Reaction #302870

Reaction equation

phenylisocyanate

2-aminonicotinic acid methyl ester

→

3-phenyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione

Yield 61.2%

Solvents

pyridine

Conditions

Workup

1. 1
   TemperatureThe mixture was refluxed for 16 hours
2. 2
   OtherThe pyridine is was removed under reduced pressure
3. 3
   workup.ADDITIONthe residue was treated with 280 ml ethanol
4. 4
   TemperatureThe mixture is refluxed for 10 minutes
5. 5
   TemperatureUpon cooling down 3-phenyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione
6. 6
   Othercrystallized from the medium
7. 7
   Otherwas recrystallized from methoxypropanol

Procedure

17.22 g (144.6 mmol, 15.7 ml) phenylisocyanate was added to a suspenssion of 7.00 g (46.0 mmol) 2-aminonicotinic acid methyl ester in dry pyridine. The mixture was refluxed for 16 hours. The pyridine is was removed under reduced pressure and the residue was treated with 280 ml ethanol. The mixture is refluxed for 10 minutes. Upon cooling down 3-phenyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione crystallized from the medium and was recrystallized from methoxypropanol. 6.73 g (61%) 3-phenyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione was isolated (m.p. 304° C.).

Source