Donor synthesis

even using such in situ technology, most synthetically usefiil Gly-T catalysed reactions require the use of NTPs as starting materials. Enzymatic 

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Selenium-containing donors, synthesis and manufacture of, 22 212 Selenium dichloride, 22 75t Selenium diethyldithiocarbamate, 22 73t Selenium dioxide, 22 73t, 75t, 88 toxicify of, 22 95 Selenium disulfide, 22 73t Selenium hexafluoride, 22 75t, 87 toxicify of, 22 96 Selenium hypofluorite, 22 75t Selenium iodides, 22 87 Selenium monobromide, 22 75t, 88 Selenium monochloride, 22 75t, 87 in selenium recovery, 22 85 Selenium monoxide, 22 88 Selenium oxidation, selenium recovery via, 22 81-83... 

Tellurium-containing donors, synthesis and manufacture of, 22 212 Tellurium-copper alloys, 24 425-426 Tellurium crystals, 24 405-406 Tellurium decafluoride, 24 419 Tellurium dibromide, 24 420 Tellurium dichloride, 24 419-420 Tellurium diethyldithiocarbamate, 24 411 Tellurium dimethylthiocarbamate, 24 428 Tellurium dioxide, 24 407-408, 409, 411, 420, 428... 

H. Berber, T. Brigaud, O. Lefebvre, R. Plantier-Royon, C. Portella, Reactions of difluoroenoxysilanes with glycosyl donors Synthesis of difluoro-C-glycosides and difluoro-C-disaccharides, Chem. Eur. J. 7 (2001) 903-909. 

S. M. Aldoshin (Director). This session included four presentations. Professor N.P. Konovalova reported on antioxidants and donors of nitrogen monoxide (antitumor effects of nitroxides and NO-donors) the report of N.A. Sanina and S.M. Aldoshin was concerned with a new class of NO-donors (synthesis, structure, properties, and practical use of sulfur-nitrosyl complexes of iron). Free-radical mechanisms of induction and development of secondary necrosis after gun wounds were the subject of the lecture by G.N. Bogdanov L.D. Smirnov reported on pharmacological properties and promising clinical application of antioxidants of the heteroaromatic array. 

Shingu, Y, Nishida, Y, Dohi, H, Matsuda, K, Kohayashi, K, Convenient access to halide ion-catalyzed a-glycosylation free from noxious fumes at the donor synthesis, J. Carbohydr. Chem., 21, 605-611, 2002. 

Laupichler, L, Sajus, H, Thiem, J, Convenient iodonium-promoted stereoselective synthesis of 2-deoxy-a-glycosides by use of 5 -(2-deoxyglycosyl) phosphorodithioates as donors. Synthesis, 1133-1136, 1992. 

Transition metal complexes based on carboranyl ligands containing N, P, and S donors Synthesis, reactivity, and apphcations 13CCR2522. Transition metal compounds and complexes as catalysts in synthesis of acetals and orthoesters Theoretical, mechanistic, and practical aspects 12CCR2057. 

The formal carbanions and carbocations used as units in synthesis are called donor synthons and acceptor synthons. They are derived from reagents with functional groups. 

If an open-chain organic molecule contains an electron acceptor and an electron donor site, two carbon atoms may be combined intramolecularly. This corresponds to the synthesis of a monocyclic compound. 

Donor substituents on the vinyl group further enhance reactivity towards electrophilic dienophiles. Equations 8.6 and 8.7 illustrate the use of such functionalized vinylpyrroles in indole synthesis[2,3]. In both of these examples, the use of acetyleneic dienophiles leads to fully aromatic products. Evidently this must occur as the result of oxidation by atmospheric oxygen. With vinylpyrrole 8.6A, adducts were also isolated from dienophiles such as methyl acrylate, dimethyl maleate, dimethyl fumarate, acrolein, acrylonitrile, maleic anhydride, W-methylmaleimide and naphthoquinone. These tetrahydroindole adducts could be aromatized with DDQ, although the overall yields were modest[3]. 

Another synthetic strategy is based on self-assembly driven by molecular recognition between complementary TT-donors and 7T-acceptors. Examples include the synthesis of catenanes and rotaxanes that can act as controUable molecular shuttles (6,236). The TT-donors in the shuttles are located in the dumb-beU shaped component of the rotaxane and the 7T-acceptors in the macrocycHc component, or vice versa. The shuttles may be switched by chemical, electrochemical, or photochemical means. 

Direct Hydrogenation. Direct hydrogenation of lignitic and other coals has been studied by many investigators. Lignite can be slurried with an anthracene-oil solvent, heated to a temperature of 460—500°C with 1 1 CO H2 synthesis gas at pressures to 28 MPa (280 atm) in a 2 kg/h reactor. The product hquids are separated, and in a commercial process, a suitable hydrogen-donor solvent would be recycled (54). 

Frcc-Radical Reactions. Eree-radical reactions of maleic anhydride are important in polymeri2ations and monomer synthesis. Nucleophilic radicals such as the one from cyclohexane [110-82-7] serve as hydrogen donors that add to maleic anhydride at the double bond to form cyclohexylsuccinic anhydride [5962-96-9] (20) (63). 

Protection of carboxyflc acids and sulfenic acids requires efficient sdyl donors, eg, BSA, MTSA, and bis(ttimeth5isdyl)urea [18297-63-7] (BSU). BSU is often prepared in situ from hexamethyldisda2ane and urea to yield over 90% of the sdylated derivative in synthesis of cephalosporins (5). 

Biosynthesis of coen2yme A (CoA) ia mammalian cells incorporates pantothenic acid. Coen2yme A, an acyl group carrier, is a cofactor for various en2ymatic reactions and serves as either a hydrogen donor or an acceptor. Pantothenic acid is also a stmctural component of acyl carrier protein (AGP). AGP is an essential component of the fatty acid synthetase complex, and is therefore requited for fatty acid synthesis. Free pantothenic acid is isolated from hver, and is a pale yeUow, viscous, and hygroscopic oil. 

Low Oxidation State Chromium Compounds. Cr(0) compounds are TT-bonded complexes that require electron-rich donor species such as CO and C H to stabilize the low oxidation state. A direct synthesis of Cr(CO)g, from the metal and CO, is not possible. Normally, the preparation requires an anhydrous Cr(III) salt, a reducing agent, an arene compound, carbon monoxide that may or may not be under high pressure, and an inert atmosphere (see Carbonyls). 

Paraxanthine—see Xanthine, 1,7-dimethyl-Parent name nomenclature, 1, 35 Parham cycloalkylation in chroman synthesis, 3, 783 Paromomycins as pharmaceuticals, 1, 154 Partial charge transfer from donor to acceptor stacks, 1, 350 Pasteurellosis... 

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