| This thesis reports the crystallization of two new quasiracemic crystals, the synthesis of a new oxadiazinanone, and the identification of crystals of two new compounds. In previous research the quasiracemates, (5, R,6,S)-4-cyclohexyl-5-methyl-6-phenyl-2 H-1,3,4-oxadiazinan-2-one and (5S,6R)-4-isopropyl-5-methyl-6-phenyl-2 H-1,3,4-oxadiazinan-2-one, were mixed in solution and crystallized. Instead of fractionally crystallizing, as would be expected, the compounds formed quasiracemic co-crystals. This suggested that other mixtures of oxadiazinanones would be possible candidates for studying compounds which fail to fractionally crystallize.;The first step in the process involves the synthesis of oxadiazinanones, using literature methods. A 4-step process is employed involving alkylation, nitrosation, reduction and cyclization. Because the starting material, norephedrine, is a chiral molecule, the desired enantiomer is synthesized starting with the proper enantiomer of norephedrine--either the (1S,2 R) or (1R,2S) enantiomers. A new oxadiazinanone, (5R,6S)-4-cyclopentyl-5-methyl-6-phenyl-2 H-1,3,4-oxadiazinan-2-one, was synthesized. After synthesis, the oxadiazinanones are mixed together and crystallized using vapor diffusion. X-ray diffraction is used to study the structures to determine the presence of quasiracemates.;From the sixteen racemic pairs compared, it was found that quasiracemic crystals were formed from oxadiazinanones containing either an N4-cyclopentyl substituent or an N4-cyclohexyl substituent. The quasiracemic crystal formed has a lower Z' than at least one of the quasienantiomers in the structure.;Two additional compounds were synthesized, and the crystal structures were identified. These crystals were obtained when the intended N4-ethylated and N4-n-butylated oxadiazinanones failed to cyclize in the final step of the oxadiazinanone synthesis. |
