The synthesis and the 1h- and 13c-nuclear magnetic resonance spectroscopy of the cyclic sulfites of some sugars

Abstract

Treatment of methyl β- D-ribofuranoside with thionyl chloride in hexamethyl-phosphoric triamide gives two diastereoisomeric methyl 5-chloro-5-deoxy-β- D-ribo-furanoside 2,3-cyclic sulfites. Similar cyclic sulfites are formed from benzyl β- D-ribofuranoside and 1,4-anhydro- DL-ribitol. If acetonitrile is substituted for hexa-methylphosphoric triamide, the cyclic sulfites are the main products, and only traces of the chlorinated sugars are formed. 1H- and 13C-n.m.r.-spectral analysis of these reactions demonstrated that one of the diastereomers preponderates. The structure of these cyclic sulfites was established by comparison of the 1H-n.m.r. spectra with those of the propylene sulfites. Treatment of 1,2- O-isopropylidene-α- D-glucofuranose (14) with thionyl chloride in hexamethylphosphoric triamide yields 3-chloro-3-deoxy-1,2-O-isopropylidene-α- D-allofuranose 5,6-cyclic suffite. In contrast to the 2,3-cyclic suffites, which are stable, the cyclic sulfites derived from 14 slowly decompose at room temperature.