Dimethylamine → 6-dimethylamino-5-methyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone

Participants

Reaction Steps

To an ice cooled solution of 1.5 g (3.8 mmol) 6-chloro-5-methyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone in 4 mL of tetrahydrofuran, was added 22 mL (99 mmol) of 4.5M dimethylamine in ether portionwise (2-4 mL) over a period of 7 days. The reaction mixture was allowed to warm and stir at room temperature after each addition. The progress of the reaction was followed by gas chromatography and proceeded to 80% completion. The solvent was removed in vacuo and the residue was taken up in ether and washed twice with water. The organic layer was dried over MgSO4 and concentrated to yield 1.15 g crude solid product. Flash column chromatography on silica gel (gradient elution 25-30% ethyl acetate-hexane) afforded pure 6-dimethylamino-5-methyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone (compound 23), as a white solid. 1H-NMR (CDCl3) δ2.2 (3H, s); 2.35 (1H, t); 3.5 (6 H, s); 4.6 (2H, d); 7.65 (3H, m); 7.75 (2H, m).

Provenance & Evidence