Methyl 3,4-dichloro-3,4-dideoxy preparation

An X-ray crystallographic analysis has been performed44 on methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside prepared by way of reaction of methyl a-D-glucopyranoside with sulfuryl chloride the molecule has the Cl (d) conformation, and the bond distances and valency angles are similar to those in simple sugars. 

A stirred mixture of methyl 2,3-di-0-acetyl-4,6-dichloro-4,6-dideoxy-a-D-galactopyrano-side (41, 1 mmol) [prepared by acetylation (acetic anhydride-pyridine) of methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside 37], sodium azide (4 mmol), and dry N,N-... 

Chalcose (4,6-dideoxy-3-0-methyl-D-xy/o-hexose, 152) was obtained from methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside (164).240 The dichloride 164 was readily prepared by selective chlorination of methyl ot-D-glucopyranoside with... 

---