Synthesis and solid state properties of the 4-naphthyloxymethyl-2,2-dioxo-1,3,2-dioxathiolane, cyclic sulfate not available through sulfite oxidation procedure

The chiral adrenoblocker propranolol precursor 4-naphthyloxymethyl-2,2-dioxo-1,3,2-dioxathiolane, 2, was obtained in racemic and scalemic form. It was found that sulfates 2 are practically unavailable through the standard Ru-catalyzed sulfite oxidation procedure, but could be obtained by the direct action of SO2Cl2 on the corresponding vicinal diols 3. The published properties of the sulfate were corrected. Thermodynamic characteristics and binary melting phase diagram were evaluated for compound 2 by DSC. The crystal structure of rac- and scal-2 was established by single crystal X-ray analysis and the absolute configuration of scal-2 was established by the Flack method. The flexible nature of the sulfur-containing cycle, and the sensitivity of the compound conformation to homo- and heterochiral crystal environment was demonstrated.