely resembles in its general pattern of behavior. The reaction proceeds with extraordinary rapidity and is relatively free of side reactions. The types of organic compounds reduced by lithium aluminum hydride and the nature of the products are detailed in this chapter. Functional groups not reduced are discussed.
ThePechmann Reaction
Authors: Sethna Suresh , Phadke Ragini 
Published: March 2011

AbstractH. v. Pechman found that coumarin derivatives are formed when malic acid or beta‐ketonic esters are condensed with phenols in the presence of concentrated sulfuric acid. This reaction is commonly known s the Pechmann reaction. It has found extensive use. Simonis and co‐workers used phosphorus pentaoxide as the condensing agent in place of sulfuric acid and demonstrated that with the same reactants chromones rather than coumarins resulted. The condensation of a phenol and beta‐ketonic ester in the presence of phosphorus pentaoxide is sometimes called the Simonis reaction, but it is actually a variation of the Pechmann reaction and is considered in this chapter. Other condensing agents that have been used, for example, are phosphorus oxychloride, phosphoric acid, zinc chloride and others. These are discussed in the chapter. By condensing appropriately substituted phenols and beta‐ketonic esters, coumarins can be synthesized with substituents either in the benzene nucleus in the heterocyclic ring or both. The course of this reaction depends on three factors; nature of the phenol, of the beta‐ketonic ester, and the condensing agent.
TheSkraup Synthesis of Quinolines
Authors: Manske Richard H. F. , Kulka Marshall 
Published: March 2011

AbstractKonigs first synthesized quinoline in 1879 by passing allylaniline over heated litharge. Shortly after he prepared quinoline by heating the condensation product of aniline and acrolein, thus anticipating the classical Skraup synthesis. This synthesis involves a series of reactions brought about by heating a primary aromatic amine, in which at least one position ortho to the amino group is unsubstituted, with glycerol, sulfuric acid, and an oxidizing agent. The product is a quinoline containing only those substituents that were originally present in the aromatic amine. Quinolines substituted in the hetero ring may be obtained by a modified Skraup synthesis in which a substituted acrolein or a vinyl ketone is used in place of glycerol.
Hydrogenolysis of Benzyl Groups Attached to Oxygen, Nitrogen, or Sulfur
Authors: Hartung Walter H. , Simonoff Robert 
Published: March 2011

AbstractThe benzyl group and a variety of substituted benzyl groups attached to an oxygen atom as in alcohols, ethers, acetals, or esters; to an amino nitrogen atom; or to a sulfur atom in thio ethers may be removed as toluene, or the corresponding substituted toluene, by hydrogenolysis. Other chemical and catalytic methods have been employed to bring about these debenzylations. It is the purpose of this chapter to give illustrations of both types of debenzylations so that their usefulness may be appreciated.
Epoxidation and Hydroxylation of Ethylenic Compounds with Organic Peracids*One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.
Authors: Swern Daniel 
Published: March 2011

AbstractOxiranes and alpha‐glycols can be prepared from olefins by a variety of methods. One of the most important and generally applicable of these is the oxidation of ethylenic compounds with organic peracids. Depending on the peracid employed and/or operating conditions either an oxirane or an alpha‐glycol can be obtained in good yield. It is important to note that the oxidation step both in epoxidation and hydroxylation reactions with organic peracids is the conversion of the olefin to the oxirane.
Catalytic Hydrogenation of Esters to Alcohols
Authors: Adkins Homer 
Published: March 2011

AbstractIn the presence of suitable catalysts esters react with hydrogen to form alcohols. The reaction is reversible, the relative concentrations of esters and alcohols at equilibrium being determined by the temperature and particularly by the pressure of hydrogen. The conversion of esters to alcohols may proceed either by hydrogenation or by hydrogenolysis. There is no experimental basis for the choice of one hypothesis over another, the use of the term hydrogenation in this chapter is matter of convenience and does not imply a choice of mechanism. The catalyst most suitable for the preparation of alcohols from esters by reacting with hydrogen under pressure is copper chromium oxide. This chapter deals almost exclusively with this catalyst, However, certain other catalysts of limited usefulness are considered.
The Acylation of Ketones to Form β‐Diketones or β‐Keto Aldehydes
Authors: Hauser Charles R. , Swamer Frederic W. , Adams Joe T. 
Published: March 2011

AbstractUnder certain conditions, a ketone having an alpha‐hydrogen atom may be acylated with an ester, an acid anhydride, or an acid chloride to form a β‐ketone or, when the acylating agent is a formic ester, a β‐keto aldehyde. The process consists in the replacement of an alpha‐hydrogen atom of the ketone by an acyl group. The reaction involves a carbon‐carbon condensation. The acylation of ketones with esters has generally been effected by means of a basic reagent, such as sodium, sodium ethoxide, etc. The acylation of ketones to form β‐diketones may also occur with acid anhydrides by means of an acidic reagent boron trifluoride. In this chapter the basic reagent and boron trifluoride methods of acylation are considered separately. They are compared with other methods.
TheSommelet Reaction
Authors: Angyal S. J. 
Published: March 2011

AbstractThe Sommelet reaction is the process whereby aldehydes are produced from alkyl halides by the action of hexamine. The reaction is essentially a conversion of an amine into an aldehyde, a process in itself that is not particularly useful because aldehydes are frequently more readily available than the corresponding primary amines, It is fortunate therefore that the required amines can be prepared by the interaction of alkyl halides with hexamine, i.e., with the same reagent that serves to convert the amines into aldehdyes, It is this combined form that was discovered by Sommelet.The Sommelet reaction, when started with a halide, proceeds in three stages: (1) formation of a hexaminium salt; (2) hydrolysis of this salt to an amine and its methylene derivative; and (3) formation of an aldehdye (the Sommelet reaction proper).
The Synthesis of Aldehydes from Carboxylic Acids
Authors: Mosettig Erich 
Published: March 2011

AbstractThe Rosenmund reduction of acid chlorides to the corresponding aldehydes was discussed in volume 4 of this series. There are a number of other less direct methods by which carboxylic acids can be converted into aldehydes and the purpose of this chapter is to consider the more useful of these procedures. Three of these methods, the hydrolytic decomposition of Reissert's compounds, the method of Grundmann, and the reductive desulfurization of thiol esters require acid chlorides as intermediates and in the respect are competitive with the Rosenmund reduction of acid chlorides. In the fourth method method, the McFadyen and Stevens synthesis, acid chlorides may be used for the preparation of the intermediate acyl hydrazides. Two additional methods, (Sonn and Muller, and Stephen) are based on the intermediate imido chlorides. These methods listed appear to be the one ones developed to the point where further discussion is profitable.
The Metalation Reaction with Organolithium Compounds
Authors: Gilman Henry , Morton John W. 
Published: March 2011

Abstract
The term metalation denotes the replacement of hydrogen by metal to yield a true organometallic compound. The replacement of hydrogen by metal in a compound such as acetoacetic acid is not generally classed as a metalation reaction in this sense because the resulting salt is not a typical organometallic compound. This distinction is matter of degree. The ability to yield ortho priducts, usually unmixed with para or other isomers, distinguishes the metalation reaction from the more familiar types of substitutions and makes possible the preparation of many products not readily available by other routes. The derivative most commonly prepared from a metalation product has been the carboxylic acid, made by the reaction of the lithium compound with carbon dioxide. This reaction is useful in the study of metalation products because the usual metalating agents, the alkyllithium compounds, yield volatile acids which are easily separated from the acids of higher molecular weight obtained from the metalated products themselves.
The Cleavage of Non‐Enolizable Ketones with Sodium Amide. TheHaller‐Bauer Reaction
Authors: Hamlin K. E. , Weston Arthur W. 
Published: March 2011

AbstractIn this chapter the Haller‐Bauer is defined as the action of sodium amide on a non‐enolizable ketone causing cleavage of a carbon‐to‐carbon bond and resulting in the formation of an amide and a hydrocarbon. Textbook definitions have limited the reaction to the alkylation of ketones in which sodium amide acts a condensing agent or have considered it a combination of the alkylation and cleavage reactions. Haller and Bauer reported the isolation of benzamide after the treatment of benzophenone with sodium amide in boiling benzene or toluene and followed this observation with an extended study of the reaction. A modification of the Haller‐Bauer reaction involving the use of a fused eutectic mixture of sodium an potassium amides has been applied to certain alicyclic and bicyclic terpenoid ketones as well as to some amides.
The Alkylation of Esters and Nitriles
Authors: Cope Arthur C , Holmes H. L , House Herbert O 
Published: March 2011

AbstractThis chapter is concerned with the reactions of metal salts (enolates) of active methylene compounds with alkylating agents such as alkyl halides to produce allyl derivatives. The first example of this reaction is found in the literature when Geuther prepared ethyl alpha‐ethyl acetoacetate by the reaction of the sodium enolate of ethyl acetoacetate with ethyl iodide. The active methylene compounds considered in the chapter include malonic esters, cyanoacetic esters, malonitriles, monocarboxylic esters and mononitriles. These classes of compounds are characterized by the presence of one or more acidic hydrogen atoms attached to carbon. Only C‐alkylation has been observed with active methylene compounds and are discussed here. Several alternative methods for the preparation of alkyl and aryl derivatives of carboxylic esters and nitriles have been included.
The Synthesis of β‐Lactams
Authors: Sheehan John C. , Corey Ellas J. 
Published: March 2011

Abstract
The four‐membered ring appears to be the smallest cyclic system that is capable of accommodating the amide function as a constituent. Such four‐membered cyclic amides are commonly referred to as beta‐lactams. The reluctance with which beta‐lactams are formed using conventional methods of lactam synthesis has necessitated unique approaches to the problem. After 1943, interest in beta‐lactams was stimulated by the importance of natural penicillins. Although there are at present several useful approaches to the beta‐lactam ring systems, the synthesis of beta‐lactams by a single general method is not possible. In principle, the synthesis of the beta‐lactam ring might be accomplished by the formation of one, two, three, or all four bonds of the ring during the cyclization step. Of these four possibilities, only the last has been realized.
TheBeckmann Rearrangement
Authors: Guy Donaruma L. , Heldt Walter Z. 
Published: March 2011

AbstractThe rearrangement of a ketoxime to the corresponding amide was discovered in 1886 by E. Beckmann and is known as the Beckmann rearrangement. The rearrangement is brought about by acids, including Lewis acids. The more common rearranging agents are concentrated sulfuric acid, phosphorus pentachloride in ether, and Beckmann's mixture, hydrogen chloride in a mixture of acetic acid and acetic anhydride. The Beckmann rearrangement is used frequently to determine the structure of ketones, by identification of the acid and amine obtained by hydrolysis of the amide formed by the rearrangement. There is no uniform convention for the designation of the stereochemistry of oximes in the literature. The conventions used in this chapter for the configurations of ketoximes and aldoximes are explained.
The
D
emjanov and
T
iffeneau‐
D
emjanov Ring Expansions
Authors: Smith Peter A. S , Baer Donald R 
Published: March 2011

Abstract
The reaction of aminomethylcycloalkanes with nitrous acid to produce cycloalkanols in which the ring is larger by one carbon atom is known as the Demjanov rearrangement. The first example of this type of ring expansion was encountered in 1901, but was not recognized until 1903 when cyclopentanol was identified as one of the products formed from cyclobutanemethylamine. Since that time the reaction has extended to rings of many sizes. Olefins almost invariably accompany the alcohols that are formed. The Demjanov rearrangement includes within its scope the rearrangements that occur when acyclic amines are treated with nitrous acid as well as other ring expansion detailed in this chapter. The Tiffeneau‐Demjanov ring expansion is used here to designate ring enlargements by pinacolic deamination. This ring expansion can be made the key step in the conversion of a cyclic alcohol or ketone into its next ring homolog.
Olefins from Amines: TheHofmann Elimination Reaction and Amine Oxide Pyrolysis
Authors: Cope Arthur C. , Trumbull Elmer R. 
Published: March 2011

AbstractThe conversion of an amine to an olefin by elimination of the nitrogen atom and an adjoining hydrogen atom is a useful procedure for degradation and synthesis. The Hofmann exhaustive methylation method has been used most often to bring about change, but other methods as the thermal decomposition of amine oxides and the pyrolysis of amine phosphates or acetyl or benzoyl derivative have often been employed to advantage. This chapter reviews the Hofmann elimination because of its extensive history. Alternative methods are considered.
The Preparation of Olefins by the Pyrolysis of Xanthates. TheChugaev Reaction
Authors: Nace Harold R. 
Published: March 2011

AbstractIn this chapter the Chugaev reaction is defined as the thermal decomposition of the xanthate ester of an alcohol that contains at least one beta‐hydrogen atom to produce one or more olefins, carbon oxysulfide and a mercaptan. The formation of olefins by the pyrolysis of xanthates was discovered in 1899 by Chugaev in connection with his studies on the optical properties of xanthates and other compounds. He subsequently employed the reaction in his investigation of terpenes and demonstrated both its utility as an olefin‐forming reaction and its usefulness in structural determination. The reaction, which is particularly valuable for the conversion of sensitive alcohols to the corresponding olefins without the rearrangement of the carbon skeleton is analogous to the thermal decomposition of carboxylic esters of alcohols and other derivatives such as carbamates and carbonates, to yield olefins.
Halocyclopropanes from Halocarbenes
Authors: Parham William E. , Schweizer Edward E. 
Published: March 2011

Abstract
This chapter reviews methods for the generation of halocarbenes and the reaction of the latter with unsaturated substrates. Chemical transformations of the derived halocyclopropanes are discussed in sufficient detail to demonstrate the synthetic utility of this class. The formation of dihalocyclopropanes from dihalocarbenes was first accomplished in 1954 by Doering and Hoffmann who used chloroform t‐ butoxide to generate the dichlorocarbene. Since that time a variety of other methods have been developed for the generation of halocarbenes. The various methods are discussed.
Free Radical Additions to Olefins to Form Carbon‐Carbon Bonds
Authors: Walling Cheves , Huyser Earl S. 
Published: March 2011

Abstract
Some of the most useful reactions in synthetic organic chemistry involve the addition of reagents across the double bonds of olefins. These reactions, which can occur by a variety of mechanisms involving electrophilic, nucleophilic or radical intermediates, have been the subject of numerous mechanistic studies. Electrophilic additions involve polar reagents, and in general the direction of addition follows Markownikoff's rule. Nucleophilic additions require rather special and drastic conditions unless the olefin contains strong electron‐withdrawing substituents. Radical reactions are very general in scope, but are markedly influenced by light, oxygen, peroxides, and various inhibitors. The direction of addition in free‐radical reaction is commonly the opposite of that encountered in the electrophilic ionic (Markownikoff) additions. Hence these free‐radical additions have been referred to as Anti‐Markownikoff, abnormal or Karasch addition reactions. This chapter is concerned with the synthetic aspects of Kharasch addition reactions that result in the formation of a new carbon‐carbon bond.
The
C
hapman Rearrangement
Authors: Schulenberg J. W. , Archer S. 
Published: March 2011

Abstract
The thermal conversion of aryl N‐arylbenzimidates to N‐aroyldiphenylamines is known as the Chapman rearrangement. The starting materials for the Chapman rearrangement have been referred to as imino ethers, imido esters, imidates, and by miscellaneous other names. Roger and Neilson have named all the compounds as imidates. This chapter does not name the rearrangement products according to Chemical Abstracts, which lists the compounds as derivatives of benzanilide or benzamide. Here the products are called aroyldiarylamines. All of the compounds obtained by amide hydrolysis are named diarylamines. The Chapmann rearrangement has been shown to be an intramolecular reaction in which a 1,3 shift of an aryl group from oxygen to nitrogen occurs.
α‐Amidoalkylations at Carbon
Authors: Zaugg Harold E. , Martin William B. 
Published: March 2011

AbstractThis chapter is concerned with reactions that lead to the formation of a new carbon‐carbon bond by the replacement of X (eg, halogen, ‐OH, ‐OR, ‐OCOR, ‐NHCOR ‐NR 2 or NR3) from an electrophilic reagent, RCON(R')CH(R”)X. The R' group may be hydrogen or alkyl or an acyl group. In a few cases a sulfonyl group may replace the acyl group of the electrophilic reagent. The nucleophiles that react with these reagents fall into two broad groups: aromatic compounds and aliphatic compounds containing reactive methylene or methane groups. Methods for preparing the electrophilic reagents are included in this chapter.
The Wittig Reaction
Authors: Maercker Adalbert 
Published: March 2011

AbstractIn 1953 Wittig and Geissler found that reaction of benzophenone with methylenetriphenylphosphorane gave 1,1‐diphenylethylene and triphenylphosphine oxide in almost quantitative yield; the phosphine had been prepared from triphenylmethylphosphonium bromide and phenyl lithium. The discovery led to the development of a new method for the synthesis of olefins, under the name Wittig reaction. One advantage of this new method is that the carbonyl group is replaced specifically by a carbon‐carbon double bond without the formation of isomeric olefins. In contrast, the older method of converting carbonyl compounds to olefins using the Grignard reaction usually give a mixture of isomeric olefins. Another advantage is the Wittig reaction is carried out under mild conditions. Discussions of modern techniques for the preparation of methylene phosphoranes are included in this review.
TheKnoevenagel Condensation
Authors: Jones G. 
Published: March 2011

AbstractKnoevenagel's first papers in this field were concerned with the condensation of formaldehyde with diethyl malonate and with ethyl benzoylacetate. The catalyst was ethylamine. A number of other aldehydes were reported to condense similarly with diethyl malonate, ethyl benzoylacetate, ethyl benzoylpyruvate, and acetylacetone under the influence of various primary and secondary amines. In 1896, Knoevenagel reported benzaldehyde with ethyl aceoacetate condensed at room temperature in the presence of piperdine to give a bis compound, but that when the reaction was run in a freezing mixture, the product was acetoacetate. For the purposes of this chapter, the Knoevenagel condensation is defined as the reaction between an aldehyde or ketone or any compound having an active methylene group, brought about by an organic base or ammonia and their salts.
Preparation of Ketones from the Reaction of Organolithium Reagents with Carboxylic Acids
Authors: Jorgenson Margaret J. 
Published: March 2011

AbstractThe reaction of organolithium reagents and carboxylic acids constitutes a simple general method for the synthesis of ketones. This preparative route is the method of choice for direct conversion of carboxylic acid to ketones. It is the purpose of this chapter to evaluate critically the scope and limitations of this reaction and to recommend optimal conditions for its applications. The reaction of organolithium reagents with carboxylic acid is limited to the preparation of acyclic ketones. Although the objective of this reaction, the formation of unsymmetrical ketones, the method is clearly applicable to the synthesis of symmetrical ketones. Two different routes are possible and are discussed. To date, the reaction has been applied only to the preparation of monoketones.