Carboxymethyl group

Azoleacetic acids with a carboxymethyl group also decarboxylate readily, e.g. all three thiazole isomers, by a mechanism similar to that for the decarboxylation of /3-keto acids cf. Section 4.02.3.1.2. The mechanism has been investigated in the oxazole case, (396) (397) (398) <72JCS(P2)1077). 

Similarly, the position of the acyl group in derivatives formed by the reaction with acetic hydride or benzoyl chloride and the position of the carboxymethyl group in the derivative formed by the reaction with chloracetic acid are not established. ... 

Starches can have a hydrogen replaced by something else, such as a carboxymethyl group, making carboxymethyl starch. 

Adding the carboxymethyl group makes the starch less prone to damage by heat and bacteria. Carboxymethyl starch is used as an additive in oil drilling mud. It is also used in the goo that makes ultrasound examinations so messy. Carboxymethyl starch is also called a starch ether. 

Carboxymethyl groups make the starch more hydrophilic (water-loving), and aid in cross-linking. This makes carboxymethyl starch useful in aspirin and other tablets to make them disintegrate quickly. 

I4, (o) 5FU. aDegree of substitution of carboxymethyl groups based on the number of sugar groups. 

Various compounds bearing a carboxymethyl group at position 1 and a car-boxymethylamino function at position 3, including ACE inhibitors (27, 28), have been claimed as cholecystokinin (CCK)-antagonists [76-78]. Analogous compounds with a 3-hydroxy-2-oxopropyl moiety at position I are also claimed to be useful as antihypertensives and CCK antagonists [79],... 

The amide type local anesthetic lidocaine is broken down primarily in the liver by oxidative N-dealkylation. This step can occur only to a restricted extent in prilocaine and articaine because both carry a substituent on the C-atom adjacent to the nitrogen group. Articaine possesses a carboxymethyl group on its thiophen ring. At this position, ester cleavage can occur, resulting in the formation of a polar -COO group, loss of the amphiphilic character, and conversion to an inactive metabolite. 

A stereochemical property of compounds arising from the ability of an enzyme s active site to distinguish between two chemically identical substituents covalently bound to a tetrahedral center (usually carbon and, in some cases, phosphorus). Prochirality is also termed prostereoisomerism. The classical example is citrate with its two carboxymethyl group substituents. Likewise, the Cl carbon atom of ethanol has two prochiral hydrogens. See Chirality Chirality Probes... 

Gly is derived from Ser by removal of the carboxymethyl group of the side chain. 

Simple considerations such as these account adequately for many of the familiar reactions of substituted 7r-deficient heterocycles, such as nucleophilic displacement, tautomerism in hydroxy, mercapto and amino heterocycles, facile deprotonation of alkyl substituents, decarboxylation of carboxymethyl groups and electrophilic substitution of benzo-fused and aryl-substituted heterocycles. These individual effects are discussed separately in the following subsections. 

Side-chain carboxylic acids containing a carboxymethyl group a or y to the ring nitrogen are susceptible to facile decarboxylation (Scheme 75). The process is analogous to that with /3-keto acids and it is often very difficult to isolate the compounds (64CPB588). In consequence, it is usual to isolate them as esters or other suitable derivatives (see example in Scheme 55) (550SC(3)413). 

In contrast, when the carboxymethyl group is placed /3 to the ring nitrogen the acids are much more stable and higher temperatures are needed to effect decarboxylation (Scheme 76) (59JA740). 

A carboxymethyl group at position 4 of the quinolizinium ring undergoes decarboxylation in excellent yield (Scheme 42) (76JCS(P1)341). 

Pyridines with an a- or y-carboxymethyl group (e.g. 685) undergo facile decarboxylation by a zwitterion mechanism (685 — 688) somewhat similar to that for the decarboxylation of 3-keto acids (cf. Section 3.2.3.1.1). Carboxymethylpyridines often decarboxylate spontaneously on formation thus, hydrolysis of (689) gives (690). The corresponding 2- and 4-pyridone and 2- and 4-pyrone acids are somewhat more stable, e.g. (691) decarboxylates at 170°C. 3-Pyridineacetic acid shows no pronounced tendency to decarboxylate. 

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