Amino acids polyhydroxylated

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. ... 

C-Alkylation has also been observed in intramolecular reactions where the O-alkylation is not favoured.76 This property has been recently exploited in a stereocontrolled intramolecular cyclization of nitronate of nitro sugar 101 (Scheme 32), that provided the novel bicyclic nitrolactone 102, a synthetic precursor of tripeptide 103, that includes the first reported polyhydroxylated cyclopentane (3-amino acid.77... 

The efficient addition-cyclization sequence described above could be successfully applied to the preparation of the polyhydroxylated y-amino acid (-)-detoxinine [73], The crucial key step in this fairly short synthesis is the chelate-controlled addition of lithiated benzyloxyallene 120 (R = Bn) to the chiral N-benzyl-substituted imine 121 as shown in Scheme 8.31. The required skeleton of the natural product was generated in good overall yield. 

Polyamino acids are easy to prepare by nucleophUe-initiated polymerisation of amino acid JV-carboxyanhydrides. Polymers such as poly-(L)-leucine act as robust catalysts for the epoxi-dation of a wide range of electron-poor alkenes, such as y-substituted a,Ji-unsaturated ketones. The optically active epoxides so formed may be transformed into heterocyclic compounds, polyhydroxylated materials and biologically active compounds such as dUtiazem and taxol side chain. 

Sweet Polyhydroxyl or polyhydrogenated compounds, alpha amino acids... 

Few medicines based on boron are known, in general boric acid or a boronic acid serve to esterify an a-diol or an o-diphenol. This is the case for the emetic antimony borotartrates of the ancient pharmacopoeias, for the injectable catecholamine solutions, for tolboxane, which is close to meprobamate and which was commercially available as a tranquillizer some decades ago, and also for the phenylboronic esters of chloramphenicol. Boro-mycine was the first natural product containing boron. It is a complex between boric acid and a polyhydroxylated tetradentate macrocycle. Some boronic analogues of amino acids were prepared as chymotrypsine and elastase inhibitors. The most important medical use of derivatives of boron derivatives is the treatment of some tumours by neutron capture therapy, " the problem here being to ensure a sufficient concentration of the product in the tumour being treated. 

Humic acids are built from the polyhydroxylated benzene derivatives synthesized by soil fungi. These polyphenols are autoxidable and easily form the corresponding quinones, which add other phenolic compounds, amines, or amino acids by nucleophilic substitutions (see Fig. 165). The resulting products may be subjected to further oxidation or substitution. The high molecular weight, extremely complex, brown compounds formed are termed humic acids. Humic acids, which may also be derived from lignins (D 22.2.3), represent the major portion of the organic substance of soils. 

There have been reports on new routes to 2-amino-2-deoxyaldonic acids (polyhydroxylated a-aminoacids). One approach to compounds of this type is illustrated by the... 

In another report, a compound assumed to be a polyhydroxylated derivative of an aromatic amino acid isolated from shrimp was demonstrated to function as an antioxidant (Pasquel and Babbitt, 1991). This indicates that there are still many interesting ingredients to be found in the marine environment. 

Strongly polar. These may include amino alcohols, hydroxyl acids, polyhydroxyl alcohols, polyprotic acids, polyphenols, thiols, and molecules containing nitrogen, oxygen, phosphorus, sulfur, or halogen atoms. 

A series of complex polyhydroxylated cyclamino acids 15-19 have been prepared by Fleet s group as analogues of the potent trehalase inhibitor, trehazolin 14. A central feature of this chemistry was the use of either an azide- or fluoride-mediated intramolecular aldol reaction of the carbohydrate-derived lactones carrying a 2-azido (ot 2-iodo) substituent as illustrated in Scheme 4. 

The taurine residue can also be found as an amide derivative of the 26-carboxylic acid function in the 3p,5a,6p,15a-polyhydroxylated steroids 328 and 329, which were obtained from the starfish Myxoderma platyacanthum [245]. The structures of both compounds were determined from spectral data and chemical correlations. The bile of the sunfish Mola mola has been shown to contain a new bile acid conjugated with taurine (330) together with sodium taurocholate. Compound 330 was identified as sodium 2-[3a,7a, 11 a-trihydroxy-24-oxo-5P-cholan-24-yl]amino]ethane-sulfonate on the basis of its physicochemical data and chemical transformations [246]. 

Heteroatom-substituted carbohydrates are efficiently assembled by the enzymatic aldol condensation of DHAP with an appropriately appended aldehyde. Iminocyclitols that are inhibitors of glycosidases, such as deoxynojirimycin and deoxymannojirimycin, are simply prepared by condensation of azo-substituted aldehydes under the FDP protocol followed by dephosphorylation and palladium mediated reductive animation (Scheme 5.18a).39 In addition a number of polyhydroxylated pyrrolidines that are efficient glucosidase inhibitors have been synthesized by this chemo-enzymatic strategy (Scheme 5.18 ).1" 30,40 If the palladium mediated hydrogenation is done in the presence of hydrochloric acid, an amino-sugar intermediate is formed as its hydrochloride salt. Treatment with base then forms polyhydroxylated imines, instead of iminocyclitols (Scheme 5.19).41... 

Chem. Descrip. 2-Pyrrolidone CAS 616-45-5 EINECS/ELINCS 204-648-7 Uses Monomer for polypyrrolidone solvent for polymers, insecticides, polyhydroxylic alcohols, sugars, iodine, specialty inks used in petrol, processing and acrylonitrile mfg. solvenL solubilizer, intermediate for pharmaceuticals plasticizer/coalescing agent for actylic latexes, actylic-styrene copolymers in emulsion-type floor coalings intermediate for N-methylol derivs., alkaloids related to peganine, amino-butyric acid derivs. adhesives... 

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