Conversion COOH functional group

Selective reduction of —COOH to —CHiOH. Chemoselective reduction of car-boxylic acids is possible by in situ conversion to the carboxymethyleneiminium salt by reaction with the Vilsmeier reagent (DMF and oxalyl chloride). This salt is then reduced with NaBH4 (2 equiv.) to the alcohol (equation I). Various functional groups are tolerated bromo, cyano, ester, and C=C (even when conjugated to COOH). 

This polycondensation reaction follows a second-order kinetics at conversions up to about 98. It becomes a third-order reaction at higher conversion where it is catalyzed by [COOH] end groups. In the presence of water, the overall rate of reaction is a function... 

GVGVP GFGVP GVGVP GVGK[NMeN]P) D-K/IF of Table 5.5, where n is for the aspartic acid residue with the side chain, -CH2-COOH, that accompanies the N-methyl nicotinamide functional group attached to a lysine side chain. Reduction of NMeN to form NMeN shifts the transition zone for protonation of the carboxyl function by 2.5 pH units. This shows electrochemical transduction, the conversion of electrical energy into chemical energy. In particular, the reduction reaction is carried out near pH 9, where the reduced NMeN is most stable. 

Organoboranes are important in organic synthesis as reactive intermediates. Reactions have been developed by which the boron atom may be replaced by a wide variety of functional groups, such as —H, —OH, —NH2, —Br, —1, and —COOH.The present experiment demonstrates the conversion of an organoborane to an alcohol by oxidation with alkaline hydrogen peroxide. It is not necessary to isolate the organoborane prior to its oxidation. This simplification is particularly fortuitous in this case, since most alkylboranes, when not in solution, are pyrophoric (spontaneously flammable in air). 

Placing functional groups on the terminal chain end(s) of anionic polymers (e.g. by conversion of active centres to —OH and —COOH groups) by reaction with ethylene oxide or carbon dioxide, followed by hydrolysis, is of interest because of the potential for further chain extension and reactions through the reactive end groups. Diene polymers with functional groups have been prepared with mono- and multi-lithium initiators, as well as with functionalized organolithium initiators. 

Conversely, dramatic amounts of induced defects throughout functionalization hamper the intrinsic mobUily of carriers along CNTs, which is not desirable in any case (Naeimi et al. 2009 Liu et al. 2011 Zhong et al. 2011). The carboxylation technique not only functionalizes the CNTs exterior with COOH groups, but also leaves behind unfavorable stractures, thus hampering their potential for practical purposes (Zhong et al. 2011). This in turn compromises the mechanical properties of CNTs. Moreover the concentrated acids or strong oxidants often used for CNTs functionalization are environmental unfriendly (Liu et al. 2011). 

The chemical structures of monomers derived from chohc acid, the most frequently used bUe acid in this respect, are shown in Fig. 9. The methacrylate derivatives of bile acids, containing one (lithochohc acid), two (deoxychohc acid), or three (cholic acid) OH groups (see Scheme 1 la), have been prepared. The COOH is protected by an ester group, and the OH at C3 position can be selectively functionalized with methacryloyl and a spacer in between [211, 212]. The (co)polymerization is initiated by AIBN at elevated temperature with or without comonomers (i.e., styrene and MM A). High MWs are acquired at low monomer conversion. 

If the initial concentration of the carboxyHc acid group is [—COOH]q, then its concentration at any time can be expressed as a function of the conversion, p, as follows ... 

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