1,8-Diazabicyclo(5.4.0)undec-7-ene → 8-ethyl-4-methyl-2-(methylthio)pyrido[2,3-d]pyrimidin-7(8H)-one

Participants

Reaction Steps

To a solution of (E)-ethyl-3-(4-(ethylamino)-6-methyl-2-(methylthio)pyrimidin-5-yl)acrylate (16.8 g, 59.8 mmol) in DIPEA was added 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 18.21 g, 119.6 mmol) at room temperature. Then the reaction mixture was heated to reflux and reacted for 15 h. After evaporation of solvent, the residue was triturated with acetone. The product 8-ethyl-4-methyl-2-(methylthio)pyrido[2,3-d]pyrimidin-7(8H)-one (10.77 g, 77% yield) was collected by filtration. 1H NMR (400 MHz, CDCl3): δ 7.78 (d, J=9.6 Hz, 1H), 6.63 (d, J=9.6 Hz, 1H), 4.5 (q, J=7.2 Hz, 2H), 2.67 (s, 3H), 2.62 (s, 3H), 1.33 (t, J=7.2 Hz, 3H).

Provenance & Evidence