Carbonic acid-guanidine (1:1) → 6-{2-[(4-Methoxybenzyl)oxy]-4-methylpyridin-3-yl}-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-2-amine

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Reaction Steps

A solution of 3-dimethylaminomethylene-2′-(4-methoxybenzyloxy)-4′-methyl-2,3,5,6-tetrahydro[1,3′]bipyridinyl-4-one (5.21 g, 13.66 mmol) in methanol (340 ml) was treated with guanidine carbonate (9.84 g, 54.63 mmol), followed by addition of sodium acetate trihydrate (14.87 g, 109.28 mmol) and the reaction mixture was refluxed for 3 hours. The solvent was removed in vacuo and the residue was partitioned between water and dichloromethane. The separated organic layer was dried (MgSO4), filtered, and concentrated to a red oil. The oil was taken up in a minimal volume of EtOAc and allowed to stand overnight at room temperature. The resulting yellow, crystalline solid was collected, washed with EtOAc, and dried to give the title compound (1.91 g). The mother liquor was concentrated and the residue was eluted through a flash column (silica gel 60, 230-400 mesh, EtOAc) to obtain an additional lot of the title compound (1.05 g) The total amount 2.96 g, 57%). HPLC analysis showed the compound has a purity of 98%.

Provenance & Evidence