Sodium borohydride (0.24 g, 6.3 mM) was added in portions to a stirred suspension of 2,6-dimethyl-4-[2-(2-metbylphenyl)acetamidophenyl thiocyanate (0.5 g, 1.6 mM), in ethanol (20 mL). After 30 minutes, acetone (0.47 mL, 6.4 mM) was added to remove excess sodium borohydride and the mixture stirred for 10 minutes to give a clear yellow solution containing 2,6-dimethyl-4-[2-(2-methylphenyl)acetamido]benzenethiol. Nitromethane (0.09 mL, 1.6 mM) was then added followed, after 10 minutes, by a solution of potassium ferricyanide (0.53 g, 1.6 mM) in water (10 mL). Progress of the reaction was followed by standard thin layer chromatographic (tlc) analysis. After 1 hour, unreacted thiol remained and so further nitromethane (0.45 mL, 0.8 mM) and a solution of potassium ferricyanide (0.27 g, 0.8 mM) in water (5 mL) was added. After about a further 1 hour, thiol was no longer detectable by tlc analysis. Water (500 mL) was then added. The reaction mixture was acidified to pH4 with 2M HCl and extracted with ethyl acetate. The extracts were dried (MgSO4) and the solvent evaporated. The sticky, orange solid was triturated with ether. The orange filtrate was separated and the solid residue discarded. The filtrate was evaporated to give (2,6-dimethyl-4-[2-(2-methylphenyl)acetamido]phenylthio)nitromethane as an orange/brown solid, m.p. 152° C. (decomposition) in 20% yield and which was used without purification.
