John M. McGill

Hydride reagents for stereoselective reductive amination. An improved preparation of 3-endo-tropanamine

Abstract The reductive amination of substituted cyclohexanones with sodium triacyloxy-borohydrides derived from NaBH 4 and various carboxylic acids provides highly diastereoselective conversions to protected axial amines. This method was applied to the stereoselective preparation of 3-endo-tropanamine.

Conformational analysis of dirithromycin and epi-dirithromycin

Abstract The solution conformations of dirithromycin (3) and epi-dirithromycin (4) were determined by NMR spectroscopy and molecular mechanics calculations. Dirithromycin exists in a “folded-in” conformation which is similar to its crystalline conformation, while epi-dirithromycin exists in a ”folded out” conformation which is similar to the crystalline conformation of erythromycin A hydroiodide dihydrate. Included is a discussion of the kinetically versus thermodynamically controlled formation of the remote aminal stereocenter.