Reaction #1559

Reaction equation

trifluoroacetic anhydride

5-aminocarbonylmethyl-6-ethyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone

Compound 275

5-aminocarbonylmethyl-6-ethyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone

pyridine

→

6-ethyl-5-cyanomethyl-6-ethyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone

Yield 49.8%

Solvents

ether

THF

Conditions

Workup

1. 1
   workup.ADDITIONwas added
2. 2
   Washwashed with 20 mL of saturated aqueous NaHCO3
3. 3
   Dryingdried over MgSO4
4. 4
   OtherRemoval of the solvent
5. 5
   workup.WAITleft 0.24 g of crude product as a yellow solid
6. 6
   WashFlash chromatography on 30 g of silica gel, eluting sequentially with 50, 75 and 100% ether in hexanes

Procedure

A stirred suspension of 0.25 g (0.85 mmol) of 5-aminocarbonylmethyl-6-ethyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone (Compound 275) in 12 mL of THF was cooled in an icebath and 0.15 mL (1.9 mmol) of pyridine was added followed by 0.13 mL (0.92 mmol) of trifluoroacetic anhydride. The mixture was stirred in the ice bath for 4 h, diluted with 80 mL of ether, washed with 20 mL of saturated aqueous NaHCO3 and dried over MgSO4. Removal of the solvent left 0.24 g of crude product as a yellow solid. Flash chromatography on 30 g of silica gel, eluting sequentially with 50, 75 and 100% ether in hexanes afforded 0.13 g of 6-ethyl-5-cyanomethyl-6-ethyl-2-phenyl-3-propargyl-4(3H)-pyrimidinone (Compound 277) as a white solid, m.p. 178°-180° C. 1 H-NMR (CDCl3) 1.3(3H,t), 2.4(1H,t), 2.75(2H,q), 3.75(2H,s), 4.6(2H,d), 7.55(3H,m), 7.7(2H,m).

Source