Synthesis of m‐nitrophenylacetate photocages
LE3 .A278 2009
Bachelor of Science
In this thesis, the m.nitrophenyl propionate photocage was synthesized with acetate attached. This was achieved via an 8.step procedure starting from mnitroacetophenone. The first step was the reduction of m.nitroacetophenone to 1.(3. nitrophenyl)ethanol by addition of NaBH4. The second step was bromination of 1.(3. nitrophenyl)ethanol to 1.(1.bromoethyl).3.nitrobenzene by addition of PBr3. The third step was cyanide substitution to yield 2.(3.nitrophenyl)propanenitrile, which was hydrolyzed in the fourth step to yield the photocage starting material, 2.(3. nitrophenyl)propanoic acid. This was subsequently protected as a t.butyl ester by addition of tBoc2O and t.butanol to yield tert.butyl 2.(3.nitrophenyl)propanoate. In the sixth step, paraformaldehyde was added to yield tert.butyl 3.hydroxy.2.methyl.2.(3. nitrophenyl)propanoate. Acetate was then added in the form of acetic anhydride to yield tert.butyl 3.acetoxy.2.methyl.2.(3.nitrophenyl)propanoate. In the final step, the compound was deprotected using TiCl4 to yield the final product, 3.acetoxy.2.methyl.2. (3.nitrophenyl)propanoic acid (m.nitrophenylacetate photocage). m.Nitrophenylacetate photocages showed the release of acetate by photodecarboxylation with no competitive pathways. No resonance is available to the meta isomer making the release rate fast. The alkene photoproduct which results from the photoreaction is the only photoproduct seen. The fast release rate above 300 nm, with no competitive pathways, makes it ideal for use in biological systems.
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