Cyanamide → (1-{6-[Trifluoromethyl]pyridin-3-yl}ethyl)(methyl)lambda4-sulfanylidenecyanamide

Participants

Reaction Conditions

Reaction Steps

Acetonitrile (50 mL), cyanamide (1.14 grams, 27.1 mmoles) and 3-[1-(methylthio)ethyl]-6-(trifluoromethyl)pyridine (5.00 grams, 22.6 mmoles, 99+% assay) were combined in a 100 mL, 3-necked round bottom flask equipped with a thermowell/K-thermocouple, stopper, nitrogen oil bubbler and magnetic stir bar. The stirred solution was cooled to about −5° C. with an acetone/ice bath. To this solution was added 55.96 grams of an aqueous 6.0 wt % calcium hypochlorite solution (3.36 grams of calcium hypochlorite, 23.5 mmoles, 65% available chlorine) dropwise over 44 minutes. Some undissolved solids were present in the calcium hypochlorite solution and were added as well. The temperature was kept below 0° C. during the addition. The pale yellow reaction mixture was allowed to stir at about 0° C. for 65 minutes. To the yellow reaction mixture was added 0.53 g (2.8 mmoles) of sodium metabisulfite, in portions as a solid to destroy any remaining oxidant. A white flocculant was present in the reaction mixture. It was removed by vacuum filtration of the entire reaction mixture through a medium sintered glass filter funnel. The filtrate was transferred to a separatory funnel and the phases were allowed to settle. The phases were separated and the aqueous phase re-extracted with acetonitrile (10 mL) and (15 mL). Sodium chloride (10.01 grams) was added to the aqueous phase during the second extraction to facilitate a phase break. The organics were combined and this acetonitrile/sulfilimine solution was used directly in the following oxidation. LC analysis indicated a 1.00:1.08 area ratio of the two sulfilimine isomers and showed sulfilimine at 80 area % and sulfoxide (two isomers) at 13 area %.

Provenance & Evidence