Abstract

Two-photon absorption (TPA) has become popular for biological applications, owing to its advantageous property of being able to achieve photophysical reactivities at long wavelengths in the near infrared region, it minimizes photodamage to materials and biological samples. Furthermore, deep tissue penetration and lower scattering can be achieved with long wavelengths. TPA photocleavable molecules are able to act as protecting groups for biological systems, creating caged compounds. An example of these types of biological cages in the literature are caged neurotransmitters, glutamate. Molecules that exhibit good TPA cross section are BNSF-Glu and BNSMB-Glu.1 This experiment aims to replace the double bond linking the chromophore with the photolabile units in BNSF and BNSMB with a triple bond through Sonogashira coupling to discern the effect of this change to their photocleavage properties. This modification was made in hopes of increasing the photocleavage properties of BNSF and BNSMB by increasing the number of electrons in the conjugated system. We report the synthesis of triple bond versions of BNSMB and BNSF, serving as cages for phenylalanine for future photocleavage experiments.

Reference:

1. Gug, S., Bolze, F., Specht, A., Bourgogne, C., Goeldner, M., & Nicoud, J. Angewandte Chemie International Edition, 2008, 47(49), 9525-9529.