Selective replacement of primary hydroxyl groups in carbohydrates: preparation of some carbohydrate derivatives containing halomethyl groups

Selective halogenation of hydroxymethyl groups in sugars and nucleosides has been achieved by use of triphenylphosphine and carbon tetrahalides (chloride, bromide, or iodide) in pyridine. Methyl α-d-glucopyranoside, 1,2,-O-isopropylidene-α-d-glucofuranose, inosine, and uridine give almost quantitative yields of their primary halomethyl analogs. Similarly, 6,6′-dichloro-6,6′-dideoxysucrose is prepared from sucrose. Chlorination and bromination of 5,6-anhydro-1,2-O-isopropylidene-α-d-glucofuranose by these reagents give 6-chloro-6-deoxy-1,2-O-isopropylidene-α-d-glucofuranose and 6-bromo-6-deoxy-1,2-O-iso-propylidene-α-d-glucofuranose, respectively.