Chiral Calcium Complexes as Brønsted Base Catalysts for Asymmetric Addition of α-Amino Acid Derivatives to α,β-Unsaturated Carbonyl Compounds
作者:Susumu Saito、Tetsu Tsubogo、Shū Kobayashi
DOI:10.1021/ja0709730
日期:2007.5.1
promote the catalyticasymmetric 1,4-addition reactions and [3+2] cycloaddition reactions of α-amino acidderivatives with α,β-unsaturated carbonyl compounds have been developed. The reactions proceeded smoothly in the presence of 5−10 mol % of the chiral calcium catalyst to afford the desired adducts in high yields with high diastereo- and enantioselectivities. A wide range of α,β-unsaturated esters and
4-addition and [3 + 2] cycloaddition reactions using chiral calcium species prepared from calcium isopropoxide and chiral bisoxazoline ligands have been developed. Glycine Schiff bases reacted with acrylic esters to afford 1,4-addition products, glutamic acid derivatives, in high yields with high enantioselectivities. During the investigation of the 1,4-addition reactions, we unexpectedly found that a [3
A three dimensional, innervated artificial tissue comprising a bio-synthetic matrix is provided. The artificial tissue supports cell growth, including surface coverage and three-dimensional cell in-growth, as well as nerve in-growth. Methods of preparing the innervated artificial tissue and methods of innervating artificial tissues or tissue substitutes are also provided. The artificial tissue is useful for in vitro testing of various pharmaceutical, cosmetic and household products.
A bio-synthetic matrix comprising a hydrogel which is formed by cross-linking a synthetic polymer and a bio-polymer is provided. The matrix is robust, biocompatible and non-cytotoxic and is capable of supporting cell in-growth in vivo. The matrix can be tailored to further comprise one or more bioactive agents. The matrix may also comprise cells encapsulated and dispersed therein, which are capable of proliferating upon deposition of the matrix in vivo. Methods of preparing the bio-synthetic matrix and the use of the matrix in vivo for tissue engineering or drug delivery applications are also provided.
Ink contains at least one of a compound represented by the following chemical formula 1, a compound represented by chemical formula 2, a compound represented by chemical formula 3, or a compound represented by chemical formula 4.