To a room temperature slurry of 7.26 g of product from Example 82, 60 ml of methyl alcohol and 9.5 ml of 5N hydrochloric acid/methanol is added, dropwise, 2.55 g of 3-pyridinecarboxaldehyde. After 10 minutes, a total of 1.64 g of sodium cyanoborohydride is very carefully added in 3 separate portions over 1.5 hours. The initial reaction is vigorous. The reaction mixture is stirred at room temperature for 68 hours, diluted with water, made basic with potassium hydroxide and extracted with methylene chloride. The methylene chloride extract is washed with saturated sodium chloride, dried and concentrated in vacuo. The residue is purified by column chromatography (silica gel: 90% ethyl acetate/hexane) to give 7.2 g of the desired product as colorless crystals.
