A-Carboxyl groups

Salicylic acid. The preparation of salicylic acid by passing carbon dioxide into dry sodium phenoxide at 170-190° is the classical example of the Kolbe-Schmltt reaction. The latter is a method for introducing a carboxyl group directly into a phenol nucleus. 

On account of the high degree of stability of the thiazole ring a large variety of substituted derivatives yield thiazolecarboxylic acids upon oxidation. The oxidation of a methyl group or a substituted methyl group to a carboxyl group has been accomplished in a few instances. 

Because it may be oxidized to a carboxyl group (Section 11 13) a methyl group can be used to introduce the nitro substituent m the proper position... 

When a carboxyl group is attached to a ring the parent ring is named (retaining the final e) and the suffix carboxylic acid is added as shown m entries 8 and 9... 

A primary or secondary alkyl side chain on an aromatic ring is converted to a carboxyl group by reaction with a strong oxidizing agent such as potassium permanga nate or chromic acid... 

Section 19 15 An intramolecular esterification can occur when a molecule contains both a hydroxyl and a carboxyl group Cyclic esters are called lactones and are most stable when the nng is five or six membered... 

Acyl Halides. Acyl halides, in which the hydroxyl portion of a carboxyl group is replaced by a halogen, are named by placing the name of the corresponding halide after that of the acyl radical. When another group is present that has priority for citation as principal group or when the acyl halide is attached to a side chain, the prefix haloformyl- is used as, for example, in fiuoro-formyl-. 

Many trivial names exist for acids these are listed in Table 1.11. Generally, radicals are formed by replacing -ic acid by -oyL When a trivial name is given to an acyclic monoacid or diacid, the numeral 1 is always given as locant to the carbon atom of a carboxyl group in the acid or to the carbon atom with a free valence in the radical RCO—. 

A linear molecule has a carboxyl group at one end and an amino group at the other, such as poly(e-caprolactam) ... 

If a polyamide is prepared in the presence of a large excess of dicarboxylic acid, the average chain will have a carboxyl group at each end ... 

The A/-carboxyl group is lost duting the reaction, and no additional deprotection step is requited (104). Benzene reacts with A/-carboxyglyciae anhydride to give aminomethyl phenyl ketone however, it does not react with other A/-carboxy-a-amino acid anhydrides (105). 

A hydroxyl group is situated ortho to a carboxyl group which as a bidentate ligand is terminally metallized on the fiber when aftertreated with dichromate. An example is Alizarine Yellow GG [584-42-9] (50) (Cl Mordant Yellow 1 Cl 14025). Cr(III) has a coordination number of six, and therefore normally two dye molecules of the sahcyhc type are chelated to the metal ion. 

Ring closure resulting from attack of a heteroatom on a carboxyl group or its equivalent is merely a case of intramolecular esterification or amide formation. The y-butyrolactones or pyrrolidones obtained from such reactions are usually regarded as the province of aliphatic chemistry, so only a few examples are offered by way of illustration in Scheme 15. 

Muzolimine (710), a 1-substituted 2-pyrazolin-5-one derivative, is a highly active diuretic, differing from the structures of other diuretics since it contains neither a sulfonamide nor a carboxyl group. It has a saluretic effect similar to furosemide and acts in the proximal tubule and in the medullary portion of the ascending limb of the loop of Henle. Pharmacokinetic studies in dogs, healthy volunteers and in patients with renal insufficiency show that the compound is readily absorbed after oral administration (B-80MI40406). 

Ph3COSiMc3, Me3SiOTf, CH2CI2, 0°, 0.5 h, 73-97% yield. These conditions will also introduce the trityl group on a carboxyl group. The primary hydroxyl of persilylated ribose was selectively derivatized. 

The SEM ester was used to protect a carboxyl group where DCC-mediated esterification caused destruction of the substrate. It was formed from the acid and SEM chloride (THF, 0°, 80% yield) and was removed solvolytically. The ease of removal in this case was attributed to anchimeric assistance by the phosphate group. Normally SEM groups are cleaved by treatment with fluoride ion. Note that in this case the SEM group is removed considerably faster than the phenyl groups from the phosphate. ... 

All of the 20 amino acids have in common a central carbon atom (Co) to which are attached a hydrogen atom, an amino group (NH2), and a carboxyl group (COOH) (Figure 1.2a). What distinguishes one amino acid from another is the side chain attached to the Ca through its fourth valence. There are 20 different side chains specified by the genetic code others occur, in rare cases, as" the products of enzymatic modifications after translation. 

Figure 1.2 Proteins are built up by amino acids that are linked by peptide bonds to form a polypeptide chain, (a) Schematic diagram of an amino acid. Illustrating the nomenclature used in this book. A central carbon atom (Ca) is attached to an amino group (NH2), a carboxyl group (COOH), a hydrogen atom (H), and a side chain (R). (b) In a polypeptide chain the carboxyl group of amino acid n has formed a peptide bond, C-N, to the amino group of amino acid + 1. One water molecule is eliminated in this process. The repeating units, which are called residues, are divided into main-chain atoms and side chains. The main-chain part, which is identical in all residues, contains a central Ca atom attached to an NH group, a C =0 group, and an H atom. The side chain R, which is different for different residues, is bound to the Ca atom.

This was transformed into the quaternary d-bromocamphorsulphonate, m.p. 265°, but no resolution has yet been effected. The lactam of 3-carboxyhexahydrocarbazole-1 ll-)3 8 -dipropionic acid (XXIV, with a carboxyl group at C ), CigH jO N, rn.p. 257-8°, has also been prepared. The same authors, with Holmes, have synthesised the lactam of 11-ethylhexahydrocarbazole-l-)3-propionic acid, Ci,H3iON, m.p. 106-8-107-5°, of which (XXrV) is a carboxy-derivative. 

Besides sulfur tetrafluonde, only a very few reagents can convert a carboxylic group into a trifluoromethyl group... 

The difluoromethyl group in chlorofluoroalkanes can be oxidized into a carboxylic group by a mixture of chlorine and dinitrogen tetroxide at high temperatures [2] (equation 1)... 

Potassium permanganate oxidation of a vinyl group to a carboxyl group can be used to prepare fluormated carboxyhc acids with aliphatic [3/ ] (equanon 30) or alicychc 39] (equation 31) skeletons... 

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