Investigation of Anomalous Effects in the Deprotonation and Alkylation of Ketones Patrick Kelly-Goss 2004 Background • Development of new methods for synthesizing amino acids is highly desired – Often biologically active – Useful for biochemistry experiments – Medicine Background •Alkylation of aminoketones - Adds alkyl group - Deprotonated (H+ removed) by base - 2 or 3 eq. usually used. • 1980 Hoye et al. study - Used 1 eq. O NH O O N H R O Problem • Mid-1990s Tetrahedron Letters R study • Should bond at No. 1 carbon O N H O O R N H – Most acidic • Bonds at No. 3 carbon O – 2nd most acidic Hypothesis • During Cr-mediated oxidation, Cr+6 ion bonds to No. 1 carbon. • Blocks most receptive bond site, forcing alkyl group to bond to No. 3 carbon. O HN R O Cr Methods Synthesis –Two ketones • Oxidation –Two methods • Alkylation • Testing Synthesis of Ketones • Under Schotten Baumen conditions – Derived from aminopropanol – Using benzyl chloride (top) and benzoyl chloride (bottom) • Produces two alcohols H2 N OH Cl + Ch2 Cl2 OH + OH O O H2 N N H Cl Ch2 Cl2 N H OH Oxidation of Ketones • Two different methods used – RuCl3 – Chromic acid (H2CrO4) • Total of four test groups • Purified using MPLC Oxidation of Ketones O O Cr OH N H OH OH O O O Cr OH N H N H N H O O OH N H OH RuCl3 N H OH O O O O N H RuCl3 OH N H O Alkylation of Ketones • Add alkyl (R–) group to ketone using standard procedures • Check structure via NMR • Not completed O O N H Strong Base O R'X R N H O Results • No alkylations completed – Testing impossible • Difficulty encountered in oxidation – – – – Very low yields (< 2%) Confusing NMR spectra TLC revealed wrong product taken Most lost in MPLC Results NMR spectrum of middle (incorrect) layer NMR spectrum of top (correct) layer Results • MPLC allowed to run for significantly longer than expected requirement – Ketones successfully synthesized, oxidized • Work halted due to time constraints – No alkylation completed – No meaningful data Discussion • Original Tet. Letters study – Wrong eq. base used – Would change which protons stripped – May explain bonding “error” • Little to explain • Should future work be desired: – Determine if different bases would have effect O R N H O Acknowledgements • Ms. Fruen • Team Research • Dr. Rita Majerle Investigation of Anomalous Effects in the Deprotonation and Alkylation of Ketones Patrick Kelly-Goss 2004