[CH2:1]([C:3]1[N:4]=[C:5]([N:18]2[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]2)[NH:6][C:7](=O)[C:8]=1[CH:9]([CH2:14][CH2:15][CH3:16])[C:10]([O:12][CH3:13])=[O:11])[CH3:2].P(Cl)(Cl)([Cl:26])=O.CN(C)C1C=CC=CC=1>C1(C)C=CC=CC=1>[Cl:26][C:7]1[C:8]([CH:9]([CH2:14][CH2:15][CH3:16])[C:10]([O:12][CH3:13])=[O:11])=[C:3]([CH2:1][CH3:2])[N:4]=[C:5]([N:18]2[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]2)[N:6]=1To a suspension of methyl 2-(4-ethyl-6-oxo-2-(piperidin-1-yl)-1,6-dihydropyrimidin-5-yl)pentanoate (2.53 g; 7.86 mmol) in dry toluene (15 mL) under nitrogen atmosphere were 5carefully added phosphorus oxychloride (7.30 mL; 79 mmol) and dimethylaniline (0.794 mL; 6.29 mmol) and the reaction mixture was heated under reflux for 3 h. The volatiles were removed under reduced pressure (while the reaction mixture was still at elevated temperature), the residue was cooled in an ice-bath and quenched by adding crushed ice and a saturated solution of sodium hydrogen carbonate until neutralization. The aqueous layer was extracted with ethyl acetate, the organics were collected, dried over magnesium sulphate, filtered and concentrated under reduced pressure. Purification by flash-chromatography on silica gel using a gradient of ethyl acetate (1-10%) in heptane furnished 0.352 g (8.6%, over 3 last steps) of the title compound as a yellow oil.
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