Synthesis of Bexarotene Analogs for the Treatment of Breast Cancer

Bexarotene is a synthetic analog of 9-cis-retinoic acid and ligand for the retinoid X receptor which has a history of clinical success in the treatment of T-cell lymphoma. Bexarotene has also shown potential for treating a variety of other cancers, which we seek to explore in this project. The potential of bexarotene lies in its unique mechanisms and wide application, however, it has shown limited effectiveness thus far in the treatment of breast and lung cancer, with moderate levels of efficacy and symptoms such as cutaneous toxicity, hyperlipidemia, and hypothyroidism. For this project several analogs of bexarotene were synthesized with the intentions of making a more potent ligand that can be used to treat these carcinomas while minimizing harmful side effects. We were successful in synthesizing a large variety of analogs over the span of roughly two years, including iso-chroman derivatives of bexarotene and NEt-TMN, in addition to a new series of analogs of the reported NEt-TMN derivative. These analogs were analyzed via melting point determination and nuclear magnetic resonance (NMR) spectroscopy to confirm the molecular structure and determine purity, and it is our intent to continue with further testing of these compounds to determine their effectiveness as well as the side effects they are likely to cause with levels of toxicity. Recent studies suggest that continuing the analysis of these compounds and other rexinoids like the ones described herein is a worthwhile endeavor as similar rexinoids have shown in numerous assays to be more potent and less toxic in the treatment of cancers when compared with bexarotene.