A-Aminoacetic acid

Alkylation of trifluoro- and trichloroacetamides with a-bromoacetic esters has been utilized for the synthesis of a wide range of a-aminoacetic acids [11-13] (Table 5.13). Hydrolysis of the intermediate a-trihaloacetamidoacetic esters with methanolic potassium hydroxide converts the methyl and ethyl esters directly into the amino carboxylic acids. /-Butyl a-aminoacetates are more stable, but they are hydrolysed under phase-transfer catalytic conditions (see Chapter 9.2). Reaction of the trihaloacetamides with 1,4-dibromobutane and 1,5-dibromopentane and subsequent hydrolysis provides a simple route to pyrrolidine-2-carboxylic acid (75%) and piperidine-2-carboxylic acid (58%) [11, 12],... 

Selected examples of the synthesis of a-aminoacetic acids via the intermediate trifluoroacetamido... 

Glycine (Gly, G), a-aminoacetic acid H2N-CH2-COOH, C2H5NO2, Ml, 75.07 Da, a proteinogenic amino acid. 

Glycine (i.e., a-aminoacetic acid) interacts with one mole of henzoyl chloride, in the presence of 10% wtv) NaOH solution, to 3neld henzoyl glycine with the elimination of one mole of HCl. The excess of 10% NaOH solution serves two purposes, namely first, to remove the rmreacted henzoyl chloride as explained under section 4.2.1 Eq. d) and secondly, the HCl eliminated reacts with NaOH to 3neld NaCl. Interestingly, hoth sodium henzoate and sodium chloride are water-soluhle, whereas the desired product henzoyl glycine being insoluble may be separated easily. 

The lUPAC naming system uses a 2 instead of the a and names the a-amino acids as members of a series of 2-amino carboxylic acids (Fig. 23.2). In practice, the systematic name is rarely used, and common names are retained for most of these molecules. Biochemists tend to view amino acids as substituted a-aminoacetic acids. In this frame of mind, there is an R group on C(2). This R group is called the amino acid side chain. Note that as long as R doesn t equal H, the amino acids contain a stereogenic carbon atom. 

A further variant of Method B is the acylation of a 2-aminobenzophenone with a protected a-amino acid chloride, followed by conversion of the product 11 into the 2-(aminoacet-amido)benzophenone 12 by reaction with hydrobromic acid in acetic acid.196... 

Palladium-catalysed asymmetrie allylations of various carbonyl compounds have been studied by Hiroi et al. using various types of chiral sulfonamides derived from a-amino acids. In particular, the chiral bidentate phosphinyl sulfonamide derived from (5)-proline and depicted in Scheme 1.63 was employed in the presence of palladium to eatalyse the allylation of methyl aminoacetate diphenyl ketimine with allyl aeetate, leading to the eorresponding (7 )-product with a moderate enantioseleetivity of 62% ee. This ligand was also applied to the allylation of a series of other nueleophiles, as shown in Seheme 1.63, providing the eorresponding allylated produets in moderate enantioseleetivities. 

The first example of a stable geminal enediol derivative of a carboxylic acid, isolated as its platinum(II) complex, has been reported.324 Treatment of [Pt(OH2)2(en)]2+ with /V,/V-bis(phos-phonomethyl)aminoacetic acid yields zwitterionic [Pt(bpmaa)(en)] (bpmaaH = 7V,7V-bis(phosphono-methyl)aminoacetic add), which upon crystallization from water (pH 1) affords the corresponding enol tautomer (130), as determined by X-ray crystallography and IR spectroscopy. 

Glycine (Gly or G) (aminoacetic acid, aminoethanoic acid) is a nonpolar, neutral, aliphatic amino acid with the formula HOOCCH(NH2)H. Gly is the simplest amino acid and plays important roles in peptide and protein chains. It does not contain a side chain and can thus fit into secondary structures where larger amino acids cannot. Gly acts as a transmitter in the CNS where it accomplishes several functions. Gly is a precursor of porphyrins. Gly, Pro, aspartate, Ser, and Asn enable reverse turns. The acylated amino group of Gly can accept a second acyl group to give rise to a diacylamide. ... 

It undergoes double decomposition reactions in solution with a number of metal salts. It reacts with glyoxal producting glycine (aminoacetic acid)... 

An unusual BMMA reagent, A -[bis(methylthio)methylene]aminoacetic acid ethyl ester, leads to the annulation of 446b, thereby forming compound 448 (Scheme 35) <1995H(40)851>. 

In analogy to the carboxylate binding by zinc-containing cyclodextrin 10 (see Sect. 2), Lewis acidic centers such as a copper(II) histamine unit may also serve for the chelation of the (deprotonated) 2-aminoacetate substructure of a-amino acids [51], Rizzarelli, Marchelli et al. used a respective j8-cyclodextrin derivative for the formation of the ternary complexes 36 and 37 with racemic... 

Impellizzeri G, Maccarrone G, Rizzarelli E, Vecchio G, Corradini R, Marchelli R (1991) Angew Chem Int Ed Engl 30 1348. The capacity of the aminoacetate subunit of a-amino acids to chelate Lewis-acidic centers has also been used in U-tube experiments with lipophilic Cu(II) complexes (a) and phenylboronic acid (b), respectively, as transport mediators a) Scrimin P, Tonellato U, Zanta N (1988) Tetrahedron Lett 29 4967 b) Mohler LK, Czarnik AW (1993) J Am Chem Soc 115 7037... 

Dinitrobenzoates. The following experimental details are for glycine (aminoacetic acid) and may be easily adapted for any other amino acid. Dissolve 0-75 g. of glycine in 20 ml. of N sodium hydroxide solution and add 2 32 g. of finely powdered 3 5-dinitrobenzoyl chloride. Shake the mixture vigorously in a stoppered test-tube the acid chloride soon dissolves. Continue the shaking for 2 minutes, filter (if necessary) and acidify with dilute hydrochloric acid to Congo red. Recrystallise the derivative immediately from water or 50 per cent, alcohol. 

Complexes with IMDA and related ligands.—A series of three substituted aminoacetic acids, IMDA, HIMDA and NTA constitute another set of very interesting ligands. The stability constants of the iminodiacetic acid (IMDA) [ 465], N-hydroxyethyliminodiacetic acid (HIMDA) 466 and nitrilotriacetic acid (NTA) complexes are compared in Table 34. Based on log k values the following trend of stability is noted. The... 

Nitrilotriacetic acid N(CH2C02H)3 (nta) was first obtained by Heintz in 1862 from an ammon-iacal solution of monochloroacetic acid. Other products, i.e. glycolic, aminoacetic and iminodiacetic acids, were also formed. The next paper concerned with the preparation of aminopolycarboxylic acids appeared after 1930. A procedure similar to that given above, based on the treatment of ethylenediamine with monochloroacetic acid in presence of sodium hydroxide, was reported in 1935 by I.G.-Farbenindustrie.5 In a more recent version of the chloroacetic acid process, reaction (1) is carried out at 40-90 °C. For the preparation of edta, good yields of the tetrasodium salt can be obtained using appropriate conditions. The conversion to the insoluble free acid is achieved by acidification with a mineral acid. 

Intramolecular electron transfer in a stepwise manner from the amine substrate to die silver(III) center in a 1 2 complex, [Ag(OH)4] -iV,/V-dimcthylanilinc, has been observed.44 The kinetics of oxidation of some aliphatic, heterocyclic, and aromatic aldehydes towards bis(dihydrogentellurato)cuprate(III) and argentate(III) in alkaline medium have been studied.45 A negative salt effect was observed in the oxidation of aminoacetic acid by diperiodatocuprate(III) complex in alkaline medium.46 The oxidation of glutamic acid by thallium(III) perchlorate is catalysed by Ru(M), Os(III), and Nd(III) in a free radical mechanism and the rate is inversely dependent on [H+] concentration.47... 

Monosilatranones are rather stable to hydrolysis and alcoholysis. Thus, V,V-bis(2-hydroxyethyl)aminoacetic acid is formed in only 50% yield when l-(3 -trifluoromethylphe-nyl)silatran-3-one) (148) is treated with H2O/THF at room temperature for 7 h. 148 (80%) is recovered from a MeOH/THF mixture upon prolonged (9 h) heating381. 

Aminoacetic acid is the simplest example of an a-amino acid. Among the 20 biologically most important amino acids, its structure is unique in two ways. First, it possesses no sidechain attached to the methylene carbon. Second, the lack of any substituent (other than hydrogen) means that aminoacetic acid, more commonly called glycine, is achiral. The other 19 essential or common amino acids possess sidechains attached in a stere-ochemically identical fashion. 

Proteins are natural polymers composed of a-amino acids linked by amide (peptide) bonds. Except for glycine (aminoacetic acid), protein-derived amino acids are chiral and have the L configuration. Table 17.1 lists the names, one- and three-letter abbreviations, and structures of the 20 common amino acids. Of these, eight (the essential amino acids) cannot be synthesized in the bodies of adult humans and must be ingested in food. 

The term amino acid might mean any molecule containing both an amino group and any type of acid group however, the term is almost always used to refer to an a-amino carboxylic acid. The simplest a-amino acid is aminoacetic acid, called glycine. Other common amino acids have side chains (symbolized by R) substituted on the a carbon atom. For example, alanine is the amino acid with a methyl side chain. 

The Gabriel-malonic ester synthesis begins with (V-phthalimidomalonic ester. Think of (V-phthalimidomalonic ester as a molecule of glycine (aminoacetic acid) with the amino group protected as an amide (a phthalimide in this case) to keep it from acting as a nucleophile. The acid is protected as an ethyl ester, and the a position is further activated by the additional (temporary) ester group of diethyl malonate. 

Aluminum Identification Test, 753 Aluminum Magnesium Silicate, 41 Aluminum Potassium Sulfate, 21 Aluminum Sodium Sulfate, 21 Aluminum Sulfate, 22 Ambrette Seed Liquid, 23 Ambrette Seed Oil, 23, 596 Aminoacetic Acid, 186 A-[4-[[(2-Amino-l,4-dihydro-4-oxo-6-pteridinyl)methyl] amino] benzoyl] -l-glutamic Acid, 157 3 - Amino-7-dimethylamino-2-methylphenazine Chloride, 861 L-2-Aminoglutaramic Acid, 175 L-2-Amino-5-guanidinovaleric Acid, 32, (S3)5... 

Disposition in the Body. Readily absorbed after oral administration. It is conjugated with aminoacetic acid to form p-aminohippuric acid which is excreted in the urine together with a small amount of / -aminobenzoyl glucuronide, / -acetamido-benzoyl glucuronide, and traces of / -acetamidohippuric acid, p-acetamidobenzoic acid, and unchanged aminobenzoic acid. Aminobenzoic acid may be detected in the urine as a metabolite of amethocaine, benzocaine, and procaine. 

Amino acids constitute a particularly important class of bifiinctional compounds the two functional groups in an amino acid are, respectively, basic and acidic, the compounds are amphoteric, and in fact exist as zwit-terions or inner salts. For example, glycine, the simplest amino acid, exists mosdy in the zwitterion form shown first, rather than as aminoacetic acid... 

INNER COORDINATION COMPOUNDS A particular type of non-localized bond occurs in the so-called inner coordination compounds. This group of compounds may be illustrated by reference to the copper salt of aminoacetic acid (glycine). This compound dissociates only weakly in solution, it possesses a colour similar to the ammino complexes of copper and does not react with ammonia. These properties all tend to show that copper atom has a saturated valency and may be explained by considering the copper as bound to both the hydroxyl and the amino groups. In accordance with our concept of the nature of the bond between a metal and an amino group in such a compound, the structure of the complex will be represented by resonance amongst the forms I to IX X... 

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