Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Conformational restriction introduction

The introduction of conformational restrictions into flexible active molecules is a well-known strategy for trying to increase their potency and/or selectivity toward their biological targets.1 Several methods have been used for constraining flexible molecules. Cyclic derivatives of hnear peptides or peptidomimetics can thus be prepared by reactions involving side-chain... [Pg.182]

Modification of the backbone to a six-membered aminopipecolyl (pipPNA) was expected to introduce constraints to the PNA backbone. The introduction of a pipPNA monomer at the C-terminus was tolerated as determined by its melting temperature with a DNA target, but when introduced into the central portion of PNA, it was quite destabilising. The conformationally restricted piperidinone PNA adenine monomers 3R,6R pip-PNA (28) and its 3S-isomer have been incorporated into PNA for hybridisation studies. Introduction of the pip-PNA was found to be detrimental to duplex stability. [Pg.445]

Oligoureas are characterized by (i) hydrogen bonding groups inside the backbone (ii) chiral centers (iii) significant degree of conformational restriction and (iv) backbone NH groups available for the introduction of additional side chain functionalities. Such structures should provide new classes of folded polymers with novel conformational features... [Pg.268]

Note that the conformational space of a flexible molecule and hence the computational screening for biologically relevant geometries is usually very complex. Thus, a reliable approach in the search for biologically active conformations is the systematic introduction of geometric constraints in an active molecule, leading to a series of related and conformationally restricted molecules (see Thble 13.1). [Pg.562]

Fig. 15.3 Synthetic analogues of Glu. Several tactics were used for conformational restriction the introduction of liphophilic groups for reducing the flexibility and of cycles for limiting the rotatable bounds. Fig. 15.3 Synthetic analogues of Glu. Several tactics were used for conformational restriction the introduction of liphophilic groups for reducing the flexibility and of cycles for limiting the rotatable bounds.
Extensive synthetic efforts have been made into the preparation of highly complex nucleosidic building blocks, whereby functionalization and conformational restriction were introduced via multiple ring incorporation into the glycosidic framework of the nucleotides. The introduction of such complexity has come at a price as these compounds often require lengthy synthetic sequences to achieve both chemoselectivity and stereochemical definition. [Pg.108]

Surely, the introduction of a covalent bond between the aromatic ring of an a-amino acid residue and the peptide backbone has proven to be a useful further conformation restriction. For example, 1,2,3,4-tetrahydroisoquinoline carboxylic acid (Tic) is a cyclic constrained analog of phenylalanine (Figure 5), in which a methylene bridge is placed between the a-nitrogen, and 2 -carbon of the aromatic ring (Kazmierski Hruby, 1988). [Pg.302]

This chapter deals with the design of reactors which do not conform to these ideal models its attention is restricted to constant volume, single phase, isothermal reactors which are operated in the steady state. It is not intended to be a state of the art review of non-ideal reactor design methods, but rather an introduction to basic ideas and techniques frequently, the reader will be referred to more extended or specific coverage of the material being considered. [Pg.223]

The first part of the chapter reviews progress in the synthesis of monodisperse semiconductor NCs and gives a basic introduction to their specific physical properties. In conformity with the literature, the term monodisperse is used here to describe colloidal samples, in which the standard deviation of the particle diameter does not exceed 5%. Throughout the text we will restrict ourselves to the description of binary II-VI (CdSe, CdS, CdTe, ZnSe, etc.), III-V (InP, InAs), and IV-VI (PbS, PbSe, PbTe) semiconductor NCs. These systems exhibit optical properties that can be varied in the visible part of the spectrum, the near UV or near IR by changing the NC size and/or composition. [Pg.156]


See other pages where Conformational restriction introduction is mentioned: [Pg.447]    [Pg.390]    [Pg.154]    [Pg.139]    [Pg.139]    [Pg.322]    [Pg.81]    [Pg.702]    [Pg.561]    [Pg.68]    [Pg.93]    [Pg.317]    [Pg.77]    [Pg.188]    [Pg.363]    [Pg.372]    [Pg.222]    [Pg.31]    [Pg.199]    [Pg.233]    [Pg.243]    [Pg.245]    [Pg.188]    [Pg.363]    [Pg.372]    [Pg.308]    [Pg.84]    [Pg.205]    [Pg.243]    [Pg.258]    [Pg.410]    [Pg.327]    [Pg.7]    [Pg.202]    [Pg.90]    [Pg.149]    [Pg.53]    [Pg.53]    [Pg.298]    [Pg.267]    [Pg.211]    [Pg.215]   


SEARCH



Conformation conformational restriction

Conformation conformationally restricted

Conformational restriction

© 2024 chempedia.info