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 SO ₂Cl ₂ 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.