Amino acid conjugates

UETAL. Poly(a-amino acid) Drug Conjugates... 

Pagels, P., Starke, D., Kramer, W., Hepatobiliary transport of bile add amino add, bile add peptide, and bile acid oligonucleotide conjugates in rats, Hepatology 1999, 30, 1257-1268. 

The conversion experience is found in Ingold s response to a paper presented by Robinson at the Chemical Society in the summer of 1925 and sent to Ingold before its publication in 1926. Robinson s paper, written with J. Allen, A. E. Oxford, and John C. Smith, classified conjugated systems into nine categories of reactants, two of them "anionoid" and the rest "cationoid." "Crotonoid" and "crotenoid" were two of the nine types. This was a detailed and cumbersome classification, based on studies of crotonic acid, amino acids, and their salts, in which crotenoid was an instance of anionoid (electron donor) reaction and crotonoid of cationoid (or electron acceptor) reaction. 

It has been shown that the Claisen rearrangement of lithium enolates of amino acid enynol esters allows the synthesis of very sensitive y, 5-unsaturated amino acids with conjugated enyne side chains.The chelate-enolate Claisen rearrangement has also been applied to the synthesis of unsaturated polyhydroxylated amino acids, polyhydroxylated piperidines, and unsaturated peptides. ... 

The amino acids in question are the basic amino acids lysine, arginine, and histidine, and the acidic amino acids aspartic acid and glutamic acid. The side-chain functions of these amino acids, ionized at pH 7 (see Box 4.7), act as acids or bases. In a reverse sequence, protons may be acquired or donated to regenerate the conjugate acids and conjugate bases. 

The preparation of a number of gibberellic acid amino-acid conjugates has also been described. ... 

Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata. III. Fatty acid-amino acid conjugates in herbivore oral secretions are necessary and sufficient for herbivore-specific plant responses. Plant Physiology 125 ... 

Repeat question 2 but select five different drugs to demonstrate the following phase II processes acetylation, sulfo-nylation, glucuronidation, conjugation with an amino acid, and conjugation with glutathione. 

An alpha plot for a buffer (or an amino acid) shows the percentage of each component in a buffer system as a function of pH. Alpha for a given species is the percent of all the material that is present in that form. So, when alpha for the conjugate acid form is 75%, the ratio of conjugate acid to conjugate base is 75 25. Naturally, the sum of the alpha values for the conjugate acid and the conjugate base add up to 100%. 

Common amino acids that conjugate xenobiotics are glycine, glutamine, taurine, and serine, the anionic forms of which are shown below ... 

An acid-base conjugate pair can act as a buffer, resisting changes in pH. From a titration curve of an acid the inflexion point indicates the pK value. The buffering capacity of the acid-base pair is the ptC 1 pH unit. In biological fluids the phosphate and carbonate ions act as buffers. Amino acids, proteins, nucleic acids and lipids also have some buffering capacity. In the laboratory other compounds, such as TRIS, are used to buffer solutions at the appropriate pH. 

Jacobsen et al. have shown that cyanoacetate derivatives undergo conjugate addition to ,/i-unsaturated imides in the presence of a chiral Al-oxo salen complex 32 to afford the corresponding product in up to 98% ee (Scheme 16) [19]. When an a-amino cyanoacetate was used, a highly functionalized lactam 33 was obtained in one step. Another example of Lewis acid-catalyzed conjugate addition of cyclic 1,3-dicarbonyl compounds to 2-oxobutenoate employed the chiral Cu-bisoxazoline complex 34 (Scheme 17) [20]. 

New amino acid-tetrahydropterin conjugates were synthesized from A2-isobutyryl-6,7-dimethyl-5,6,7,8-tetrahydropterin (169) by either direct acylation (170) or via a succinate linker (171) followed by removal of protecting groups and ammonia treatment to deblock selectively the isobutyryl group (Scheme 26) <89MI 718-08). 

HALITSCHKE, R SCMTTKO, U., POHNERT, G., BOLAND, W., BALDWIN, I.T., Molecular interactions between the specialist herbivore Manduca sexta (Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata. III. Fatty acid-amino acid conjugates in herbivore oral secretions are necessary and sufficient for herbivore-specific plant responses. Plant Physiol., 2001,125, 711-717. 

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