Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Benzyl ketones carboxylic acid chloride

Dilithium tetrachlorocuprate is recommended as an additive for cross coupling of Grignard compounds with tosylates even allylic and benzylic acetates give good yields . a-Methylene-ketones, -carboxylic acids and -lactones have been prepared via sulfides and sulfoxides. A convenient and general synthesis of acetylene derivatives from boranes via the reaction of iodine with lithium 1-alkynyltriorganoborates has been published ar-Nitrostyrenes can be easily obtained by a Wittig synthesis with formaldehyde in an aqueous medium . A new synthesis of unsym. ketones by reaction of dialkyldiloroboranes with lithium aldimines has recently been published . Metallo aldimines have also served for the synthesis of a variety of other compound classes such as a-hydroxyketones, a-keto acids, nitriles, and for the asym. synthesis of a-amino acids . Polycondensations of malononitriles with benzylic chlorides have been carried out quantitatively under mild conditions in dimethyl sulfoxide with triethylamine as acid acceptor . Carbonyl compounds can react with dibromoacetonitrile to yield a-bromo esters with additional carbon atom . ... [Pg.10]

Benzyl ketones from carboxylic acid chlorides... [Pg.206]

Differences in solubility of the reactants may for example be utilized as follows. Sodium iodide is much more soluble in acetone than are sodium chloride or sodium bromide. Upon treatment of an alkyl chloride or bromide with sodium iodide in acetone, the newly formed sodium chloride or bromide precipitates from the solution and is thus removed from equilibrium. Alkyl iodides can be conveniently prepared in good yields by this route. Alkyl bromides are more reactive as the corresponding chlorides. Of high reactivity are a-halogen ketones, a-halogen carboxylic acids and their derivatives, as well as allyl and benzyl halides. [Pg.113]

Two years later, the same group reported a formal synthesis of ellipticine (228) using 6-benzyl-6H-pyrido[4,3-f>]carbazole-5,ll-quinone (6-benzylellipticine quinone) (1241) as intermediate (716). The optimized conditions, reaction of 1.2 equivalents of 3-bromo-4-lithiopyridine (1238) with M-benzylindole-2,3-dicarboxylic anhydride (852) at —96°C, led regioselectively to the 2-acylindole-3-carboxylic acid 1233 in 42% yield. Compound 1233 was converted to the corresponding amide 1239 by treatment with oxalyl chloride, followed by diethylamine. The ketone 1239 was reduced to the corresponding alcohol 1240 by reaction with sodium borohydride. Reaction of the alcohol 1240 with f-butyllithium led to the desired 6-benzylellipticine quinone (1241), along with a debrominated alcohol 1242, in 40% and 19% yield, respectively. 6-Benzylellipticine quinone (1241) was transformed to 6-benzylellipticine (1243) in 38% yield by treatment with methyllithium, then hydroiodic acid, followed... [Pg.327]

The equivalence of sulfur and oxygen in this ring system carries over to NSAIDs as well. Preparation of the sulfur analogue of isoxepac (6-4) starts with the alkylation of thiophenol (27-1) with benzyl chloride (26-1). Cyclization of the intermediate thioether (27-2) then affords the homothioxanthone (27-3). The carboxyl side chain is then extended by means of the Amdt-Eistert homologation reaction. The acid is thus hrst converted to its acid chloride by means of thionyl chloride. Reaction with excess diazomethane leads to the diazoketone (27-4). Treatment of that intermediate with silver benzoate and triethylamine leads the ketone to rearrange to an acetic acid. There is thus obtained tiopinac (27-5) [28]. [Pg.530]

CoNO(CO)3] (93) catalyzes the carbonylation of benzyl bromides and chlorides to give carboxylic acids.403 The reactions, carried out in a two-phase system, occurred at normal temperature and pressure and their behaviour was quite different to that observed when [Co2(CO)8] is used as catalyst. The anion [CoH(NO)(CO)2] is believed to be a key intermediate, formed by attack of hydroxide on (93) followed by loss of C02. Ketones, bibenzyls and other by-products were detected in low yields. The mechanism of the carbonylation is given in Scheme 24. [Pg.270]

The at complex from DIB AH and butyllithium is a selective reducing agent.16 It is used tor the 1,2-reduction of acyclic and cyclic enones. Esters and lactones are reduced at room temperature to alcohols, and at -78 C to alcohols and aldehydes. Acid chlorides are rapidly reduced with excess reagent at -78 C to alcohols, but a mixture of alcohols, aldehydes, and acid chlorides results from use of an equimolar amount of reagent at -78 C. Acid anhydrides are reduced at -78 C to alcohols and carboxylic acids. Carboxylic acids and both primary and secondary amides are inert at room temperature, whereas tertiary amides (as in the present case) are reduced between 0 C and room temperature to aldehydes. The at complex rapidly reduces primary alkyl, benzylic, and allylic bromides, while tertiary alkyl and aryl halides are inert. Epoxides are reduced exclusively to the more highly substituted alcohols. Disulfides lead to thiols, but both sulfoxides and sulfones are inert. Moreover, this at complex from DIBAH and butyllithium is able to reduce ketones selectively in the presence of esters. [Pg.170]

Carbonylation with iron carbonyls parallels that of cobalt carbonyls. Benzylic chlorides and bromides are carbonylated with Fe(CO)5 in the presence of base. Esters are realized when carbonylation is performed in alcohols under 1 atm of CO with catalytic amounts of iron pentacarbonyl415. Under phase transfer conditions, two predominant routes are available. With catalytic amounts of iron under a CO atmosphere and strongly basic conditions, the carboxylic acids are realized in reasonable yields415,416, whereas mild bases [Ca(OH)2l, stoichiometric amounts of iron carbonyl and the omission of CO give dibenzyl ketones417. In at least a few cases, it is possible to prepare unsymmetrical methyl benzyl ketones418, des Abbayes and coworkers have observed the formation of acyltetracarbonyl anion (52) under the reaction conditions, and have proposed the catalytic cycle in Scheme 8 for the ketone formation418. [Pg.1339]

The reaction of ethyl thiophen-2-carboxylate with triphenylphosphine-CCI4 gave (159), which upon acidic hydrolysis afforded the dichloromethyl ketone. 2-Thenoyl chloride reacts with some piperazine derivatives. Trimethylsilyldiazomethane has been used as a safe reagent in the Arndt-Eistert reaction for the transformation of 2-thenoyl chloride into benzyl 2-thienylacetate. ... [Pg.103]

Benzyl alcohol at 155.4°C Tetrahydrofuran, acetone-carbon disulfide mixtures, methyl ethyl ketone Toluene, xylene, methylene chloride, ethylene chloride, perchloroethylene-acetone mixtures, 1,2-dichlorobenzene, tetrahydrofurfuryl alcohol, dioxane, acetone-oarbon disulfide mixtures, cyclopentanone, diisopropyl ketone, mesityl oxide, isophorone, dimethyl-formamide, nitrobenzene, hexamethyl-phosphoramide, tricresyl phosphate Aliphatic and aromatic hydrocarbons, vinyl chloride monomer, alcohols, glycols, aniline, acetone, carboxylic acids, acetic anhydride, esters, nitroparaffins, carbon disulfide, nonoxidizing mineral acids, concentrated alkalies... [Pg.359]


See other pages where Benzyl ketones carboxylic acid chloride is mentioned: [Pg.253]    [Pg.300]    [Pg.2540]    [Pg.134]    [Pg.385]    [Pg.462]    [Pg.18]    [Pg.242]    [Pg.259]    [Pg.599]    [Pg.192]    [Pg.121]    [Pg.25]    [Pg.91]    [Pg.256]    [Pg.256]    [Pg.436]    [Pg.463]    [Pg.756]    [Pg.756]    [Pg.589]    [Pg.359]    [Pg.2303]    [Pg.273]    [Pg.256]    [Pg.204]    [Pg.273]    [Pg.1]    [Pg.311]    [Pg.756]    [Pg.180]    [Pg.448]    [Pg.311]   
See also in sourсe #XX -- [ Pg.27 ]




SEARCH



Benzyl carboxylation

Benzyl chloride

Benzylic chlorides

Carboxylates chloride

Carboxylic acid chlorides

Carboxylic acids acid chlorides

Carboxylic ketones

Ketones carboxylation

Ketones carboxylic acids

© 2024 chempedia.info