Total Synthesis

Our current research focuses primarily on the genus Erythrina, which has proven to be a fruitful source of species containing antimicrobial agents belonging to various flavonoid structural classes. In particular, Erythrina variegata L. (Leguminosae) is widely known in China as a folk medicine, primarily being used as an antibacterial, anti-inflammatory, antipyretic, and antiseptic agent.6 E. variegata (Leguminosae) is a Samoan tree with brilliant red flowers, locally known as the “gatae.” Samoan healers prepare extracts of the bark in coconut oil and apply the extracts externally for swellings and inflammation, called in Samoa as “fula” and “fula la’au.”  Phytochemical investigation of the non-alkaloidal secondary metabolites revealed the presence of one cinnamylphenol and several isoflavonoids. This project is based upon synthesizing two of the previously unknown isoflavonoids Initially,  5,7,4'-trihydroxy-6-(3,3-dimethylallyloxiranylmethyl)isoflavone (1) and isoflavonoid- 5,4’-dihydroxy-8-(3,3-dimethylallyl)-2’’-methoxyisopropylfurano[4,5:6,7]isoflavone (2). 

Polymers

Our research project involves synthesizing a series of poly(4-vinylphenol) derivatives. Such polymers will be weak polyacids due to presence of the hydroxyl group attached to the phenyl ring. The aromatic character, very weak acidity, and hydrogen bonding capability of 4-vinylphenol and derivatives will yield polyelectrolytes with a rich suite of chemical and physical properties that are much different than most traditional weak polyanions.  The monomers are prepared from benzaldehyde starting material, which is being further derivativized using Friedel-Crafts chemistry. The polymerization is carried out using traditional techniques. The molecular weight, thermal properties, and dissociation behavior of these polymers is also being investigated.

Multilayer

Polyvinylphenol based polymers are weak polyacids due to the hydroxyl group attached to the phenyl ring. The aromatic character, very weak acidity, and hydrogen bonding capability of 4-vinylphenol and derivatives will yield polyelectrolytes with a rich suite of chemical and physical properties that are much different than most weak polyanions. Multilayered films of the phenol-based polymers have been prepared using the layer-by-layer assembly technique. The counter polycations investigated include polyallylamine, PDMAC, polyaniline and derivatives. The film growth has been followed using UV-visible spectroscopy, while their thickness, roughness, swelling, and morphology will be investigated using atomic force microscopy and Interference Microscope.  The combination of aromaticity, hydrogen bonding, and variable charge density is expected to produce films with unique bulk and surface properties.

Methodology

Our research project is for the development of a new methodology for the synthesis of the useful moiety, alpha-hydroxy carbonyl.  By utilizing the ability of dialkoxy disulfide to thermally fragment to an carbonyl and an alcohol, it should be possible to convert a 1,2-diol into an alpha-hydroxy carbonyl functionality. 

New Antimicrobial Agents

The development of new antibiotics has become increasingly important as more and more strains of drug-resistant bacteria are being discovered.  It is well known that phenol and many of its derivatives are antimicrobial agents.  However, a comprehensive study of the structure-activity-relationship (SAR) has not been undertaken.  Our research is to initial examine how modification of the acidity and lipophilicity of phenol derivatives alters biological activity to ultimately elucidate a SAR profile.  This will provide a foundation to synthesize additional derivatives to further increase biological activity.

Diabetes

Diabetes is a disease that affects 18.2 million Americans.  Approximately 90-95% of these cases are type II diabetes.  It has been found that this disease is directly linked to an over activity of protein tyrosine phosphatase 1B (PTP1B), which dephosphorylates the multiple tyrosine residues within the insulin receptor (IR) protein.  Our research project is to develop a library of compounds which may act as inhibitors towards PTP1B.