Thio-sugars. Part IV. Thio-analogues of 3,6-anhydro-sugars: a proof of the configuration of 3-thio-D-glucose

Abstract

3,6-Dideoxy-3,6-epithio-1,2-O-isopropylidene-α-D-glucofuranose has been synthesised by two routes: (i) partial hydrolysis of the disulphide derived from 1,2 : 5,6-di-O-isopropylidene-3-thio-α-D-glucose, selective toluene-p-sulphonation of the hydroxy-groups at C-6 and C-6′, reduction of the disulphide linkage with lithium aluminium hydride, and ring closure with base; (ii) partial hydrolysis of 1,2 : 5,6-di-O-isopropylidene-3-O-tosyl-α-D-allose, selective toluene-p-sulphonation at C-6, replacement of this primary group with thiobenzoate (S-ester) to give 6-S-benzoyl-1,2-O-isopropylidene-6-thio-3-O-tosyl-α-D-allofuranose, and treatment with base. 6-S-Benzoyl-1,2-O-isopropylidene-6-thio-3-O-tosyl-α-D-glucofuranose, synthesised in an analogous way, does not give a 3,6-epithio-compound. Methyl 3,6-dideoxy-3,6-epithio-β-D-glucopyranoside has been synthesised via methyl 3-O-tosyl-D-allopyranoside.

The ¹H n.m.r. spectra of the thio-compounds, and of some intermediates, are recorded and discussed.