Phosphorus oxychloride → HCID 19973430, compound
Reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([O:8][CH3:9])=[CH:4][C:3]=1[C:10]1[N:11]=[CH:12][C:13](=O)[NH:14][CH:15]=1.O=P(Cl)(Cl)[Cl:19]>>[Cl:19][C:13]1[CH:12]=[N:11][C:10]([C:3]2[CH:4]=[C:5]([O:8][CH3:9])[CH:6]=[CH:7][C:2]=2[F:1])=[CH:15][N:14]=1Participants
3
Procedure
A solution of 5-(2-fluoro-5-methoxyphenyl)-pyrazin-2-one in POCl3 was heated at 100° C.-110° C. in a sealed tube for 16 h. After evaporating the remaining POCl13 under reduced pressure, the brown residue was taken up in EtOAc and washed (3×) with saturated aqueous NaHCO3 solution. The EtOAc solution was then dried (Na2SO4) and concentrated under reduced pressure leaving a brown oil. The oil was filtered through a pad of silica gel (30% EtOAc/hexanes eluent) and the solvents were again evaporated under reduced pressure. The oil was taken up in CH2Cl2, heated for 5 min. with decolorizing charcoal and filtered through celite. Evaporation of the solvent afforded 2-chloro-5-(2-fluoro-5-methoxyphenyl) pyrazine as a light-brown oil.
Workup
- customAfter evaporating the remaining POCl13 under reduced pressure
- washwashed (3×) with saturated aqueous NaHCO3 solution
- dry with materialThe EtOAc solution was then dried (Na2SO4)
- concentrationconcentrated under reduced pressure
- customleaving a brown oil
- filtrationThe oil was filtered through a pad of silica gel (30% EtOAc/hexanes eluent)
- customthe solvents were again evaporated under reduced pressure
- temperatureheated for 5 min. with decolorizing charcoal
- filtrationfiltered through celite
- customEvaporation of the solvent
Sources & evidence
- ORD record
- ord-107ff369bcb746959e2042be942e1533
- Source dataset
- uspto-grants-1999_06
- Patent number
- US05910590
Reaction notes
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