Carboxylic acids, anhydrides compounds

Carboxylic acid anhydrides compounds of the type RCOCR can also serve as sources of acyl cations and m the presence of aluminum chloride acylate benzene One acyl unit of an acid anhydride becomes attached to the benzene ring and the other becomes part of a carboxylic acid... 

Friedel-Crafts acylation of aromatic compounds (Section 12 7) Acyl chlorides and carboxylic acid anhydrides acylate aromatic rings in the presence of alumi num chloride The reaction is electrophil ic aromatic substitution in which acylium ions are generated and attack the ring... 

Friedel-Crafts acylation (Section 12 7) An electrophilic aro matic substitution in which an aromatic compound reacts with an acyl chloride or a carboxylic acid anhydride in the presence of aluminum chlonde An acyl group becomes bonded to the nng... 

Closely related to the carboxylic acids and nitriles discussed in the previous chapter are the carboxylic acid derivatives, compounds in which an acyl group is bonded to an electronegative atom or substituent that can net as a leaving group in a substitution reaction. Many kinds of acid derivatives are known, but we ll be concerned primarily with four of the more common ones acid halides, acid anhydrides, esters, and amides. Esters and amides are common in both laboratory and biological chemistry, while acid halides and acid anhydrides are used only in the laboratory. Thioesters and acyl phosphates are encountered primarily in biological chemistry. Note the structural similarity between acid anhydrides and acy) phosphates. 

Similar additions have been successfully carried out with carboxylic acids, anhydrides, acyl halides, carboxylic esters, nitriles, and other types of compounds. These reactions are not successful when the alkene contains electron-withdrawing groups such as halo or carbonyl groups. A free-radical initiator is required, usually peroxides or UV light. The mechanism is illustrated for aldehydes but is similar for the other compounds ... 

Man-made mineral fibre Mixed hydrocarbons (C3 to CIO) in air Total hexavalent chromium compounds in air Aromatic carboxylic acid anhydrides in air... 

The classes of compounds that are conveniently considered together as derivatives of carboxylic acids include the acyl chlorides, carboxylic acid anhydrides, esters, and amides. In the case of simple aliphatic and aromatic acids, synthetic transformations... 

One of the most systematic investigations into the use of organic chemical microscopy was made by Dunbar and his associates, who used a series of specific reagents to develop specific tests for various functional groups. Methods were developed for amines [24,25], carboxylic acids, anhydrides, and acid chlorides [26,27], aldehydes and ketones [28], hydroxy compounds [29], amino acids [30], and cations [31]. 

Hill, C.A.S. and Papadopoulos, A.N. (2002). The pyridine-catalysed acylation of pine sapwood and phenolic model compounds with carboxylic acid anhydrides. Determination of activation energies and entropy of activation. Holzforschung, 56(2), 150-156. 

Similar additions have been successfully carried out with carboxylic acids, anhydrides,561 acyl halides, carboxylic esters, nitriles, and other types of compounds.562... 

Anilino-553 and the three 3-tolylaminobenzo[6]thiophenes554 undergo the Bernthsen reaction when heated with an aliphatic carboxylic acid anhydride and zinc chloride 1o yield polycyclic compounds (e.g., 181 from 3-m-tolylaminobenzo[6]thiophene and acetic anhydride), They give analogous arsenic derivatives (e.g., 182 from 3-p-tolylaminobenzo[6]thiophene) when heated with arsenic trichloride in o-dichlorobenzene.553,554... 

Main Chain Polymers. Another system of dye attached polymers is a polyamic acid and a polyimide with a Tt-electron conjugation in the main chain. The Tt-electron conjugated system is not an intramolecular charge transfer system, unlike the azo and stilbene dye mentioned above. The polyamic acids (PAAs) were obtained through the reaction of a carboxylic acid anhydride and a diamine. A Tt-electron conjugated system exists in the diamine compound. These polyamic acids were soluble in conventional solvents and... 

In the Friedel-Crafts acylation, carboxylic acid chlorides and carboxylic acid anhydrides are activated with stoichiometric amounts of A1C13 (Section 5.2.7). However, this activation is only possible in the presence of very weak nucleophiles such as aromatic compounds. Stronger nucleophiles would react with the A1C13 instead of the carboxylic acid derivative. If one wants to acylate such stronger nucleophiles—for example, alcohols or amines—with car-... 

Among the electron acceptors which exhibit the sensitization 133 are various nitro compounds, cyano-compounds, some organic acids such as phthalic acid, carboxylic acid anhydrides, quinones, etc. The most efficient electron accepting sensitizer known to date is 2,4,7-trinitro-9-fluorenone (TNF)134,135. Not surprisingly,... 

Depending on the nature of the anhydride, the ratio of the reagents, and the reaction temperature, tellurium tetrakis[fluoroalkoxides] and carboxylic acid anhydrides reacted to yield fluoroalkyl carboxylates, tellurium dioxide, acyloxy tellurium tris[fluoroalkoxide], bis[acyloxy] tellurium bis[fluoroalkoxides], tetrakis[acyloxy] tellurium compounds, or bis[fluoroalkoxy] tellurium oxides4. 

The starting materials for the preparation of 1,3-benzotellurazoles are aromatic tellurium compounds that contain an amino functionality in an orv/to-position to the tellurium atom. The reduction of 2-benzeneazophenyl tellurium trichloride with sodium borohydride in ethanol generates 2-aminobenzenetellurol. This compound is acylated with carboxylic acid anhydrides and the acylaminobenzenetellurol cyclized by treatment with concentrated... 

Photocationic initiators. Epoxy resins can be cross-linked by compounds containing active hydrogen, e.g., carboxylic acids, anhydrides, amines, phenols etc., or by the ionic polymerization process. Lewis acids such as BF3 and usually a crystalline complex of BF3 with amines, e.g., BF3 NH2C2H5, can be used for curing reaction at 80-100° C [124]. 

The two most useful routes to (32) and some of its derivatives are (i) the ring closure of the Af-aminodiazinium salt (342) with carboxylic acids, anhydrides or acid chlorides as previously mentioned for the pyridazines and pyrimidines (75JHC107) and (ii) the cyclodehydration of the hydroxyiminomethyleneamino compound (343) with polyphosphoric acid as reported herein for the pyridine, pyridazine and pyrimidine analogs (74JOC2143). These two methods are shown in Scheme 59. 

Quinazoline is transformed into quinoline derivatives 5 or 6 on treatment with active methylene compounds in the absence of a base catalyst or with carboxylic acid anhydrides. The possible mechanism involves an addition, ring opening between the 2- and 3-positions and a ring-closure sequenceor an addition, ring opening between the 3- and 4-positions and a ring-closure sequence. All possible mechanisms involve 4-substituted 3,4-dihydroquinazoli-nes formed by addition to the 3,4-double bond of quinazoline (cf p 165) as intermediates. ... 

Thietanone 1,1-dioxides are unknown, although the tetraphenyl compound may be an intermediate in the oxidation of the 2-thietanone 308 with m-chloro-perbenzoic acid to the sulfinic-carboxylic acid anhydride 331. The methods discussed below apply to 3-thietanone 1,1-dioxides and derivatives. 

The reaction of aliphatic carboxylate esters or ethers with carbon monoxide in the presence of nickel or a nickel derivative, iodine or an iodine compound, and an organic trivalent Group VA element compound and DBU under pressure gave carboxylic acid anhydrides (79GEP2844371). 

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