Substituted benzyl carbamate herbicides are synthesized using the appropriate benzyl chloroformate and a substituted benzyl amine in an inert solvent. The compound, 4,5-dimethoxy-2-nitrobenzyl chloroformate (1  ) is a fine powder. A literature survey also showed that 1  is being used as a caged precursor to the capsaicin receptor TRPV1 and the ioniotropic purinergic receptor P2X2, in which the photorelease of its active compounds allow the agonists to be administered to neuron cells. In this undergraduate research project, we analyzed the solvolytic rates of reaction of 1  in a variety of organic solvents with widely varying nucleophilicity and ionizing power values. The reaction rates at 25.0oC were determined using acid-base titrations over a select period of time. The addition of water to any pure organic solvent except 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) caused an increase in the reaction rate, hinting that water induces the leaving group to break quicker. However in HFIP the exact opposite occurs; where the addition of water decreases the rate of reaction. This suggests that 1  may follow a dual pathway which is strongly dependent on both solvent nucleophilicity and solvent polarity (H-bonding effects). This project is supported, in part, by the Delaware INBRE and EPSCoR programs - supported by grants from the National Center for Research Resources-NCRR (5P20RR016472-12) and the National Institute of General Medical Sciences - NIGMS (8 P20 GM103446-12) from the National Institutes of Health (NIH); a National Science Foundation (NSF) Delaware EPSCoR grant EPS-0814251; and a NSF ARI-R2 grant 0960503.

Employing linear free energy relationships (LFERs) to deduce solvolytic reaction mechanisms

245th National Meeting (2013)

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