Hydrogen Peroxide → 3-benzyl-2-(hydroxymethyl)-4H-pyrido[1,2-a]pyrimidin-4-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 4.0 g (13.24 mmol) of the product from Step 4 (14), 1.0 g (1.32 mmol) of dichloro[1,1′-bis(diphenylphosphino)ferrocene] palladium(II) dichloromethane adduct, and 8.4 g (39.72 mmol) of K3PO4 in 30 mL of DMF was heated to 80° C. To the resulting solution was added dropwise 40 mL (19.9 mmol) of B-Benzyl-9-BBN and stirred at 80° C. under nitrogen for 12 hours. The reaction was then cooled to 0° C. and excess 1N NaOH was added to the reaction mixture. Excess 30% H2O2 was then added to the mixture at 0° C. resulting in significant gas evolution. Stirring continued for at least one additional hour or until gas ceased to evolve. The mixture was extracted with ethyl acetate (3×) and washed with saturated Na2O3S2 and brine. The organic layers were combined, dried over MgSO4 and activated carbon, and the solvent was removed in vacuo. The resulting material was subjected to flash chromatography on a 10 cm column. Elution with a gradient of 100% hexanes, 20% ethyl acetate in hexanes, 33% ethyl acetate in hexanes, 43% ethyl acetate in hexanes, 50% ethyl acetate in hexanes, 57% ethyl acetate in hexanes, 67% ethyl acetate in hexanes, and 100% ethyl acetate yielded 3.2 g (12.0 mmol, 91%) of 3-benzyl-2-(hydroxymethyl)-4H-pyrido[1,2-a]pyrimidin-4-one (15) as a pale yellow solid.

Provenance & Evidence