Photochemical Transformations of Chalcone-Vitamin E Hybrids

Chalcone-vitamin E hybrids 6'-O-tosyl-3,4,5-trimethoxy-o-tocopherol-chalcone (1), 3,4,5-trimethoxy-o-tocopherol-chalcone (2), 6'-O-tosyl-3,4,5-trimethoxy-o-tocopherol-retrochalcone (3) and 3,4,5-trimethoxy-o-tocopherol-retrochalcone (4) were synthesized as part of a search for new biological activities in these types of derivatives. We report herein on the photoisomerization products of hybrids 1-4, and the effects of the solvent and substitution patterns in producing secondary products such as flavanone 6, 3-deoxyanthocyanidin 8, and hemiketal 10. Photochemically-induced changes are considered important since structural modifications and/or the presence of additional products can affect the biological activity of this type of semisynthetic hybrids.