Xiao-Shu He

Thiaphysovenol phenylcarbamates: X-ray structures of biologically active and inactive anticholinesterase agents

The X-ray structure of the biologically active phenylcarbamate (4), and the biologically inactive phenylcarbamate (5) of the thiaphysovenol series, reveal that the two aromatic ring systems are differently oriented towards each other. The absolute configuration of both compounds, determined by using the anomolous scattering from the sulfur atoms, was found to be (3aS-cis)

DI-(2,2,2-Trichloroethyl)-Carbonate: Byproduct in Reactions with 2,2,2-Trichloroethyl Chloroformate

Abstract 2,2,2-Trichloroethyl chloroformate (1) in higher boiling solvents, particularly in the presence of potassium carbonate and potassium bicarbonate, affords undesired di-(2,2,2-trichloroethyl)-carbonate (2) as a byproduct. When chemically pure chloroformate was used, addition of carbonates was found to be unnecessary in N-demethylation reactions.