Jozef Hodyl PhD Thesis - Theses - Flinders University

phenolic oxygen of 66 or 67 over Pd/C catalyst under an atmosphere of hydrogen in2 days. Both were formed in quantitative yield. 1 H and 13 C spectral properties174, 175correspond with literature values.Step 4, of the p-HTPE substituted phenoxy epoxide synthesis gave 59 in 63%yield and 60 in 70% yield. This was achieved by initial deprotonation of the phenolicoxygen of 69 or 70. The resulting phenoxides then engage in a nucleophilicsubstitution reaction involving enantiomerically pure glycidyl tosylate, 58, giving therequired products. This reaction was conducted at a temperature of 50 oC tosafeguard the glycidyl functionality. Higher temperatures can affect kinetic stabilityadversely and contribute to ring opening of the oxirane moiety generating an176 177unwanted vicinal diol.The HTPE epoxides 59 and 60 are new compounds. 1 H HMR and 13 C NMRspectra for both 59 and 60 exhibit the appearance of resonances for the 1,2-epoxypropane moiety that are consistent with literature values for epoxide 56. 94Chemical shifts for the HTPE appendages are in agreement with those found for theprecursors of these compounds. Optical rotation studies were conducted on 59 and60 to ensure that racemisation had not occurred. For 59: [α] 25 D = +4.21 o (c 2.19,MeOH); and, for 60 [α] 25 D = +2.35 o (c 2.13, MeOH). Whilst the presence of a nonzero[α] 25 D value does not guarantee that full optical purity has been preserved laterreaction of three equivalents of each epoxide with monoprotected cyclen and theobservation of the product as a single diastereomer, in each case, proves that it has.2.5 Preparation of tri-N-alkylated cyclen receptor precursorsTo obtain the cbz-protected, tri-N-alkylated-cbz-protected cyclen derivatives 71, 72and 73, three molar equivalents of the previously synthesised chiral epoxides 56, 59or 60 were introduced into a stirring solution of mono-cbz-protected cyclen, 50, in45