Isolation and structural determination of non-racemic tertiary cathinone derivatives.

The racemic tertiary cathinones N,N-dimethylcathinone (1), N,N-diethylcathinone (2) and 2-(1-pyrrolidinyl)-propiophenone (3) have been prepared in reasonable yield and characterized using NMR and mass spectroscopy. HPLC indicates that these compounds are isolated as the anticipated racemic mixture. These can then be co-crystallized with (+)-O,O'-di-p-toluoyl-D-tartaric, (+)-O,O'-dibenzoyl-D-tartaric and (−)-O,O'-dibenzoyl-L-tartaric acids giving the single enantiomers S and R respectively of 1, 2 and 3, in the presence of sodium hydroxide through a dynamic kinetic resolution. X-ray structural determination confirmed the enantioselectivity. The free amines could be obtained following basification and extraction. In methanol these are reasonably stable for the period of several hours, and their identity was confirmed by HPLC and CD spectroscopy.

An unusual samarium diiodide mediated reductive ring contraction of a tricyclic oxazine to a highly-functionalized cyclopentane and cyclobutane.

[reaction--see text] Samarium diiodide mediated reductive ring contraction of a substituted tricyclo[2.2.2]oxazine at 25 degrees C leads to a mixture of cyclopentane and cyclobutane rearrangement products with complete diastereoselectivity in each case. At -78 degrees C, the anticipated amidocyclohexanol reduction product is obtained exclusively, while the cyclopentane is the sole product at reflux in THF.