Detail of "3618-96-0"

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Application of empirical design methodologies to the study of the influence of reaction conditions and N-a-protecting group structure on the enzymatic X-Phe-Leu-NH2 dipeptide synthesis in buffer/dimethylformamide solvent systems

Application of empirical design methodologies to the study of the influence of reaction conditions and N-a-protecting group structure on the enzymatic X-Phe-Leu-NH2 dipeptide synthesis in buffer/dimethylformamide solvent systems. Calvet, S.; Clapes, P.; Vigo, J. P.; Xaus, N.; Jorba, X.; Mas, R. M.; Torres, J. L.; Valencia, G.; Serralheiro, M. L.; et al.Several reagents with their cas registry numbers 129397-81-5 and 3618-96-0 are used here. (CID, CSIC, Barcelona 08034, Spain). Biotechnol. Bioeng., 39(5), 539-49 (English) 1992. CODEN: BIBIAU. ISSN: 0006-3592. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Section cross-reference(s): 9, 22 The influence of five different N-terminal protecting groups and reaction conditions (temp. and DMF content) on the a-chymotrypsin-catalyzed synthesis of the dipeptide deriv. R-Phe-Leu-NH2 [R = OHC (For, Ac, Me3CO2C (Boc) PhCH2O2C (Z), 9-fluorenylmethoxycarbonyl] was studied. Groups such as For, Ac, Boc, and Z always rendered good peptide yields (82-85%) at low reaction temps. and DMF concns., which depended on the Na protection choice. Boc and Z were the most reactive Na groups and, in addn., the most suitable for peptide synthesis. On the other hand, the use of empirical design methodologies allowed, with minimal experimentation and by multiple regression, to deduce an equation, which correlates the logarithm of the first order kinetic const. (log k') with reaction temp., DMF concn., and hydrophobicity (log P values) of the different protecting groups. The predictive value of the equation was tested by comparing the performance of another protective group, such as alkyloxycarbonyl (Aloc), with the performance predicted by said equation. Exptl. and calcd. k' values were in good agreement. .

Molecular recognition in cyclodextrin complexes of amino acid derivatives: the effects of kinetic energy on the molecular recognition of a pseudopeptide in a nonconstraining host environment as revealed by a temperature-dependent crystallographic study

All Rights Reserved. Molecular recognition in cyclodextrin complexes of amino acid derivatives: the effects of kinetic energy on the molecular recognition of a pseudopeptide in a nonconstraining host environment as revealed by a temperature-dependent crystallographic study. Clark, Joanna L.; Peinado, Jessica; Stezowski, John J.; Vold, Robert L.; Huang, Yuanyuan; Hoatson, Gina L. (Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA). Journal of Physical Chemistry B, 110(51), 26375-26387 (English) 2006 American Chemical Society. CODEN: JPCBFK. ISSN: 1520-6106. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Section cross-reference(s): 22, 75 The crystal structure of a triclinic 2:2 inclusion complex of b-cyclodextrin with N-acetyl-L-phenylalanine Me ester has been detd. at several temps. between 298 and 20 K to further study mol. recognition using solid-state supramol. b-cyclodextrin complexes. The study revealed kinetic energy-dependent changes in guest mol. conformations, orientations, and positions in the binding pocket presented by the crystal lattice. Accompanying these changes were observable differences in guest-guest interactions and hydrogen-bonding interactions in the binding pocket that involved guest mols., water of hydration mols., and b-cyclodextrin mols. On the basis of the differences obsd. in the crystal structures, a solid-state example of a system that displayed the properties of both classical and quantum chem. models. was presented. At higher temps., the structure conformed to a classical mech. 923019-93-6 and 3618-96-0 are cas registry numbers of chemicals which are used as reagents here. model with dynamic disorder. At lower temps., the observations conformed to examples in which there is static disorder representative of models in which quantum states differing in conformation, position, and orientation of components in the crystal structure are occupied. Ab initio theor. calcns. on the different guest mol. conformations have been carried out. Superpositions of theor. electrostatic surface potential diagrams on the obsd. mol. positions in the complexes provided confidence that the deconvolution of the guest mol. disorder is acceptable. Temp.-dependent solid-state magic angle spinning deuteron NMR measurements provided evidence for large-amplitude, diffusive motion on a microsecond time scale in the complex. .