Bromoacetate Bromoacetyl, reactions

Haloacetyl Method The haloacetyl method uses supports that contain lodoacetyl or bromoacetyl groups for the immobilization of ligands through sulfhydryl residues. These supports are usually prepared via the reaction of an amine-containing material with iodoacetic or bromoacetic acid in the presence of ethyldimethylaminopropyl carbodii-mide (EDC) at pH 4 to 5. EDC reacts with the carboxylic acid in iodo- or bromoacetic acid... 

Recently, ionic liquids with amino acids as anions were synthesized by neutralization between [C2mim][OH] and amino acids [88], Tetrabutylphosphonium amino acids [P(C4)4][AA] were synthesized by the reaction of tetrabutylphosphonium hydroxide [P(C4)4][OH] with amino acids, including glycine, L-alanine, l-/1-alanine, L-serine and L-lysine [89], The esters or amide derivatives of bromoacetic acid were either commercially available or formed in one step via the reaction of bromoacetyl bromide with the appropriate alcohol or amine [90-92], An advantage of this route is that a wide range of ester and amide side chains can be prepared easily. For ionic liquids with anions other than bromide, a metathesis reaction was employed to introduce the counter ion of choice. Additionally, functionalized ionic liquids with electrophilic alkene-type appendages were synthesized. 

When the polyene chain is extended from the ends towards the centre, acetic acid (9) is used as starting material. In a two-step, one-pot procedure, this can be converted into ethyl bromoacetate (10) by reaction with phosphorus tribromide and bromine in a Hell-Vollhardt-Zelinsky reaction [20,41], yielding the bromoacetyl bromide, which is subsequently quenched by adding ethanol, to give the labelled ethyl bromoacetate (W) in a yield of 86% [42]. Ethyl bromoacetate (10) is also available commercially in labelled form, but its preparation from acetic acid is an economically attractive alternative. 

Bromoacetyl-p-aminobemylsuccinic Acid. Bromoacetic acid, 1.5 mmoles, and 1.5 mmoles of AT-hydroxysuccinimide dissolved in 6 ml of dioxane are coupled with 1.5 mmoles of dicyclohexylcarbodiimide for 2 hr at 0°. The urea derivative is removed by filtration, and the active ester in the dioxane solution is coupled with 1.2 mmoles of p-aminobenzyl-succinic acid dissolved in 4 ml of 80% dioxane. The reaction mixture is kept at room temperature for 6 hr and then evaporated to dryness. The oily residue is dissolved in ethyl acetate. The organic phase is washed twice with H2O, dried over NagSO, and evaporated to dryness. The compound crystallizes from ethyl acetate-petroleum ether m.p. 126°. 

Hi. BrAcEK [N- N"-Bromoacetyl-N -DNP-h-lysyl)-p-aminophenyl-/3-lactoside]. To a solution of bromoacetic acid (1 mmole) in p-dioxane (3 ml) are added A-hydroxysuccinimide (1.1 mmoles) and dicyclohexylcarbodiimide (1.5 mmoles). After reaction at room temperature for 90 min, the precipitated di cyclohexyl urea is removed by filtration and washed with dimethylformamide the combined filtrates are added to a solution of EK compound" (0.25 mmole) in dimethylformamide (2 ml). After 2 hr at room temperature, the solution is flash-evaporated to dryness, dissolved in the upper phase of n-butanol water glacial acetic acid (4 5 1, 10 ml), and separated for 50 transfers by countercurrent distribution. The upper phase from tubes 31 through 45 and lower phase from 34 through 42 are combined and flash-evaporated to dryness. The residue is triturated with ether and dried. The tritiated form of BrAcEK is obtained by using... 

Reduction of nitrophenylated oligonucleotides prior to acetylation increases the alkaline lability of the nitrophenyl phosphoester bond. Aminophenyl derivatives should, therefore, be used in acetylation reactions without unnecessary delay. It has been reported that amino-phenylated thymidylic acid can be bromoacetylated with the iV -hydroxy-succinimide ester of bromoacetic acid. This method was devised for acetylations of primary aliphatic amino groups. It is not feasible for acetylation of aminophenylated oligonucelotides. Instead, the anhydride of bromoacetic acid is employed in the acetylation reactions. Nucleosides are not attacked under the conditions of the acetylation reactions employed. 

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