p-Toluenesulfonic acid → 5-(2-Methylphenyl)aminomethyl-4-methylamino-2-methylthiopyrimidine

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Reaction Conditions

Reaction Steps

A mixture of 300 mg (1.6 mmol) of 4-methylamino-2-methylthiopyrimidine-5-carboxaldehyde, 0.20 ml (1.8 mmol) of o-toluidine and 59 mg (0.3 mmol) of 4-toluenesulfonic acid in 50 ml of toluene was heated at reflux with azeotropic removal of water for 18 hours. The mixture was cooled and evaporated. The residue was dissolved in 40 ml of ethanol and heated to 70° C. 300 mg (8 mmol) of sodium borohydride were added cautiously and the mixture was heated at 70° C. for 2 hours. A further 300 mg (0.8 mmol) of sodium borohydride were added cautiously and the heating was continued for a further hour. The mixture was cooled and then evaporated. The residue was partitioned between 50 ml of 2M aqueous sodium hydroxide solution and 50 ml of ethyl acetate. The organic phase was dried over magnesium sulfate, filtered and evaporated. The residue was subjected to column chromatography on silica gel using diethyl ether/hexane (1:1) for the elution. Product-containing fractions were combined and evaporated to give 190 mg (43%) of 5-(2-methylphenyl)aminomethyl-4-methylamino-2-methylthiopyrimidine as a white solid. [Mass spectrum (ESI) MH+ =275].

Provenance & Evidence