L chemical synthesis

Graham, R.A., Morosin, B., Horie, Y., Venturini, E.L., Boslough, M., Carr, M.J., and Williamson, D.L., Chemical Synthesis Under High Pressure Shock Loading, in Shock Waves in Condensed Matter (edited by Gupta, Y.M.), Plenum, New York, 1986, pp. 693-711. 

Jain, R. K. Matta, K. L., Chemical synthesis of a hexasaccharide comprising the Lewis(x) determinant linked beta-(l->6) to a linear trimannosyl core and the precursor pentasaccharide lacking fucose. Carbohydr. Res. 1996,282, 101-111. 

Goldstein, I. J., and Hullar, T. L., Chemical Synthesis of Polysaccharides, 21, 431-512 Gomez Sanchez, A. See Garcia Gonzalez, F. 

Spedding, P. L. Chemical synthesis by gas-phase discharge Nature. 1967,214, 124-126... 

Guo Z, Bishop L. Chemical synthesis of GPIs and GPI-anchored glycopep-tides. Euro J Org Chem 2004 3585-3596. 

Hexanedione [110-13-4] (acetonylacetone) is one of the most widely used 1,4-diketones. It is a colorless high boiling Hquid prepared by the hydrolysis of 2,5-dimethylfuran (332,333), by oxidation of 2,5-hexanediol (334) or 5-hexen-l-one (335), and from allylacetone (336). Its main use is in solvent systems and as a raw material for chemical synthesis. It is reportedly not highly toxic (336). 

In many cases only the racemic mixtures of a-amino acids can be obtained through chemical synthesis. Therefore, optical resolution (42) is indispensable to get the optically active L- or D-forms in the production of expensive or uncommon amino acids. The optical resolution of amino acids can be done in two general ways physical or chemical methods which apply the stereospecific properties of amino acids, and biological or enzymatic methods which are based on the characteristic behavior of amino acids in living cells in the presence of enzymes. 

An estimation of the amount of amino acid production and the production methods are shown ia Table 11. About 340,000 t/yr of L-glutamic acid, principally as its monosodium salt, are manufactured ia the world, about 85% ia the Asian area. The demand for DL-methionine and L-lysiae as feed supplements varies considerably depending on such factors as the soybean harvest ia the United States and the anchovy catch ia Pern. Because of the actions of D-amiao acid oxidase and i.-amino acid transamiaase ia the animal body (156), the D-form of methionine is as equally nutritive as the L-form, so that DL-methionine which is iaexpensively produced by chemical synthesis is primarily used as a feed supplement. In the United States the methionine hydroxy analogue is partially used ia place of methionine. The consumption of L-lysiae has iacreased ia recent years. The world consumption tripled from 35,000 t ia 1982 to 100,000 t ia 1987 (214). Current world consumption of L-tryptophan and i.-threonine are several tens to hundreds of tons. The demand for L-phenylalanine as the raw material for the synthesis of aspartame has been increasing markedly. 

L-Ascorbic acid biosynthesis in plants and animals as well as the chemical synthesis starts from D-glucose. The vitamin and its main derivatives, sodium ascorbate, calcium ascorbate, and ascorbyl palmitate, are officially recognized by regulatory agencies and included in compendia such as the United S fates Pharmacopeia/National Formula (USP/NF) and the Food Chemicals Codex (FCC). 

Chemical Synthesis. The first synthesis of ascorbic acid was reported ia 1933 by Reichsteia and co-workers (14,39—42) (Fig. 4). Similar, iadependent reports pubHshed by Haworth and co-workers followed shordy after this work (13,43—45). L-Xylose (16) was converted by way of its osazone (17) iato L-xylosone (18), which reacted with hydrogen cyanide forming L-xylonitfile (19). L-Xylonitfile cyclized under mild conditions to the cycloimine of L-ascorbic acid. Hydrolysis of the cycloimine yielded L-ascorbic acid. The yield for the conversion of L-xylosone to L-ascorbic acid was ca 40%. 

The chemical syntheses of l,24(R),25-trihydroxy-vitamiQ [56142-94-0] and l,24(3),25-trihydroxy-vitamiQ D [56142-95-1] were reported (131,132) ki 1975. The chemical synthesis of 25,26-dihydroxy-vitamin [29261 -12-9] has also been described, and it has been determined that the biologically occurring epimer is 25(R),26-dihydroxy-vitamin (117,133—135). The 23,25-dihydroxy-24-oxo metabohte has been isolated (136) as well. 1 a-Hydroxycalcitroic acid (l-hydroxy-24-nor-9,10-secochola-5,7-10(19)-ttien-23-oic acid) [71204-89-2], 25-hydroxy-26,23-lactone vitamin [71203-34-6],... 

T. Blizzard, M. H. Eisher, H. Mrozik, and T. L. Sbib, iu G. Lukacs and M. Ohno, eds.. Recent Progress in the Chemical Synthesis of Antibiotics., Spriuger-Vedag, Berlin, Heidelberg, Germany, 1990. 

N.N. Thadhani, Shock-Induced Chemical Synthesis of Intermetallic Compounds, in Shock Compression of Condensed Matter—1989 (edited by S.C. Schmidt, J.N. Johnson, and L.W. Davison), Elsevier Science, Amsterdam, 1990, pp. 503-510. 

Poly(L-malic acid) denotes a family of polyesters derived from L-malic acid as the building unit. By chemical synthesis, three kinds of poly(L-malic acid) have been obtained, depending on the molecular position of the ester bond the a-type(I) [1], the j8-type(II) [2], and the a,j8-mixed-type(III) [3). 

It is well known that the 1-phosphates of the ketoses, L-fuculose (51) and L-rhamnulose (52) have considerable biochemical interest. Their chemical synthesis has not been described as far as is known to the writer, but the rate of acid hydrolysis of L-fuculose 1-phosphate, obtained by enzymatic synthesis, has been determined by Heath and Ghalambor (20) and that of L-rhamnulose 1-phosphate by H. Sawada (48) and by Chiu and Feingold (II). They found that the rate of... 

In this chapter we consider amino acid production by fermentation and by chemo-enzymatic methods. We first consider the stereochemistry of amino adds and the importance of chirality in chemical synthesis. General approaches to amino add fermentation and recovery of amino adds from fermentation broths are then dealt with, followed by a detailed consideration of the production of L-phenylalanine by direct fermentation. Later in this chapter, chemo-enzymatic methods of amino acid... 

Enzymic and Chemical Synthesis of the a-l 2-glucosidic Linkage Enzymic Synthesis, S. A. Barker, E. J. Bourne, P. M. Grant, andM. Stacey, Nature, 178(1956) 1221-1223. 

Similar experiments suggested that 4-hydroxy-L-threonine (43) was an intermediate in synthesis of the three-carbon unit, C-6, C-5, C-5 (after decarboxylation). This was rigorously proved by a chemical synthesis of 4-hydroxy-L-(2,3-13C2)threonine. Incubation of E. coli mutant WG2 with this substrate produced a sample of pyridoxol that was examined by l3C NMR. The presence of doublets in the signals originating from C-5 and C-6 of pyridoxol exclusively, showed that the C-2-C-3 bond of the substrate had been incorporated intact into the predicted site (Scheme 18).42... 

Use of Radio-Frequency Plasma in Chemical Synthesis S. M. L. Hamblyn and B. G. Reuben... 

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