JV-hydroxysuccinimide

Labeling of nucleic acids via JV-hydroxysuccinimide (NHS) esters of fluorescein (Research Organics) or Eu -chelates is straightforward. Nucleic acid should then possess reactive amino groups. These can be introduced by transamination (Section 7.8.1) or by using amino-hexyl-dNTP or AH-NTP as precursors during enzymatic probe synthesis (Section 7.6.2.2 Folsom et al., 1989). After AH-NTP incorporation in RNA (or AH-dNTP in DNA and heat-denaturation), the nucleic acid is diluted to 1 p,g in 25 p,l of HjO and added to 25 xl of freshly prepared 0.4 M sodium bicarbonate (pH about 8.2) and then to 10 pel of ester in DMF (1.7 mg/ml of ester final concentration). After incubation for 2 h, the reaction is stopped by adding 50 g.1 of 1... 

More recently, newer types of blocking agents have been reported such as -hydroxyphthalimide and JV-hydroxysuccinimide (64). aromatic triazoles (65). and substituted imidazolines and tetrahydropyrimidines (66). Ulrich et al. (67-69) have demonstrated that raacrocyclic ureas will dissociate thermally to yield amido isocyanates ... 

Similar simple reactions can be carried out in solution. Terminal hydroxy groups can be esterified with trifluoroacetic anhydride or glutaric anhydride , although the reaction in the latter case is probably incomplete. Amino groups in the monolayer of cysteamine were reported to react with active esters, such as JV-hydroxysuccinimide (equation 8) . No characterization of the resultant monolayer was, however, given. Cysteamine mono-layers were also acylated with terephthaloyl chloride and an isocyanate derivative . ... 

The syntheses of the cyclic esters (9) and (10) derived from oxalic and phthalic acids have been achieved using the acid dichlorides and methyl 4,6-0-benzylidene-a-D-glucopyranoside. The compounds 2-, 3-, and 6-amino-6-deoxy-D-glucose have been converted into their iV-(3-hydroxytetradecanoyl) derivatives by treatment with JV-hydroxysuccinimide and 3-hydroxytetradecanoic acid. The m.s. of the TMS derivatives provided data useful in locating the position of the A -acyl group. 

For most biological studies, the ICPs have been prepared in the form of a flat film although some tubular structures have also been prepared. An evolving area of interest is the synthesis of high surface area bioactive colloidal systems [32]. PPy-polystyrene core latex particles with an inner core 600 nm in diameter have been functionalized with JV-succinimidyl ester [33,34] and JV-hydroxysuccinimide [35] to introduce protein-binding capacity. Functionalization of these particles exhibited a high degree of... 

Hydrolysis at pH 5 of the exo- and endo-cis-carboxyphosphates (660) reveals carboxyl assistance accelerating the rate by 10 . ° The C—N bond cleavage accompanying Eschweiler-Clark methylation of (661) involves a 1,3-hydride transfer. The conformation of 3-(iV-methylamino)thiocarbonylcamphor is revealed by i.r., u.v., c.d., 4nd dipole moment studies. An imidazolyl bicycloheptanol cinnamate (662) has been prepared as a model for the enzyme chymotrypsin, and the hydroxy-imide (663) is superior to JV-hydroxysuccinimide in effecting (along with DCC) synthesis of peptides. ... 

Symbols EDC l-ethyl-3-(3-methylaminopropyl)carbodiimide, DCC JV,N -dicyclohexylcabordiimide, HOBt hydroxybenzotriazole, NHS JV-hydroxysuccinimide, MNps metal nanoparticles, DBU l,8-Diazabicyclo[5.4.0]undec-7-ene, and PMDETA JV,JV,N, N, N "-pentamethyldiethylenetrianiine, DMF dimethylformamide. 

Peptide Coupling. These thiol esters have been used in the synthesis of several dipeptides. Many of the examples involve highly sterically hindered amino acids and result in very good yields and high optical purity (eq A). There are many useful active esters for peptide coupling, such as pentafluorophenol, p-nitrophenol, and jV-hydroxysuccinimide. However, these do not work as well with the hindered amino acids shown in eq 4. Additionally, there are many direct coupling procedures therefore the 2-pyridylthiol esters have not been used frequently. 

Figure 2.10 Synthesis of JV-hydroxysuccinimid side functional polymer and postfunctionalization with sugar amine to obtain final a glycopolymer. ...

Method A. A solution of 1.1 mg (9.6 /amoles) of jV-hydroxysuccinimide (purified by recrystallization from ethyl acetate) in 20 /tl of redistilled dimethylformamide and a solution of 2.3 mg (11 /imoles) of. V,A -dicyclo-hexylcarbodiimide (purified by distillation) in 20 /xl of the same solvent are added sequentially to a lyophilized powder of 2-["C]bromoacetic acid (1.3 mg, 9.3 /imoles 27 Ci/mole). After mixing, the resultant clear solution is incubated at room temperature for 45 min. A precipitate of crystalline dicyclohexylurea forms in the course of the incubation. A micropipette, made by drawing out the narrow part of a disposable Pasteur pipette (9 inches long), is used to transfer the supernatant liquid, without disturbing the precipitate, to a 12-ml conical centrifuge tube containing 7.4 mg (8.3 //.moles) of (sodium salt pentahydrate). Two rinses, each with 20 //I of dimethylformamide, are transferred similarly. 

The amine derivative [NHNP-E, compound (I) ] (100 mg, 0.3 mmole) is partially dissolved in 2 ml of ether-dioxane mixture (1 1). Triethyla-mine (0.08 ml, 0.57 mmole) is added, and the mixture is heated to 50° to complete neutralization. Then jV-hydroxysuccinimide ester of bromoacetic acid, dissolved in 0.2 ml of dioxane, is added (0.3 mmole 10% excess), and the reaction is carried out at room temperature with occasional stirring. After 1 hr the reaction mixture is evaporated and the residue is washed with ether and water at pH 5.5. The white precipitate is dried over H0SO4. Overall yield 40%. 

A-(Ethyl-2-diazomalonyl)Phe-tRNA is obtained by acylation of Phe-tRNA with ethyl-2-diazomalonyl-JV-hydroxysuccinimide ester. The praparation of the reagent and its reaction with tRNA are schematically represented in Fig. 1. 

The best known group of this class is the t-butyloxycarbonyl(t-BOC) (45). Since its introduction as an amino-protecting group in peptide synthesis about seven years ago it became second in use only to the benzyloxycarbonyl group. Due to the instability of t-butylchloro-formate the /-butyloxycarbonyl derivatives are obtained by reaction of the corresponding isocyanate with t-butanoD or by the action of the amine with t-butyl-/ -nitrophenyl carbonate t-butylazido-formate , <-butylcyanoformate , t-butyl JV-hydroxysuccinimide... 

It is possible to convert the azide to a stable form that may be conveniently handled by reaction with JV-hydroxysuccinimide ... 

Esters of 3-hydroxypyridines [139], iV-hydroxysuccinimide [140], JV-hydroxyphthalimide [141], and iV-hydroxypiperidine [142] also of various iV-iV-dialkyl substituted hydroxylamines [142] have found analogous use in peptide synthesis to activate the carbonyl group of the acid towards nucleophilic attack and... 

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