First Advisor

Mark Woods

Date of Award

Winter 3-22-2024

Document Type


Degree Name

Bachelor of Science (B.S.) in Biochemistry and University Honors






Contrast media (Diagnostic imaging) -- Research, Chemical synthesis, Cyclen-based ligand




The ratio of products resulting from a reaction of cyclen (1,4,7,10-tetraazacyclododecane) and benzyl (S)-2-bromopropanoate substituent arm is analyzed in three polar aprotic solvents at varying concentrations of cyclen and temperatures. This is for a future design of experiments procedure to determine the optimal experimental conditions for selective DO3MBn ester production without the use of a protecting group. It was found that the reaction completion time is less than 24 hours at reaction temperatures at or above 50 °C and less than 3 days for reaction temperatures at 30 °C regardless of the cyclen concentrations or equivalents of substituent arm used in this study. Choice of polar aprotic solvent does not appear to matter in terms of reaction completion time, however the use of DMF and DMSO with this reaction resulted in an unknown [M + 44]+ peak observed in the mass spectra for di- and tri-substituted products. Additionally, unexpected behavior was observed surrounding the ratio of products over the first two hours of the reaction, with the ratio of tetra-substituted to tri-substituted product being greater than expected. Included in this study is a separation of DO2MBn ester and DO3MBn ester accomplished using HPLC, with pure 1H NMR spectra for both ligands.

Persistent Identifier

Available for download on Thursday, February 27, 2025

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