Acetonitrile → HCID 86739371, compound

Participants

Reaction Steps

7-chloromethyl-3-phenyl-5H-thiazolo[3,2-a]pyrimidine-5-one, m.p. 194°-195° C. (7.8 g), prepared according to Example 5, was reacted with triphenylphosphine (8 g) in acetonitrile (250 ml) under stirring at the reflux temperature for 24 hours. After cooling the solution was concentrated in vacuo to a small volume, diluted with isopropyl ether and the precipitate was filtered to give 11 g of [3-phenyl-5H-thiazolo[3,2-a]pyrimidine-5-one-7-yl]-methyl-triphenylphosphonium chloride, which was suspended in dimethylsulfoxide (50 ml) and treated with potassium tert-butoxide (2.46 g) dissolved in dimethylsulfoxide (50 ml) under stirring at room temperature. The solution of the ylide so obtained was reacted with 3-pyridine-carboxaldehyde (2.36 g) at room temperature for 60 minutes then the reaction mixture was diluted with ice water and neutralized with NaH2PO4. The precipitate was filtered and washed with water: crystallization from CH2Cl2 -methanol gave 2.8 g of 3-phenyl-7-trans-[ 2-(3-pyridyl)-ethenyl]-5H-thiazolo[3,2-a]pyrimidine-5-one, m.p. 270°-272° C., NMR (CDCl3) δ ppm: 6.17 (s) (1H, C-6 proton), 6.70 (s) (1H, C-2 proton), 6.97 (d) (1H, β-ethenyl proton), 7.34 (dd) (1H, C-5 pyridyl proton), 6.39 (s) (5H, phenyl protons), 7.77 (d) (1H, α-ethenyl proton), 7.87 (m) (1H, C-4 pyridyl proton), 8.54 (m) (1H, C-6 pyridyl proton), 8.80 (dd) (1H, C-2 pyridyl proton); JHαHβ =16 Hz.

Provenance & Evidence