Carboxylic acids derivatization

Sastry, M., Patil, V, and Sainkar, S.R.J. 1998. Electrostatically controlled diffusion of carboxylic acid derivatized silver colloidal particles in thermally evaporated fatty amine films. Journal of Physical Chemistry B, 102 1404-10. 

The anhydride was formed as a side product in this reaction impacting yield. However, in an RP mobile phase, both the mesylate and anhydride would revert back to the carboxylic acid. Derivatization would produce the same product for both the mesylate and the anhydride. The reaction components were separated and quantihed under NP conditions using a diol column with a 0.1v/v% TFA in heptane/THF mobile phase (Figure 14-2). This method was used monitor the reaction such that the level of the carboxylic acid intermediate was less than 0.5% in the reaction mixture. 

Palladium-catalyzed cyclopropanation using diazomethane has been achieved stereoselectively on a series of a,)9-unsaturated carboxylic acids derivatized with camphorsultam as a chiral auxiliary. The selectivity of the reaction produces cyclopropanated products 22 with the absolute configuration. The stereoselectivity of the reactions is temperature dependent. Several A-enoylsultams 21 were successfully cyclopropanated in this manner. It was found that branching at the a- or /i-carbons disfavors complete conversion an electron-withdrawing substituent at the )9-position is particularly unfavorable. The chiral auxiliary was removed by using titanium(IV) isopropoxide in benzyl alcohol followed by alkaline hydrolysis of the intermediate ester providing cyclopropanated derivatives 23b of high diastereomeric purity. ... 

Recently, Bayliss et al. [132] described the synthesis of anthracene-9-carbonyl chloride and its aplications as a label for fluorescence and UV absorbance detection of hydroxy compounds. The preparation and properties of esters of short-chain alcohols, diols, trichothecene mycotoxins and sterols were investigated. Anthracene-9-carbonyl chloride was prepared from commercial anthracene-9-carboxylic acid. Derivatization was carried out in acetonitrile free from water or active hydrogen compounds. The reaction rate was dejjendent on the structure of the alcohol. The derivatization of diethylene glycol was complete at ambient temp>erature within 10 min (0.25 M reagent) or 30 min (0.1 M reagent) without a catalyst, but required 1 h for diolesteroL testosterone and the trichothecene T-2 toxin. For sterically hindered alcohols such as t-butanol and 17a-methyl-testosterone, more than 10 h, or refluxing for 1 h, was needed to complete the reaction. The derivatives had absorption maxima at 250 run. Both normal and reversed phase HPLC were applied to the separation of the derivatives. 

Keeping the above-mentioned prerequisites in mind, a ROMP-based precipitation copolymerization setup was created. In this setup, living homopolymers prepared from a functional monomer were finally cross-linked to form polymeric beads approximately 30-60 pm in size. For the s)mthesis of carboxylic acid-derivatized particles, DMN-H6 was used as a CTOss-linker and its copolymerization with NDCA using the well-defined Schrock initiator Mo(N-2,6-i-Pr2-(C6H3) (CHCMe2Ph)(OCMe(CF3)2)2 was established for the synthesis of high-capacity, wc-dicarboxylic acid-derivatized resins (Scheme 18). 

There are ill-defined limits on EI/CI usage, based mostly on these issues of volatility and thermal stability. Sometimes these limits can be extended by preparation of a suitable chemical derivative. For example, polar carboxylic acids generally give either no or only a poor yield of molecular ions, but their conversion into methyl esters affords less polar, more volatile materials that can be examined easily by EL In the absence of an alternative method of ionization, EI/CI can still be used with clever manipulation of chemical derivatization techniques. 

A.ldehyde Syntheses. Aromatic (Ar) carboxylic acids are reduced to the corresponding aldehydes by a sequence of steps known as the McFadyen-Stevens reaction. The acid is converted to the hydrazide, derivatized with benzenesulfonylchloride, then decomposed to the aldehyde in hot glycol in the presence of a base ... 

Pentafluorobenzyl bromide has been used in the derivatization of mercaptans [55] and phenols [36], m the analysis of prostaglandins [37], and in quantitative GC-MS [5S] 1,3 Dichlorotetrafluoroacetone is used for the derivatization of amino acids to the corresponding cyclic oxazolidinones and allows the rapid analysis of all 20 protein ammo acids [d] Pentafluorophenyldialkylchlorosilane derivatives have facilitated the gas chromatographic analysis of a wide range of functionally substituted organic compounds, including steroids, alcohols, phenols, amines, carboxylic acids, and chlorohydrms [4]... 

Methyl-substituted primary alcohols can be separated after derivatization with [6-methoxy-2,5,7,8-tetramethylchromane-2-carboxylic acid] (Trolox M methyl ether) [13] while sec.- and tert.-alcohols are derivatized with 2-dimethylamino-l,3-dimethyl-octahydro-lf/-l,3,2-benzodiazaphosphole [14] (Eig. 7-5). 

The latter approach is used in the enantioselective determination of a Phase I metabolite of the antihistaminic drug, terfenadine. Terfenadine is metabolized to several Phase I compounds (Fig. 7-13), among which the carboxylic acid MDL 16.455 is an active metabolite for which plasma concentrations must often be determined. Although terfenadine can be separated directly on Chiralpak AD - an amy-lose-based CSP - the adsorption of the metabolite MDL 16.455 is too high to permit adequate resolution. By derivatizing the plasma sample with diazomethane, the carboxylic acid is converted selectively to the methyl ester, which can be separated in the presence of all other plasma compounds on the above-mentioned CSP Chiralpak AD [24] (Fig. 7-14). Recently, MDL 16.455 has been introduced as a new antihistaminic drug, fexofenadine. 

C. Aromatic Carboxylic Acids (See the following derivatization procedures.)... 

GC separation of derivatized carboxylic acids, 46-52 bacterial fatty acids, 51-52 bile acids, 50-51 C6-C24 monocarboxylic acids and dicarboxylic acids, 51 cyano acids, 52 higher-boiling acids, 49 itaconic acid, citraconic acid, and mesaconic acid, 49... 

The Ugi reaction is the four-component condensation of an amine, aldehyde or ketone, carboxylic acid and isocyanide to give an o -acylamino amide [22-24], Although this process has the potential to introduce considerable diversity, the products themselves are not heterocycles but through appropriate choice of substrates, latent functionality in one of the precursors can intercept either an intermediate or further derivatize the acylamino amide Ugi product through post-modification. Thus variants of the Ugi reaction have been investigated under microwave-assisted conditions for the synthesis of diverse heterocyclic libraries [16,19-24],... 

Reactions of Free and Derivatized Carboxylic Acids and Carbon Dioxide... 

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