Pyridoxal hydrochloride → 4'-[(3-Hydroxy-5-hydroxymethyl-2-methyl-pyridin-4-ylmethyl)-amino]-biphenyl-2-sulfonic acid tert-butylamide

Participants

Reaction Conditions

Reaction Steps

In a 250 mL three-necked round bottom flask fitted with a condenser and a Dean-Stark trap, a mixture of pyridoxal hydrochloride (330 mg, 1.62 mmol), 4′-amino-biphenyl-2-sulfonic acid tert-butylamide (494 mg, 1.62 mmol), p-toluenesulfonic acid monohydrate (68 mg, 0.36 mmol) in toluene (150 mL) was heated at 100° C. under nitrogen atmosphere for 3 hours. The solvent was then evaporated and the crude product was dissolved in dichloromethane (70 mL), cooled down to 0° C. and then sodium borohydride (163 mg, 4.32 mmol) and methyl alcohol (15 mL) were added. The reaction mixture was stirred at room temperature overnight, after which the solvent was removed. The residue was diluted with saturated aqueous sodium bicarbonate and extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, filtered and evaporated. The crude product was purified by column chromatography on silica gel using a mixture of dichloromethane:methyl alcohol (9:1) as eluant to give 4′-[(3hydroxy-5-hydroxymethyl-2-methyl-pyridin-4-ylmethyl)-amino]-biphenyl-2-sulfonic acid tert-butylamide (7) (178 mg, 24% overall yield for two steps) as a colorless solid.

Provenance & Evidence