Benzylglutamic acid

Bacteriochlorophyll, Y23 Baikiain, AlO Balchanolide, T21 Balfourodine, K31 Balfourolone, K30 Baptifoline, K21 Batatic acid, T17 Batrachotoxinin A, K36 Baurenol, T42 Baurenone, T42 Benchrotrenes, X9 Benzoin, A23 Benzoquinolizines, A5 Benzoyl allylhippuric acid, AlO Benzylglutamic acid, A32 3-O-benzylglycerol, A14 Betanidin, K17 Betanin, K17 Betulafolienetriol, T51 Betulenols, T28 Betulinic acid, T43 Betulin, T43 Beyerane, T35 Beyerol, T35 Bianthryls, X0 7 Biaryls, K2-4, K20, K27, Y2, YIO, Y15, Y17-18, X3, X6, XIO... 

N-Acetyl-L-prolyl-L-4-hydroxyproline, 46B, 475 0.5 H2O, Cyclo(hexaglycyl) hemihydrate, 28, 525 Ci2H2oBrN6g, (+)-2-Benzylglutamic acid hydrobromide dihydrate, 32B, 232... 

Benzoyl allylhippuric acid, AlO Benzylglutamic acid, A32 3-0-benzylglycerol, A14 Bertyadianol, T14 ... 

Enantiomer-selective polymerization of a-amino acid NCAs has been reported [270-274]. In the polymerization of y-benzylglutamate NCA using [(+)-C2H5(CH3)CHCOO]2NiPBu5 in dioxane at 30°C, the enantiopurity of monomeric units in the polymer chain was estimated to be (-) 34% ee at 28% polymer yield [272]. 

When we determine values of 7 for benzene rings attached to polymers, we find that they are much shorter than for benzene itself they are in fact at the lower limit of usefulness of the direct method. We have found (3) that for the phenyl resonance of a low molecular weight polystyrene in carbon disulfide 7 is only about 0.4 0.1 sec. at 25°. For the backbone protons, 7 is even shorter and cannot be measured by the direct method. For the phenyl groups of poly-y-benzylglutamate in trifluoroacetic acid, 7 is 0.7 0.1 sec. Recently, more reliable values have been obtained for polystyrene by the spin echo method (72). For a polymer of molecular weight 63000 in tetrachloroethylene, three 7 X values could be resolved. At 25°, these were 0.033 sec. for the aliphatic protons, 0.076 sec. for the ortho protons and 0.20 sec. for the meta-para protons. The temperature coefficients for all three Tt values correspond to a heat of activation of about 3 kcal/mole. The differences in the absolute Tx values at the aromatic positions can be explained in terms of of differences in the sums of r e in equation (56). The shorter aliphatic Tj value probably reflects also a longer correlation time for backbone... 

The helix-coil transition of poly-L-benzylglutamate (PLBG) has been studied by inelastic light scattering technique (52). Fig. 3 shows the change in the diffusion constants of PBLG in dichloroacetic acid-dichloroethane mixtures. As the solvent composition is varied from the pure non-hydro-... 

Finally we must know how ordered or disordered the polymer is. If the forces between residues are not strong compared to the solvent-residue interactions, or if different helical conformations have nearly the same stability, then there may be different conformations present in solution. We usually expect a polymer to become more ordered as the temperature is decreased, but this is not necessarily true. If solvent—residue attractions dominate at low temperature, a polymer may change from an ordered helix at high temperature to a disordered coil at low temperature. Poly-y-benzylglutamate in ethylene dichloride-dichloro-acetic acid shows this behavior [1]. 

---