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Carboxylic functions

Sections 27 15 through 27 17 describe the chemistry associated with the protection and deprotection of ammo and carboxyl functions along with methods for peptide bond formation The focus m those sections is on solution phase peptide synthesis Section 27 18 shows how these methods are adapted to solid phase synthesis... [Pg.1137]

While the previous receptors are typically used in organic solvents, except for the cyclodextrins, there are special cases of cyclophane receptors supphed with peripheral charges (ammonium units) (107—12) or ionizable groups (carboxylate functions) (113,114) (Fig. 17) to allow substrate recognition, as in nature, in an aqueous medium, profiting from the solvophobic effects of water (115). [Pg.184]

Because lactic acid has both hydroxyl and carboxyl functional groups, it undergoes iatramolecular or self-esterificatioa and forms linear polyesters, lactoyUactic acid (4) and higher poly(lactic acid)s, or the cycUc dimer 3,6-dimethyl-/)-dioxane-2,5-dione [95-96-5] (dilactide) (5). Whereas the linear polyesters, lactoyUactic acid and poly(lactic acid)s, are produced under typical condensation conditions such as by removal of water ia the preseace of acidic catalysts, the formation of dilactide with high yield and selectivity requires the use of special catalysts which are primarily weakly basic. The use of tin and ziac oxides and organostaimates and -titanates has been reported (6,21,22). [Pg.512]

Nylon resins are made by numerous methods (53) ranging from ester amidation (54) to the Schotten-Baumann synthesis (55). The most commonly used method for making nylon-6,6 and related resins is the heat-induced condensation of monomeric salt complexes (56). In this process, stoichiometric amounts of diacid and diamine react in water to form salts. Water is removed and further heating converts the carboxylate functions to amide linkages. Chain lengths are controlled by small amounts of monofunctional reagents. The molten finished nylon resin can be dkectly extmded to pellets. [Pg.266]

The Dim ester was developed for the protection of the carboxyl function during peptide synthesis. It is prepared by transesterification of amino acid methyl esters with 2-(hydroxymethyl)-l,3-dithiane and Al(/-PrO)3 (reflux, 4 h, 75°, 12 torr, 75% yield). It is removed by oxidation [H2O2, (NH4)2Mo04 pH 8, H2O, 60 min, 83% yield]. Since it must be removed by oxidation it is not compatible with.sulfur-containing amino acids such as cysteine and methionine. Its suitability for other, easily oxidized amino acids (e.g., tyrosine and tryptophan) must also be questioned. It is stable to CF3CO2H and HCl/ether. - ... [Pg.243]

Neoprene AF ( 963). It is a polychloroprene modified with methacrylic acid. Although it is a slow-crystallizing elastomer, the cohesive strength develops very rapidly and it has improved creep resistance at high temperature compared with Neoprene AC or AD. The improved properties of Neoprene AF are derived from the interaction between the carboxyl functionality with the metal oxides added in the solvent-borne polychloroprene adhesives. [Pg.593]

The most important single reactions produced in the carboxyl functionality of the resin acids are salt formation, Diels-Alder additions, and esterification. Other reactions, such as disproportionation and polymerization, are less important. For some specific applications, rosins are subjected to a combination of these reactions. [Pg.602]

Polyfluorinated a-diketones react with 1,2-diainino compounds, such as ortlio-phenylenediamine, to give 2,3-substituted quinoxalmes [103] Furthermore, the carboxyl function of trifluoropyruvates offers an additional electrophilic center. Cyclic products are obtained with binucleophiles [13, 104] With aliphatic or aromatic 1,2-diamines, six-memhered heterocycles are formed Anilines and phenols undergo C-alkylation with trifluoropyruvates in the ortho position followed by ring closure to form y-lactams and y-lactones [11, 13, 52, 53, 54] (equation 23). [Pg.851]

The use of carbonate precursor (56) allows the introduction of a carboxylic function in the cycloadduct. The proposed mechanism involves internal delivery of a Pd-bound carbon dioxide to the TMM unit as depicted in Scheme 2.17 [27, 28]. [Pg.67]

A key step in the synthesis of 13-membered meta ansa and 14-membered para ansa peptide alkaloids involves catalytic hydrogenolysis of carbobenzyl-oxypeptide pentafluorophenyl esters. The most suitable solvent is dioxane with addition of a catalytic amount of pyrrolidinopyridine and 2% ethanol. Temperature should not exceed 90°C. The authors believe that after deblocking, the amino function remains on the surface until ring formation with the activated carboxylic function is accomplished (/5/). [Pg.161]

Ethyl H-, 2-diazepine-l-carboxylate functions as a 2 -component in the Diels-Alder reaction with tetrachloro-l,2-benzoquinone to give a mixture of the regioisomers 20 and 21.100... [Pg.345]

Aromatic diazonium salts react easily in neutral aqueous solution with thiols such as N-acetylcysteine, forming compounds of the type Ar — N2 —S —CH2CH(NHAc) COOH. Nifontov et al. (1990) suggested that such compounds, e.g., that of 5-diazo-imidazole-4-carboxylate, function as a form of transport depot for cytotoxic diazo-carboxylate in the human body. [Pg.117]

The first example of microwave-promoted solid-phase methodology in heterocyclic chemistry was the arylation of thiophene and indole via Suzuki couplings on TentaGel S RAM resin, as demonstrated by Hallberg and coworkers in 1996, before temperature- and pressure-controlled microwave instruments were even available [189]. Three years later Schotten and coworkers presented analogous but aqueous Suzuki couplings of 5-bromo-thiophene anchored to PEG soluble support via a carboxylic function at its C-2 position [116]. Unfortunately, this work was performed in a do-... [Pg.122]

An interesting variation of this reaction that made use of a three-component, one-pot solventless procedure with the corresponding trialkyl phosphites gave dramatically improved yields of many heterosubstituted glyphosate phosphonate diesters (37). When exactly one equivalent of water, 25, and tris-p-chloroethyl phosphite were mixed and heated under neat conditions for a few hours, nearly quantitative yields of displaced p-chloroethanol and the desired triester product 27 were obtained. If desired, the displaced alcohol was first removed by vacuum distillation, or the mixture could be hydrolyzed directly to GLYH3. Various oxygen, sulfur, nitrogen, cyano, and carboxylate functionalities were similarly accommodated in the trialkyl phosphite. [Pg.23]

Primary phosphines (R-PHj) are an important ciass of compounds in organophosphorus chemistry. Aithough discovered over a century ago, their chemistry and appiications have gained prominence in recent years. This review discusses recent deveiopments on synthesis, moiecuiar structure, properties, and appiications of primary phosphines. In particular, discussions on synthesis and properties emphasize recent results from our laboratory on the chemical architecture of amide, thioether, and carboxylate functionalized primary bisphos-phines. The utility of bromo- and aminopropyl phosphines (X(CH2)3PH2 X=Br or NH2) as building blocks to produce designer primary phosphines that display exceptional oxidative stability is described. The review also discusses the utility of carboxylate functionalized primary phosphines for incorporation on to peptides and their potential applications in catalysis and biomedicine. [Pg.121]

Scheme 7. Synthesis of carboxylate functionalized primary phosphine 18... Scheme 7. Synthesis of carboxylate functionalized primary phosphine 18...
The carboxylate functionalized primary bisphosphines P2S2COOH 18 and P2N2COOH 19 (Schemes 7 and 8) provide new opportunities for use in catalytic and biomedical motifs. The carboxylate groups in 18 and 19 can be used to conjugate these phosphine hgating units on to peptides or proteins. [Pg.136]


See other pages where Carboxylic functions is mentioned: [Pg.231]    [Pg.794]    [Pg.815]    [Pg.75]    [Pg.166]    [Pg.296]    [Pg.596]    [Pg.85]    [Pg.4]    [Pg.16]    [Pg.561]    [Pg.815]    [Pg.40]    [Pg.91]    [Pg.164]    [Pg.570]    [Pg.635]    [Pg.635]    [Pg.50]    [Pg.243]    [Pg.251]    [Pg.553]    [Pg.601]    [Pg.760]    [Pg.772]    [Pg.43]    [Pg.8]    [Pg.169]    [Pg.121]    [Pg.128]    [Pg.130]   
See also in sourсe #XX -- [ Pg.308 ]

See also in sourсe #XX -- [ Pg.308 ]




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Acid, carboxylic water-polymer functional group

Bases carboxylic acid functionality

Bases carboxylic acid functionality attachment

Biotin, carboxylations with function

Carbohydrate functionalized polymers carboxylic acid

Carbon nanotubes functionalizing carboxylic acid functionalities

Carbonyl functional groups carboxylic acids

Carboxyl ester lipase function

Carboxyl functional group

Carboxyl functional thermoplastic acrylic

Carboxyl functional vinyl copolymer resin

Carboxyl functionality

Carboxyl functionality

Carboxyl groups, protection functional group

Carboxyl radicals functional group comparability

Carboxyl radicals functional group compatability

Carboxyl-functionalized

Carboxyl-functionalized MWNT

Carboxylate functional groups

Carboxylate functionality

Carboxylate functionality

Carboxylate functionality, polymers

Carboxylate-functionalized polymer

Carboxylation functionalized polymers

Carboxylic acid derivatives, functional groups

Carboxylic acid derivatives, functional groups among

Carboxylic acid function, alternatives

Carboxylic acid functional group

Carboxylic acid-functionalized mesogen

Carboxylic acid-functionalized tris

Carboxylic acids functional class nomenclature

Carboxylic acids functional group and compound clas

Carboxylic acids functional groups, glucuronic acid

Carboxylic acids, functional derivatives

Carboxylic acids, functional derivatives Acid anhydrides, Amides, carbonic

Carboxylic acids, functional derivatives characteristic reactions

Carboxylic acids, functional derivatives compounds

Carboxylic acids, functional derivatives nomenclature

Carboxylic acids, functional derivatives reaction with alcohols

Carboxylic acids, functional derivatives reaction with water

Carboxylic acids, functional derivatives reactions with organometallic

Carboxylic acids, functional derivatives reduction

Carboxylic acids, functional derivatives structure

Carboxylic acids, functional derivatives sulfonamides

Carboxylic function activation, during

Carboxylic function activation, during peptide synthesis

Carboxylic function, introduction

Carboxylic functional groups

Carboxylic functionalities

Carboxylic functionalities

Carboxylic functionalized

Carboxylic functionalized

Carboxylic functionalized SWCNTs

Carboxylic-functionalization

Carboxylic-functionalization

Cephalosporin 3-carboxyl-functionalized

Defect Functionalization - Transformation of Carboxylic Functions

Functional carboxylic acid

Functional derivatives, of carboxylic acids

Functional group activation carboxylic acids

Functional group equivalents carboxylic acids

Functional group equivalents protected carboxylic acids

Functional groups carboxy 1/carboxylate

Functional groups carboxylic amides

Functional groups carboxylic esters

Functional groups, organic carboxylic acid

Functionalization to Form Carboxyl Groups

Functionalized carboxylate

Functionalized carboxylate

Functionally Substituted Triorganogermanium Carboxylates

Functionally Substituted Triorganolead Carboxylates

Latent carboxylic acid functional group

Linkers for Carboxyl Functions

Olefins and Functional Derivatives in the Presence of Carboxylic Acids, Thiols, Amines or Hydrogen Chloride

Peptide Chain at the Carboxyl Function of MDP

Porphyrins carboxylate-functionalized

Reactions at the Carboxyl Functions

Reactive Polymers with Carboxylic Acid Functionality

Reducible Functional Groups Reductive Amination with Carboxylic Acids

Resins carboxyl-functionalized

Saturated carboxylic acids, functional groups

Single-walled carbon nanotube carboxylic acid-functionalized SWNTs

Tetraphenylporphyrins with carboxylate functionalities

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