Hydrochloric Acid → 6-[2-(3-Chloro-4-isopropoxy-phenyl)-ethyl]-6-cyclopentyl-3-(5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylmethyl)-4-hydroxy-5,6-dihydro-pyran-2-one

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Reaction Steps

6-[2-(3-Chloro-4-isopropoxy-phenyl)-ethyl]-6-cyclopentyl-dihydro-pyran-2,4-dione (0.3 g, 0.79 mmol) and 5,7-Dimethyl-[1,2,4]triazolo[1,5-a]pyrimidine-2-carbaldehyde (0.17 g, 0.95 mmol, described in Step 3 of example B(75)) were dissolved in 3:1 MeOH/CH2Cl2 (4 mL). To this suspension, Me2NH.BH3 (0.07 g, 1.19 mmol) was added as a solid from top. After stirring 1 h at room temperature, the reaction mixture became clear and it was stirred for an additional 5 hours. After this time, 1 M HCl (1 mL) was added and the reaction stirred for 30 minutes at room temperature, the solvent was the evaporated to half the volumen and extracted 3 times with 10% MeOH/CH2Cl2 (10 mL). The organic phase was dried over MgSO4 and evaporated. The residue purified by flash column chromatography (80% EtOAc in hexanes) to eliminate unreacted pyrone and reduced 5,7-Dimethyl-[1,2,4]triazolo[1,5-a]pyrimidine-2-carbaldehyde, then 3% MeOH/CH2Cl2 to give the product (0.1 g, 24%) as a white solid.

Provenance & Evidence