Synthesis of a second generation naphthopyran metal-binding photoswitch
|Institution:||California State University, Los Angeles|
|Keywords:||Chemistry; Organic chemistry|
|Full text PDF:||http://pqdtopen.proquest.com/#viewpdf?dispub=1597156|
The aim of this project was to increase the calcium binding affinity of our previously developed photochromic 3H-naphtho[2,1-b]pyran 1, a light-controlled reversible binding switch used to study the effects of cellular calcium oscillations. A naphthopyran derivative 2 containing electron donating aryl substituents is the current synthetic target. We hypothesize that due to increased electron density to the chelating oxygen via methoxy aryl substituents, the methoxy substituents would provide an increased binding affinity of the photochemically ring-opened form of naphthopyran derivative 2 compared to that of naphthopyran derivative 1. The modification on the aryl substituents of naphthopyran derivative 1 should maintain a 10-fold difference in binding affinity between the thermally stable closed and higher binding affinity open form. Ultimately, it is expected that the aryl substituted naphthopyran derivative 2 would be a more efficient tool to study cellular oscillatory calcium signaling at a molecular level. Progress towards the synthesis of target molecule 2 concluded with the synthesis of intermediate compounds 3–7. N-BOC naphthopyran 3 and propargyl alcohol 4 were synthesized with yields of 55–59 % and 70–83 % respectively. N-BOC naphthopyran 5 was produced at 81 % yield. N-BOC deprotection afforded naphthopyran 6 at 91 % yield. Esterification yielded alkylated naphthopyran 7 at 25 % purified yield.