Sodium Thiosulfate → HCID 11810229, compound

Participants

Reaction Steps

The mixture of 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α- and β-D-galactopyranosyl nitrates (II and III) (0.781 g, 2.09 mmole) prepared as described in either Example I or Example II was added to a suspension of anhydrous lithium iodide (1.86 g, 14 mmole) in anhydrous acetonitrile (3 ml). This mixture was stirred in the dark at room temperature for 15-17 minutes and then poured into an ice cold 1% aqueous solution of sodium thiosulfate. A dichloromethane (10 ml) extract was dried over sodium sulfate, filtered and evaporated to give a white foam which discolored upon standing. The p.m.r. spectrum of this compound in CDCl3 showed no remaining starting material and contained a doublet with J=4.0 Hz at 6.93 p.p.m. which was assigned to the anomeric proton of 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α-D-galactopyranosyl iodide (XXIV). This α-D-iodide (XXIV) (2.09 mmole) was immediately treated with a molar equivalent of either tetraethylammonium chloride (0.344 g, 2.09 mmole) dissolved in anhydrous acetonitrile (2 ml) or lithium chloride (0.081 g, 2.0 mmole) at ambient temperature. After 1.5 minutes, the solution was poured into ice cold water (10 ml) and extracted with cold dichloromethane (10 ml). The organic solution was dried and evaporated to give a light yellow syrup which, on trituration with ethyl ether, afforded crystalline 3,4,6-tri-O-acetyl-2-azido-2-deoxy-β-D-galactopyranosyl chloride (XXIII) in 50-60% yield; m.p. 102°-104°, [α]D25 -16.5 (c 1, chloroform).

Provenance & Evidence