This project is aimed at inventing and studying novel molecules that can imitate natural enzymes. In the first part of the project we will study novel catalysts that imitate the enzymes belonging to the class called cytochrome P-450. In our enzyme mimics substrates are bound to the catalyst and then hydroxylations or epoxidations are performed at sites determined only by the geometry of the catalyst/substrate complex. This is in contrast to the normal situation in chemical syntheses in which the intrinsic reactivities of the substrates play a major role in determining where reactions occur--frequently they play the only role. We propose to 1) improve the way in which substrates are bound to the enzyme mimics, in particular using a """"""""point and ring"""""""" plan including metal ion coordination for binding commonly available substrates; 2) extend the work to novel substrates, including those that are themselves flexible; and 3) develop practical reagents for the oxidations. We expect that such biomimetic synthetic reactions could be applied to the synthesis and manufacturing of useful medicinal compounds in the pharmaceutical industry. ? ? The second part of the project deals with artificial enzymes -- enzyme mimics -- that are based on synthetic polymers, including dendrimers. Here we perform the reactions in water and take advantage of the fact that the interior of the polymer is non-aqueous, as is true in enzymes as well. Thus we obtain hydrophobic binding of substrates but very rapid reactions in the polymer interiors. We will be working with various polymers, and modifying them with hydrophobic units. We propose reactions catalyzed by enzyme mimics that have coenzymes either attached or reversibly bound, with the aim of developing biomimetic methods to synthesize amines such as amino acids as well as products from the special catalysis that thiamine and other thiazolium ions produce. We will be focusing on producing products with high enantiomeric excesses, in part by using chiral polyamines produced by the reduction of polypeptides. Here too the health relevance is the development of novel synthetic methods that could be useful in the manufacture of medicinal compounds. In addition, both parts of the project will help us understand natural enzymes. ? ?
