Simple amino acids alcohol

Phosphazene polymers can act as biomaterials in several different ways [401, 402,407]. What is important in the consideration of skeletal properties is that the -P=N- backbone can be considered as an extremely stable substrate when fluorinated alcohols [399,457] or phenoxy [172] substituents are used in the substitution process of the chlorine atoms of (NPCl2)n> but it becomes highly hydrolytically unstable when simple amino acid [464] or imidazole [405-407] derivatives are attached to the phosphorus. In this case, an extraordinary demolition reaction of the polymer chain takes place under mild hydrolytic conditions transforming skeletal nitrogen and phosphorus into ammonium salts and phosphates, respectively [405-407,464]. This opens wide perspectives in biomedical sciences for the utilization of these materials, for instance, as drug delivery systems [213,401,405,406,464] and bioerodible substrates [403,404]. 

Hydrolytic enzymes such as proteases, esterases and lipases are ready-to-use catalysts for the preparation of optically active carboxylic acids, amino acids, alcohols, and amines. The area is sufficiently well researched to be of general applicabihty for a wide range of synthetic problems. Consequently, about two thirds of the reported research on biotransformations involves these areas. This is facilitated by the fact that a considerable collection of commercially available proteases and lipases is available in conjunction with techniques for the improvement of their selectivities. The development of simple models aimed at the prediction of the stereochemical outcome of a given reaction is still a challenge and will be the subject of future studies. A search for novel esterases to enrich the limited number of available enzymes and for lipases showing anti-Kazlauskas stereospecificities would be a worthwhile endeavor. 

The chiral auxiliary sugar can be isolated by pentane extraction of the crude hydrolysis reaction mixture. The amino acids can then be purified by ion exchange chromatography. The shortcoming of this methodology is that simple amino acids such as phenylalanine are difficult to separate from the hydrolyzed by-product 2-aminobenzyl alcohol (155). According to Linderman and coworkers, the size of the... 

Simple esters cannot be allylated with allyl acetates, but the Schiff base 109 derived from o -amino acid esters such as glycine or alanine is allylated with allyl acetate. In this way. the o-allyl-a-amino acid 110 can be prepared after hydrolysis[34]. The Q-allyl-o-aminophosphonate 112 is prepared by allylation of the Schiff base 111 of diethyl aminomethylphosphonates. [35,36]. Asymmetric synthesis in this reaction using the (+ )-A, jV-dicyclohex-ylsulfamoylisobornyl alcohol ester of glycine and DIOP as a chiral ligand achieved 99% ec[72]. 

Fig. 7-6). Two unichiral amides which have been known capable of this reaction are 1-phenylethylamine [15] and l-(l-naphthyl)ethylamine [16]. Marfey s reagent [N-a-(2,4-dinitro-5-fluorophenyl)-L-alaninamide] was introduced as a reagent to deriva-tize amino acids with cyclopentane, tetrahydroisoquinoline or tetraline structures [17]. Simple chiral alcohols such as 2-octanol can also be used to derivatize acids such as 2-chloro-3-phenylmethoxypropionic acid [18]. 

Simple Amines, Alcohols and Amino Acid Derived Amino Alcohols as Chiral Catalysts... 

To obtain information about the structural requirements of a ligand capable of catalyzing the addition of dialkylzincs to aldehydes, various simple amines, alcohols and amino acid derived amino alcohols were tested as chiral catalysts (Table 27). 

Hadzija, O. and Keglevic, D., Simple method for the separation of amino acids, amino sugars, and amino alcohols related to the peptidoglycan components on a standard amino acid analyzer, /. Chromatogr., 138, 458, 1977. 

The variety and extent of research devoted to ligands carrying both O- and N-donors is simply immense. The type of cobalt(III) systems extant include amino acids, amino alcohols, amino ethers, amino phosphates, amino phenolates, as well as amide and imine analogs of these. These are met as simple chelates or more elaborate polydentates. Here, we highlight a strictly limited selection of examples to illustrate the type of systems reported no attempt at exhaustive review has been made. 

When sulfamate esters 114 are used as substrates, six-membered-ring formation is favored, and results in the selective formation of 1,2,3-oxathiazinane-2,2-dioxide heterocycles 115.251 Nevertheless, five-membered cyclic sulfamidates could be obtained when no alternative cyclization was possible. 1,3-Amino alcohols and related /2-amino acids are thus readily accessible from the same simple alcohols 113 by converting them into sulfamates 114 (Equation (90)). Furthermore, in comparison to the carbamate reaction (Scheme 9), the sulfamate substrates have... 

Serine is one of two amino acids that possess a simple alcohol function. 

Imines and (Af,(9)-acetals from fluoral are useful precursors of trifluoromethyl nitrogen-containing molecules amines, amino alcohols, amino acids, peptidomimetic units, heterocycles, and so on (Figure 2.50). These simple Af-derivatives of fluoral are easily prepared from the hydrate or the hemiacetal. Imines of fluoral react in [2 + 1 ]... 

The oxidation of various alcohols by the poly(e-carbobenzoxy-L-lysine)-Cu complex was studied by Welch et aL127. The polymer catalyst showed selectivity in oxidation by virtually excluding alcohols of bulky structure such as diisopropyl and diisobutyl carbinol while admitting simple alcohols arch as n-butyl, iso-butyl, and sec-butyl. It was suggested from structural studies that the selectivity of the polymer catalyst resulted from the highly complex geometry of the molecular cage formed by the helix and the amino acid side chain around the coordinated Cu. The... 

In many kinds of research it is important to have simple and sensitive means for analysis of amino acids, particularly in small quantities. Detection of amino acids can be achieved readily by the ninhydrin color test, whereby an alcoholic solution of the triketone, ninhydrin, is heated with an amino acid and produces an intense blue-violet color. The sensitivity and reliability of this test is such that 0.1 micromole of amino acid gives a color intensity reproducible to a few per cent, provided that a reducing agent such as stannous chloride is present to prevent oxidation of the colored salt by dissolved oxygen. 

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