Reaction #302871

Reaction equation

n-hexyl isocyanate

2-aminonicotinic acid methyl ester

→

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

Yield 30.8%

Solvents

pyridine

Conditions

Workup

1. 1
   TemperatureThe mixture was refluxed for 24 hours
2. 2
   OtherThe pyridine was removed under reduced pressure
3. 3
   workup.ADDITIONthe residue was treated with 160 ml ethanol
4. 4
   TemperatureThe mixture was refluxed for 10 minutes
5. 5
   OtherThe crude 3-hexyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione crystallized from the medium
6. 6
   Otherwas purified by preparative column chromatography on straight phase silica (eluent:ethyl acetate:cyclohexane 1:2)
7. 7
   Other3-hexyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione crystallized upon evaporation of the eluent

Procedure

17.46 g (137.3 mmol, 20 ml)n-hexyl isocyanate was added to a suspension of 5.31 g (34.9 mmol) 2-aminonicotinic acid methyl ester in 130 ml dry pyridine. The mixture was refluxed for 24 hours. The pyridine was removed under reduced pressure and the residue was treated with 160 ml ethanol. The mixture was refluxed for 10 minutes. The crude 3-hexyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione crystallized from the medium and was purified by preparative column chromatography on straight phase silica (eluent:ethyl acetate:cyclohexane 1:2). 3-hexyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione crystallized upon evaporation of the eluent. 2.66 g (310) of 3-hexyl-1H-pyrido[2,3-d]pyrimidine-2,4-dione was isolated (m.p. 166-168° C.)

Source