Cyclodextrin effect on solvolysis of substituted benzoyl chlorides

A kinetic study was carried out on the solvolysis of substituted benzoyl chlorides in the presence of alpha-, beta- and gamma-CD. Combination of the substituent dependent mechanism for solvolysis of benzoyl chlorides and the complexation ability of the cyclodextrin yields the following experimental behavior: (i) catalysis by beta- and gamma-CD for solvolysis of electron-attracting substituted benzoyl chlorides due to the reaction with its hydroxyl group C(6); (ii) absence of alpha-CD influence on solvolysis of benzoyl chlorides with electron withdrawing substituents; (iii) inhibition of solvolysis of benzoyl chlorides with electron-donating groups. This behavior is observed for solvolysis of meta/para substituted substrates in the presence of beta-CD, solvolysis of meta-substituted benzoyl chlorides in the presence of alpha-CD and solvolysis of para-substituted benzoyl chlorides in the presence of gamma-CD. This decrease in the rate constant is a consequence of the complexation of the substrate in the cyclodextrin cavity and its low solvation ability, causing the rate of solvolysis in its interior to be negligible. (iv) The solvolysis of meta-substituted benzoyl chlorides in the presence of gamma-CD yields a new behavior where the reaction of the complexed substrate is not negligible in the interior of the cyclodextrin cavity, which has been interpreted as a consequence of incomplete expulsion of hydration water from its cavity when the complexation takes place. (v) The experimental results obtained in the presence of alpha-CD show that meta-substituted benzoyl chlorides give rise to host : guest complexes with 1 : 1 stoichiometries, whereas those which are para-substituted cause a 2 : 1 stoichiometry to be formed. This difference in behavior has been interpreted taking into account the size of the different benzoyl chlorides and their accommodation in the alpha-CD cavity.     

钯催化下全氟碳负离子的产生及其反应

2-三氟甲基-3-氧杂-八氟己酸烯丙酯或2,5-二(三氟甲基)-3,6-二氧杂-十二氟壬酸烯丙酯可在钯的作用下产生相应的全氟碳负离子. 这些碳负离子能够质子化或者对取代苯甲酰氯发生亲核进攻, 后者为芳基氟烷基酮的合成提供了一条简捷途径. 另一方面,上述含氟酸的甲酯和取代苯甲酰氯在钯的作用下同样能发生反应而生成相应的芳基氟烷基酮.     

The role of water release from the cyclodextrin cavity in the complexation of benzoyl chlorides by dimethyl-β-cyclodextrin

The influence of temperature on the solvolysis of substituted benzoyl chlorides in the presence of dimethyl-β-cyclodextrin (DM-β-CD) was studied. Based on the influence of the DM-β-CD concentration on chemical reactivity in this process, the cyclodextrin has a catalytic effect on the solvolysis of 4-nitrobenzoyl chloride (4-NO₂) but an inhibitory effect on that of 4-methoxy-(4-MeO), 3-chloro-(3-Cl) and 3-trifluoromethyl-(3-CF₃) benzoyl chlorides. These disparate effects are related to a difference in reaction mechanism; thus, DM-β-CD catalyses associative solvolysis and inhibits dissociative solvolysis. Examining the influence of temperature on the solvolytic process allowed the stoichiometry of the host-guest complexes formed to be established. The formation constants for the complexes of meta-substituted benzoyl chlorides increased with increasing temperature. On the other hand, the equilibrium formation constants for the 1:1 host-guest complexes of para-substituted benzoyl chlorides exhibited the opposite trend. The equilibrium formation constant for 2:1 host-guest complexes for the para-substituted benzoyl chlorides increased with increasing temperature. These differences are ascribed to the release of water from the DM-β-CD cavity during the formation of the host-guest complex.     

Effects of zwitterionic vesicles on the reactivity of benzoyl chlorides

A systematic study on the solvolysis reaction of substituted benzoyl chlorides in the presence of zwitterionic vesicles of dipalmitoyl phosphatidylcholine (DPPC) has been performed. Size, shape, surface charge, and polarity of the interface of the vesicular aggregates were determined using various techniques. The application of the pseudophase formalism allowed us to obtain the thermodynamic and kinetic coefficients characteristic of the reaction. The effects of vesicular aggregates on the solvolysis of benzoyl chlorides, which are known to be sensitive to the physical properties of the medium, depend on the nature of the substrate. For benzoyl chlorides with electron-donating groups, which react predominantly through a dissociative mechanism which is strongly affected by medium properties, the rate constant decreases as the vesicle concentration increases. On the other hand, for benzoyl chlorides with electron-withdrawing groups, which react mainly via an associative pathway, DPPC vesicles catalyze the solvolysis reaction.     

An Improved Method Forthe Conversion Ofcertain Aromatic Carboxylic Acids into Benzylic Chlorides

A novel one-pot procedure, which affords benzylic chlorides in about 70% yield, involves reduction of benzoyl chlorides by aqueous sodium borohydride as a key step.     

Cyclodextrin effect on solvolysis of ortho benzoyl chlorides

A kinetic study was carried out on the solvolysis of ortho benzoyl chlorides in the presence of α-, β- and γ-Cyclodextrin (CD). The solvolysis mechanism of benzoyl chlorides is sensitive to the substituents, and to the solvent in which the reaction takes place. In water, the behaviour exhibited by benzoyl chlorides which have electron-attracting groups, is consistent with an associative mechanism whilst electron-donating substituents induce a dissociative mechanism. The results obtained in the presence of CD show a decrease in the observed rate constant, k _obs, as the CD concentration increases. This behaviour can be explained if these substrates undergo solvolysis through a dissociative path in the presence of α-, β- and γ-CD.     

An efficient synthesis of chalcones based on the Suzuki reaction

A general method for the synthesis of chalcones based on the Suzuki reaction either between cinnamoyl chlorides and phenylboronic acids or between benzoyl chlorides and phenylvinylboronic acids is described.     

Fluorine-containing heterocycles: XVIII. Monofluoro derivatives of quinazolines and 1,3-benzothiazin-4-ones

5- and 7-Fluoro-substituted quinazolines and 1,3-benzothiazin-4-ones were synthesized starting from 2-amino-6-fluorobenzonitrile and mono- and difluoro-substituted benzoic acid derivatives. The reactivities of di- and tetrafluoro-substituted benzoyl chlorides and benzoyl isothiocyanates in cyclocondensations leading to fluorinated quinazolines and 1,3-benzothiazines were compared.     

Modification of some mono- and bispiperidols exhibiting growth-regulating properties

Procedures for esterification of biologically active mono-and bispiperidols by reactions with benzoyl and terephthaloyl chlorides were developed.     

Synthesis and Characterization of Some New Indoline-Based 1,2,4-Triazole Derivatives

Russian Journal of Organic Chemistry - Three-component reaction of substituted benzoyl chlorides, ammonium thiocyanate, and isatin in anhydrous acetone gave a series of novel...     

Ugi reaction of thiouridocarboxylic acids: A synthesis of thiourea-peptoids

Benzoylthioureidocarboxylic acids, prepared from benzoyl chlorides, potassium thiocyanate, and α-aminoacids, are used as acid components in the Ugi reaction to produce thiourea-peptoids in moderate to good yields.     

Straightforward Approach Toward Dihydrothiazoles via Intramolecular Bromocyclization

An intramolecular bromonium ion–assisted cyclization with sulfur as an internal nucleophile is described. Starting from benzoyl chlorides, this method provides an easy procedure for the synthesis of dihydrothiazole derivatives in moderate to good yields.     

Quinazolines. 4*. Acylation of quinazoline-2,4-diones with aromatic acids chlorides in the presence of ferric chloride hexahydrate

The interaction of quinazoline-2,4-diones with aromatic acids chlorides in nitrobenzene has been investigated in the presence of FeCl₃·6H₂O. Optimum conditions for the acylation reaction have been developed, the used 4-substituted benzoyl chlorides have been put in order of relative activity, depending on the degree of their electrophilicity.     

Synthesis of cellulose benzoates under homogeneous conditions in an ionic liquid

The ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction medium was studied for the synthesis of cellulose benzoates by homogeneous acylation of dissolved cellulose with benzoyl chlorides in the absence of any catalysts. Cellulose benzoates with a degree of substitution (DS) in the range from about 1 to 3.0 were accessible under mild conditions. The DS of cellulose derivatives increased with the increase of the molar ratio of benzoyl chloride/anhydroglucose unit (AGU) in cellulose, reaction time, and reaction temperature. Benzoylation of cellulose with some 4-substituted benzoyl chlorides including 4-toluoyl chloride, 4-chlorobenzoyl chloride and 4-nitrobenzoyl chloride was also readily carried out under mild conditions. Furthermore, regioselectively substituted mixed cellulose esters were synthesized in this work. All products were characterized by means of FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopy. In addition, at the end of benzoylation of cellulose, the ionic liquid AmimCl was easily recycled. When the recycled AmimCl was used as the reaction media, the cellulose benzoate with a similar DS was obtained under comparable reaction conditions.     

Esters of heterocyclic γ-amino alcohols

Reduction of cis-3-cyano-4-hydroxypiperidines with lithium aluminum hydride (LAH) gave cis-3-aminomethyl-4-hydroxypiperidines, which were converted to cis-3-dimethylaminomethyl-4-hydroxypiperidines by methylation with formaldehyde and formic acid. Acylation of the methylated compounds with benzoyl and cinnatnoyl chlorides gave the corresponding esters. Condensation of cis-3-aminomethyl-4-hydroxypiperidines with formaldehyde gave perhydropyrido[3,4-e][1,3]oxazines, which were converted to 3-methylaminomethyl-4-hydroxypiperidines by means of LAH. The cis isomers of the corresponding O,N-diacyl derivatives of these amino alcohols were obtained by acylation with acetic anhydride and benzoyl and cinnamoyl chlorides.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1363–1368, October, 1978.     

负载FeCl~3的皂土催化合成二芳基酮

在负载FeCl~3的皂土上由苯甲酰氯和苯甲醚发生Friedel-Crafts酰化反应合成了系列二芳基酮化合物,该方法具有产率高,操作简单,催化剂易再生等优点。     

High-Throughput Synthesis of Alkylbenzophenones with Indium Triflate in the Absence of Solvents Using Microwave

Abstract

A series of alkylbenzophenones were rapidly and efficiently prepared from alkylbenzenes and benzoyl chlorides by Friedel-Crafts acylation catalyzed with indium triflate under solvent-free conditions by microwave heating.     

First catalytic and green synthesis of aryl-(Z)-vinyl chlorides and its plausible addition-elimination mechanism

Via a catalytic cycle in the presence of scandium triflate (2 mol %)/DMF (1 mol %)/benzoyl chloride (5 mol %), aromatic ketones were treated with bis(trichloromethyl) carbonate (BTC) to afford aryl-(Z)-vinyl chlorides. All metal triflates tested in the reaction showed highly catalytic activity. A plausible addition-elimination mechanism was proposed. The present work describes the first catalytic and green route to the synthesis of aryl-(Z)-vinyl chlorides. [reaction: see text]     

S(N)2 Mechanism for Alcoholysis, Aminolysis, and Hydrolysis of Acetyl Chloride

First-order solvolysis rate constants are reported for solvolyses of acetyl chloride in methanol and MeOD, and in binary aqueous mixtures with acetone, acetonitrile, ethanol, methanol, and trifluoroethanol at 0 degrees C. Product selectivities (S = [MeCOOR]/[MeCOOH] x [water]/[alcohol]) are reported for solvolyses in ethanol/ and methanol/water at 0 degrees C. Solvolyses of acetyl chloride show a high sensitivity to changes in solvent ionizing power, consistent with C-Cl bond cleavage. As the solvent is varied from pure ethanol (or methanol) to water, S values and rate-rate profiles show no evidence for the change in reaction channel observed for solvolyses of benzoyl and trimethylacetyl chlorides. However, using rate ratios in 40% ethanol/water and 97% trifluoroethanol/water (solvents of similar ionizing power but different nucleophilicities) to compare sensitivities to nucleophilic attack, solvolyses of acetyl chloride are over 20-fold more sensitive to nucleophilic attack than benzoyl chloride. The solvent isotope effect of 1.29 (MeOH/MeOD) for acetyl chloride is similar to that for p-methoxybenzoyl chloride (1.22) and is lower than for benzoyl chloride (1.55). Second-order rate constants for aminolyses of acetyl chloride with m-nitroaniline in methanol at 0 degrees C show that acetyl chloride behaves similarly to p-methoxybenzoyl chloride, whereas benzoyl chloride is 40-fold more sensitive to the added amine. The results indicate mechanistic differences between solvolyses of acetyl and benzoyl chlorides, and an S(N)2 mechanism is proposed for solvolyses and aminolyses by m-nitroaniline of acetyl chloride (i.e. these reactions are probably not carbonyl additions, but a strong sensitivity to nucleophilic attack accounts for their high rates).     

Palladium-catalyzed direct cross-coupling of potassium styryltrifluoroborates and benzoyl chlorides—a one step method for chalcone synthesis

A direct cross-coupling reaction of benzoyl chlorides and potassium styryltrifluoroborates to the corresponding α,β-unsaturated aromatic ketones in the presence of PdCl₂(d^tbpf) catalyst under microwave heating is developed.