Acids, amino diamino

Numerous amino acids—including diamino- and oxyamino-acids— have also been synthesised of recent years by Neuberg and his coworkers and by Sorensen. Our knowledge of these acids should render the task of identifying a new unit in the protein molecule less laborious than it has hitherto been. Their preparation was no doubt due to the possibility of the presence of other units than those above described, which possibility will not be excluded until the quantity of products isolated reaches lOO per cent. 

Others CPSs have been prepared in a similar way and characterized at different steps by physicochemical methods. For example, the structure of the chiral selector iV-[2 -(5)-hydroxypropyl]-Ar, /V -bis(3,5- dichlorobenzoyl)-(f ,f )-tra i- 1,2-diamino-cyclohexane was solved by X-ray analysis and its absolute configuration confirmed unambiguously [73]. These CPS phases were used to resolve a large number of racemic mixtures belonging to different classes of organic compounds, such as a-aryloxyacetic acids, alcohols, sulfoxides, selenoxides, phosphinates, amino acids, amino alcohols, etc. 

S -(4-Hydroxybenzyl)-glutathione (phenolic peptide) i.-a-Amino-y-oxalylaminobutyric acid (amino acid) I.-3-Oxalylamino-2-aminopropionic acid (= 3-JVOxalyl-2,3-diamino propionic acid (3-ODAP (3-Ar-Oxalylamino-L-alanine I.-BOAA)... 

Problem 36.7 Suggest a way to separate a mixture of amino acids into three fractions monoamino monocarboxylic acids, monoamino dicarboxylic acids (the acidic amino acids), and diamino monocarboxylic acids (the basic amino acids). 

Diamino-cyclobutene-diones as a-amino carboxylic acid surrogates Diamino-cyclobutene-dione was proposed by Kinney et al e m original surrogate of the a-amino carboxylic acid function (Figure 15.25). 

Polypeptides, which contain amino dicarboxylic acids or diamino acids can also exist in isomeric forms asparagyl-monoglycine can exist in the two forms. 

IV. Basic amino acids, or diamino, monocarboxylic acids, containing an additional amino group lysine, arginine, histidine. 

There also exists an acidregioselective condensation of the aldol type, namely the Mannich reaction (B. Reichert, 1959 H. Hellmann, 1960 see also p. 291f.). The condensation of secondary amines with aldehydes yields Immonium salts, which react with ketones to give 3-amino ketones (=Mannich bases). Ketones with two enolizable CHj-groupings may form 1,5-diamino-3-pentanones, but monosubstitution products can always be obtained in high yield. Unsymmetrical ketones react preferentially at the most highly substituted carbon atom. Sterical hindrance can reverse this regioselectivity. Thermal elimination of amines leads to the a,)3-unsaturated ketone. Another efficient pathway to vinyl ketones starts with the addition of terminal alkynes to immonium salts. On mercury(ll) catalyzed hydration the product is converted to the Mannich base (H. Smith, 1964). 

Amino groups are acetylated normally and are converted to hydroxy compounds with nitrous acid. Tlie 2,3-diamino [2,3-f>] derivative gives an imidazolo fused pyridopyrazine with acetic anhydride (75USP3898216). The oxidative removal of hydrazino groups has been used to give ring-unsubstituted derivatives (79JHC305). 

Chemical Name 1-(L-Threo-3 6-diamino-4-hydroxyhexanoic acid)-6-[L-2-(2-amino-1,4,5,6-tetrahydro-4-pyrimidinyl)glycine] viomycin... 

A mixture of 2 g of 4,5-diamino-6-mercaptopyrimidine and 10 ml of 9B% formic acid was heated at 70°C for two hours and then evaporated to dryness on the steam bath to give as a residue, 7-amino-thiazolo (5,4-d) pyrimidine. 

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