J Valine

The stereoselective allylation of carbon-nitrogen multiple bonds have also been studied. The addition of allylzinc bromide to aromatic imines derived from (. S j-valine esters was affected by reversibility, which caused the lowering of the diastereoisomeric ratio with increasing reaction time. The retroallylation reaction could be avoided by performing the reaction in the presence of trace amounts of water or by using CeC - 7H2O as the catalyst with a decreased reaction rate.71... 

The most versatile chiral auxiliaries should also be available as both enantiomers. Now, for the valine-derived one here, this is not the case—(J )-valine is quite expensive since it is not found in natrue. However, by starting with the natruaUy occruring (and cheap) compound norephedrine, we can make an auxiliary that, although not enantiomeric with the one derived from (S)-valine, acts as though it were. Here is the synthesis of the auxiliary. 

Crucial to this class of inhibitors was the discovery of (1 J ,25)-l-amino-2-vinylcyclopropane carboxylic acid (vinyl-ACC A) as a PI residue [99]. Initially, several reports appeared describing chemically stable replacements for the cysteine residue at the PI position of all tra i-cleaved substrates. An aliphatic side chain with two (aminobutanoic acid) or three (nor-valine) carbon atoms seemed to be an acceptable replacement, with only a moderate loss in potency and improved chemical stability [96, 100]. An improved PI... 

Stepanian, S. G., Reva, I. D., Radchenko, E. D., Adamowicz, 1999, Combined Matrix-Isolation Infrared and Theoretical DFT and Ab Initio Study of the Nonionized Valine Conformers , J. Phys. Chem. A, 103, 4404. 

Peters, D., and J. Peters. 1982. Quantum Theory of the Structure and Bonding in Proteins Part 13. The p branched hydrocarbon side chains valine and isoleucine. J. Mol. Struct. (Theochem) 88,157-170. 

Schafer, L., S. Q. Kulp-Newton, K. Siam, V. J. Klimkowski, and C. Van Alsenoy. 1990a. Ab Initio Studies of Structural Features Not Easily Amenable to Experiment. Part 71. Conformational analysis and structural study of valine and threonine. J. Mol. Struct. (Theochem) 209, 373-385. 

Viviana, W., J.-L. Rivail, and I. G. Csizmadia. 1993a. Peptide Models n. Intramolecular Interactions and Stable Conformations of Glycine, Alanine, and Valine Peptide Analogues. Theor. Chim. Acta 85,189-197. 

Csaszar, A. G. 1992. Conformers of Gaseous Glycine, J. Am. Chem. Soc. 114,9568-9575. de Dios, A. C., J. G. Pearson, and E. Oldfield. 1993. Chemical Shifts in Proteins An Ab Initio Study of Carbon-13 Nuclear Magnetic Resonance Chemical Shielding in Glycine, Alanine, and Valine Residues, J. Am. Chem. Soc. 115, 9768-9773. 

Transport of L-valine-acyclovir via the oligopeptide transporter in the human intestinal cell line, Caco-2., J. Pharmacol. Exp. Ther. 1998, 286, 1166-1170... 

V.A. Basiuk, Pyrolysis of valine and leucine at 500°C identification of less volatile products using gas chromatography Fourier Transform infrared spectroscopy mass spectrometry, J. 

Meienhofer J, Waki M, Heimer EP, Lambros TJ, Makofske RC, Chang CD (1979) Solid phase synthesis without repetitive acidolysis. Preparation of leucyl-alanyl-glycyl-valine using 9-fluorenylmethyloxycarbonylamino acids. Int J Pep Prot Res 13 35 -2... 

H. E. Umbarger and B. Brown, Isoleucine and valine metabolism in Escherichia coli. VIII. The formation of acetolactate. J. Biol. Chem. 233, 1156 1160 (1958). 

The maximum observed free energy difference between two enantiomeric host-guest complexes in which one 1,1 -dinaphthyl element is the only source of chirality in the crown ether is about 0.3 kcal mol-1. Improvement of the free energy difference can be achieved by introduction of two such elements. Unfortunately crown ethers with three 1,1 -dinaphthyl groups did not form complexes with primary ammonium salts (de Jong et al., 1975). The dilocular chiral crown ether [294] forms complexes of different stability with R- and 5-cr-phenylethylammonium hexafluorophosphate. The (J )-J J -[284] complex was the more stable by 0.3 kcal mol-1 at 0°C (EDC value 1.77) (Kyba et al., 1973b). Crown ether [284] also discriminates between the two enantiomers of phenylglycine methyl ester hexafluorophosphate and valine methyl ester... 

FR Ahmed, FMF Chen, NL Benoiton. The crystal structure of N,N-bismethoxycar-bonyl-L-valyl-L-valine, a product of the rearrangement of the symmetrical anhydride of N-methoxycarbony I -1.-valine. Can J Chem 64, 1396, 1986. 

Table 6.4. First-Order (in s J) and Second-Order (in M 1 s ) Rate Constants for the Hydrolysis ofN-(Phenylacetyl)glycyl-D-valine (6.47) at 37° [69]... 

Kennedy J, Turner G. (1996) 5-(L-a-aminoadipyl)-L-cysteinyl-D-valine synthetase is a rate limiting enzyme for penicillin production in Aspergillus nidulans. Mol Gen Genet 253 189-197. 

Kuwata, K. T Valin, L. C. Converse, A. D. Quantum Chemical and Master Equation Studies of the Methyl Vinyl Carbonyl Oxides Formed in Isoprene Ozonolysis. J. Phys. Chem. A 2003, 109, 10710-10725. 

Mortimore, G.E., and Mondon, C.E. (1970). Inhibition by insulin of valine turnover in liver. Evidence for a general control of proteolysis. J. Biol. Chem. 245,2375-2383. 

Ru(PPh3)(H2O)j(SB "0 constimtes a series of complexes, made from RuClj(PPh3)3 and a chiral Schiff base SB obtained from salicylaldehyde and the L-forms of alanine, valine, serine, arginine, cysteine and aspartic acid. They were characterised by IR, circular dichroism, H and C[ H] NMR spectroscopies and by cyclic voltammetry. The supposed structure of one is shown in Fig. 1.41 [917]. 

Boatman, J. F., M. Luria, C. C. Van Valin, and D. L. Wellman, Continuous Atmospheric Sulfur Gas Measurements Aboard an Aircraft A Comparison between the Flame Photometric and Fluorescence Methods, Atmos. Environ., 22, 1949-1955 (1988). 

Luria, M., C. C. Van Valin, J. F. Boatman, D. L. Wellman, and R. F. Pueschel, Sulfur Dioxide Flux Measurements over the Western Atlantic Ocean, Atmos. Enriron., 21, 1631-1636 (1987). 

Pueschel, R. F., C. C. Van Valin, R. C. Castillo, J. A. Kadlecek, and E. Ganor, Aerosols in Polluted versus Nonpolluted Air Masses Long-Range Transport and Effects of Clouds, J. Clim. Appl. Meteorol., 25, 1908-1917 (1986). 

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