Sulfur Dioxide → HCID 60081415, compound

Participants

Reaction Conditions

Reaction Steps

The product from Step B (2.31 g, 7.86 mmol) was dissolved in dry THF (35 mL) and cooled in a dry ice/isopropanol bath (-78° C.) under nitrogen. n-Butyllithium (4.1 mL of a 2.1M solution in hexanes, 8.65 mmol) was added dropwise and the mixture stirred for 45 min; excess sulfur dioxide was introduced into the flask until the solution tested acidic to moist litmus paper. The reaction mixture was evaporated to a residue which was dissolved in water (40 mL) followed by the addition of sodium acetate trihydrate (5.35 g, 39.3 mmol) and hydroxylamine-O-sulfonic acid (2,67 g, 23.58 mmol). This mixture was stirred at room temperature for 4 hr and extracted with ethyl acetate (5×8 mL). The combined extracts were washed with a saturated aqueous sodium chloride solution, dried (MgSO4) and evaporated to a residue which was purified by column chromatography (silica, gradient 3:1 hexane/ethyl acetate to 7:3 methylene chloride/methanol) to give the desired product as an oil (0.91 g, 34%). This oil was converted to the sodium salt by dissolving it in ethanol (1.5 mL) and adding 2N NaOH (1.26 mL). Ethyl ether was added to the cloud point and the product which precipitated was isolated by filtration under nitrogen to give the desired salt (0.81 g, 90%): mp 90°-92° C. Analysis. Calculated for C10H13N2O2S3Na-H2O: C, 30.30; H, 4.32; N, 7.07. Found: C, 30.29; H, 4.13; N, 6.97.

Provenance & Evidence