Esterification carboxymethylation

Carboxymethyl-l,5-naphthyridine 1-oxide (13, R = H) underwent esterification to 4-ethoxycarbonylmethyl-l,5-naphthyridine 1-oxide (13, R = Et) (substrate, SOCl2, EtOH, reflux until clear 88%)814 also analogs (see original for details).330... 

A carboxyl group can be introduced in almost any compound by various methods. In cases where a free thiol is present, the carboxyl group can be introduced easily by reaction with bromo- or iodoacetic acid. This reaction is very mild and is usually performed at pH around 8-9. When the hapten contains a hydroxyl group, carboxylic acid may be introduced by one of the following methods (a) carboxymethylation of the hydroxyl group with bromo- or iodoacetic acid (b) esterification with dicarboxylic acid anhydrides, such as succinic anhydride, to yield hemi-succinates, which are unstable above pH 9 (c) reaction with phosgene, which results in the formation of chlorocarbonates. ... 

For example, 5-acryloyloxyethoxycarbonylmethyl-7-hydroxy-1,2,4-triazolo[1.5-a]pyrimidine, c.f. Figure 9.7, can be obtained from 7-hydroxy-5-carboxymethyl-l,2,4-triazolo[l,5-a]pyrimidine by esterification with 2-hydroxyethyl acrylate. This compound has a vinyl group, thus it can be copolymerized with vinylic monomers. 2-Acrylamido-2-methylprop-... 

Alkylation of metal chelates of sucrose with allyl halides and sodium bromo-acetate in DMSO yielded mono-O-allylated and mono-O-carboxymethylated derivatives. A new acidic monosaccharide from the O-specific lipopolysaccharide of Shigella dysenteriae type 3 has been identified as 4-0-[(/ )-l-carboxy-ethyl]-D-glucopyranose on the basis of chemical and mass-spectral evidence and by its synthesis by alkylation of methyl 2,3,6-tri-0-benzyl-a(P)-D-glucopyranoside with (5)-2-chloropropionic acid, esterification (with diazomethane), hydrogenolysis, and acid hydrolysis. ... 

A study has been made of the thermal stability of amylose and some of its derivatives, viz., amylose palmitate, amylose succinate, and sodium carboxy-methylamylose. Results indicated that except for amylose succinate, esterification increased the thermal stability of all the amylosic derivatives compared to amylose. The order of stability noted was amylose palmitate > amylose acetate > amylose propionate > amylose > sodium carboxymethyl-amylose > amylose succinate. 

Various sulfonium compounds as substrate for the enzyme Various sulfonium compounds were tested for their ability as methyl donor for the carboxymethyl esterification of ACTH by the action of protein methylase II. As shown in Table I, besides the natural methyl donor, only S-adenosyl-L-(2-hydroxy-4-methylthio)-butyric acid showed a moderate activity. The other compounds were found to be inactive within the limits of accuracy of the analyti-cal test. 

A series of covalently supported ILs with magnetite core and silica gel shell were prepared for the immobilization of C. rugosa lipase [123]. The immobihzation of lipase was realized by adsorbing the lipase onto the support in a buffer solution. The immobilization promoted the thermal resistance of Hpase dramatically. The native lipase lost 70% activity after being treated at 60 °C. After immobihzation, its activity was maintained at >90%. The supported Hpase also had better reusabihty in the esterification reaction of oleic acid and butanol. The supported hpase retained 92% of its initial activity for the second ran, while its native counterpart retained only 35%. This makes the use of expensive enzymes more practical. Moreover, desorption experiments showed that the supported Hpase could endure 200 mM NaCl, Figure 2.39, while the commercial carboxymethyl cellulose-supported hpase lost about 90% of the enzyme when the NaCl concentration was 150 mM. 

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